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1.
Microbiol Res ; 232: 126392, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31841935

RESUMO

Bacterial cell surface adhesins play a major role in facilitating host colonization and subsequent establishment of infection. The surface of Mycobacterium tuberculosis, owing to the complex architecture of its cell envelope, expresses numerous adhesins with varied chemical nature, including proteins, lipids, lipoproteins, glycoproteins and glycopolymers. Studies on mycobacterial adhesins show that they bind with multifarious host receptors and extracellular matrix (ECM) components. In this review we have highlighted the adhesins that are abundantly present on the mycobacterial surface and their interactions with host receptors. M. tuberculosis interacts with various host cell surface receptors such as toll like receptors, C-type lectin receptors, scavenger receptors, and Fc and complement receptors. Apart from these, ECM components like fibronectin, collagen, elastin, laminin, fibrillin and vitronectin also provide binding sites for surface adhesins of the tubercle bacilli. M. tuberculosis adhesins include proteins with and without signal peptide sequence and transmembrane proteins. Other surface adhesin macromolecules of M. tuberculosis comprises of lipids, glycolipids and glycopolymers. The interaction between the mycobacterial adhesins and their host receptors result in adhesion of the microbe to the host cells, induction of immune response and aid in the pathogenesis of the disease. A thorough understanding of the different M. tuberculosis surface adhesins and host receptors will provide a better picture of interaction between them at molecular level. The information gained on adhesins and host receptors will prove beneficial in developing novel therapeutic strategies such as the use of anti-adhesin molecules to hinder the adhesion of bacteria to the host cells, thereby preventing establishment of infection. The surface molecules discussed in this review will also benefit in identification of new drug targets, diagnostic markers or vaccine candidates against the deadly pathogen.


Assuntos
Adesinas Bacterianas/química , Adesinas Bacterianas/metabolismo , Mycobacterium tuberculosis/metabolismo , Antituberculosos , Proteínas de Bactérias , Sítios de Ligação , Proteínas da Matriz Extracelular/química , Proteínas da Matriz Extracelular/metabolismo , Interações Hospedeiro-Patógeno/fisiologia , Humanos , Sinais Direcionadores de Proteínas , Receptores de Superfície Celular/química , Receptores de Superfície Celular/metabolismo , Proteínas de Transporte Vesicular
2.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 35(8): 744-749, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31638572

RESUMO

Objective To demonstrate HpaA can intensify the inflammatory response and gastric mucosa injury by IL-21 from induced T cell. Methods Biopsy specimens were taken from gastric mucosa of 56 patients with H.pylori infection before and after H.pylori radical elimination by endoscope. The levels of IL-21, matrix metalloproteinase-2 (MMP2) and MMP9 from the biopsy were detected by reverse transcription PCR and Western blot analysis. Meanwhile, the recombinant HpaA was cloned, expressed and purified to stimulate the magnetic cell sorting CD3+ T cells from healthy donors' peripheral blood mononuclear cells (PBMCs), and the level of IL-21 in the supernatant fluid was detected by ELISA. Thereafter, AGS cells were cultured and Western blot analysis was performed to detect the levels of MMP2 and MMP9 in the AGS cells with human IL-21 and anti-IL-21 antibody treatment for 24 hours. Results The protein levels of IL-21 and MMP2 and MMP9 in gastric mucosa infected with H. pylori was significantly higher than that in gastric mucosa after radical treatment of H. pylori. Meanwhile, the recombinant HpaA promoted IL-21 secretion by induced CD3+T cells in vitro. IL-21 stimulated the expression of MMP2 and MMP9 in AGS cells. When IL-21 was blocked by the antibody, the levels of MMP2 and MMP9 in AGS cells decreased significantly. Conclusion HpaA plays a significant role in the gastric mucosa injury caused by H.pylori infection through IL-21 from induced T cells.


Assuntos
Adesinas Bacterianas , Mucosa Gástrica , Interleucinas , Linfócitos T , Adesinas Bacterianas/metabolismo , Mucosa Gástrica/lesões , Mucosa Gástrica/fisiopatologia , Infecções por Helicobacter/imunologia , Infecções por Helicobacter/fisiopatologia , Helicobacter pylori/imunologia , Helicobacter pylori/metabolismo , Humanos , Interleucinas/metabolismo , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Linfócitos T/metabolismo
3.
Infect Immun ; 87(12)2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31591167

RESUMO

Virulence genes are regulated by a complex regulatory network in Staphylococcus aureus Some of the regulators are global in nature and affect many downstream genes. MgrA is a multiple-gene regulator that has been shown to activate genes involved in capsule biosynthesis and repress surface protein genes. The goal of this study was to demonstrate the biological significance of MgrA regulation of capsule and surface proteins. We found that strain Becker possessed one fibronectin-binding protein, FnbA, and that FnbA was the predominant protein involved in invasion of nonphagocytic HeLa cells. By genetic analysis of strains with different amounts of capsule, we demonstrated that capsule impeded invasion of HeLa cells by masking the bacterial cell wall-anchored protein FnbA. Using variants with different levels of mgrA transcription, we further demonstrated that MgrA negatively impacted invasion by activating the cap genes involved in capsule biosynthesis and repressing the fnbA gene. Thus, we conclude that MgrA negatively impacts cell invasion of S. aureus Becker by promoting capsule and repressing FnbA.


Assuntos
Adesinas Bacterianas/metabolismo , Cápsulas Bacterianas/metabolismo , Regulação Bacteriana da Expressão Gênica/genética , Infecções Estafilocócicas/patologia , Staphylococcus aureus/patogenicidade , Adesinas Bacterianas/genética , Cápsulas Bacterianas/genética , Linhagem Celular Tumoral , Células HeLa , Humanos , Polissacarídeos Bacterianos/metabolismo , Infecções Estafilocócicas/genética , Staphylococcus aureus/genética , Virulência/genética
4.
Nat Commun ; 10(1): 4644, 2019 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604911

RESUMO

In mammalian cells, the internal and external leaflets of the plasma membrane (PM) possess different phospholipids. Phosphatidylserine (PS) is normally confined to the inner (cytoplasmic) membrane leaflet. Here we report that the adhesin CPn0473 of the human pathogenic bacterium Chlamydia pneumoniae (Cpn) binds to the PM of human cells and induces PS externalization but unexpectedly not apoptosis. PS externalization is increased in human cells exposed to infectious Cpn cells expressing increased CPn0473 and reduced in exposure to Cpn expressing decreased CPn0473. CPn0473 binds specifically to synthetic membranes carrying PS and stimulates pore formation. Asymmetric giant unilamellar vesicles (GUVs) in which PS is restricted to the inner leaflet reveal that CPn0473 induces PS externalization in the absence of other proteins. Thus our identification of CPn0473 as a bacterial PS translocator capable of specific and apoptosis-independent PS externalization during infection extends the spectrum of mechanisms intracellular pathogens use to enter host cells.


Assuntos
Adesinas Bacterianas/fisiologia , Chlamydophila pneumoniae/fisiologia , Fosfatidilserinas/metabolismo , Adesinas Bacterianas/metabolismo , Interações entre Hospedeiro e Microrganismos , Humanos , Lipídeos de Membrana/química , Lipídeos de Membrana/metabolismo , Proteínas de Transferência de Fosfolipídeos/metabolismo
5.
Artigo em Inglês | MEDLINE | ID: mdl-31263685

RESUMO

Enolase is an evolutionarily conserved enzyme involved in the processes of glycolysis and gluconeogenesis. Mycoplasma hyopneumoniae belongs to Mycoplasma, whose species are wall-less and among the smallest self-replicating bacteria, and is an important colonizing respiratory pathogen in the pig industry worldwide. Mycoplasma hyopneumoniae enolase (Mhp Eno) expression is significantly increased after infection and was previously found to be a virulence factor candidate. Our studies show that Mhp Eno is a cell surface-localized protein that can adhere to swine tracheal epithelial cells (STECs). Adhesion to STECs can be specifically inhibited by an Mhp Eno antibody. Mhp Eno can recognize and interact with plasminogen with high affinity. Here, the first crystal structure of the mycoplasmal enolase from Mycoplasma hyopneumoniae was determined. The structure showed unique features of Mhp Eno in the S3/H1, H6/S6, H7/H8, and H13 regions. All of these regions were longer than those of other enolases and were exposed on the Mhp Eno surface, making them accessible to host molecules. These results show that Mhp Eno has specific structural characteristics and acts as a multifunctional adhesin on the Mycoplasma hyopneumoniae cell surface.


Assuntos
Adesinas Bacterianas/química , Adesinas Bacterianas/metabolismo , Membrana Celular/metabolismo , Mycoplasma hyopneumoniae/enzimologia , Fosfopiruvato Hidratase/química , Fosfopiruvato Hidratase/metabolismo , Adesinas Bacterianas/genética , Adesinas Bacterianas/isolamento & purificação , Animais , Cristalografia por Raios X , Células Epiteliais/microbiologia , Modelos Moleculares , Mycoplasma hyopneumoniae/metabolismo , Mycoplasma hyopneumoniae/patogenicidade , Fosfopiruvato Hidratase/genética , Fosfopiruvato Hidratase/isolamento & purificação , Plasminogênio/metabolismo , Pneumonia Suína Micoplasmática/microbiologia , Conformação Proteica , Alinhamento de Sequência , Análise de Sequência de Proteína , Especificidade da Espécie , Ressonância de Plasmônio de Superfície , Suínos , Fatores de Virulência
6.
Infect Immun ; 87(10)2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31358567

RESUMO

Enteropathogenic Escherichia coli (EPEC) is a leading cause of moderate to severe diarrhea among young children in developing countries, and EPEC isolates can be subdivided into two groups. Typical EPEC (tEPEC) bacteria are characterized by the presence of both the locus of enterocyte effacement (LEE) and the plasmid-encoded bundle-forming pilus (BFP), which are involved in adherence and translocation of type III effectors into the host cells. Atypical EPEC (aEPEC) bacteria also contain the LEE but lack the BFP. In the current report, we describe the complete genome of outbreak-associated aEPEC isolate E110019, which carries four plasmids. Comparative genomic analysis demonstrated that the type III secreted effector EspT gene, an autotransporter gene, a hemolysin gene, and putative fimbrial genes are all carried on plasmids. Further investigation of 65 espT-containing E. coli genomes demonstrated that different espT alleles are associated with multiple plasmids that differ in their overall gene content from the E110019 espT-containing plasmid. EspT has been previously described with respect to its role in the ability of E110019 to invade host cells. While other type III secreted effectors of E. coli have been identified on insertion elements and prophages of the chromosome, we demonstrated in the current study that the espT gene is located on multiple unique plasmids. These findings highlight a role of plasmids in dissemination of a unique E. coli type III secreted effector that is involved in host invasion and severe diarrheal illness.


Assuntos
Escherichia coli Enteropatogênica/genética , Proteínas de Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Genoma Bacteriano , Plasmídeos/química , Sistemas de Secreção Tipo III/genética , Adesinas Bacterianas/genética , Adesinas Bacterianas/metabolismo , Criança , Mapeamento Cromossômico , Escherichia coli Enteropatogênica/classificação , Escherichia coli Enteropatogênica/isolamento & purificação , Escherichia coli Enteropatogênica/metabolismo , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/patologia , Proteínas de Escherichia coli/metabolismo , Fímbrias Bacterianas/genética , Fímbrias Bacterianas/metabolismo , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Interações Hospedeiro-Patógeno/genética , Humanos , Filogenia , Plasmídeos/metabolismo , Sistemas de Secreção Tipo III/metabolismo , Sistemas de Secreção Tipo V/genética , Sistemas de Secreção Tipo V/metabolismo
7.
Microbiol Spectr ; 7(3)2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31215505

RESUMO

In addition to SecA of the general Sec system, many Gram-positive bacteria, including mycobacteria, express SecA2, a second, transport-associated ATPase. SecA2s can be subdivided into two mechanistically distinct types: (i) SecA2s that are part of the accessory Sec (aSec) system, a specialized transporter mediating the export of a family of serine-rich repeat (SRR) glycoproteins that function as adhesins, and (ii) SecA2s that are part of multisubstrate systems, in which SecA2 interacts with components of the general Sec system, specifically the SecYEG channel, to export multiple types of substrates. Found mainly in streptococci and staphylococci, the aSec system also contains SecY2 and novel accessory Sec proteins (Asps) that are required for optimal export. Asp2 also acetylates glucosamine residues on the SRR domains of the substrate during transport. Targeting of the SRR substrate to SecA2 and the aSec translocon is mediated by a specialized signal peptide. Multisubstrate SecA2 systems are present in mycobacteria, corynebacteria, listeriae, clostridia, and some bacillus species. Although most substrates for this SecA2 have canonical signal peptides that are required for export, targeting to SecA2 appears to depend on structural features of the mature protein. The feature of the mature domains of these proteins that renders them dependent on SecA2 for export may be their potential to fold in the cytoplasm. The discovery of aSec and multisubstrate SecA2 systems expands our appreciation of the diversity of bacterial export pathways. Here we present our current understanding of the mechanisms of each of these SecA2 systems.


Assuntos
Adenosina Trifosfatases/metabolismo , Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Adenosina Trifosfatases/genética , Adesinas Bacterianas/metabolismo , Bactérias/genética , Proteínas de Bactérias/genética , Bactérias Gram-Positivas/genética , Bactérias Gram-Positivas/metabolismo , Proteínas de Membrana Transportadoras/genética , Mycobacterium/metabolismo , Staphylococcus/metabolismo , Streptococcus/metabolismo
8.
Int J Med Microbiol ; 309(5): 331-337, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31176600

RESUMO

Bacteria often express numerous virulence factors. These virulence factors make them successful pathogens, by e.g. mediating attachment to host cells and thereby facilitating persistence or invasion, or by contributing to the evasion of the host immune system to allow proliferation and spread within the host and in the environment. The site of first contact of Gram negative bacteria with the host is the bacterial outer membrane (OM). Consisting of an asymmetrical lipid bilayer with phospholipids forming the inner, and lipopolysaccharides forming the outer leaflet, the OM harbors numerous integral membrane proteins that are almost exclusively ß-barrel proteins. One distinct family of OM ß-barrel proteins strongly linked to bacterial virulence are the autotransporter (AT) proteins. During the last years huge progress has been made to better understand the mechanisms underlying the insertion of AT proteins into the OM and also AT function for interaction with the host. This review shortly summarizes our current knowledge about outer membrane protein (OMP) and more specifically AT biogenesis and function. We focused on the AT proteins that we haved studied in most detail: i.e. the Yersinia adhesin A (YadA) and invasin of Yersinia enterocolitica (Ye) as well as its homolog intimin (Int) expressed by enteropathogenic Escherichia coli. In addition, this review provides a short outlook about how we could possibly use this knowledge to fight infection.


Assuntos
Adesinas Bacterianas/metabolismo , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Escherichia coli/metabolismo , Sistemas de Secreção Tipo V/metabolismo , Escherichia coli Enteropatogênica/metabolismo , Virulência , Fatores de Virulência/metabolismo , Yersinia enterocolitica/metabolismo
9.
Int J Med Microbiol ; 309(5): 344-350, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31178419

RESUMO

Type III secretion systems (T3SS) play a crucial role for virulence in many Gram-negative bacteria. After tight bacterial contact to host cells, the T3SS injects effector proteins into the host cells, which leads to cell invasion, tissue destruction and/or immune evasion. Over the last decade several attempts were made to characterize the host-cell interactions which precede and determine effector protein injection during infection. The development of the TEM-ß-lactamase reporter was an important breakthrough to achieve this goal. By this means it was demonstrated that during infection with many Gram-negative pathogens such as Salmonella, Pseudomonas or Yersinia the main targets of T3SS are leukocytes of the myeloid lineage such as neutrophils, macrophages or dendritic cells. This is due to the recruitment of these cells to the site of infection, but also due to the specific interplay between bacterial and host cells. Comprehensive studies on Yersinia pestis, Yersinia enterocolitica and Yersinia pseudotuberculosis effector translocation show that adhesins such as Invasin (Inv), Yersinia adhesin A (YadA) and attachment and invasion locus (Ail) are critical for effector translocation. Here, mainly the complex interaction of YadA and Ail with various host cell receptor repertoires on leukocytes and the modulatory effects of serum factors direct effector translocation predominantly towards myeloid cells. The current understanding suggests that mostly protein based interactions between bacteria and host determine host cell specific effector translocation during Yersinia infection. However, for Shigella dysenteriae infection it was shown that glycan-glycan interactions can also play a critical role for the adhesion preceding effector translocation. In addition, the Shigella infection model revealed that the activation status of cells is a further criterium directing effector translocation into a distinct cell population. In this review the current understanding of the complex and species-specific interaction between bacteria and host cells leading to type III secretion is discussed.


Assuntos
Aderência Bacteriana , Interações entre Hospedeiro e Microrganismos , Transporte Proteico , Sistemas de Secreção Tipo III/metabolismo , Adesinas Bacterianas/metabolismo , Animais , Proteínas da Membrana Bacteriana Externa/metabolismo , Humanos , Shigella/imunologia , Shigella/patogenicidade , Virulência/imunologia , Fatores de Virulência/metabolismo , Yersinia/imunologia , Yersinia/patogenicidade
10.
Appl Microbiol Biotechnol ; 103(14): 5679-5688, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31104097

RESUMO

Serovars of Salmonella enterica are common food-borne bacterial pathogens. Salmonella typhi, which causes typhoid, is the most dangerous of them. Though detailed molecular pathogenesis studies reveal many virulence factors, inability to identify their biochemical functions hampers the development of diagnostic methods and therapeutic leads. Lack of quicker diagnosis is an impediment in starting early antibiotic treatment to reduce the severe morbidity and mortality in typhoid. In this study, employing bioinformatic prediction, biochemical analysis, and recombinantly cloning the active region, we show that extracellularly secreted virulence-associated protein, small intestinal invasion factor E (SiiE), possesses a sulfite oxidase (SO) domain that catalyzes the conversion of sodium sulfite to sodium sulfate using tungsten as the cofactor. This activity common to Salmonella enterica serovars seems to be specific to them from bioinformatic analysis of available bacterial genomes. Along with the ability of this large non-fimbrial adhesin of 600 kDa binding to sialic acid on the host cells, this activity could aid in subverting the host defense mechanism by destroying sulfites released by the immune cells and colonize the host gastrointestinal epithelium. Being an extracellular enzyme, it could be an ideal candidate for developing diagnostics of S. enterica, particularly S. typhi.


Assuntos
Adesinas Bacterianas/metabolismo , Salmonella enterica/enzimologia , Salmonella enterica/patogenicidade , Sulfito Oxidase/metabolismo , Fatores de Virulência/metabolismo , Aderência Bacteriana , Biologia Computacional , Salmonella enterica/genética , Salmonella typhimurium , Sulfatos/metabolismo , Sulfito Oxidase/genética , Sulfitos/metabolismo , Tungstênio/metabolismo , Virulência
11.
PLoS Pathog ; 15(5): e1007773, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31107907

RESUMO

Neutrophil-derived networks of DNA-composed extracellular fibers covered with antimicrobial molecules, referred to as neutrophil extracellular traps (NETs), are recognized as a physiological microbicidal mechanism of innate immunity. The formation of NETs is also classified as a model of a cell death called NETosis. Despite intensive research on the NETs formation in response to pathogens, the role of specific bacteria-derived virulence factors in this process, although postulated, is still poorly understood. The aim of our study was to determine the role of gingipains, cysteine proteases responsible for the virulence of P. gingivalis, on the NETosis process induced by this major periodontopathogen. We showed that NETosis triggered by P. gingivalis is gingipain dependent since in the stark contrast to the wild-type strain (W83) the gingipain-null mutant strain only slightly induced the NETs formation. Furthermore, the direct effect of proteases on NETosis was documented using purified gingipains. Notably, the induction of NETosis was dependent on the catalytic activity of gingipains, since proteolytically inactive forms of enzymes showed reduced ability to trigger the NETs formation. Mechanistically, gingipain-induced NETosis was dependent on proteolytic activation of protease-activated receptor-2 (PAR-2). Intriguingly, both P. gingivalis and purified Arg-specific gingipains (Rgp) induced NETs that not only lacked bactericidal activity but instead stimulated the growth of bacteria species otherwise susceptible to killing in NETs. This protection was executed by proteolysis of bactericidal components of NETs. Taken together, gingipains play a dual role in NETosis: they are the potent direct inducers of NETs formation but in the same time, their activity prevents P. gingivalis entrapment and subsequent killing. This may explain a paradox that despite the massive accumulation of neutrophils and NETs formation in periodontal pockets periodontal pathogens and associated pathobionts thrive in this environment.


Assuntos
Adesinas Bacterianas/imunologia , Infecções por Bacteroidaceae/imunologia , Cisteína Endopeptidases/imunologia , Armadilhas Extracelulares/imunologia , Neutrófilos/imunologia , Peritonite/imunologia , Porphyromonas gingivalis/imunologia , Porphyromonas gingivalis/patogenicidade , Receptor PAR-2/metabolismo , Adesinas Bacterianas/metabolismo , Animais , Infecções por Bacteroidaceae/metabolismo , Infecções por Bacteroidaceae/microbiologia , Infecções por Bacteroidaceae/patologia , Células Cultivadas , Cisteína Endopeptidases/metabolismo , Armadilhas Extracelulares/microbiologia , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/microbiologia , Neutrófilos/patologia , Peritonite/metabolismo , Peritonite/microbiologia , Receptor PAR-2/imunologia , Transdução de Sinais
12.
Nat Commun ; 10(1): 1967, 2019 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-31036849

RESUMO

Autotransporters are the largest family of outer membrane and secreted proteins in Gram-negative bacteria. Most autotransporters are localised to the bacterial surface where they promote colonisation of host epithelial surfaces. Here we present the crystal structure of UpaB, an autotransporter that is known to contribute to uropathogenic E. coli (UPEC) colonisation of the urinary tract. We provide evidence that UpaB can interact with glycosaminoglycans and host fibronectin. Unique modifications to its core ß-helical structure create a groove on one side of the protein for interaction with glycosaminoglycans, while the opposite face can bind fibronectin. Our findings reveal far greater diversity in the autotransporter ß-helix than previously thought, and suggest that this domain can interact with host macromolecules. The relevance of these interactions during infection remains unclear.


Assuntos
Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Glicosaminoglicanos/metabolismo , Escherichia coli Uropatogênica/metabolismo , Adesinas Bacterianas/química , Adesinas Bacterianas/metabolismo , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/metabolismo , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Fatores de Virulência/química , Fatores de Virulência/metabolismo
13.
Artigo em Inglês | MEDLINE | ID: mdl-31069179

RESUMO

Streptococcus suis is an important porcine bacterial pathogen and a zoonotic agent causing a variety of pathologies including sudden death, septic shock, and meningitis. Though serotype 2 is the most studied serotype due to its presence worldwide, serotype 9 is responsible for the greatest number of porcine cases in Spain, the Netherlands, and Germany. Regardless of its increasing importance, very few studies have investigated S. suis serotype 9 virulence factors and pathogenesis. Antigens I/II (AgI/II) are multimodal adhesion proteins implicated in host respiratory tract and oral cavity persistence of various pathogenic human streptococci. It was recently demonstrated that AgI/II is involved in various bacterial functions for serotype 9, participating in the initial steps of the pathogenesis of the infection. However, its contribution to the systemic infection remains unknown. As such, we evaluated herein the role of the S. suis serotype 9 AgI/II in the interactions with phagocytes and the development of systemic disease in a mouse model of infection. Results demonstrated that the presence of AgI/II is important for the development of clinical systemic disease by promoting bacterial survival in blood possibly due to its effect on S. suis phagocytosis, as shown with macrophages and dendritic cells. Furthermore, AgI/II directly participates in dendritic cell activation and pro-inflammatory mediator production following recognition by the Toll-like receptor pathway, which may contribute to the exacerbated systemic inflammation responsible for host death. Taken together, this study demonstrates that the S. suis serotype 9 AgI/II is important for virulence during systemic infection and development of disease. In fact, this is the first study to describe a role of an AgI/II family member in systemic bacterial disease.


Assuntos
Adesinas Bacterianas/metabolismo , Aderência Bacteriana , Células Dendríticas/microbiologia , Interações Hospedeiro-Patógeno , Macrófagos/microbiologia , Infecções Estreptocócicas/fisiopatologia , Streptococcus suis/crescimento & desenvolvimento , Animais , Antígenos de Bactérias/metabolismo , Modelos Animais de Doenças , Camundongos , Sorogrupo
14.
Acta Crystallogr F Struct Biol Commun ; 75(Pt 5): 377-384, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31045567

RESUMO

With better tools for data processing and with synchrotron beamlines that are capable of collecting data at longer wavelengths, sulfur-based native single-wavelength anomalous dispersion (SAD) phasing has become the `first-choice' method for de novo protein structure determination. However, for many proteins native SAD phasing can be simplified by taking advantage of their interactions with natural metal cofactors that are stronger anomalous scatterers than sulfur. This is demonstrated here for four unique domains of a 1.5 MDa calcium-dependent adhesion protein using the anomalous diffraction of the chelated calcium ions. In all cases, low anomalous multiplicity X-ray data were collected on a home-source diffractometer equipped with a chromium rotating anode (λ = 2.2909 Å). In all but one case, calcium SAD phasing alone was sufficient to allow automated model building and refinement of the protein model after the calcium substructure had been determined. Given that Ca atoms will be present in a significant percentage of proteins that remain uncharacterized, many aspects of the data-collection and processing methods described here could be broadly applied for routine de novo structure elucidation.


Assuntos
Adesinas Bacterianas/química , Proteínas de Bactérias/química , Cálcio/química , Gelo/análise , Marinomonas/química , Adesinas Bacterianas/genética , Adesinas Bacterianas/metabolismo , Sequência de Aminoácidos , Organismos Aquáticos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Cálcio/metabolismo , Cátions Bivalentes , Clonagem Molecular , Temperatura Baixa , Cristalografia por Raios X , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Modelos Moleculares , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Difração de Raios X
15.
PLoS Negl Trop Dis ; 13(5): e0007401, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31071095

RESUMO

BACKGROUND: Syphilis affects approximately 11 million people each year globally, and is the third most prevalent sexually transmitted bacterial infection in the United States. Inability to independently culture and genetically manipulate Treponema pallidum subsp. pallidum, the causative agent of this disease, has hindered our understanding of the molecular mechanisms of syphilis pathogenesis. Here, we used the non-infectious and poorly adherent B314 strain of the Lyme disease-causing spirochete, Borrelia burgdorferi, to express two variants of a known fibronectin-binding adhesin, Tp0136, from T. pallidum SS14 and Nichols strains. Using this surrogate system, we investigated the ability of Tp0136 in facilitating differential binding to mammalian cell lines offering insight into the possible role of this virulence factor in colonization of specific tissues by T. pallidum during infection. PRINCIPAL FINDINGS: Expression of Tp0136 could be detected on the surface of B. burgdorferi by indirect immunofluorescence assay using sera from a secondary syphilis patient that does not react with intact B314 spirochetes transformed with the empty vector. Increase in Tp0136-mediated adherence of B314 strain to human epithelial HEK293 cells was observed with comparable levels of binding exhibited by both Tp0136 alleles. Adherence of Tp0136-expressing B314 was highest to epithelial HEK293 and C6 glioma cells. Gain in binding of B314 strain expressing Tp0136 to purified fibronectin and poor binding of these spirochetes to the fibronectin-deficient cell line (HEp-2) indicated that Tp0136 interaction with this host receptor plays an important role in spirochetal attachment to mammalian cells. Furthermore, preincubation of these cell lines with fibronectin-binding peptide from Staphylococcus aureus FnbA-2 protein significantly inhibited binding of B314 expressing Tp0136. CONCLUSIONS: Our results show that Tp0136 facilitates differential level of binding to cell lines representing various host tissues, which highlights the importance of this protein in colonization of human organs by T. pallidum and resulting syphilis pathogenesis.


Assuntos
Adesinas Bacterianas/metabolismo , Fibronectinas/metabolismo , Sífilis/metabolismo , Sífilis/microbiologia , Treponema pallidum/metabolismo , Adesinas Bacterianas/genética , Animais , Borrelia burgdorferi/genética , Borrelia burgdorferi/metabolismo , Feminino , Fibronectinas/genética , Expressão Gênica , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Ligação Proteica , Sífilis/genética , Treponema pallidum/genética
16.
J Med Microbiol ; 68(7): 978-985, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31136296

RESUMO

PURPOSE: Biofilm formation and resistance to last-line antibiotics have restricted chemotherapy options toward infection eradication. METHODOLOGY: Fifty K. oxytoca isolates were collected from patients with antibiotic-associated haemorrhagic colitis (AAHC). Antibiotic susceptibility tests were conducted and phenotypic biofilm formation was assessed using microtitre tissue plate (MTP) assay. PCR was employed to amplify the adhesins, extended-spectrum ß-lactamases (ESBLs), carbapenemase and colistin resistance genes. The expression of adhesin genes was evaluated using quantitative real-time PCR (RT-qPCR).Results/Key findings. The previous antibiotic consumption and hospitalization (P<0.05) and older ages (P=0.0033) were significantly associated with AAHC. None of the isolates produced biofilm strongly, but 70% of them produced moderate-level biofilm. The blaCTX-M (12/14), the blaIMP (8/14 MICIMI =4 µg ml-1 ) and blaOXA-48-like (5/14) and mcr-1 (4/14) genes were predominant, three of which harbouring all the genes. The expression of matB (0.023) and mrkA (0.011) was significantly different between multidrug-resistant and susceptible isolates. Furthermore, moderately biofilm producer isolates significantly exhibited higher expression of fimA (P=.0117), pilQ (P=0.002) and mrkA (P=0.020) genes compared to biofilm non-producers. No significant difference regarding gene expression was observed among ESBL alleles. CONCLUSION: Bacterial attachment by adhesins and biofilm formation among extensive drug-resistant K. oxytoca isolates hinder the efficient infection eradication. Hence, control and surveillance studies should be performed and other therapeutic auspicious approaches must be taken into account against AAHC, biofilm formation and drug resistance spread. Furthermore, previous antibiotic consumption and long-term hospitalization should be controlled.


Assuntos
Adesinas Bacterianas/metabolismo , Biofilmes/crescimento & desenvolvimento , Colite/microbiologia , Hemorragia Gastrointestinal/microbiologia , Regulação Bacteriana da Expressão Gênica/fisiologia , Klebsiella oxytoca/metabolismo , Adesinas Bacterianas/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/efeitos adversos , Criança , Pré-Escolar , Colite/patologia , Fezes/microbiologia , Feminino , Hemorragia Gastrointestinal/patologia , Humanos , Lactente , Infecções por Klebsiella/microbiologia , Klebsiella oxytoca/efeitos dos fármacos , Klebsiella oxytoca/genética , Klebsiella oxytoca/fisiologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real , Adulto Jovem
17.
PLoS Genet ; 15(5): e1008022, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31075103

RESUMO

Bacteria are often attached to surfaces in natural ecosystems. A surface-associated lifestyle can have advantages, but shifts in the physiochemical state of the environment may result in conditions in which attachment has a negative fitness impact. Therefore, bacteria employ numerous mechanisms to control the transition from an unattached to a sessile state. The Caulobacter crescentus protein HfiA is a potent developmental inhibitor of the secreted polysaccharide adhesin known as the holdfast, which enables permanent attachment to surfaces. Multiple environmental cues influence expression of hfiA, but mechanisms of hfiA regulation remain largely undefined. Through a forward genetic selection, we have discovered a multi-gene network encoding a suite of two-component system (TCS) proteins and transcription factors that coordinately control hfiA transcription, holdfast development and surface adhesion. The hybrid HWE-family histidine kinase, SkaH, is central among these regulators and forms heteromeric complexes with the kinases, LovK and SpdS. The response regulator SpdR indirectly inhibits hfiA expression by activating two XRE-family transcription factors that directly bind the hfiA promoter to repress its transcription. This study provides evidence for a model in which a consortium of environmental sensors and transcriptional regulators integrate environmental cues at the hfiA promoter to control the attachment decision.


Assuntos
Adesinas Bacterianas/genética , Caulobacter crescentus/genética , Regulação Bacteriana da Expressão Gênica , Redes Reguladoras de Genes , Histidina Quinase/genética , Polissacarídeos Bacterianos/genética , Fatores de Transcrição/genética , Adesinas Bacterianas/metabolismo , Aderência Bacteriana , Caulobacter crescentus/metabolismo , Ecossistema , Meio Ambiente , Interação Gene-Ambiente , Histidina Quinase/metabolismo , Polissacarídeos Bacterianos/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Transdução de Sinais/genética , Fatores de Transcrição/metabolismo , Transcrição Genética
18.
Res Vet Sci ; 124: 352-356, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31060015

RESUMO

Erysipelothrix rhusiopathiae is the causative agent of animal erysipelas and human erysipeloid. E. rhusiopathiae CbpB has been reported to be a protective antigen, but its pathogenic roles are not known. The aim of this study was to evaluate the ability of CbpB to act as an adhesin in E. rhusiopathiae adhesion to porcine endothelial cells as well as a host plasminogen- and fibronectin- binding protein. Recombinant CbpB (rCbpB) was successfully obtained, and it was found that E. rhusiopathiae CbpB was located on the cell surface of E. rhusiopathiae. Moreover, CbpB exhibited binding activity to porcine endothelial cells. Recombinant CbpB successfully bound to host plasminogen but was unable to bind to fibronectin. In conclusion, our work suggested that CbpB is a virulence factor of E. rhusiopathiae.


Assuntos
Adesinas Bacterianas/imunologia , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Erysipelothrix/imunologia , Adesinas Bacterianas/genética , Adesinas Bacterianas/metabolismo , Animais , Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Células Endoteliais/microbiologia , Infecções por Erysipelothrix/imunologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sus scrofa , Suínos , Doenças dos Suínos/imunologia
19.
Comp Immunol Microbiol Infect Dis ; 63: 131-135, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30961808

RESUMO

The aim of the study was to determine whether the presence of the Yersinia virulence plasmid could affect the production of enterotoxin YstA by Y. enterocolitica strains isolated from pigs which are the main source of infection for humans. The phenotypic features characteristic for the Yersinia virulence plasmid were detected on CRMOX agar in 8 out of 12 strains producing enterotoxin YstA, in 5 out of 12 doubtful strains, and in 11 out of 12 strains not producing YstA. Autoagglutination ability was detected in all 12 Y. enterocolitica strains that were positive in the suckling mice bioassay, in 11 doubtful strains and 10 negative strains. CRMOX+ colonies were generally ystA, myfA, virF and yadA positive, while CRMOX- colonies were only ystA and myfA positive. The amplicons of yadA were not detected in 2 (8.3%) out of 24 CRMOX+ and virF positive strains. The results of this study indicate that the presence of pYV does not affect the enterotoxin-producing ability of Y. enterocolitica strains.


Assuntos
Toxinas Bacterianas/biossíntese , Enterotoxinas/biossíntese , Plasmídeos/genética , Yersinia enterocolitica/genética , Yersinia enterocolitica/metabolismo , Adesinas Bacterianas/metabolismo , Animais , Antígenos de Bactérias/metabolismo , Proteínas da Membrana Bacteriana Externa/metabolismo , Meios de Cultura/farmacologia , DNA Bacteriano/genética , Humanos , Camundongos , Suínos , Doenças dos Suínos/microbiologia , Yersinia enterocolitica/patogenicidade
20.
PLoS Pathog ; 15(4): e1007713, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-31009507

RESUMO

Staphylococcus aureus expresses a number of cell wall-anchored proteins that mediate adhesion and invasion of host cells and tissues and promote immune evasion, consequently contributing to the virulence of this organism. The cell wall-anchored protein clumping factor B (ClfB) has previously been shown to facilitate S. aureus nasal colonization through high affinity interactions with the cornified envelope in the anterior nares. However, the role of ClfB during skin and soft tissue infection (SSTI) has never been investigated. This study reveals a novel role for ClfB during SSTIs. ClfB is crucial in determining the abscess structure and bacterial burden early in infection and this is dependent upon a specific interaction with the ligand loricrin which is expressed within the abscess tissue. Targeting ClfB using a model vaccine that induced both protective humoral and cellular responses, leads to protection during S. aureus skin infection. This study therefore identifies ClfB as an important antigen for future SSTI vaccines.


Assuntos
Adesinas Bacterianas/metabolismo , Infecções Cutâneas Estafilocócicas/microbiologia , Staphylococcus aureus/imunologia , Vacinas/imunologia , Fatores de Virulência/metabolismo , Virulência , Adesinas Bacterianas/genética , Adesinas Bacterianas/imunologia , Animais , Aderência Bacteriana , Feminino , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Infecções Cutâneas Estafilocócicas/imunologia , Infecções Cutâneas Estafilocócicas/metabolismo , Vacinas/administração & dosagem , Fatores de Virulência/genética , Fatores de Virulência/imunologia
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