Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Más filtros

Banco de datos
Tipo de estudio
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Mol Microbiol ; 118(4): 443-456, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36054485

RESUMEN

The Lyme disease agent, Borrelia burgdorferi, harbors a significantly reduced genome and relies on the scavenging of critical nutrients from its tick and mammalian hosts for survival. Riboflavin salvage has been shown to be important for B. burgdorferi infection of mice, yet the contributions of riboflavin to B. burgdorferi metabolism and survival in the tick remain unknown. Using a targeted mass spectrometry approach, we confirmed the importance of bb0318, the putative ATPase component of an ABC-type riboflavin transporter, for riboflavin salvage and the production of FMN and FAD. This analysis further revealed that Δbb0318 B. burgdorferi displayed increased levels of glycerol 3-phosphate compared to the wild-type. The glycerol 3-phosphate dehydrogenase activity of GlpD was found to be FAD-dependent and the transcription and translation of glpD were significantly decreased in Δbb0318 B. burgdorferi. Finally, gene bb0318 was found to be important for maximal spirochete burden in unfed larvae and essential for survival in feeding ticks. Together, these data demonstrate the importance of riboflavin salvage for B. burgdorferi carbon metabolism and survival in ticks.


Asunto(s)
Borrelia burgdorferi , Ixodes , Enfermedad de Lyme , Animales , Ratones , Adenosina Trifosfatasas , Borrelia burgdorferi/genética , Carbono , Mononucleótido de Flavina , Flavina-Adenina Dinucleótido , Mamíferos , Oxidorreductasas , Riboflavina
2.
PLoS Pathog ; 17(8): e1009869, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34415955

RESUMEN

The Lyme disease spirochete Borrelia burgdorferi relies on uptake of essential nutrients from its host environments for survival and infection. Therefore, nutrient acquisition mechanisms constitute key virulence properties of the pathogen, yet these mechanisms remain largely unknown. In vivo expression technology applied to B. burgdorferi (BbIVET) during mammalian infection identified gene bb0562, which encodes a hypothetical protein comprised of a conserved domain of unknown function, DUF3996. DUF3996 is also found across adjacent encoded hypothetical proteins BB0563 and BB0564, suggesting the possibility that the three proteins could be functionally related. Deletion of bb0562, bb0563 and bb0564 individually and together demonstrated that bb0562 alone was important for optimal disseminated infection in immunocompetent and immunocompromised mice by needle inoculation and tick bite transmission. Moreover, bb0562 promoted spirochete survival during the blood dissemination phase of infection. Gene bb0562 was also found to be important for spirochete growth in low serum media and the growth defect of Δbb0562 B. burgdorferi was rescued with the addition of various long chain fatty acids, particularly oleic acid. In mammals, fatty acids are primarily stored in fat droplets in the form of triglycerides. Strikingly, addition of glyceryl trioleate, the triglyceride form of oleic acid, to the low serum media did not rescue the growth defect of the mutant, suggesting bb0562 may be important for the release of fatty acids from triglycerides. Therefore, we searched for and identified two canonical GXSXG lipase motifs within BB0562, despite the lack of homology to known bacterial lipases. Purified BB0562 demonstrated lipolytic activity dependent on the catalytic serine residues within the two motifs. In sum, we have established that bb0562 is a novel nutritional virulence determinant, encoding a lipase that contributes to fatty acid scavenge for spirochete survival in environments deficient in free fatty acids including the mammalian host.


Asunto(s)
Proteínas Bacterianas/metabolismo , Ácidos Grasos/deficiencia , Regulación Bacteriana de la Expresión Génica , Interacciones Huésped-Patógeno , Lipasa/metabolismo , Enfermedad de Lyme/microbiología , Factores de Virulencia/metabolismo , Animales , Proteínas Bacterianas/genética , Borrelia burgdorferi/fisiología , Femenino , Ixodes/microbiología , Enfermedad de Lyme/inmunología , Enfermedad de Lyme/metabolismo , Masculino , Ratones , Ratones Endogámicos C3H , Ratones Endogámicos NOD , Factores de Virulencia/genética
3.
Infect Immun ; 89(10): e0021621, 2021 09 16.
Artículo en Inglés | MEDLINE | ID: mdl-34181460

RESUMEN

Lyme disease is a multistage inflammatory disease caused by the spirochete Borrelia burgdorferi transmitted through the bite of an infected Ixodes scapularis tick. We previously discovered a B. burgdorferi infectivity gene, bbk13, that facilitates mammalian infection by promoting spirochete population expansion in the skin inoculation site. Initial characterization of bbk13 was carried out using an intradermal needle inoculation model of mouse infection, which does not capture the complex interplay of the pathogen-vector-host triad of natural transmission. Here, we aimed to understand the role of bbk13 in the enzootic cycle of B. burgdorferi. B. burgdorferi spirochetes lacking bbk13 were unable to be acquired by naive larvae fed on needle-inoculated mice. Using a capsule feeding approach to restrict tick feeding activity to a defined skin site, we determined that delivery by tick bite alleviated the population expansion defect in the skin observed after needle inoculation of Δbbk13 B. burgdorferi. Despite overcoming the early barrier in the skin, Δbbk13 B. burgdorferi remained attenuated for distal tissue colonization after tick transmission. Disseminated infection by Δbbk13 B. burgdorferi was improved in needle-inoculated immunocompromised mice. Together, we established that bbk13 is crucial to the maintenance of B. burgdorferi in the enzootic cycle and that bbk13 is necessary beyond early infection in the skin, likely contributing to host immune evasion. Moreover, our data highlight the critical interplay between the pathogen, vector, and host as well as the distinct molecular genetic requirements for B. burgdorferi to survive at the pathogen-vector-host interface and achieve productive disseminated infection.


Asunto(s)
Proteínas Bacterianas/genética , Borrelia burgdorferi/genética , Borrelia burgdorferi/patogenicidad , Enfermedad de Lyme/microbiología , Animales , Ixodes/microbiología , Ratones , Ratones Endogámicos C3H , Ratones Endogámicos NOD , Piel/microbiología , Mordeduras de Garrapatas/microbiología
4.
Infect Immun ; 86(6)2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29555678

RESUMEN

Staphylococcus aureus nasal carriage is a common condition affecting both healthy and immunocompromised populations and provides a reservoir for dissemination of potentially infectious strains by casual contact. The factors regulating the onset and duration of nasal S. aureus colonization are mostly unknown, and a human-relevant animal model is needed. Here, we screened 17 pig-tailed macaques (Macaca nemestrina) for S. aureus carriage, and 14 of 17 animals tested positive in the nose at one or both screening sessions (8 weeks apart), while the other 3 animals were negative in the nose but positive in the pharynx at least once. As in humans, S. aureus colonization was densest in the nose, and treatment of the nostrils with mupirocin ointment effectively cleared the nostrils and 6 extranasal body sites. Experimental nasal S. aureus colonization was established with 104 CFU/nostril, and both autologous and nonautologous strains survived over 40 days without any apparent adverse effects. A human nasal S. aureus isolate (strain D579, sequence type 398) was carried in 4 of 6 animals for over 3 weeks. Nostrils that did eradicate experimentally applied S. aureus exhibited neutrophilic innate immunity marked by elevated nasal interleukin-1ß (IL-1ß), IL-8, and monocyte chemotactic protein 1 levels and a 10-fold decreased IL-1 receptor antagonist/IL-1ß ratio within 7 days postinoculation, analogous to the human condition. Taken together, pig-tailed macaques represent a physiological model of human S. aureus nasal carriage that may be utilized for testing natural colonization and decolonization mechanisms as well as novel classes of anti-S. aureus therapeutics.


Asunto(s)
Macaca nemestrina/microbiología , Nariz/microbiología , Staphylococcus aureus/fisiología , Animales , Portador Sano , Femenino , Genotipo
5.
bioRxiv ; 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38260563

RESUMEN

Flagella propel pathogens through their environments yet are expensive to synthesize and are immunogenic. Thus, complex hierarchical regulatory networks control flagellar gene expression. Spirochetes are highly motile bacteria, but peculiarly in the Lyme spirochete Borrelia burgdorferi, the archetypal flagellar regulator σ28 is absent. We rediscovered gene bb0268 in B. burgdorferi as flgV, a broadly-conserved gene in the flagellar superoperon alongside σ28 in many Spirochaetes, Firmicutes and other phyla, with distant homologs in Epsilonproteobacteria. We found that B. burgdorferi FlgV is localized within flagellar motors. B. burgdorferi lacking flgV construct fewer and shorter flagellar filaments and are defective in cell division and motility. During the enzootic cycle, B. burgdorferi lacking flgV survive and replicate in Ixodes ticks but are attenuated for dissemination and infection in mice. Our work defines infection timepoints when spirochete motility is most crucial and implicates FlgV as a broadly distributed structural flagellar component that modulates flagellar assembly.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA