Abstract:
:The two-component regulatory system, GraRS, appears to be involved in staphylococcal responses to cationic antimicrobial peptides (CAPs). However, the mechanism(s) by which GraRS is induced, regulated, and modulated remain undefined. In this study, we used two well-characterized MRSA strains (Mu50 and COL) and their respective mutants of graR and vraG (encoding the ABC transporter-dependent efflux pump immediately downstream of graRS), and show that (i) the expression of two key determinants of net positive surface charge (mprF and dlt) is dependent on the cotranscription of both graR and vraG, (ii) reduced expression of mprF and dlt in graR mutants was phenotypically associated with reduced surface-positive charge, (iii) this net reduction in surface-positive charge in graR and vraG mutants, in turn, correlated with enhanced killing by a range of CAPs of diverse structure and origin, including those from mammalian platelets (tPMPs) and neutrophils (hNP-1) and from bacteria (polymyxin B), and (iv) the synthesis and translocation of membrane lysyl-phosphatidylglycerol (an mprF-dependent function) was substantially lower in graR and vraG mutants than in parental strains. Importantly, the inducibility of mprF and dlt transcription via the graRS-vraFG pathway was selective, with induction by sublethal exposure to the CAPs, RP-1 (platelets), and polymyxin B, but not by other cationic molecules (hNP-1, vancomycin, gentamicin, or calcium-daptomycin). Although graR regulates expression of vraG, the expression of graR was codependent on an intact downstream vraG locus. Collectively, these data support an important role of the graRS and vraFG loci in the sensing of and response to specific CAPs involved in innate host defenses.
journal_name
Infect Immunjournal_title
Infection and immunityauthors
Yang SJ,Bayer AS,Mishra NN,Meehl M,Ledala N,Yeaman MR,Xiong YQ,Cheung ALdoi
10.1128/IAI.05669-11subject
Has Abstractpub_date
2012-01-01 00:00:00pages
74-81issue
1eissn
0019-9567issn
1098-5522pii
IAI.05669-11journal_volume
80pub_type
杂志文章abstract::Eperythrozoon coccoides is a common blood parasite of rodents and the etiological agent of a chronic infection present in many mouse colonies. After primary infection, mice develop a parasitemia and anemia followed by a chronic, latent infection. During the acute phase of infection, mice manifest a striking suppressio...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.4.4.425-430.1971
更新日期:1971-10-01 00:00:00
abstract::Intrauterine infections lead to serious complications for mother and fetus, including preterm birth, maternal and fetal death, and neurological sequelae in the surviving offspring. Improving maternal and child heath is a global priority. Yet, the development of strategies to prevent and treat pregnancy-related disease...
journal_title:Infection and immunity
pub_type: 杂志文章,评审
doi:10.1128/IAI.00801-17
更新日期:2018-05-22 00:00:00
abstract::Legionella pneumophila is a gram-negative facultative intracellular parasite of macrophages. Although L. pneumophila is the causative agent of a severe pneumonia known as Legionnaires' disease, it is likely that most infections caused by this organism are cleared by the host innate immune system. It is predicted that ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.02049-05
更新日期:2006-06-01 00:00:00
abstract::In swine, the most common and severe enterotoxigenic Escherichia coli (ETEC) infections are caused by strains that express K88 (F4)(+) fimbriae, heat-labile enterotoxin (LT), heat-stable enterotoxin b (STb), and enteroaggregative E. coli heat-stable toxin 1. Previous studies based on a design that involved enterotoxin...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.01743-07
更新日期:2008-07-01 00:00:00
abstract::The endothelium is a specific target for Bartonella henselae, and endothelial cell infection represents an important step in the pathogenesis of cat scratch disease and bacillary angiomatosis. Mechanisms of Bartonella-endothelial cell interaction as well as signaling pathways involved in target cell activation were an...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.69.8.5088-5097.2001
更新日期:2001-08-01 00:00:00
abstract::A set of four monoclonal antibodies was produced against a highly purified pepsin extract of type 5 streptococcal M protein. Three of the four antibodies cross-reacted with purified M proteins from heterologous serotypes and opsonized the respective heterologous organisms. Our studies suggest that monoclonal antibodie...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.46.1.267-269.1984
更新日期:1984-10-01 00:00:00
abstract::An attenuated Salmonella typhi Ty21a vaccine was administered to 18 infants and toddlers (less than or equal to 24 months old) to determine its safety and immunogenicity. The vaccination (10(9) CFU per dose, three doses) was well tolerated. However, after the vaccination there was no evidence of a humoral or cellular ...
journal_title:Infection and immunity
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1128/IAI.59.11.4291-4293.1991
更新日期:1991-11-01 00:00:00
abstract::Secreted and surface-exposed antigens of intracellular pathogens are thought to provide target structures for detection by the host immune system. The major secreted product of intracellular Leishmania mexicana amastigotes, a proteophosphoglycan (aPPG), is known to contribute to the establishment of the parasitophorou...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.67.10.5379-5385.1999
更新日期:1999-10-01 00:00:00
abstract::Mortality associated with acute lung injury (ALI) induced by lipopolysaccharide (LPS) remains high in humans, warranting improved treatment and prevention strategies. ALI is characterized by the expression of proinflammatory mediators and extensive neutrophil influx into the lung, followed by severe lung damage. Under...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.72.12.7247-7256.2004
更新日期:2004-12-01 00:00:00
abstract::Serotype b-specific polysaccharide antigen (SPA) was extracted from whole cells of Actinobacillus actinomycetemcomitans Y4 by autoclaving and purified by chromatography on DEAE-Sephadex A-25 and Sephacryl S-300. SPA induced the release of monocyte and leukocyte chemotactic factors by human monocytes. Polymyxin B had a...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.64.7.2563-2570.1996
更新日期:1996-07-01 00:00:00
abstract::Trypanosoma cruzi is a protozoan parasite that can initiate mucosal infection after conjunctival exposure. The anatomical route of T. cruzi invasion and spread after conjunctival parasite contamination remains poorly characterized. In the present work we have identified the sites of initial invasion and replication af...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00319-06
更新日期:2006-10-01 00:00:00
abstract::Clostridium difficile is recognized as the major cause of antibiotic-associated colitis. C. difficile produces two toxins, A (enterotoxin) and B (cytotoxin), that are implicated in the pathogenesis of the colitis. We examined the dose responses, time course, and synergism of these two toxins in ligated rabbit intestin...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.56.3.582-588.1988
更新日期:1988-03-01 00:00:00
abstract::An effective vaccine for Vibrio cholerae is not yet available for use in the developing world, where the burden of cholera disease is highest. Characterizing the proteins that are expressed by V. cholerae in the human host environment may provide insight into the pathogenesis of cholera and assist with the development...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00585-08
更新日期:2008-09-01 00:00:00
abstract::Merozoite surface proteins of Plasmodium falciparum play a critical role in the invasion of human erythrocytes by the malaria parasite. Here we describe the identification of a novel protein with a molecular mass of 40 kDa that is found on the merozoite surface of P. falciparum. We call this protein merozoite surface ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.65.11.4460-4467.1997
更新日期:1997-11-01 00:00:00
abstract::Disruption of the healthy intestinal microbiome and homeostasis of the intestinal immune system, which are closely interactive, are two key factors for ulcerative colitis. Here, we show that MI-2, a selective inhibitor of mucosa-associated lymphoid tissue lymphoma translocation-1 (MALT1), alleviated excessive inflamma...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00091-18
更新日期:2018-11-20 00:00:00
abstract::Antimicrobial peptides (AMPs), such as β-defensins and cathelicidins, are essential components of innate and adaptive immunity owing to their extensive multifunctional activities. However, their role in fungal infection in vivo remains elusive. In this study, we investigated the protective effect of murine β-defensin ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00179-13
更新日期:2013-08-01 00:00:00
abstract::The production of delta-toxin is supposed to be responsible for various pathophysiological effects during infection with Staphylococcus aureus. We compared the effects of delta-toxin with the structurally related bee venom toxin melittin on granulocyte functions and inflammatory mediator release. Delta-toxin and melit...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.58.6.1653-1659.1990
更新日期:1990-06-01 00:00:00
abstract::The immune response of mice to live, heat-killed, or autoclaved Mycobacterium leprae was investigated. After sensitization with 10(7) organisms in each group, recipient mice were transfused with the sensitized splenocytes 28 days later. A selected number of these mice were infected with 5 X 10(3) M. leprae, and the re...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.43.1.79-83.1984
更新日期:1984-01-01 00:00:00
abstract::Human enterotoxigenic Escherichia coli (ETEC) producing colonization factor antigen III (CFA/III) and coli surface antigens 4, 5, and 6 (CS4, CS5, and CS6) of CFA/IV were examined ultrastructurally and for ability to adhere to human small intestinal enterocytes and to cultured human intestinal mucosa. Strains of serot...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.57.11.3364-3371.1989
更新日期:1989-11-01 00:00:00
abstract::Host resistance to African trypanosomiasis is partially dependent on an early and strong T-independent B-cell response against the variant surface glycoprotein (VSG) coat expressed by trypanosomes. The repetitive array of surface epitopes displayed by a monotypic surface coat, in which identical VSG molecules are clos...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.73.5.2690-2697.2005
更新日期:2005-05-01 00:00:00
abstract::We utilized magnetic resonance imaging to visualize lesions in the lungs of guinea pigs infected by low-dose aerosol exposure to Mycobacterium tuberculosis. Lesions were prominent in such images, and colorized three-dimensional reconstructions of images revealed a very uniform distribution in the lungs. Lesion numbers...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.72.10.5963-5971.2004
更新日期:2004-10-01 00:00:00
abstract::Immunity to reinfection in the genital tract of female guinea pigs with the agent of guinea pig inclusion conjunctivitis was found to be dependent upon an intact humoral immune response. Cell-mediated immunity in the absence of humoral immunity had no apparent role in resistance to challenge infection. ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.39.1.463-465.1983
更新日期:1983-01-01 00:00:00
abstract::Antimicrobial factors were analyzed in samples of whole saliva from 31 children, aged 0.8 to 3.8 years. When compared with the adult reference group, the children displayed similar levels of lysozyme, salivary peroxidase, and hypothiocyanite (OSCN-), whereas the amounts of immunoglobulins (isotypes A, G, and M), lacto...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.51.1.49-53.1986
更新日期:1986-01-01 00:00:00
abstract::Mucosa-associated invariant T (MAIT) cells are an innate-like T cell subset in mammals that recognize microbial vitamin B metabolites presented by the evolutionarily conserved major histocompatibility complex class I (MHC I)-related molecule, MR1. Emerging data suggest that MAIT cells may be an attractive target for v...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00524-20
更新日期:2020-12-15 00:00:00
abstract::Haemophilus ducreyi expresses 2 OmpA homologs, designated MOMP and OmpA2, whose genes are arranged in tandem on the chromosome. Northern blot analysis indicated that momp and ompA2 are transcribed independently. Sequences of the momp open reading frame (ORF) lacking the transcriptional start site were amplified by PCR...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.68.5.2602-2607.2000
更新日期:2000-05-01 00:00:00
abstract::Antigen 2 (Ag2), a major immunoreactive component of Coccidioides immitis mycelium- and spherule-phase cell walls, was recently cloned in our laboratory and was shown to elicit T-cell responses in Coccidioides-immune mice. In this investigation, we evaluated recombinant Ag2 (rAg2) and PCR-generated Ag2 truncations for...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.65.8.3376-3380.1997
更新日期:1997-08-01 00:00:00
abstract::Immunoglobulin class-specific antibodies were measured by a solid-phase radioimmunoassay in serum, bronchoalveolar washings (BAW), lung cell lysates, and spleen cell lysates in germfree mice after intranasal (i.n.) and intraperitoneal (i.p.) primary and secondary 10(5), 10(4), and 10(3) mean tissue culture infective d...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.17.3.521-527.1977
更新日期:1977-09-01 00:00:00
abstract::Bordetella parapertussis, a respiratory tract pathogen commonly regarded as noninvasive, was found to invade HeLa 229 cell monolayers. Following treatment of the monolayers with gentamicin, numbers of viable B. parapertussis recovered were comparable to those of invasive Salmonella and Shigella isolates. Invasion occu...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.57.4.1240-1247.1989
更新日期:1989-04-01 00:00:00
abstract::Pathogenicity islands (PAIs) are chromosomal clusters of pathogen-specific virulence genes often found at tRNA loci. In the Yersinia pseudotuberculosis 32777 chromosome, we characterized a 98-kb segment that has all of the characteristic features of a PAI, including insertion in a (phenylalanine) tRNA gene, the presen...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.72.8.4784-4790.2004
更新日期:2004-08-01 00:00:00
abstract::A chimeric recombinant protein composed of the lktA gene product from Pasteurella haemolytica fused to bovine interleukin-2 (IL-2) was made. The LKT-IL-2 chimera was compared with recombinant bovine IL-2 with regard to the ability to induce proliferative responses and LAK cell activity in bovine peripheral blood monon...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.60.2.565-570.1992
更新日期:1992-02-01 00:00:00