Abstract:
:Streptococcus pneumoniae is a fermentative microorganism and causes serious diseases in humans, including otitis media, bacteremia, meningitis, and pneumonia. However, the mechanisms enabling pneumococcal survival in the host and causing disease in different tissues are incompletely understood. The available evidence indicates a strong link between the central metabolism and pneumococcal virulence. To further our knowledge on pneumococcal virulence, we investigated the role of lactate dehydrogenase (LDH), which converts pyruvate to lactate and is an essential enzyme for redox balance, in the pneumococcal central metabolism and virulence using an isogenic ldh mutant. Loss of LDH led to a dramatic reduction of the growth rate, pinpointing the key role of this enzyme in fermentative metabolism. The pattern of end products was altered, and lactate production was totally blocked. The fermentation profile was confirmed by in vivo nuclear magnetic resonance (NMR) measurements of glucose metabolism in nongrowing cell suspensions of the ldh mutant. In this strain, a bottleneck in the fermentative steps is evident from the accumulation of pyruvate, revealing LDH as the most efficient enzyme in pyruvate conversion. An increase in ethanol production was also observed, indicating that in the absence of LDH the redox balance is maintained through alcohol dehydrogenase activity. We also found that the absence of LDH renders the pneumococci avirulent after intravenous infection and leads to a significant reduction in virulence in a model of pneumonia that develops after intranasal infection, likely due to a decrease in energy generation and virulence gene expression.
journal_name
Infect Immunjournal_title
Infection and immunityauthors
Gaspar P,Al-Bayati FA,Andrew PW,Neves AR,Yesilkaya Hdoi
10.1128/IAI.02005-14subject
Has Abstractpub_date
2014-12-01 00:00:00pages
5099-109issue
12eissn
0019-9567issn
1098-5522pii
IAI.02005-14journal_volume
82pub_type
杂志文章abstract::Fifteen clinical isolates of Trichomonas vaginalis were evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with transfer to nitrocellulose and by immunoblots probed with human sera. All T. vaginalis isolates showed similar banding patterns by Coomassie brilliant blue and silver staining of the elec...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.51.1.250-253.1986
更新日期:1986-01-01 00:00:00
abstract::Escherichia coli O157:H7 carries a chromosomal msbB1 and a plasmid-encoded msbB2 gene. We characterized msbB2 function as a homologue of msbB1 by examination of wild-type organisms and mutant strains that lacked functional msbB1, msbB2, and both msbB1 and msbB2. The msbB double-mutant strain generated pentaacyl lipid ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.72.2.1174-1180.2004
更新日期:2004-02-01 00:00:00
abstract::Bordetella pertussis adenylate cyclase-hemolysin (AC-Hly), encoded by the cyaA gene, belongs to the RTX family of toxins with extensive glycine-rich repeats in the carboxy-terminal portion. AC-Hly possesses both adenylate cyclase toxic and hemolytic activities that depend on a posttranslational modification mediated b...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.61.9.3583-3589.1993
更新日期:1993-09-01 00:00:00
abstract::Virus population dynamics in the lungs, trachea, and nasopharynx of Swiss-ICR mice were studied after respiratory challenge with mouse-adapted preparations of strain A2/Aichi/2/68 influenza virus. Markedly higher doses of virus were required to produce infection with nasopharyngeal challenge than with bronchoalveolar ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.13.2.438-447.1976
更新日期:1976-02-01 00:00:00
abstract::Clostridium difficile toxins A and B (TcdA and TcdB) are the causative agents of antibiotic-associated pseudomembranous colitis. Mucosal mast cells play a crucial role in the inflammatory processes underlying this disease. We studied the direct effects of TcdA and TcdB on the human mast cell line HMC-1 with respect to...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00195-07
更新日期:2007-08-01 00:00:00
abstract::Mammalian hosts often develop distinct immune response against the diverse parasitic helminths that have evolved for immune evasion. Interleukin-25 (IL-25), an IL-17 cytokine family member, plays a key role in initiating the protective immunity against several parasitic helminths; however, the involvement and underlyi...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00646-13
更新日期:2013-10-01 00:00:00
abstract::The virulence and fitness in vivo of the major human pathogen Staphylococcus aureus are associated with a cell-to-cell signaling mechanism known as quorum sensing (QS). QS coordinates the production of virulence factors via the production and sensing of autoinducing peptide (AIP) signal molecules by the agr locus. Her...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.01216-13
更新日期:2014-03-01 00:00:00
abstract::Conditions are described for the production of an extracellular cytotoxin or CHO cell-killing factor by Vibrio fluvialis, a recently recognized enteric pathogen. The cell-killing factor was ammonium sulfate precipitable, heat labile, and inactivated by proteases, and had an isoelectric point (estimated by sucrose dens...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.46.3.773-777.1984
更新日期:1984-12-01 00:00:00
abstract::Infection with Histoplasma capsulatum results in a subclinical infection in immunocompetent hosts due to an effective cellular immune response. By contrast, immunodeficient individuals can have a severe disseminated and potentially fatal disease. In a previous study, it was demonstrated that normal mice infected intra...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.65.3.936-942.1997
更新日期:1997-03-01 00:00:00
abstract::Formation of compact colonies of Staphylococcus aureus in serum-soft agar is mainly a result of a reaction between protein A and the Fc-part of immunoglobulin G and not a clumping factor-fibrinogen reaction. ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.6.4.583-586.1972
更新日期:1972-10-01 00:00:00
abstract::L929 cell populations persistently infected for more than 600 days exhibited cell cycle distributions and generation times similar to those of uninfected cells. The RNA and protein contents of these long-term-infected cells, as determined by flow cytometry and correlated with the cell cycle, were likewise approximatel...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.55.7.1731-1733.1987
更新日期:1987-07-01 00:00:00
abstract::Oligosaccharide (OS)-protein conjugates are promising candidate vaccines against encapsulated bacteria, such as Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae. Although the effects of several variables such as OS chain length and protein carrier have been studied, little is known about th...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.71.12.6915-6920.2003
更新日期:2003-12-01 00:00:00
abstract::Phagosome acidification is an important component of the microbicidal response by infected eukaryotic cells. Thus, intracellular pathogens that reside within phagosomes must either block phagosome acidification or be able to survive at low pH. In this work, we studied the effect of phagosomal acidification on the surv...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.68.9.5401-5404.2000
更新日期:2000-09-01 00:00:00
abstract::Virulent Streptococcus suis serotype 2 strains are invasive extracellular bacteria causing septicemia and meningitis in piglets and humans. One objective of this study was to elucidate the function of complement in innate immune defense against S. suis. Experimental infection of wild-type (WT) and C3(-/-) mice demonst...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00080-14
更新日期:2014-06-01 00:00:00
abstract::Salmonella enterica serovar Pullorum is worldwide a poultry pathogen of considerable economic importance, particularly in those countries with a developing poultry industry. In addition to the characteristic high mortality rates among young chicks, one of the features of Salmonella serovar Pullorum infection is that i...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.69.12.7873-7879.2001
更新日期:2001-12-01 00:00:00
abstract::Oligosaccharides (OSs) related to the pneumococcal type 14 capsular polysaccharide (Pn14PS) were studied for their ability to inhibit the binding between anti-PS14 antisera and native PS14. A synthetic tetrasaccharide corresponding to the repeating unit of the Pn14PS, a hexasaccharide mimic, and an octasaccharide frag...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.70.9.5107-5114.2002
更新日期:2002-09-01 00:00:00
abstract::Macrophage-dependent killing of facultative intracellular bacteria was markedly impaired by overt erythrocytic Plasmodium yoelii or Plasmodium berghei infection of mice. P. yoelii infection was capable of ablating not only the macrophage microbicidal capacity of "normal" animals but also the bactericidal capacities of...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.31.1.396-407.1981
更新日期:1981-01-01 00:00:00
abstract::Mice were infected with Chlamydia trachomatis (L2/434) and at various intervals after infection their lymphoid cells were tested directly for cytotoxic activity against Chlamydia-infected L929 cells. In a modified cell-mediated lympholysis assay, splenic, lymph node, and peritoneal exudate cells did not significantly ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.39.3.1271-1274.1983
更新日期:1983-03-01 00:00:00
abstract::A major goal of current vaccine development is the induction of strong immune responses against protective antigens delivered by mucosal routes. One of the most promising approaches in that respect relies on the use of live recombinant vaccine carriers. In this study, Mycobacterium bovis BCG was engineered to produce ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.66.12.5669-5676.1998
更新日期:1998-12-01 00:00:00
abstract::Brucella abortus is a class III zoonotic bacterial pathogen able to survive and replicate inside host cells, including macrophages. Here we report a multidimensional transposon sequencing analysis to identify genes essential for Brucella abortus growth in rich medium and replication in RAW 264.7 macrophages. The const...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00312-18
更新日期:2018-07-23 00:00:00
abstract::Interferon regulatory factor 1-deficient (IRF-1(-/-)) mice infected with virulent Brucella abortus 2308 at 5 x 10(5) CFU developed acute hepatitis similar to many natural hosts but, unlike natural hosts, IRF-1(-/-) mice were unable to resolve infection and died. In contrast, IRF-1(-/-) mice survived when infected at 5...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.70.12.7004-7012.2002
更新日期:2002-12-01 00:00:00
abstract::Four strains of Staphylococcus aureus of a phage type other than the second group, isolated from patients with impetigo and Ritter's disease, were found to produce an exotoxin similar to those reported by Melish et al. (1972), Kapral and Miller (1971), and Arbuthnott et al. (1973). This toxin could elicit a general ex...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.10.4.851-861.1974
更新日期:1974-10-01 00:00:00
abstract::Toll-like receptors (TLRs) are a major component of the pattern recognition receptor repertoire that detect invading microorganisms and direct the vertebrate immune system to eliminate infection. In chickens, the differential biology of Salmonella serovars (systemic versus gut-restricted localization) correlates with ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.73.4.2344-2350.2005
更新日期:2005-04-01 00:00:00
abstract::Administration of free muramyl tripeptide phosphatidylethanolamide (MTPPE) or liposome-encapsulated MTPPE (LE-MTPPE) in a twofold-lower dose at 24 h before bacterial inoculation resulted in clearance of intravenously inoculated Klebsiella pneumoniae by tissue macrophages, whereas in control mice, bacteria were not eff...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.60.11.4891-4897.1992
更新日期:1992-11-01 00:00:00
abstract::The protein P2 comprises a large proportion of the outer membrane of nontypable Haemophilus influenzae and functions as a porin. In view of the importance of the protein as a surface antigen, the present study was designed to purify and analyze P2 with particular emphasis on detection of antigenic determinants express...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.56.5.1084-1089.1988
更新日期:1988-05-01 00:00:00
abstract::Many of the proinflammatory effects of gram-negative bacteria are elicited by the interaction of bacterial lipopolysaccharide (LPS) with Toll-like receptor 4 (TLR4) expressed on host cells. TLR4 signaling leads to activation of NF-kappa B and transcription of many genes involved in the inflammatory response. In this s...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.71.8.4414-4420.2003
更新日期:2003-08-01 00:00:00
abstract::A recombinant 23-kDa protein (rBPI23) derived from human bactericidal/permeability-increasing protein (BPI) possesses potent endotoxin-neutralizing abilities in vitro and in vivo. Binding of rBPI23 to those endotoxins (lipopolysaccharides [LPSs]) encountered clinically would be a prerequisite for efficacy in decreasin...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.62.8.3564-3567.1994
更新日期:1994-08-01 00:00:00
abstract::Evidence is presented that the chronicity of infection in CBA mice after injection of Brucella abortus 19 is related to a number of factors: (i) the relative resistance of B. abortus to macrophage killing, which allowed some bacteria to survive the peak of macrophage activity occurring at 14 days; (ii) the decline in ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.23.2.197-205.1979
更新日期:1979-02-01 00:00:00
abstract::Oophorectomized, estrogen-treated rats were immunized by the intravaginal or intranasal route with a mannoprotein extract (MP) or secreted aspartyl proteinases (Sap) of Candida albicans, with or without cholera toxin as a mucosal adjuvant. Both routes of immunization were equally effective in (i) inducing anti-MP and ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.70.5.2725-2729.2002
更新日期:2002-05-01 00:00:00
abstract::Free lipid A of Bordetella pertussis, Neisseria meningitidis, and Escherichia coli lipopolysaccharide (LPS) was prepared by hydrolysis in acetate buffer (pH 4.5); in addition, lipid A from B. pertussis and E. coli was prepared by hydrolysis in mineral acid (HCl). The precipitates obtained were purified by extraction m...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.54.2.465-471.1986
更新日期:1986-11-01 00:00:00