Abstract:
:A parasitic protozoan, Leishmania mexicana amazonensis, was previously made resistant to tunicamycin (J.A. Kink and K.-P. Chang, Proc. Natl. Acad. Sci. USA 84:1253-1257, 1987). In the present study, six different tunicamycin-resistant variants were biologically and biochemically compared with their parental wild type to further delineate the mechanism of tunicamycin resistance and that of their virulence observed. In contrast to their parental wild type, all tunicamycin-resistant variants were found to grow and differentiate in tunicamycin-containing medium. The 50% lethal doses of tunicamycin for variants resistant to 10 or 80 micrograms of tunicamycin per ml were 20- and 100-fold higher, respectively, than that of the wild type. Specific activity of the microsomal N-acetylglucosamine-1-phosphate transferase was 4- to 12-fold higher in the tunicamycin-resistant cells than in their parental wild type and tunicamycin-sensitive revertants. The level of the enzyme activity is proportional to the degree of drug resistance. Inhibition kinetics studies showed that the enzyme from all groups was equally sensitive to the drug, with a 50% effective concentration of 1 to 1.3 micrograms of tunicamycin per ml. Thus, tunicamycin resistance of the variants is caused primarily by an increased level of their enzyme without alteration of its structure. Protein glycosylation determined by the incorporation of 2-D-[3H]mannose was about twofold higher in the tunicamycin-resistant variants than in their parental wild type. The increased glycosyltransferase activity in the latter apparently renders their protein glycosylation insensitive to the inhibition by tunicamycin. A major membrane glycoprotein of 63 kilodaltons (gp63) on the leishmania surface was found to be about threefold higher in the tunicamycin-resistant variants than in the wild type, as determined by immunoprecipitation with a monoclonal antibody specific for this antigen. Tunicamycin treatment of the wild type and tunicamycin-resistant variants caused changes in the electrophoretic mobility of this molecule, indicating a higher degree of its glycosylation in the latter cells. The tunicamycin-resistant variants parasitized macrophages in vitro more effectively than did the wild type, accounting for their virulence seen in mice. Thus, a high level of the glycosyltransferase enables the tunicamycin-resistant cells not only to overcome the inhibitory effect of tunicamycin on protein glycosylation but also to express their virulence, possibly by regulating N glycosylation of leishmanial proteins critical for leishmanias to establish intracellular parasitism.
journal_name
Infect Immunjournal_title
Infection and immunityauthors
Kink JA,Chang KPdoi
10.1128/IAI.55.7.1692-1700.1987subject
Has Abstractpub_date
1987-07-01 00:00:00pages
1692-700issue
7eissn
0019-9567issn
1098-5522journal_volume
55pub_type
杂志文章abstract::Lipopolysaccharide (LPS) structure impacts the bactericidal action of cationic peptides, such as polymyxin B (PMB), and sensitivity to killing by normal human serum (NHS). Cultivation of different subspecies strains of Yersinia pestis isolated from unrelated geographic origins at various temperatures (mammals, 37 degr...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.73.11.7324-7331.2005
更新日期:2005-11-01 00:00:00
abstract::The recently introduced choleragen-induced rat foot edema model has been employed as a bioassay for evaluating the immunogenicity of three purified preparations containing cholera exo-enterotoxin antigen, choleragen, choleragenoid, and Formalin-treated choleragen (formagen). The results indicated that choleragen evoke...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.1.5.468-473.1970
更新日期:1970-05-01 00:00:00
abstract::In the present study, the roles of interleukin 12 (IL-12) and IL-18 and their possible interaction during superantigen-induced responses were studied by injection of staphylococcal enterotoxin B (SEB) into mice. These data suggest that the role of IL-12 in SEB-induced responses is limited to sustaining gamma interfero...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.69.9.5949-5952.2001
更新日期:2001-09-01 00:00:00
abstract::A veronal buffer extract of Salmonella typhi was used as the reference antigen and its corresponding rabbit antiserum as the reference antibody in crossed immunoelectrophoresis to analyze antibodies in sera obtained from typhoid patients and carriers. Four precipitating antibodies were regularly detected. Three were a...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.43.3.1110-1113.1984
更新日期:1984-03-01 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
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.74.3.1768-1776.2006
更新日期:2006-03-01 00:00:00
abstract::Lipopolysaccharide (LPS) is one of the most potent trigger substances for monocytes and macrophages causing secretion of tumor necrosis factor alpha (TNF-alpha) and other inflammatory mediators. The nature of the nuclear factors involved in human TNF-alpha gene regulation is still unknown. Nuclear factor kappa B (NF-k...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.63.4.1529-1534.1995
更新日期:1995-04-01 00:00:00
abstract::EspC is an autotransporter protein secreted by enteropathogenic Escherichia coli (EPEC). The pathogenic role of EspC in EPEC infection is unknown. We have shown that the purified EspC produces enterotoxicity and cytotoxicity; for the latter effect, EspC must be internalized. However, the internalization mechanism is u...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.74.4.2293-2303.2006
更新日期:2006-04-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.19.2.570-574.1978
更新日期:1978-02-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.67.3.1338-1346.1999
更新日期:1999-03-01 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::Burkholderia pseudomallei, a causative agent of melioidosis, is a Gram-negative facultative intracellular bacterium that can survive and multiply in macrophages. Previously, we demonstrated that B. pseudomallei failed to activate gene expression downstream of the MyD88-independent pathway, particularly the expression ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.01254-10
更新日期:2011-07-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.70.8.4045-4052.2002
更新日期:2002-08-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00575-16
更新日期:2016-09-19 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.61.11.4629-4636.1993
更新日期:1993-11-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.74.3.1941-1943.2006
更新日期:2006-03-01 00:00:00
abstract::Immunomodulatory agents potentially represent a new class of broad-spectrum antimicrobials. Here, we demonstrate that prophylaxis with immunomodulatory cytosine-phosphate-guanidine (CpG) oligodeoxynucleotide (ODN), a toll-like receptor 9 (TLR9) agonist, confers protection against Yersinia pestis, the etiologic agent o...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00316-13
更新日期:2013-06-01 00:00:00
abstract::GNA33 is a membrane-bound lipoprotein with murein hydrolase activity that is present in all Neisseria species and well conserved in different meningococcal isolates. The protein shows 33% identity to a lytic transglycolase (MltA) from Escherichia coli and has been shown to be involved in the degradation of both insolu...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.72.4.1914-1919.2004
更新日期:2004-04-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.36.3.1028-1035.1982
更新日期:1982-06-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:
更新日期:1980-09-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.47.3.831-833.1985
更新日期:1985-03-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00122-08
更新日期:2008-11-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.5.1.91-97.1972
更新日期:1972-01-01 00:00:00
abstract::A simple and convenient method was developed for the preparation of Streptococcus pneumoniae type 14 polysaccharide (Pn14PS)-tetanus toxoid (TT) conjugate vaccines, using terminally linked Pn14PS fragments of different lengths. Native Pn14PS was simultaneously depolymerized and activated for conjugation by partial N-d...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.66.6.2441-2446.1998
更新日期:1998-06-01 00:00:00
abstract::Trehalose 6,6'-dimycolate (TDM) plays important roles in the development of granulomatous inflammation during infection with Mycobacterium spp., Rhodococcus spp., etc. To reveal the augmenting effect of TDM on vascular endothelial growth factor (VEGF) production and neovascularization, we investigated murine granuloma...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.68.4.2043-2052.2000
更新日期:2000-04-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.2.6.742-749.1970
更新日期:1970-12-01 00:00:00
abstract::Type III and type VI secretion systems (T3SSs and T6SSs, respectively) are critical virulence determinants in several Gram-negative pathogens. In Burkholderia pseudomallei, the T3SS-3 and T6SS-1 clusters have been implicated in bacterial virulence in mammalian hosts. We recently discovered a regulatory cascade that co...
journal_title:Infection and immunity
pub_type: 杂志文章
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更新日期:2011-08-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.60.10.4192-4199.1992
更新日期:1992-10-01 00:00:00
abstract::Burkholderia cenocepacia, a member of the B. cepacia complex, is an opportunistic pathogen that causes serious infections in patients with cystic fibrosis. We identified a six-gene cluster in chromosome 1 encoding a two-component regulatory system (BCAL2831 and BCAL2830) and an HtrA protease (BCAL2829) hypothesized to...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.01581-06
更新日期:2007-04-01 00:00:00
abstract::The blood-stage development of malaria parasites is initiated by the invasion of merozoites into susceptible erythrocytes. Specific receptor-ligand interactions must occur for the merozoites to first attach to and then invade erythrocytes. Because the invasion process is essential for the parasite's survival and the m...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.62.12.5581-5586.1994
更新日期:1994-12-01 00:00:00