bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional and Immunogenic Characterization of Two Cloned Regions of
Streptococcus mutans
Glucosyltransferase I
Authors: Jespersgaard Christina , Hajishengallis George , Greenway Terrence E. , Smith Daniel J. , Russell Michael W. , Michalek Suzanne M. 
Published: December 2019

ABSTRACT

Glucosyltransferase (GTF) enzymes of mutans streptococci are considered virulence factors due to their ability to synthesize adhesive glucans, which facilitate cell-to-cell adherence and accumulation. In this study we report the cloning, expression, and characterization of the catalytic (CAT) and glucan-binding (GLU) domains of
S. mutans
GTF-I encoded by
gtfB
. The CAT and GLU polypeptides represent amino acid residues 253 to 628 and 1183 to 1473, respectively, of
S. mutans
GTF-I. Antibodies to recombinant CAT and GLU were generated in rabbits and purified by affinity chromatography. Purified anti-CAT antibodies significantly inhibited water-insoluble glucan synthesis by
S. mutans
and
S. sobrinus
GTFs (
P
< 0.0001 and
P
< 0.05, respectively). The purified anti-GLU antibodies significantly inhibited both water-insoluble and water-soluble glucan synthesis by
S. mutans
GTFs (
P
< 0.0001 and
P
< 0.05, respectively). These results demonstrate that anti-CAT and anti-GLU antibodies are capable of inhibiting a variety of GTF activities. Since antibodies to
S. mutans
in saliva are implicated in protection against disease, we next assessed the ability of CAT and GLU polypeptides to induce mucosal antibody responses in mice. Intranasal (i.n.) immunization of mice with CAT showed significantly (
P
< 0.005) elevated levels of specific immunoglobulin G (IgG) antibody activity in serum and specific IgA antibody activity in serum, saliva, vaginal washes, and fecal samples. GLU immunized animals showed significantly (
P
< 0.005) elevated levels of specific IgA antibody activity in serum and vaginal secretions. Taken together, these results demonstrate that the recombinant CAT and GLU polypeptides are effective in inducing both mucosal and systemic immune responses. The ability of these polypeptides to induce a mucosal IgA immune response in mice after i.n. immunization supports their use as subunit vaccine candidates in the development of an anticaries vaccine.
Isolation and Characterization of Rugose Form of
Vibrio cholerae
O139 Strain MO10
Authors: Mizunoe Yoshimitsu , Wai Sun Nyunt , Takade Akemi , Yoshida Shin-Ichi 
Published: December 2019

ABSTRACT

An extracellular exopolysaccharide (slime) is produced by
Vibrio cholerae
O139 MO10 in response to nutrient starvation. The presence of this slime layer on the cell surface and its subsequent release have been shown to be associated with biofilm formation and the change from a normal smooth colony morphology to a rugose one. An immunoelectron microscopic examination demonstrated that there is an epitope common to the exopolysaccharide antigen of
V. cholerae
O1 and that of O139 MO10.
Interleukin-5 Transgenic Mice Show Enhanced Resistance to Primary Infections withNippostrongylus brasiliensisbut Not Primary Infections withToxocara canis
Authors: Dent Lindsay A. , Daly Christine M. , Mayrhofer Graham , Zimmerman Trudy , Hallett Ann , Bignold Leon P. , Creaney Jenette , Parsons Jim C. 
Published: December 2019

ABSTRACTIn this study, interleukin-5 (IL-5) transgenic mice with lifelong eosinophilia were assessed for resistance to primary infections with two tissue-invading nematodes,Nippostrongylus brasiliensisandToxocara canis. Relative to nontransgenic littermates, three lines of IL-5 transgenic mice with varying degrees of eosinophilia all displayed enhanced resistance toN. brasiliensis. Although the timing of final worm expulsion was similar in transgenic and nontransgenic hosts, intestinal worms in transgenic mice were fewer in number throughout infection, failed to increase in size over the course of the infection, and were much less fecund. In contrast,T. canislarvae were recovered in similar numbers from tissues of transgenic mice with “low” or “high” eosinophilia and from nontransgenic mice. These results and other data suggest that eosinophils can contribute to host resistance to some parasite species. Parasite transit time through the host may correlate with relative sensitivity to eosinophils.
Role of Nitric Oxide in Lipopolysaccharide-Induced Hepatic Injury ind-Galactosamine-Sensitized Mice as an Experimental Endotoxic Shock Model
Authors: Morikawa Akiko , Kato Yutaka , Sugiyama Tuyoshi , Koide Naoki , Chakravortty Dipshika , Yoshida Tomoaki , Yokochi Takashi 
Published: December 2019

ABSTRACTThe role of nitric oxide (NO) in lipopolysaccharide (LPS)-induced hepatic injury was studied ind-galactosamine (d-GalN)-sensitized mice. The inducible isoform of NO synthase (iNOS) was immunohistochemically detected on hepatocytes around blood vessels in livers of mice injected withd-GalN and LPS not on hepatocytes in mice injected withd-GalN or LPS alone, although mRNA for iNOS was found in those mice. Nitrotyrosine (NT) was also found in livers of mice injected withd-GalN and LPS. The localization of NT was consistent with that of iNOS, and the time courses of NT and iNOS expression were almost the same. Expression of iNOS and NT was detected exclusively in the hepatic lesions of mice injected withd-GalN and LPS. Anti-tumor necrosis factor alpha neutralizing antibody inhibited iNOS and NT expression and hepatic injury. The results suggested that NO from iNOS may play a role in LPS-induced hepatic injury ond-GalN-sensitized mice as an experimental endotoxic shock model.
Generation of CD8+T-Cell Responses toMycobacterium bovisand Mycobacterial Antigen in Experimental Bovine Tuberculosis
Authors: Liébana Ernesto , Girvin Robert M. , Welsh Michael , Neill Sydney D. , Pollock John M. 
Published: December 2019

ABSTRACTProtective immunity against tuberculosis is considered to be essentially cell mediated, and an important role for CD8+T lymphocytes has been suggested by several studies of murine and human infections. The present work, using an experimental model of infection withMycobacterium bovisin cattle, showed that liveM. boviselicits the activation of CD8+T cells in vitro. However, a sonic extract prepared fromM. bovis(MBSE) and protein purified derivative (PPDb) also induced a considerable degree of activation of the CD8+T cells. Analysis of proliferative responses of peripheral blood mononuclear cells, purified CD8+T cells, and CD8+T-cell clones toM. bovisand to soluble antigenic preparations (MBSE, PPDb) showed that the responses of all three types of cells were always superior for live mycobacteria but that strong responses were also obtained with complex soluble preparations. Furthermore, while cytotoxic capabilities were not investigated, the CD8+T cells were found to produce and release gamma interferon in response to antigen (live and soluble), which indicated one possible protective mechanism for these cells in bovine tuberculosis. Finally, it was demonstrated by metabolic inhibition with brefeldin A and cytochalasin D at the clonal level that an endogenous pathway of antigen processing is required for presentation to bovine CD8+cells and that presentation is also dependent on phagocytosis of the antigen.
Borrelia burgdorferiSpirochetes Induce Mast Cell Activation and Cytokine Release
Authors: Talkington Jeffrey , Nickell Steven P. 
Published: December 2019

ABSTRACTThe Lyme disease spirochete,Borrelia burgdorferi, is introduced into human hosts via tick bites. Among the cell types present in the skin which may initially contact spirochetes are mast cells. Since spirochetes are known to activate a variety of cell types in vitro, we tested whetherB. burgdorferispirochetes could activate mast cells. We report here that freshly isolated rat peritoneal mast cells or mouse MC/9 mast cells cultured in vitro with live or freeze-thawedB. burgdorferispirochetes undergo low but detectable degranulation, as measured by [5-3H] hydroxytryptamine release, and they synthesize and secrete the proinflammatory cytokine tumor necrosis factor alpha (TNF-α). In contrast to findings in previous studies, whereB. burgdorferi-associated activity was shown to be dependent upon protein lipidation, mast cell TNF-α release was not induced by either lipidated or unlipidated recombinant OspA. This activity was additionally shown to be protease sensitive and surface expressed. Finally, comparisons of TNF-α-inducing activity in known low-, intermediate-, and high-passageB. burgdorferiB31 isolates demonstrated passage-dependent loss of activity, indicating that the activity is probably plasmid encoded. These findings document the presence in low-passageB. burgdorferispirochetes of a novel lipidation-independent activity capable of inducing cytokine release from host cells.
Dysregulated Production of Interleukin-8 in Individuals Infected with Human Immunodeficiency Virus Type 1 andMycobacterium tuberculosis
Authors: Meddows-Taylor Stephen , Martin Desmond J. , Tiemessen Caroline T. 
Published: December 2019

ABSTRACTInterleukin-8 (IL-8) production in vivo was monitored in four study groups: normal blood donors, patients with pulmonary tuberculosis (TB), patients with human immunodeficiency virus type 1 (HIV-1) infection, and dually infected (HIV/TB) patients. We show that whereas there was evidence of detectable levels of cell-associated IL-8 (mRNA and protein) in peripheral cells of healthy individuals, this was largely lost in the disease states studied. Coupled with this finding was significantly increased circulating levels of IL-8 in HIV-1-infected individuals with or without concomitant pulmonary TB (P< 0.001). On the other hand, the capacity of peripheral mononuclear cells to produce IL-8 spontaneously ex vivo was enhanced in HIV-1 and TB patients (P< 0.05) and many of the HIV/TB group, but their corresponding capacities to respond to various stimuli, in particular phytohemagglutinin, were significantly diminished compared to those of normal donors (P< 0.05). Circulating levels of IL-8 in a group of HIV/TB patients were significantly positively correlated with the percentage of polymorphonuclear leukocytes (PMN) in the peripheral circulation (r= 0.65;P= 0.01), the proportions of IL-8 receptor A (IL-8RA)-expressing (r= 0.86;P< 0.01) and IL-8RB-expressing (r= 0.77;P< 0.01) PMN, and the capacity of PMN to migrate in response to IL-8 as chemoattractant (r= 0.68;P< 0.01). IL-8RB fluorescence intensity, however, was negatively correlated with plasma IL-8 levels (r= −0.73;P< 0.01). Our results suggest that altered regulation of IL-8 in HIV-1 may have important implications for antimicrobial defenses and for normal immune processes.
Functional Activities and Epitope Specificity of Human and Murine Antibodies against the Class 4 Outer Membrane Protein (Rmp) of
Neisseria meningitidis
Authors: Rosenqvist Einar , Musacchio Alexis , Aase Audun , Høiby E. Arne , Namork Ellen , Kolberg Jan , Wedege Elisabeth , Delvig Alexei , Dalseg Rolf , Michaelsen Terje E. , Tommassen Jan 
Published: December 2019

ABSTRACT

Antibodies against the class 4 outer membrane protein (OMP) from
Neisseria meningitidis
have been purified from sera from vaccinees immunized with the Norwegian meningococcal group B outer membrane vesicle vaccine. The human sera and purified antibodies reacted strongly with the class 4 OMP in immunoblots, whereas experiments with whole bacteria showed only weak reactions, indicating that the antibodies mainly reacted with parts of the class 4 molecule that were not exposed. The purified human anti-class 4 OMP antibodies and the monoclonal antibodies (MAbs) were neither bactericidal nor opsonic against live meningococci. Three new MAbs against the class 4 OMP were generated and compared with other, previously described MAbs. Three linear epitopes in different regions of the class 4 OMP were identified by the reaction of MAbs with synthetic peptides. The MAbs showed no blocking effect on bactericidal activity of MAbs against other OMPs. However, one of the eight purified human anti-class 4 OMP antibody preparations, selected from immunoblot reactions among sera from 27 vaccinees, inhibited at high concentrations the bactericidal effect of a MAb against the class 1 OMP. However, these antibodies were not vaccine induced, as they were present also before vaccination. Therefore, this study gave no evidence that vaccination with a meningococcal outer membrane vesicle vaccine containing the class 4 OMP induces blocking antibodies. Our data indicated that the structure of class 4 OMP does not correspond to standard β-barrel structures of integral OMPs and that no substantial portion of the OmpA-like C-terminal region of this protein is located at the surface of the outer membrane.
Expression of the Plague Plasminogen Activator inYersinia pseudotuberculosisandEscherichia coli
Authors: Kutyrev V. , Mehigh R. J. , Motin V. L. , Pokrovskaya M. S. , Smirnov G. B. , Brubaker R. R. 
Published: December 2019

ABSTRACTEnteropathogenic yersiniae (Yersinia pseudotuberculosisandYersinia enterocolitica) typically cause chronic disease as opposed to the closely relatedYersinia pestis, the causative agent of bubonic plague. It is established that this difference reflects, in part, carriage byY. pestisof a unique 9.6-kb pesticin or Pst plasmid (pPCP) encoding plasminogen activator (Pla) rather than distinctions between shared ∼70-kb low-calcium-response, or Lcr, plasmids (pCD inY. pestisand pYV in enteropathogenic yersiniae) encoding cytotoxic Yops and anti-inflammatory V antigen. Pla is known to exist as a combination of 32.6-kDa (α-Pla) and slightly smaller (β-Pla) outer membrane proteins, of which at least one promotes bacterial dissemination in vivo and degradation of Yops in vitro. We show here that only α-Pla accumulates inEscherichia coliLE392/pPCP1 cultivated in enriched medium and that either autolysis or extraction of this isolate with 1.0 M NaCl results in release of soluble α and β forms possessing biological activity. This process also converted cell-bound α-Pla to β-Pla and smaller forms inY. pestisKIM/pPCP1 andY. pseudotuberculosisPB1/+/pPCP1 but did not promote solubilization. Pla-mediated posttranslational hydrolysis of pulse-labeled Yops inY. pseudotuberculosisPB1/+/pPCP1 occurred more slowly than that inY. pestisbut was otherwise similar except for accumulation of stable degradation products of YadA, a pYV-mediated fibrillar adhesin not encoded in frame by pCD. Carriage of pPCP byY. pseudotuberculosisdid not significantly influence virulence in mice.
Surface Expression of a Protective Recombinant Pertussis Toxin S1 Subunit Fragment in
Streptococcus gordonii
Authors: Lee Song F. , March Robert J. , Halperin Scott A. , Faulkner Gary , Gao Lingqiu 
Published: December 2019

ABSTRACT

In this study, the expression of the
Bordetella pertussis
S1 subunit was tested in
Streptococcus gordonii
, a commensal oral bacterium which has the potential to be a live oral vaccine vehicle. The DNA fragment encoding the N-terminal 179 amino acids of the S1 subunit was ligated into the middle part of
spaP
, the surface protein antigen P1 gene originating from
Streptococcus mutans
. The resulting construct, carried on the
Escherichia coli-Streptococcus
shuttle vector pDL276, was introduced into
S. gordonii
DL-1 by natural transformation. One of the transformants (RJMIII) produced a 187-kDa protein (the predicted size of the SpaP-S1 fusion protein) which was recognized by both the anti-pertussis toxin (anti-PT) and anti-SpaP antibodies, suggesting that an in-frame fusion had been made. Results from immunogold-electron microscopic studies and cellular fractionation studies showed that the fusion protein was surface localized and was mainly associated with the cell wall of RJMIII, indicating that SpaP was able to direct the fusion protein to the cell surface. A rabbit antiserum raised against heat-killed
S. gordonii
RJMIII recognized the native S1 subunit of PT in Western blotting and showed a weak neutralization titer to PT by the Chinese hamster ovary cell-clustering assay. BALB/c mice immunized with the heat-killed
S. gordonii
RJMIII were protected from the toxic effect of PT in the leukocytosis-promoting and histamine sensitization assays. In conclusion, a fragment of the S1 subunit of PT was successfully surface expressed in
S. gordonii
; the recombinant S1 fragment was found to be immunogenic and could induce protection against the toxic effect of PT in mice.
Identification of thePlasmodium chabaudiHomologue of Merozoite Surface Proteins 4 and 5 ofPlasmodium falciparum
Authors: Black Casilda G. , Wang Lina , Hibbs Alan R. , Werner Ekkehard , Coppel Ross L. 
Published: December 2019

ABSTRACTPrevious studies ofPlasmodium falciparumhave identified a region of chromosome 2 in which are clustered three genes for glycosylphosphatidylinositol (GPI)-anchored merozoite surface proteins, MSP2, MSP5, and MSP4, arranged in tandem.MSP4andMSP5both encode proteins 272 residues long that contain hydrophobic signal sequences, GPI attachment signals, and a single epidermal growth factor (EGF)-like domain at their carboxyl termini. Nevertheless, the remainder of their protein coding regions are quite dissimilar. The locations and similar structural features of these genes suggest that they have arisen from a gene duplication event. Here we describe the identification of the syntenic region of the genome in the murine malaria parasite,Plasmodium chabaudi adamiDS. Only one open reading frame is present in this region, and it encodes a protein with structural features reminiscent of both MSP4 and MSP5, including a single EGF-like domain. Accordingly, the gene has been designatedPcMSP4/5. The homologue of theP. falciparum MSP2gene could not be found inP. chabaudi; however, the amino terminus of the PcMSP4/5 protein shows similarity to that of MSP2. ThePcMSP4/5gene encodes a protein with an apparent molecular mass of 36 kDa, and this protein is detected in mature stages of the parasite. The protein partitions in the detergent-enriched phase after Triton X-114 fractionation and is localized to the surfaces of trophozoites and developing and free merozoites. ThePcMSP4/5gene is transcribed in both ring and trophozoite stages but appears to be spliced in a stage-specific manner such that the central intron is spliced from the mRNA in the parasitic stage in which the protein is expressed.
Changes in Cytokine Levels during Reactivation ofToxoplasma gondiiInfection in Lungs
Authors: Filice Gregory A. , Clabots Connie R. , Riciputi Paul E. , Goñi-Laguardia Oscar , Pomeroy Claire 
Published: December 2019

ABSTRACTWe studied cytokine proteins and mRNAs in mice with two forms ofToxoplasma gondiipneumonia resulting from reactivation of infection. In the first form, mice were infected withT. gondii, developed and recovered from systemic disease, and then developed pneumonia 3 weeks later. As pulmonary inflammation developed, levels of cytokine mRNAs for gamma interferon (IFN-γ), interleukin-2 (IL-2), IL-4, and IL-10 increased in bronchoalveolar lavage (BAL) cells or lung tissue, and the level of IFN-γ protein increased in BAL fluid. The second form of pneumonia occurred as a complication of primary cytomegalovirus (CMV) disease in mice with dormantT. gondiiinfection. During CMV disease, IL-2 mRNA levels decreased in lung tissue, IL-10 protein levels increased in lung tissue, and IL-10 protein levels increased in BAL fluid. As the mice recovered from CMV disease,T. gondiiinfection was reactivated in the lungs and was manifested asT. gondiipneumonia. During CMV-inducedT. gondiipneumonia, IFN-γ, IL-2, IL-4, and IL-10 mRNA levels increased in BAL cells or lung tissue, and both IFN-γ and IL-2 protein levels increased in BAL fluid. We concluded that both forms ofT. gondiipneumonia are accompanied by increases in both type 1 T-helper and type 2 T-helper cytokine levels in lungs. The mechanism of CMV-induced reactivation ofT. gondiiinfection in lungs may involve local decreases in IL-2 levels and/or increases in IL-10 levels.
Down Regulation ofEntamoeba histolyticaVirulence by Monoxenic Cultivation withEscherichia coliO55 Is Related to a Decrease in Expression of the Light (35-Kilodalton) Subunit of the Gal/GalNAc Lectin
Authors: Padilla-Vaca Felipe , Ankri Serge , Bracha Rivka , Koole Lucy Anna , Mirelman David 
Published: December 2019

ABSTRACTEntamoeba histolyticavirulence is related to a number of amebic components (lectins, cysteine proteinases, and amebapore) and host factors, such as intestinal bacterial flora. Trophozoites are selective in their interactions with bacteria, and the parasite recognition of glycoconjugates plays an important role in amebic virulence. Long-term monoxenic cultivation of pathogenicE. histolyticatrophozoites, strains HK-9 or HM-1:IMSS, withEscherichia coliserotype O55, which binds strongly to the Gal/GalNAc amebic lectin, markedly reduced the trophozoites’ adherence and cytopathic activity on cell monolayers of baby hamster kidney (BHK) cells. Specific probes prepared fromE. histolyticalectin genes as well as antibodies directed against the light (35-kDa) and heavy (170-kDa) subunits of the Gal/GalNAc lectin revealed a decrease in the transcription and expression of the light subunit in trophozoites grown monoxenically withE. coliO55. This effect was not observed whenE. histolyticawas grown withE. coli346, a mannose-binding type I pilated bacteria. Our results suggest that the light subunit of the amebic lectin is involved in the modulation of parasite adherence and cytopathic activity.
Characterization of the
Escherichia coli
AF/R1 Pilus Operon: Novel Genes Necessary for Transcriptional Regulation and for Pilus-Mediated Adherence
Authors: Cantey J. Robert , Blake R. K. , Williford J. R. , Moseley Steve L. 
Published: December 2019

ABSTRACT

We isolated the genetic determinant of AF/R1 pilus production in attaching/effacing
Escherichia coli
RDEC-1 and identified seven genes required for pilus expression and function. DNA sequence analysis of the structural subunit gene
afrA
corrected an error in the published sequence and extended homology with the F18 pilus subunit of pig edema
E. coli
strains. AfrB and AfrC, encoded downstream from AfrA, were required for pilus expression. AfrB was related to the usher protein PefC of
Salmonella typhimurium
plasmid-encoded fimbriae, and AfrC was related to PefD, a chaperone protein. AfrD and AfrE, encoded downstream from AfrC, were not necessary for the expression of AF/R1 pili but were required for ileal adherence as assayed by ileal brush border aggregation. Thus, the adhesive subunit of the AF/R1 pilus is distinct from the structural subunit, as is the case for Pap pili and type 1 pili. AfrD was related to FedE of the F18 fimbrial operon of the
E. coli
strain that causes edema disease in pigs. AfrE was a novel protein. AfrR and AfrS are encoded upstream from AfrA, in the opposite orientation. AfrR is related to the AraC family of transcriptional regulators, and AfrR and AfrS interact to function in a novel mode of transcriptional activation of
afrA
. AF/R1 pili mediate the adherence to Peyer’s patch M cells, ileal mucosa, and colonic mucosa in a rabbit model of diarrhea caused by enteropathogenic
E. coli
. Our observations will facilitate the further study of the phenomena of M-cell adherence.