bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of a Putative Precursor to the Major Surface Glycoprotein ofPneumocystis carinii
Authors: Sunkin Susan M. , Linke Michael J. , McCormack Francis X. , Walzer Peter D. , Stringer James R. 
Published: December 2019

ABSTRACTThe major surface glycoprotein (MSG) ofPneumocystis cariniif. sp.cariniiis a family of proteins encoded by a family of heterogeneous genes. Messenger RNAs encoding different MSGs each begin with the same 365-bp sequence, called the Upstream Conserved Sequence (UCS), which is in frame with the contiguous MSG sequence. The UCS contains several potential start sites for translation. To determine if translation of MSG mRNAs begins in the UCS, polyclonal antiserum was raised against the 123-amino-acid peptide encoded by the UCS. The anti-UCS serum reacted with aP. cariniiprotein that migrated at 170 kDa; however, it did not react with the mature MSG protein, which migrates at 116 kDa. A 170-kDa protein was immunoprecipitated with anti-UCS serum and shown to react with a monoclonal antibody against a conserved MSG epitope. To explore the functional role of the UCS in the trafficking of MSG, the nucleotide sequence encoding the UCS peptide was ligated to the 5′ end of an MSG gene and incorporated into a recombinant baculovirus. Insect cells infected with the UCS-MSG hybrid gene expressed a 160-kDa protein which was N-glycosylated. By contrast, insect cells infected with a baculovirus carrying an MSG gene lacking the UCS expressed a nonglycosylated 130-kDa protein. These data suggest that inP. carinii, translation begins in the UCS to produce a pre-MSG protein, which is subsequently directed to the endoplasmic reticulum and processed to the mature form by proteolytic cleavage.
Involvement of Bradykinin Generation in Intravascular Dissemination ofVibrio vulnificusand Prevention of Invasion by a Bradykinin Antagonist
Authors: Maruo Keishi , Akaike Takaaki , Ono Tomomichi , Maeda Hiroshi 
Published: December 2019

ABSTRACTInvolvement of bradykinin generation in bacterial invasion was examined by using a gram-negative bacillus,Vibrio vulnificus, which is known to invade the blood circulatory system and cause septicemia.V. vulnificuswas injected intraperitoneally (i.p.) into mice with or without bradykinin or a bradykinin (B2 receptor) antagonist. Dissemination ofV. vulnificusfrom peritoneal septic foci to the circulating blood was assessed by counting of viable bacteria in venous blood by use of the colony-forming assay. Intravascular dissemination ofV. vulnificusin mice was significantly potentiated by simultaneous injection with bradykinin but was markedly reduced by coadministration with the B2 antagonistd-Arg,[Hyp3, Thi5,8,d-Phe7]-bradykinin. Furthermore,V. vulnificuslethality was significantly increased when bradykinin was administered simultaneously with the bacillus, whereas it was definitely suppressed by treatment withd-Arg,[Hyp3, Thi5,8,d-Phe7]-bradykinin. Similarly, ovomacroglobulin, a potent inhibitor of theV. vulnificusprotease, showed a strong suppressive effect on theV. vulnificussepticemia. We also confirmed appreciable bradykinin production in the primary septic foci in the mouse peritoneal cavity after i.p. inoculation withV. vulnificus. It is thus concluded that bradykinin generation in infectious foci is critically involved in facilitation of intravascular dissemination ofV. vulnificus.
Protective Role of Nitric Oxide inStaphylococcus aureusInfection in Mice
Authors: Sasaki Sanae , Miura Tomisato , Nishikawa Shinsuke , Yamada Kyogo , Hirasue Mayuko , Nakane Akio 
Published: December 2019

ABSTRACTThis study was carried out to determine the role of nitric oxide (NO) inStaphylococcus aureusinfection in mice. NO production in spleen cell cultures was induced by heat-killedS. aureus. Expression of mRNA of the inducible isoform of NO synthase (iNOS) was induced in the spleens and kidneys ofS. aureus-infected mice. When mice were treated with monoclonal antibodies (MAbs) against tumor necrosis factor alpha (TNF-α) or gamma interferon (IFN-γ) beforeS. aureusinfection, the induction of iNOS mRNA expression in the kidneys was inhibited. These MAbs also inhibited NO production in spleen cell cultures stimulated with heat-killedS. aureus. NO production in the spleen cell cultures and levels of urinary nitrate plus nitrite were suppressed by treatment with aminoguanidine (AG), a selective inhibitor of iNOS. The survival rates of AG-treated mice were significantly decreased by either lethal or sublethalS. aureusinfections. However, an effect of AG administration on bacterial growth was not observed in the spleens and kidneys of mice during either type of infection. Production of TNF-α and IFN-γ was not affected by AG treatment in vitro and in vivo. These results suggest that NO plays an important role in protection from lethality by the infection, but the protective role of NO in host resistance againstS. aureusinfection was not proved. Moreover, our results show that TNF-α and IFN-γ regulate NO production while NO may not be involved in the regulation of the production of these cytokines duringS. aureusinfection.
Antigenicity of Recombinant Proteins Derived from Rhoptry-Associated Protein 1 of
Plasmodium falciparum
Authors: Fonjungo Peter N. , Stüber Dietrich , McBride Jana S. 
Published: December 2019

ABSTRACT

Rhoptry-associated protein 1 (RAP1) of
Plasmodium falciparum
is a potential component of a malaria vaccine. We have expressed in
Escherichia coli
eight recombinant RAP1 proteins representing almost the entire sequence of the mature protein and assessed the antigenicity of the proteins by immunization of mice. Antisera to six of the recombinant proteins reacted specifically with parasite-derived RAP1 (
Pf
RAP1), as determined by indirect immunofluorescence and by immunoblotting. These proteins were then used in enzyme-linked immunosorbent assays to evaluate human antibody responses to RAP1 during naturally transmitted infections in The Gambia. Immunoglobulin G (IgG) antibodies specifically reactive with the recombinant RAP1 proteins are directed mostly towards fragments containing the N-terminal sequences of mature
Pf
RAP1. The most N-terminal segment (residues 23 to 175) contains only minor epitopes, while major epitopes are outside this region. Antibodies from malaria patients do not compete for a linear epitope recognized by an inhibitory anti-RAP1 monoclonal antibody. Analysis of IgG subclass distribution shows that human anti-RAP1 antibodies are predominantly IgG1.
Analysis of the Organization of Multicopy Linear- and Circular-Plasmid-Carried Open Reading Frames in
Borrelia burgdorferi
Sensu Lato Isolates
Authors: Carlyon Jason A. , LaVoie Crystal , Sung Shian-Ying , Marconi Richard T. 
Published: December 2019

ABSTRACT

Plasmid cp8.3 of
Borrelia afzelii
IP21 carries several open reading frames (ORFs) and a 184-bp inverted repeat (IR) element. It has been speculated that this plasmid may encode factors involved in virulence or infectivity. In this report, we have characterized the distribution, molecular variability, and organization of ORFs 1, 2, and 4 and the IR elements among isolates of the
Borrelia burgdorferi
sensu lato complex. ORFs 1 and 2 are contained within a segment of cp8.3 that is bordered by the IR elements, while ORF 4 resides just outside of the IR-bordered region. By PCR, ORF 4 was amplified from most isolates while ORFs 1 and 2 were amplified from only some
B. afzelii
isolates. However, Southern hybridization analyses with ORF 1, 2, and 4 probes detected related sequences even in some isolates that were PCR negative. The ORF restriction fragment length polymorphism patterns varied widely even among isolates of the same species. Two-dimensional contour-clamped homogeneous electric field–pulsed-field gel electrophoresis and Southern hybridization detected ORF 1-, 2-, and 4-related sequences on linear and circular plasmids. In addition, an ORF 4-related sequence was detected on a previously uncharacterized, circular plasmid that is greater than 70 kb in size. The IR elements originally identified on plasmid cp8.3 of
B. afzelii
IP21 were also analyzed by Southern hybridization. Related sequences were detected in some but not all
B. burgdorferi
sensu lato isolates. These sequences are carried on plasmids in addition to cp8.3 in some isolates. Single-primer PCR analyses demonstrated that in some isolates these sequences exist with IR orientation. The data presented here demonstrate that the IR elements and the ORF 1-, 2-, and 4-related sequences are multicopy and are variable in organization and in genomic location among isolates of the
B. burgdorferi
sensu lato complex. These analyses provide additional evidence for the highly variable organization of the plasmid component of the
B. burgdorferi
sensu lato genome.
Cell Activation Mediated by Glycosylphosphatidylinositol-Anchored or Transmembrane Forms of CD14
Authors: Pugin J. , Kravchenko V. V. , Lee J.-D. , Kline L. , Ulevitch R. J. , Tobias P. S. 
Published: December 2019

ABSTRACTCD14 is a glycosylphosphatidylinositol (GPI)-anchored membrane glycoprotein which functions as a receptor on myeloid cells for ligands derived from microbial pathogens such as lipopolysaccharide (LPS). We have studied the importance of the GPI tail of CD14 in signalling with the promonocytic cell line THP-1 expressing recombinant CD14 in a GPI-anchored form (THP1-wtCD14 cells) or in a transmembrane form (THP1-tmCD14). We found that, like other GPI-anchored molecules, GPI-anchored CD14 was recovered mainly from a Triton X-100-insoluble fraction, whereas transmembrane CD14 was fully soluble in Triton X-100. LPS induced cell activation of THP1-wtCD14 and of THP1-tmCD14 (protein tyrosine kinase phosphorylation, NF-κB activation, and cytokine production) in a very similar manner. However, anti-CD14 antibody-induced cross-linking caused a rapid calcium mobilization signal only in GPI-anchored CD14 cells. Studies with pharmacologic inhibitors of intracellular signalling events implicate phospholipase C and protein tyrosine kinases in the genesis of this antibody-induced calcium signal. Our results suggest that GPI anchoring and CD14 targeting to glycolipid-rich membrane microdomains are not required for LPS-mediated myeloid cell activation. GPI anchoring may however be important for other signalling functions, such as those events reflected by antibody cross-linking.
Specific Antibody toCryptococcus neoformansAlters Human Leukocyte Cytokine Synthesis and Promotes T-Cell Proliferation
Authors: Vecchiarelli Anna , Retini Cinzia , Monari Claudia , Casadevall Arturo 
Published: December 2019

ABSTRACTAddition of a monoclonal antibody which binds theCryptococcus neoformanscapsule to suspensions of human monocytes, T lymphocytes, and cryptococcal cells (i) enhances interleukin-1β (IL-1β), tumor necrosis factor alpha, and IL-2 production; (ii) reduces IL-10 secretion; and (iii) promotes T-cell proliferation. The ability of specific antibody to influence cytokine production and lymphoproliferation suggests a mechanism by which humoral immunity can influence cell-mediated immunity.
Identification of Epitopes of Fibronectin Attachment Protein (FAP-A) ofMycobacterium aviumWhich Stimulate Strong T-Cell Responses in Mice
Authors: Holsti Matthew A. , Schorey Jeffrey S. , Brown Eric J. , Allen Paul M. 
Published: December 2019

ABSTRACTThe T-cell response to fibronectin attachment protein (FAP-A) in BALB/c and B10.BR mice was examined. Both strains developed strong T-cell responses to FAP-A, directed to single, unique epitopes. T cells from mice infected withMycobacterium aviumresponded to FAP-A, suggesting a possible role in a protective immune response.
Acute Neutropenia Decreases Inflammation Associated with Murine Vaginal Candidiasis but Has No Effect on the Course of Infection
Authors: Black C. Allen , Eyers Fiona M. , Russell Adrian , Dunkley Margaret L. , Clancy Robert L. , Beagley Kenneth W. 
Published: December 2019

ABSTRACT

We have used a mouse model of vaginal candidiasis to determine the effect of neutrophil depletion on (a) the clearance of
Candida albicans
and (b) the degree of inflammation associated with infection. No differences in recoverable yeast number or rate of clearance were observed between normal and neutrophil-depleted mice; however, vaginal inflammation was significantly decreased in neutrophil-depleted animals.
Chlamydia trachomatis
Infection in the Female Reproductive Tract of the Rat: Influence of Progesterone on Infectivity and Immune Response
Authors: Kaushic Charu , Murdin Andrew D. , Underdown Brian J. , Wira Charles R. 
Published: December 2019

ABSTRACT

As the most common cause of sexually transmitted disease in women, chlamydial infections can lead to pelvic inflammatory disease, infertility, and ectopic pregnancy. To better understand the role played by sex hormones in modulating the immune response of the genital tract to microbial infections, we have developed a rat model to study
Chlamydia trachomatis
infection. Inbred female Lewis rats were primed with progesterone and inoculated by intrauterine instillation of
C. trachomatis
(mouse pneumonitis strain MoPn) into each uterine horn. When infected animals were examined for the presence of chlamydial antigens 14 days postinfection, both the uterus and vagina were found to be positive compared to those of saline-treated animals, which did not show specific staining. The involvement of local and systemic immune systems following chlamydial infection was determined by analyzing major histocompatibility complex (MHC) class II expression in the reproductive tract and lymphocyte proliferation in response to mitogenic and chlamydia-specific stimulation of cells from the spleen and lymph nodes (LN) draining the reproductive tract. Enhanced proliferation was observed in LN following mitogenic but not antigenic (MOMP [major outer membrane protein]) stimulation. In contrast, spleen cell proliferation was lower in chlamydia-infected rats than in saline-treated controls. MHC class II expression, an indicator of inflammatory responses, was upregulated in the uterus, on glandular epithelial cells, and adjacent to glands in response to chlamydial infection. In other experiments, when rats were infected at estrus and diestrus without prior progesterone priming, chlamydial inclusions were not detected in either the uterus or vagina. However, enhanced lymphocyte proliferation was observed in response to mitogenic and MOMP stimulation in the reproductive tract-draining LN from estrous and diestrous animals. These findings indicate that under appropriate endocrine conditions, the rat uterus is susceptible to
C. trachomatis
infection and that immune responses to this pathogen can be detected locally and systemically. Further, they suggest that clearance of the infection from the reproductive tract involves immune cells from the LN draining the reproductive tract.
Differences in the Frequency of Cytokine-Producing Cells in Antigenemic and Nonantigenemic Individuals with Bancroftian Filariasis
Authors: de Almeida Adriana B. , e Silva Maria Carmelita Maia , Braga Cynthia , Freedman David O. 
Published: December 2019

ABSTRACTIndividuals with clinical manifestations of lymphatic filariasis may be currently infected or not. Twenty-five individuals from aWuchereria bancrofti-endemic area of Brazil were classified as being asymptomatic microfilaremic individuals, antigenemic individuals with clinical filariasis, or nonantigenemic individuals with clinical filariasis. Intracellular cytokine staining of mitogen-stimulated peripheral blood mononuclear cells (PBMC) showed that the frequency of either gamma interferon (IFN-γ)- or interleukin-4 (IL-4)-producing cells was higher in the nonantigenemic individuals with clinical filariasis than in the asymptomatic microfilaremic individuals (geometric means, 22.1 versus 10.7% [P= 0.02] and 2.9 versus 1.4% [P= 0.01], respectively). When the asymptomatic microfilaremic individuals and antigenemic individuals with clinical filariasis were grouped together to constitute all actively infected individuals, the frequency of IFN-γ-producing cells was also lower than in the nonantigenemic individuals with clinical filariasis (P= 0.04). Likewise, the frequency of IL-4-producing cells in the actively infected individuals was also lower than in the nonantigenemic individuals with clinical filariasis (P= 0.02). No differences in the frequency of IFN-γ-, IL-4-, or IL-5-producing cells in purified CD4 T lymphocytes were found among the groups. These findings suggest that the presence of antigenemia, which is an indicator of current active infection, is closely associated with the frequency of IFN-γ- and IL-4-producing cells in lymphatic filariasis. The differences found in the frequency of cytokine-producing cells among the three groups appear to be due to a subset of cells other than CD4 T cells.
Immunochemical Characterization of the MPB70/80 and MPB83 Proteins of
Mycobacterium bovis
Authors: Wiker Harald G. , Lyashchenko Konstantin P. , Aksoy A. Murat , Lightbody Kenneth A. , Pollock John M. , Komissarenko Sergiy V. , Bobrovnik Sergiy O. , Kolesnikova Irina N. , Mykhalsky Leonid O. , Gennaro Maria L. , Harboe Morten 
Published: December 2019

ABSTRACT

MPB70 and MPB80 (MPB70/80) and MPB83 are closely related antigens which are highly expressed in
Mycobacterium bovis
. MPB70/80 are soluble secreted antigens, while MPB83 is an exported lipoprotein associated with the bacterial surface. In the present study, these antigens had different mobilities in sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing and nonreducing conditions. These differences may be explained by the fact that MPB70 and MPB83 both have two internal cysteine residues which would create ring structures by disulfide bonding. We analyzed the structures of MPB70/80 and MPB83 by using monoclonal antibodies (MAbs) raised against bovine purified protein derivative or whole
M. bovis
cells. MAb 1-5C reacted specifically with MPB70 and MPB80, and MAb MBS43 reacted specifically with MPB83, while the other antibodies, including several previously described MAbs, bound all three antigens. MAbs and polyclonal antibodies reacted strongly with reduced protein and less well with nonreduced protein, indicating involvement of linear epitopes. Epitopes of MAbs Bov-1, 2-6B, 1-5C, and 1-1D were mapped by using synthetic peptides of MPB70. Sequence comparison showed the peptide with the 1-5C-reactive epitope to have three residues different from those in the homologous region of MPB83. Exchanges of A for S in position 112 or Q for E in position 116 abolished the reactivity of MAb 1-5C. Polyclonal rabbit antibodies to native purified MPB70 reacted strongly with peptides 6, 7, and 8 of the N-terminal half of mature MPB70. Cattle sera of experimentally
M. bovis
-infected animals recognized a broader spectrum of peptides. These findings indicate that there is diagnostic potential for these proteins and that there is also a possible role for antibodies in elucidation of the host-mycobacterium relationship involving a surface-bound and exposed lipoprotein, MPB83, and its highly homologous soluble secreted MPB70/80 counterparts.
Identification of a Gene Involved in Assembly ofActinomyces naeslundiiT14V Type 2 Fimbriae
Authors: Yeung Maria K. , Donkersloot Jacob A. , Cisar John O. , Ragsdale Pamela A. 
Published: December 2019

ABSTRACTThe nucleotide sequence of theActinomyces naeslundiiT14V type 2 fimbrial structural subunit gene,fimA, and the 3′ flanking DNA region was determined. ThefimAgene encoded a 535-amino-acid precursor subunit protein (FimA) which included both N-terminal leader and C-terminal cell wall sorting sequences. A second gene, designatedorf365, that encoded a 365-amino-acid protein which contained a putative transmembrane segment was identified immediately 3′ tofimA. Mutants in which eitherfimAororf365was replaced with a kanamycin resistance gene did not participate in type 2 fimbriae-mediated coaggregation withStreptococcus oralis34. Type 2 fimbrial antigen was not detected in cell extracts of thefimAmutant by Western blotting with anti-A. naeslundiitype 2 fimbrial antibody, but the subunit protein was detected in extracts of theorf365mutant. The subunit protein detected in this mutant also was immunostained by an antibody raised against a synthetic peptide representing the C-terminal 20 amino acid residues of the predicted FimA. The antipeptide antibody reacted with FimA isolated from the recombinantEscherichia coliclone containingfimAbut did not react with purified type 2 fimbriae in extracts of the wild-type strain. These results indicate that synthesis of type 2 fimbriae inA. naeslundiiT14V may involve posttranslational cleavage of both the N-terminal and C-terminal peptides of the precursor subunit and also the expression oforf365.
Maturation of the Arginine-Specific Proteases of
Porphyromonas gingivalis
W50 Is Dependent on a Functional
prR2
Protease Gene
Authors: Aduse-Opoku Joseph , Rangarajan Minnie , Young Katherine A. , Curtis Michael A. 
Published: December 2019

ABSTRACT

The
prpR1
of
Porphyromonas gingivalis
codes for three distinct enzymes with specificity for arginyl peptide bonds termed RI, RIA, and RIB. These three isoforms comprise the majority of the extracellular, arginine-specific protease activity in
P. gingivalis
W50. RI is a heterodimer in which the catalytic α chain is noncovalently associated with a second chain involved in adherence phenomena. RIA and RIB are both monomeric species. RIA represents the free α chain, and RIB is a highly posttranslationally modified form of the α chain which is exclusively vesicle or membrane associated and migrates as a diffuse band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In previous studies, insertional inactivation of the
prpR1
demonstrated that arginine-specific protease activity can also arise from a closely related second gene,
prR2
. In the present work, the
prR2
was insertionally inactivated in
P. gingivalis
W50 in order to establish the contribution of this locus to the arginine-specific protease activity of this periodontal bacterium. Loss of
prR2
function had several effects on
prpR1
-derived enzymes. First, the total Arg-X activity was reduced by approximately 50% relative to that of the parent strain. The reduction in total activity was a consequence of decreased concentrations of the monomeric enzymes derived from the
prpR1
, while the heterodimeric enzyme, RI, was unaffected by this mutation. Second, the chromatographic behavior of both the soluble and vesicle- or membrane-associated monomeric enzymes was radically different from the behavior of RIA and RIB from the parent strain. Finally, the vesicle- or membrane-associated enzyme in the
prR2
mutant strain lacked the extensive posttranslational additions which are found on RIB in
P. gingivalis
W50. These data suggest that the product(s) of the
prR2
plays a significant role in the maturation pathway of
prpR1
-derived enzymes, and this may contribute to the coconservation of these two genes in
P. gingivalis.