bluuebunny/crossref_metadata_2025_split huggingface dataset:
Murine Stress‐triggered Abortion is Mediated by Increase of CD8+ TNF‐α+ Decidual Cells via Substance P
Authors: JOACHIM R.A. , HILDEBRANDT M. , ODER J. , KLAPP B.F. , ARCK P.C. 
Published: December 2003

PROBLEM: Stress is known to induce abortions in mice and humans. Increased levels of abortogenic type 1 helper T‐cell cytokines and decreased levels of pregnancy protective cytokines could be linked to stress‐triggered embryonic loss. Stress promotes neurotransmitter substance P (SP) release in tissues. SP increases the production of decidual tumor necrosis factor (TNF)‐α, whereby the phenotype of these TNF‐α‐producing cells is hypothetical. The objective of the present study was to identify decidual TNF‐α‐producing cell populations that are involved in stress‐induced murine abortion.   METHOD: DBA/2J‐mated CBA/J female mice were exposed to ultrasonic sound stress on day 5.5 of pregnancy. The mice were randomized and half were treated with the SP NK1‐receptor antagonist (SP‐RA) RP 67580 (200 μg/mouse). Frequency and cytokine profile of CD8+ cells were evaluated by immunohistochemistry and flow cytometry. Degranulation of uterine mast cells was examined histologically.
RESULTS: On day 13.5 of pregnancy, the uteri were removed and the resorption rate was calculated. A mean resorption rate of 38.4% was detected in stressed mice (n=10) compared to 13.1% in non‐stressed control mice (n=11, P<0.01). Injection of SP‐RA decreased the abortion rate to 18.4% in stressed mice (n=19, P<0.01). Flow cytometry revealed a stress‐related increase of TNF‐α+/CD8+ decidual T cells, which could be abrogated by SP‐RA (P<0.05). No significant differences could be observed in numbers of mast cells and total CD8+ cells in situ.
CONCLUSION: Our data suggest that stress‐triggered abortion is mediated by SP, and SP receptor blockade abrogates stress‐triggered abortion via reduced production of TNF‐α by CD8+ T cells.
Growth Phase-Dependent Regulation and Stringent Control of
fis
Are Conserved Processes in Enteric Bacteria and Involve a Single Promoter (
fis
P) in
Escherichia coli
Authors: Mallik Prabhat , Pratt Timothy S. , Beach Michael B. , Bradley Meranda D. , Undamatla Jayanthi , Osuna Robert 
Published: December 2003

ABSTRACT

The intracellular concentration of the
Escherichia coli
factor for inversion stimulation (Fis), a global regulator of transcription and a facilitator of certain site-specific DNA recombination events, varies substantially in response to changes in the nutritional environment and growth phase. Under conditions of nutritional upshift,
fis
is transiently expressed at very high levels, whereas under induced starvation conditions,
fis
is repressed by stringent control. We show that both of these regulatory processes operate on the chromosomal
fis
genes of the enterobacteria
Klebsiella pneumoniae
,
Serratia marcescens
,
Erwinia carotovora
, and
Proteus vulgaris
, strongly suggesting that the physiological role of Fis is closely tied to its transcriptional regulation in response to the nutritional environment. These transcriptional regulatory processes were previously shown to involve a single promoter (
fis
P) preceding the
fis
operon in
E. coli
. Recent work challenged this notion by presenting evidence from primer extension assays which appeared to indicate that there are multiple promoters upstream of
fis
P that contribute significantly to the expression and regulation of
fis
in
E. coli
. Thus, a rigorous analysis of the
fis
promoter region was conducted to assess the contribution of such additional promoters. However, our data from primer extension analysis, S1 nuclease mapping, β-galactosidase assays, and in vitro transcription analysis all indicate that
fis
P is the sole
E. coli fis
promoter in vivo and in vitro. We further show how certain conditions used in the primer extension reactions can generate artifacts resulting from secondary annealing events that are the likely source of incorrect assignment of additional
fis
promoters.
Diversifying Selection at theBacillusQuorum-Sensing Locus and Determinants of Modification Specificity during Synthesis of the ComX Pheromone
Authors: Ansaldi M. , Dubnau D. 
Published: December 2003

ABSTRACTThe competence quorum-sensing system ofBacillus subtilisconsists of two-component regulatory proteins, ComP (histidine kinase) and the response regulator, ComA, an extracellular pheromone (ComX), and a protein that is needed for the proteolytic cleavage and modification of pre-ComX (ComQ). ComQ and pre-ComX are both necessary and sufficient for the production of active pheromone, which is released as an isoprenylated peptide. Laboratory strain 168 and a number of natural isolates of bacilli differ in the primary sequences of their pheromones as well as in the masses of their isoprenyl adducts. We have shown that ComX, ComQ, and the membrane-localized sensor domain of ComP are highly polymorphic in natural isolates of bacilli all closely related to the laboratory strain ofB. subtilis. In this study, we used two statistical tests (the ratio of synonymous and nonsynonymous substitution rates and the TajimaDtest) to demonstrate that these polymorphic sequences evolved by diversifying selection rather than by neutral drift. We show that the choice of isoprenyl derivative is determined by the C-terminal (mature) sequence of pre-ComX rather than by the ComQ protein. The implications of these findings for the evolution of the quorum-sensing system and for the protein-protein interactions involved in determining specificity are discussed.
pH-Dependent Catabolic Protein Expression during Anaerobic Growth of
Escherichia coli
K-12
Authors: Yohannes Elizabeth , Barnhart D. Michael , Slonczewski Joan L. 
Published: December 2003

ABSTRACT

During aerobic growth of
Escherichia coli
, expression of catabolic enzymes and envelope and periplasmic proteins is regulated by pH. Additional modes of pH regulation were revealed under anaerobiosis.
E. coli
K-12 strain W3110 was cultured anaerobically in broth medium buffered at pH 5.5 or 8.5 for protein identification on proteomic two-dimensional gels. A total of 32 proteins from anaerobic cultures show pH-dependent expression, and only four of these proteins (DsbA, TnaA, GatY, and HdeA) showed pH regulation in aerated cultures. The levels of 19 proteins were elevated at the high pH; these proteins included metabolic enzymes (DhaKLM, GapA, TnaA, HisC, and HisD), periplasmic proteins (ProX, OppA, DegQ, MalB, and MglB), and stress proteins (DsbA, Tig, and UspA). High-pH induction of the glycolytic enzymes DhaKLM and GapA suggested that there was increased fermentation to acids, which helped neutralize alkalinity. Reporter
lac
fusion constructs showed base induction of
sdaA
encoding serine deaminase under anaerobiosis; in addition, the glutamate decarboxylase genes
gadA
and
gadB
were induced at the high pH anaerobically but not with aeration. This result is consistent with the hypothesis that there is a connection between the
gad
system and GabT metabolism of 4-aminobutanoate. On the other hand, 13 other proteins were induced by acid; these proteins included metabolic enzymes (GatY and AckA), periplasmic proteins (TolC, HdeA, and OmpA), and redox enzymes (GuaB, HmpA, and Lpd). The acid induction of NikA (nickel transporter) is of interest because
E. coli
requires nickel for anaerobic fermentation. The position of the NikA spot coincided with the position of a small unidentified spot whose induction in aerobic cultures was reported previously; thus, NikA appeared to be induced slightly by acid during aeration but showed stronger induction under anaerobic conditions. Overall, anaerobic growth revealed several more pH-regulated proteins; in particular, anaerobiosis enabled induction of several additional catabolic enzymes and sugar transporters at the high pH, at which production of fermentation acids may be advantageous for the cell.
Inactivation ofompXCauses Increased Interactions of Type 1 FimbriatedEscherichia coliwith Abiotic Surfaces
Authors: Otto Karen , Hermansson Malte 
Published: December 2003

ABSTRACTDuring the initial steps of biofilm formation, bacteria have to adapt to a major change in their environment. The adhesion-induced phenotypic changes in a type 1 fimbriatedEscherichia colistrain included reductions in the levels of several outer membrane proteins, one of which was identified as OmpX. Here, the phenotypes of mutant strains that differ at theompXlocus were studied with regard to adhesion, cell surface properties, and resistance to stress and antimicrobial compounds. The kinetics of adhesion were measured online by an extended quartz crystal microbalance technique for wild-type and mutant strains with a fimbriated or nonfimbriated background. Deletion ofompXled to significantly increased cell-surface contact in fimbriated strains but to decreased cell-surface contact in a nonfimbriated strain. Phenotypic characterization of theompXmutant demonstrated thatompXinterferes with proper regulation of cell surface structures that play a key role in mediating firm contact of the cell with a surface (i.e., type 1 fimbriae, flagellae, and exopolysaccharides). These phenotypic changes were accompanied by increased tolerance to several antibiotic compounds and sodium dodecyl sulfate. Based on these results, we propose that changes in the composition of outer membrane proteins during fimbria-mediated adhesion may be part of a coordinated adaptive response to the attached mode of growth.
Identification of Residues of the Kid Toxin Involved in Autoregulation of the
parD
System
Authors: Lemonnier Marc , Santos-Sierra Sandra , Pardo-Abarrio Consolación , Díaz-Orejas Ramón 
Published: December 2003

ABSTRACT

The toxin-antitoxin system
parD
(
kis kid
) of plasmid R1 is coregulated by the coordinated action of its two gene products. Here we describe the isolation and the in vivo characterization of three single-amino-acid changes in the Kid toxin, G4E, C74Y, and E91K, that affect the coregulatory activity but preserve the toxicity of the protein.
Necessity of Meningococcal γ-Glutamyl Aminopeptidase for
Neisseria meningitidis
Growth in Rat Cerebrospinal Fluid (CSF) and CSF-Like Medium
Authors: Takahashi Hideyuki , Hirose Kenji , Watanabe Haruo 
Published: December 2003

ABSTRACT

The growth of a γ-glutamyl aminopeptidase (GGT)-deficient
Neisseria meningitidis
strain was much slower than that of the parent strain in rat cerebrospinal fluid (CSF) and in a synthetic CSF-mimicking medium, and the growth failure was suppressed by the addition of cysteine. These results suggested that, in the environment of cysteine shortage, meningococcal GGT provided an advantage for meningococcal multiplication by supplying cysteine from environmental γ-glutamyl-cysteinyl peptides.
Cysteinyl-tRNA
Cys
Formation in
Methanocaldococcus jannaschii
: the Mechanism Is Still Unknown
Authors: Ruan Benfang , Nakano Hiroaki , Tanaka Masashi , Mills Jonathan A. , DeVito Joseph A. , Min Bokkee , Low K. Brooks , Battista John R. , Söll Dieter 
Published: December 2003

ABSTRACT

Most organisms form Cys-tRNA
Cys
, an essential component for protein synthesis, through the action of cysteinyl-tRNA synthetase (CysRS). However, the genomes of
Methanocaldococcus jannaschii
,
Methanothermobacter thermautotrophicus
, and
Methanopyrus kandleri
do not contain a recognizable
cysS
gene encoding CysRS. It was reported that
M. jannaschii
prolyl-tRNA synthetase (C. Stathopoulos, T. Li, R. Longman, U. C. Vothknecht, H. D. Becker, M. Ibba, and D. Söll, Science
287:
479-482, 2000; R. S. Lipman, K. R. Sowers, and Y. M. Hou, Biochemistry
39:
7792-7798, 2000) or the
M. jannaschii
MJ1477 protein (C. Fabrega, M. A. Farrow, B. Mukhopadhyay, V. de Crécy-Lagard, A. R. Ortiz, and P. Schimmel, Nature
411:
110-114, 2001) provides the “missing” CysRS activity for in vivo Cys-tRNA
Cys
formation. These conclusions were supported by complementation of temperature-sensitive
Escherichia coli cysS
(Ts) strain UQ818 with archaeal
proS
genes (encoding prolyl-tRNA synthetase) or with the
Deinococcus radiodurans
DR0705 gene, the ortholog of the MJ1477 gene. Here we show that
E. coli
UQ818 harbors a mutation (V27E) in CysRS; the largest differences compared to the wild-type enzyme are a fourfold increase in the

K
m

for cysteine and a ninefold reduction in the
k
cat
for ATP. While transformants of
E. coli
UQ818 with archaeal and bacterial
cysS
genes grew at a nonpermissive temperature, growth was also supported by elevated intracellular cysteine levels, e.g., by transformation with an
E. coli cysE
allele (encoding serine acetyltransferase) or by the addition of cysteine to the culture medium. An
E. coli cysS
deletion strain permitted a stringent complementation test; growth could be supported only by archaeal or bacterial
cysS
genes and not by archaeal
proS
genes or the
D. radiodurans
DR0705 gene. Construction of a
D. radiodurans
DR0705 deletion strain showed this gene to be dispensable. However, attempts to delete
D. radiodurans cysS
failed, suggesting that this is an essential
Deinococcus
gene. These results imply that it is not established that
proS
or MJ1477 gene products catalyze Cys-tRNA
Cys
synthesis in
M. jannaschii
. Thus, the mechanism of Cys-tRNA
Cys
formation in
M. jannaschii
still remains to be discovered.
Flavin Mononucleotide-Binding Flavoprotein Family in the Domain
Archaea
Authors: Ding Yan-Huai R. , Ferry James G. 
Published: December 2003

ABSTRACT

The protein (AfpA, for archaeoflavoprotein) encoded by AF1518 in the genome of
Archaeoglobus fulgidus
was produced in
Escherichia coli
and characterized. AfpA was found to be a homodimer with a native molecular mass of 43 kDa and containing two noncovalently bound flavin mononucleotides (FMNs). The cell extract of
A. fulgidus
catalyzed the CO-dependent reduction of AfpA that was stimulated by the addition of ferredoxin. Ferredoxin was found to be a direct electron donor to purified AfpA, whereas rubredoxin was unable to substitute. Neither NADH nor NADPH was an electron donor. Ferricyanide, 2,6-dichlorophenolindophenol, several quinones, ferric citrate, bovine cytochrome
c
, and O
2
accepted electrons from reduced AfpA, whereas coenzyme F
420
did not. The rate of cytochrome
c
reduction was enhanced in the presence of O
2
suggesting that superoxide is a product of the interaction of reduced AfpA with O
2
. Although AF1518 was previously annotated as encoding a decarboxylase involved in coenzyme A biosynthesis, the results establish that AfpA is an electron carrier protein with ferredoxin as the physiological electron donor. The genomes of several diverse
Archaea
contained
afpA
homologs clustered with open reading frames annotated as homologs of genes encoding reductases involved in the oxidative stress response of anaerobes from the domain
Bacteria
. A potential role for AfpA in coupling electron flow from ferredoxin to the putative reductases is discussed. A search of the databases suggests that AfpA is the prototype of a previously unrecognized flavoprotein family unique to the domain
Archaea
for which the name archaeoflavoprotein is proposed.
LA COORDINATION DANS LA TRADITION GRAMMATICALE ARABE
Authors: Gharbia Abdeljabbar Ben 
Published: December 2003

AbstractNous avons essayé dans cet article de voir comment la Tradition Grammaticale Arabe a situé la coordination dans le système linguistique conçu pour rendre compte de l'architecture de la langue arabe. Nous avons montré comment l'emprise de la déclinaison, la division tripartite des parties du discours et la structure de constituance que les grammairiens arabes ont adoptées les ont conduits à marginaliser la coordination inter-phrastique, à s'intéresser essentiellement à la coordination des termes constituants de la phrase, notamment à celle des nominaux, et à étudier certains aspects de cette structure dans les chapitres consacrés aux particules et aux expansions du groupe nominal. En revanche, l'examen de certains aspects relatifs à la structure et à la sémantique de la coordination les ont amenés à soumettre la coordonnabilité des expressions à deux conditions fondamentales, à savoir l'homogénéité syntaxique et la compatibilité sémantique des conjoints. Ils ont, en outre, soulevé des questions intéressantes qui restent d'actualité, et qui concernent en particulier les coordonnants et la catégorisation.
HAND AND FOOT SYMBOLISMS: FROM ROCK ART TO THE QUR' ĀN
Authors: Achrati Ahmed 
Published: December 2003

AbstractWedded to creativity and spirituality since the dawn of humanity, the symbolisms of the hand and the foot have assumed many religious and artistic forms. This essay explores the artistic and religious significance of the hand and foot in the prehistoric rock art of North Africa and Arabia and examines their various ethnographic and mythological expressions in historical times. It then shows how these symbolisms were restructured in the Qur' n to fit a strictly iconoclastic monotheism. It is a multidisciplinary approach to a collective consciousness that finds its roots in an Afroasiatic substrate and its expression in the artistic and linguistic traditions of the eastern and southern coasts of the Mediterranean.
Adult chronic idiopathic thrombocytopenic purpura (ITP) is the manifestation of a type-1 polarized immune response
Authors: Panitsas Fotios P. , Theodoropoulou Maria , Kouraklis Alexandra , Karakantza Marina , Theodorou Georgios L. , Zoumbos Nicholas C. , Maniatis Alice , Mouzaki Athanasia 
Published: December 2003

AbstractDerangement of cellular immunity is central in the pathophysiology of adult autoimmune/idiopathic thrombocytopenic purpura (ITP). Herein we investigated cytokine gene expression in peripheral blood mononuclear cells (PBMCs) of adult chronic ITP patients and attempted to correlate cytokine polarization with the degree of thrombocytopenia. We used semiquantitative reverse-transcriptase–polymerase chain reaction (RT-PCR) to measure the expression of type-1 (interleukin-2 [IL-2], interferon γ [IFN-γ]) and type-2 (IL-4, IL-5, IL-10, IL-3, IL-13) cytokines by PBMCs from 21 patients and 11 controls. Plasma transforming growth factor β1 (TGF-β1) levels were measured by enzyme-linked immunoassay (ELISA). T helper 1 (Th1)/Th2 ([IL-2 + IFN-γ]/[IL-4 + IL-5]) cytokine mRNA ratios, thought to reflect the Th deviation of the pathogenic disease-specific T cells, and type-1/type-2 mRNA ratios, thought to reflect the overall immune response polarization, were significantly increased in ITP patients. The Th1/Th2 ratio was inversely correlated with platelet counts. TGF-β1 levels appeared suppressed in patients with active disease, though not significantly. Our findings show a clear type-1 cytokine polarization of the autoimmune response in adult ITP that persists irrespective of disease status.
The quantity and duration of FcRγ signals determine mast cell degranulation and survival
Authors: Yamasaki Sho , Ishikawa Eri , Kohno Masayuki , Saito Takashi 
Published: December 2003

AbstractImmunoglobulin E (IgE) bound to multivalent antigen (Ag) elicits mast cell degranulation but not survival; on the contrary, IgE in the absence of Ag (IgE(-Ag)) induces survival only but not degranulation. Although these distinct responses are mediated through the same receptor, FcϵRI, the molecular mechanism generating the divergence is largely unknown. We recently showed that the signals through FcRγ chain are essential for IgE(-Ag)–induced mast cell survival as well as IgE(+Ag)–induced degranulation. To determine whether the cellular output is regulated by the quantity of FcRγ signal, we expressed CD8/FcRγ chimeras (CD8/γ) in bone marrow–derived mast cells (BMMCs) from FcRγ-/- mice to manipulate the strength of FcRγ signals by anti-CD8 cross-linking. Cross-linking of CD8/γ induced mast cell survival and degranulation. Survival was induced by weaker stimulation than needed for degranulation in terms of anti-CD8 concentration and the valency of chimera. However, sustained extracellular signal-regulated kinase (Erk) activation seems to regulate survival even when the activation signal was strong enough to elicit degranulation. Generation of sustained Erk activation by active mitogen-activated protein kinase kinase (MEK) induced BMMC survival. These results suggest that the duration and the magnitude of FcRγ signals may determine mast cell survival and degranulation, respectively. (Blood. 2004;103:3093-3101)
Membrane type 1–matrix metalloproteinase (MT1-MMP) cooperates with sphingosine 1–phosphate to induce endothelial cell migration and morphogenic differentiation
Authors: Langlois Stéphanie , Gingras Denis , Béliveau Richard 
Published: December 2003

AbstractMembrane type 1–matrix metalloproteinase (MT1-MMP) has been suggested to play an important role in angiogenesis, but the mechanisms involved remain incompletely understood. Using an in vitro model of angiogenesis in which cell migration of bovine aortic endothelial cells (BAECs) and their morphogenic differentiation into capillary-like structures on Matrigel are induced by overexpression of MT1-MMP, we show that the platelet-derived bioactive lipid sphingosine 1–phosphate (S1P) is the predominant serum factor essential for MT1-MMP–dependent migration and morphogenic differentiation activities. In the presence of S1P, MT1-MMP–dependent cell migration and morphogenic differentiation were inhibited by pertussis toxin, suggesting the involvement of Gi-protein–coupled receptor-mediated signaling. Accordingly, cotransfection of BAECs with MT1-MMP and a constitutively active Gαi2 (Q205L) mutant increased cell migration and morphogenic differentiation, whereas treatment of BAECs overexpressing MT1-MMP with antisense oligonucleotides directed against S1P1 and S1P3, the predominant S1P receptors, significantly inhibited both processes. These results demonstrate that MT1-MMP–induced migration and morphogenic differentiation involve the cooperation of the enzyme with platelet-derived bioactive lipids through S1P-mediated activation of Gαi-coupled S1P1 and S1P3 receptors. Given the important contribution of platelets to tumor angiogenesis, the stimulation of endothelial MT1-MMP function by S1P may thus constitute an important molecular event linking hemostasis to angiogenesis. (Blood. 2004;103:3020-3028)
Thrombopoietin cooperates with FLT3-ligand in the generation of plasmacytoid dendritic cell precursors from human hematopoietic progenitors
Authors: Chen Wei , Antonenko Svetlana , Sederstrom Joel M. , Liang Xueqing , Chan Anissa S. H. , Kanzler Holger , Blom Bianca , Blazar Bruce R. , Liu Yong-Jun 
Published: December 2003

AbstractType 1 interferon–producing cells (IPCs), also known as plasmacytoid dendritic cell (DC) precursors, represent the key effectors in antiviral innate immunity and triggers for adaptive immune responses. IPCs play important roles in the pathogenesis of systemic lupus erythematosus (SLE) and in modulating immune responses after hematopoietic stem cell transplantation. Understanding IPC development from hematopoietic progenitor cells (HPCs) may provide critical information in controlling viral infection, autoimmune SLE, and graft-versus-host disease. FLT3-ligand (FLT3-L) represents a key IPC differentiation factor from HPCs. Although hematopoietic cytokines such as interleukin-3 (IL-3), IL-7, stem cell factor (SCF), macrophage–colony-stimulating factor (M-CSF), and granulocyte M-CSF (GM-CSF) promote the expansion of CD34+ HPCs in FLT3-L culture, they strongly inhibit HPC differentiation into IPCs. Here we show that thrombopoietin (TPO) cooperates with FLT3-L, inducing CD34+ HPCs to undergo a 400-fold expansion in cell numbers and to generate more than 6 × 106 IPCs per 106 CD34+ HPCs within 30 days in culture. IPCs derived from HPCs in FLT3-L/TPO cultures display blood IPC phenotype and have the capacity to produce large amounts of interferon-α (IFN-α) and to differentiate into mature DCs. This culture system, combined with the use of adult peripheral blood CD34+ HPCs purified from G-CSF–mobilized donors, permits the generation of more than 109 IPCs from a single blood donor.