bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of Malaria Drug Resistance Patterns in the Amazon Basin Region following Changes in Peruvian National Treatment Policy for Uncomplicated Malaria
Authors: Bacon David J. , McCollum Andrea M. , Griffing Sean M. , Salas Carola , Soberon Valeria , Santolalla Meddly , Haley Ryan , Tsukayama Pablo , Lucas Carmen , Escalante Ananias A. , Udhayakumar Venkatachalam 
Published: March 2009

ABSTRACT

Monitoring changes in the frequencies of drug-resistant and -sensitive genotypes can facilitate in vivo clinical trials to assess the efficacy of drugs before complete failure occurs. Peru changed its national treatment policy for uncomplicated malaria to artesunate (ART)-plus-mefloquine (MQ) combination therapy in the Amazon basin in 2001. We genotyped isolates collected in 1999 and isolates collected in 2006 to 2007 for mutations in the
Plasmodium falciparum
dihydrofolate reductase (Pf
dhfr
) and dihydropteroate synthase (Pf
dhps
) genes, multidrug resistance gene 1 (Pf
mdr-1
), the chloroquine (CQ) resistance transporter gene (Pf
crt
), and the Ca
2+
ATPase gene (Pf
ATP6
); these have been shown to be involved in resistance to sulfadoxine-pyrimethamine (SP), MQ, CQ, and possibly ART, respectively. Microsatellite haplotypes around the Pf
dhfr
, Pf
dhps
, Pf
crt
, and Pf
mdr-1
loci were also determined. There was a significant decline in the highly SP resistant Pf
dhfr
and Pf
dhps
genotypes from 1999 to 2006. In contrast, a CQ-resistant Pf
crt
genotype increased in frequency during the same period. Among five different Pf
mdr-1
allelic forms noted in 1999, two genotypes increased in frequency while one genotype decreased by 2006. We also noted previously undescribed polymorphisms in the Pf
ATP6
gene as well as an increase in the frequency of a deletion mutant during this period. In addition, microsatellite analysis revealed that the resistant Pf
dhfr
, Pf
dhps
, and Pf
crt
genotypes have each evolved from a single founder haplotype, while Pf
mdr-1
genotypes have evolved from at least two independent haplotypes. Importantly, this study demonstrates that the Peruvian triple mutant Pf
dhps
genotypes are very similar to those found in other parts of South America.
Involvement of SOCS3 in Regulation of CD11c
+
Dendritic Cell-Derived Osteoclastogenesis and Severe Alveolar Bone Loss
Authors: Zhang Xiaoxia , Alnaeeli Mawadda , Singh Bhagirath , Teng Yen-Tung A. 
Published: March 2009

ABSTRACT

To investigate the role of suppressor of cytokine signaling (SOCS) molecules in periodontal immunity and RANKL-mediated dendritic cell (DC)-associated osteoclastogenesis, we analyzed SOCS expression profiles in CD4
+
T cells and the effect of SOCS3 expression in CD11c
+
DCs during periodontal inflammation-induced osteoclastogenesis and bone loss in nonobese diabetic (NOD) versus humanized NOD/SCID mice. Our results of ex vivo and in vitro analyses showed that (i) there is significantly higher SOCS3 expression associated with RANKL
+
T-cell-mediated bone loss in correlation with increased CD11c
+
DC-mediated osteoclastogenesis; (ii) the transfection of CD11c
+
DC using an adenoviral vector carrying a dominant negative SOCS3 gene significantly abrogates TRAP and bone-resorptive activity; and (iii) inflammation-induced TRAP expression, bone resorption, and SOCS3 activity are not associated with any detectable change in the expression levels of TRAF6 and mitogen-activated protein kinase signaling adaptors (i.e., Erk, Jnk, p38, and Akt) in RANKL
+
T cells. We conclude that SOCS3 plays a critical role in modulating cytokine signaling involved in RANKL-mediated DC-derived osteoclastogenesis during immune interactions with T cells and diabetes-associated severe inflammation-induced alveolar bone loss. Therefore, the development of SOCS3 inhibitors may have therapeutic potential as the target to halt inflammation-induced bone loss under pathological conditions in vivo.
Early Bacterial Colonization Induces Toll-Like Receptor-Dependent Transforming Growth Factor β Signaling in the Epithelium
Authors: Beisswenger Christoph , Lysenko Elena S. , Weiser Jeffrey N. 
Published: March 2009

ABSTRACT

Colonization of the upper respiratory tract is an initial step that may lead to disease for many pathogens. To prevent compromise of the epithelial barrier, the host must monitor and tightly control bacterial levels on the mucosa. Here we show that innate immune functions of respiratory epithelial cells control colonization by
Streptococcus pneumoniae
and
Haemophilus influenzae
in a Toll-like receptor (TLR)-dependent manner. Activation of inflammatory pathways, including mitogen-activated protein kinase signaling, in respiratory epithelial cells was accompanied by the induction of the transforming growth factor β signaling cascade during early colonization. Thus, colonization resulted in upregulation of factors involved in a proinflammatory response (e.g., interleukin-6) as well as factors known to modulate the epithelial barrier (e.g., Snail-1). These in vivo data provided a link between inflammation control and maintenance of the mucosal barrier function during infection and emphasized the importance of TLR-dependent inflammatory responses of the respiratory epithelium.
Contribution of the
pst-phoU
Operon to Cell Adherence by Atypical Enteropathogenic
Escherichia coli
and Virulence of
Citrobacter rodentium
Authors: Cheng Catherine , Tennant Sharon M. , Azzopardi Kristy I. , Bennett-Wood Vicki , Hartland Elizabeth L. , Robins-Browne Roy M. , Tauschek Marija 
Published: March 2009

ABSTRACT

Strains of enteropathogenic
Escherichia coli
(EPEC) generally employ the adhesins bundle-forming pili (Bfp) and intimin to colonize the intestine. Atypical EPEC strains possess intimin but are negative for Bfp and, yet, are able to cause disease. To identify alternative adhesins to Bfp in atypical EPEC, we constructed a transposon mutant library of atypical EPEC strain E128012 (serotype O114:H2) using Tn
phoA
. Six mutants that had lost the ability to adhere to HEp-2 cells were identified, and in all six mutants Tn
phoA
had inserted into the
pstSCAB-phoU
(Pst) operon. To determine if the Pst operon is required for adherence, we used site-directed mutagenesis to construct a
pstCA
mutant of E128012. The resultant mutant showed a reduced ability to adhere to HEp-2 cells and T84 intestinal epithelial cells, which was restored by trans-complementation with intact
pstCA
. To determine if
pst
contributes to bacterial colonization in vivo, a
pstCA
mutation was made in the EPEC-like murine pathogen,
Citrobacter rodentium
. C57BL/6 mice infected perorally with the
pstCA
mutant of
C. rodentium
excreted significantly lower numbers of
C. rodentium
than those given the wild-type strain. Moreover, colonic hyperplasia and diarrhea, which are features of infections with
C. rodentium
, were not observed in mice infected with the
pstCA
mutant but did occur in mice given the trans-complemented mutant. As mutations in
pst
genes generally lead to constitutive expression of the Pho regulon, our findings suggested that the Pho regulon may contribute to the reduced virulence of the
pstCA
mutants. To investigate this, we inactivated
phoB
in the
pstCA
mutants of EPEC E128012 and
C. rodentium
and found that the
phoB
mutation restored the adherent phenotype of both mutant strains. These results demonstrate that Pst contributes to the virulence of atypical EPEC and
C. rodentium
, probably by causing increased expression of an unidentified, Pho-regulated adhesin.
The Absence of Hck, Fgr, and Lyn Tyrosine Kinases Augments Lung Innate Immune Responses toPneumocystis murina
Authors: Nelson Michael P. , Metz Allison E. , Li Shaoguang , Lowell Clifford A. , Steele Chad 
Published: March 2009

ABSTRACTSrc family tyrosine kinases (SFKs) phosphorylate immunotyrosine activation motifs in the cytoplasmic tail of multiple immunoreceptors, leading to the initiation of cellular effector functions, such as phagocytosis, reactive oxygen species production, and cytokine production. SFKs also play important roles in regulating these responses through the activation of immunotyrosine inhibitory motif-containing inhibitory receptors. As myeloid cells preferentially express the SFKs Hck, Fgr, and Lyn, we questioned the role of these kinases in innate immune responses toPneumocystis murina. Increased phosphorylation of Hck was readily detectable in alveolar macrophages after stimulation withP. murina. We further observed decreased phosphorylation of Lyn on its C-terminal inhibitory tyrosine inP. murina-stimulated alveolar macrophages, indicating that SFKs were activated in alveolar macrophages in response toP. murina. Mice deficient in Hck, Fgr, and Lyn exhibited augmented clearance 3 and 7 days after intratracheal administration ofP. murina, which correlated with elevated levels of interleukin 1β (IL-1β), IL-6, CXCL1/KC, CCL2/monocyte chemoattractant protein 1, and granulocyte colony-stimulating factor in lung homogenates and a dramatic increase in macrophage and neutrophil recruitment. AugmentedP. murinaclearance was also observed in Lyn−/−mice 3 days postchallenge, although the level was less than that observed in Hck−/−Fgr−/−Lyn−/−mice. A correlate to augmented clearance ofP. murinain Hck−/−Fgr−/−Lyn−/−mice was a greater ability of alveolar macrophages from these mice to killP. murinain vitro, suggesting that SFKs regulate the alveolar macrophage effector function againstP. murina. Mice deficient in paired immunoglobulin receptor B (PIR-B), an inhibitory receptor activated by SFKs, did not exhibit enhanced inflammatory responsiveness to or clearance ofP. murina. Our results suggest that SFKs regulate innate lung responses toP. murinain a PIR-B-independent manner.
Anaerobic Catabolism of Aromatic Compounds: a Genetic and Genomic View
Authors: Carmona Manuel , Zamarro María Teresa , Blázquez Blas , Durante-Rodríguez Gonzalo , Juárez Javier F. , Valderrama J. Andrés , Barragán María J. L. , García José Luis , Díaz Eduardo 
Published: March 2009

SUMMARY
Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach.
Inhibition of Bacterial Ribosome Assembly: a Suitable Drug Target?
Authors: Maguire Bruce A. 
Published: March 2009

SUMMARYThe assembly of bacterial ribosomes is viewed with increasing interest as a potential target for new antibiotics. The in vivo synthesis and assembly of ribosomes are briefly reviewed here, highlighting the many ways in which assembly can be perturbed. The process is compared with the model in vitro process from which much of our knowledge is derived. The coordinate synthesis of the ribosomal components is essential for their ordered and efficient assembly; antibiotics interfere with this coordination and therefore affect assembly. It has also been claimed that the binding of antibiotics to nascent ribosomes prevents their assembly. These two contrasting models of antibiotic action are compared and evaluated. Finally, the suitability and tractability of assembly as a drug target are assessed.
MEK/ERK inhibitor U0126 affects in vitro and in vivo growth of embryonal rhabdomyosarcoma
Authors: Marampon Francesco , Bossi Gianluca , Ciccarelli Carmela , Di Rocco Agnese , Sacchi Ada , Pestell Richard G. , Zani Bianca M. 
Published: March 2009

Abstract
We reported previously that the disruption of c-Myc through mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibition blocks the expression of the transformed phenotype in the embryonal rhabdomyosarcoma (ERMS) cell line (RD), thereby inducing myogenic differentiation in vitro. In this article, we investigate whether MEK/ERK inhibition, by the MEK/ERK inhibitor U0126, affects c-Myc protein level and growth of RMS tumor in an in vivo xenograft model. U0126 significantly reduced RMS tumor growth in RD cell line-xenotransplanted mice. Immunobiochemical and immunohistochemical analysis showed (a) phospho-active ERK levels were reduced by U0126 therapy and unaltered in normal tissues, (b) phospho-Myc and c-Myc was reduced commensurate with phospho-ERK inhibition, and (c) reduction in Ki-67 and endothelial (CD31) marker expression. These results indicate that MEK/ERK inhibition affects growth and angiogenic signals in tumor. The RD-M1 cultured xenograft tumor-derived cell line and the ERMS cell line TE671 responded to U0126 by arresting growth, down-regulating c-Myc, and initiating myogenesis. All these results suggest a tight correlation of MEK/ERK inhibition with c-Myc down-regulation and arrest of tumor growth. Thus, MEK inhibitors may be investigated for a signal transduction-based targeting of the c-Myc as a therapeutic strategy in ERMS. [Mol Cancer Ther 2009;8(3):543–51]
Do bentonites have contradictory characteristics? An attempt to answer unanswered questions
Authors: Christidis G. E. 
Published: March 2009

AbstractThe formation of bentonites via alteration of volcanic glassy rocks is associated with apparently contradictory mineralogical, geological and geochemical characteristics, which remain poorly understood. This contribution attempts to answer some of the questions based on the work carried out in our laboratory over the past 15 y. The first question concerns the formation of opal-CT-free bentonites from acidic precursors. It is suggested that the formation of opal-CT-free bentonites is closely related to the mechanism of eruption and emplacement of parent volcanic rocks if the temperature of the parent glass after emplacement is high and/or the establishment of hydraulic gradients coupled with high permeability after deposition of volcanic glass (i.e. diagenetic alteration) if the temperature of the parent glass is low. The second question pertains to the behaviour of Fe during bentonite formation. Based on mineralogical and geological characteristics of different bentonite deposits, it is suggested that Fe is present mainly as Fe2+ and hence may be mobilized during alteration. Oxidation of Fe may take place when bentonites are exposed to more oxidizing conditions close to the surface. Assignment of Fe as Fe2+ increases the layer charge of smectites and decreases significantly the range of layer charge. Thus the smectites may have considerably different properties when formed compared with their counterparts on the surface. The third question considers the possible influence of parent-rock chemistry on the crystal chemistry of smectites. It is proposed that the parent rock may affect the chemistry of the neoformed smectites to some degree; therefore the smectite chemistry may provide indications about the geochemical affinities of the parent rock.
X-ray diffraction and infrared characterization of Oxisols from central and southeastern Brazil
Authors: Nitzsche R. P. , Percival J. B. , Torrance J. K. , Stirling J. A. R. , Bowen J. T. 
Published: March 2009

AbstractEleven Oxisols with high clay contents, 2.6–59.7 wt.% Fe2O3, and containing hematite, goethite, magnetite and maghemite, from São Paulo, Minas Gerais and Goiás, Brazil, were studied for the purpose of microwave remote sensing applications in the 0.3 to 300 GHz range. Of special interest are: the pseudosand effect caused by Fe-oxide cementation of clusters of soil particles; the mineralogy; and whether the soil magnetic susceptibility affected by ferromagnetic magnetite and maghemite interferes with microwave propagation. Quantitative mineralogical analyses were conducted using X-ray diffraction with Rietveld refinement. Visible, near infrared and short wave infrared spectroscopic analyses were used to characterize the samples qualitatively for comparison with published spectral radiometry results. Quartz (3–88%), hematite (2–36%) and gibbsite (1–40%) occurred in all soils, whereas kaolinite (2–70%) and anatase (2–13%) occurred in nine samples. Ilmenite (1–8%) was found in eight soils and goethite (2–39%) in seven. Of the ferromagnetic minerals, maghemite occurred in seven soils (1–13%) and three contained magnetite (<2%). These results will be applied to the interpretation of the effect of Fe oxides, particularly the ferromagnetic oxides, on microwave interaction with high-Fe soils, with ultimate application to the monitoring of soil water content by microwave remote sensing.
Clay minerals from Permo-Carboniferous very low-grade metamorphic rocks from the central part of the Fore Sudetic Monocline (western Poland)
Authors: Sokalska E. T. , Dubińska E. , Kaproń G. , Kozubowski J. A. , Walski M. 
Published: March 2009

AbstractThe mafic rocks from boreholes studied here contain the assemblage typical for upper-subgreenschist to lower-greenschist facies (albite, chlorite, illite, titanite, quartz, Ti-oxide ± actinolite) as well as relict clinopyroxene.Metapelites underlying a metabasic rock sequence also record metamorphic alteration as demonstrated by the chlorite and illite crystallinities. Chlorite crystallinity suggests formation in conditions close to the subgreenschist/greenschist facies boundary, but this mineral is partly decomposed during metamorphic retrogression.
Geochemical characteristics of the alteration of volcanic and volcaniclastic rocks in the Feres Basin, Thrace, NE Greece
Authors: Marantos I. , Markopoulos Th. , Christidis G. E. , Perdikatsis V. 
Published: March 2009

AbstractThe Tertiary basin of Feres consists of sedimentary rocks, andesitic-rhyolitic volcanic rocks of K-rich calc-alkaline affinities, rocks with calc-alkaline and shoshonitic affinities and volcaniclastic fall and flow deposits. Volcanic and volcaniclastic rocks have variable concentrations of LIL elements (Ba, Sr, Rb, Th) and HFS elements (Zr, V) due to their mode of origin. The pyroclastic flows frequently show more or less intense devitrification, vapour-phase crystallization and, in some cases, evidence of fumarolic activity, as is indicated by the presence of scapolite. The volcanic and volcaniclastic rocks display various types of alteration including formation of zeolites (clinoptilolite, heulandite, mordenite, and laumontite) and smectite, as well as hydrothermal alteration (development of silicic, argillic, sericitic and propylitic zones) associated with polymetallic mineralization. The behaviour of chemical elements during alteration varies. Some are immobile and their distribution is controlled by the conditions prevailing during parent-rock formation and emplacement, but others, such as Ba and Sr, are mobile and selectively fractionate in zeolite extra-framework sites. The formation of zeolite from alteration of volcanic glass is accompanied by an increase in Mg and Al content, and a decrease in Si and Na content, whereas Ca is not affected by alteration. In certain pyroclastic flows, there is a significant difference in K-content between incipient glass and altered rock, due to K-feldspar formation during devitrification and vapour-phase crystallization.
Palaeoenvironmental significance of clay minerals in Upper Cenomanian–Turonian sediments of the Western High Atlas Basin (Morocco)
Authors: Daoudi L. , Rocha F. , Ouajhain B. , Dinis J. L. , Chafiki D. , Callapez P. 
Published: March 2009

AbstractUpper Cenomanian–Turonian clay mineral assemblages of sediments cropping out in the Western High Atlas basin are studied in four sections. Smectite and mixed-layer illite-smectite (I-S) have been identified as major constituents of the deposits. The composition of clay associations in black shales and associated sediments varies considerably according to age, but usually depends either on the general lithology, the abundance of organic matter, or the depth of burial. A distinct correlation is evident between clay mineral distribution and sea-level. Smectite and mixed-layer I-S with greater percentages of smectite layers increase in sediments deposited during transgressive periods, whereas they decrease progressively in the shallower facies deposited during regression in favour of illite and mixed-layer I-S with a greater percentage of illite. The vertical evolution and lateral distribution of clay assemblages and their relationships with sea-level as well as the palaeogeographic conditions prevailing during the Late Cenomanian–Turonian period (flattened topography and arid climate), indicate a detrital origin of the smectite minerals and a distribution pattern controlled by differential settling processes.
Acute graft-versus-host disease transiently impairs thymic output in young patients after allogeneic hematopoietic stem cell transplantation
Authors: Clave Emmanuel , Busson Marc , Douay Corinne , Peffault de Latour Régis , Berrou Jeannig , Rabian Claire , Carmagnat Maryvonnick , Rocha Vanderson , Charron Dominique , Socié Gérard , Toubert Antoine 
Published: March 2009

Abstract
Long-term T-cell reconstitution after hematopoietic stem cell transplantation (HSCT) is dependent on patient thymic function and affected by graft-versus-host disease (GVHD). To assess the impact of acute GVHD (aGVHD) on thymic function, we followed a cohort of 93 patients who received HSCT from a human histocompatibility leukocyte antigen-identical sibling, mainly for hematologic malignancies. Thymic output was measured by signal-joint T-cell receptor excision circles (sjTREC) real-time polymerase chain reaction. Absolute sjTREC number was lower at 6 months in patients with aGVHD (P = .014), associated with lower absolute counts of naive CD4 T cells at 6 and 12 months (P = .04 and .02), and persistent abnormalities in T-cell repertoire diversity. Age and aGVHD affected thymic function independently in multivariate analysis. In patients less than 25 years of age, thymic function recovered almost totally at 1 year. As a marker of thymocyte proliferation, we quantified the βTREC generated during the T-cell receptor β-chain recombination, in a group of 20 age-matched patients. Mean βTREC level was reduced at 6 months in patients with aGVHD, indicating an impact on early thymic differentiation rather than on intrathymic proliferation. These data show that aGVHD or its treatment has a transient impact on thymic function in younger patients in the first months after HSCT.