bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diverse
Borrelia burgdorferi
Strains in a Bird-Tick Cryptic Cycle
Authors: Hamer Sarah A. , Hickling Graham J. , Sidge Jennifer L. , Rosen Michelle E. , Walker Edward D. , Tsao Jean I. 
Published: January 2011

ABSTRACT

The blacklegged tick
Ixodes scapularis
is the primary vector of the most prevalent vector-borne zoonosis in North America, Lyme disease (LD). Enzootic maintenance of the pathogen
Borrelia burgdorferi
by
I. scapularis
and small mammals is well documented, whereas its “cryptic” maintenance by other specialist ticks and wildlife hosts remains largely unexplored because these ticks rarely bite humans. We quantified
B. burgdorferi
infection in a cryptic bird-rabbit-tick cycle. Furthermore, we explored the role of birds in maintaining and moving
B. burgdorferi
strains by comparing their genetic diversity in this cryptic cycle to that found in cycles vectored by
I. scapularis.
We examined birds, rabbits, and small mammals for ticks and infection over a 4-year period at a focal site in Michigan, 90 km east of a zone of
I. scapularis
invasion. We mist netted 19,631 birds that yielded 12,301 ticks, of which 86% were
I. dentatus
, a bird-rabbit specialist. No resident wildlife harbored
I. scapularis
, and yet 3.5% of bird-derived ticks, 3.6% of rabbit-derived ticks, and 20% of rabbit ear biopsy specimens were infected with
B. burgdorferi
. We identified 25 closely related
B. burgdorferi
strains using an rRNA gene intergenic spacer marker, the majority (68%) of which had not been reported previously. The presence of strains common to both cryptic and endemic cycles strongly implies bird-mediated dispersal. Given continued large-scale expansion of
I. scapularis
populations, we predict that its invasion into zones of cryptic transmission will allow for bridging of novel pathogen strains to humans and animals.
Prevalence and Characterization of Non-O157 Shiga Toxin-ProducingEscherichia coliIsolates from Commercial Ground Beef in the United States
Authors: Bosilevac Joseph M. , Koohmaraie Mohammad 
Published: January 2011

ABSTRACTEscherichia coliO157:H7 is a Shiga toxin (stx)-producingE. coli(STEC) strain that has been classified as an adulterant in U.S. beef. However, numerous other non-O157 STEC strains are associated with diseases of various severities and have become an increasing concern to the beef industry, regulatory officials, and the public. This study reports on the prevalence and characterization of non-O157 STEC in commercial ground beef samples (n= 4,133) obtained from numerous manufacturers across the United States over a period of 24 months. All samples were screened by DNA amplification for the presence of Shiga toxin genes, which were present in 1,006 (24.3%) of the samples. Then, culture isolation of an STEC isolate from all samples that containedstx1and/orstx2was attempted. Of the 1,006 positive ground beef samples screened forstx, 300 (7.3% of the total of 4,133) were confirmed to have at least one strain of STEC present by culture isolation. In total, 338 unique STEC isolates were recovered from the 300 samples that yielded an STEC isolate. All unique STEC isolates were serotyped and were characterized for the presence of known virulence factors. These included Shiga toxin subtypes, intimin subtypes, and accessory virulence factors related to adherence (saa,iha,lifA), toxicity (cnf,subA,astA), iron acquisition (chuA), and the presence of the large 60-MDa virulence plasmid (espP,etpD,toxB,katP,toxB). The isolates were also characterized by use of a pathogenicity molecular risk assessment (MRA; based on the presence of various O-islandnlegenes). Results of this characterization identified 10 STEC isolates (0.24% of the 4,133 total) that may be considered a significant food safety threat, defined by the presence ofeae,subA, andnlegenes.
A Novel Sterol Desaturase-Like Protein Promoting Dealkylation of Phytosterols in Tetrahymena thermophila
Authors: Tomazic Mariela L. , Najle Sebastián R. , Nusblat Alejandro D. , Uttaro Antonio D. , Nudel Clara B. 
Published: January 2011

ABSTRACT

The gene TTHERM_00438800 (
DES24
) from the ciliate
Tetrahymena thermophila
encodes a protein with three conserved histidine clusters, typical of the fatty acid hydroxylase superfamily. Despite its high similarity to sterol desaturase-like enzymes, the phylogenetic analysis groups Des24p in a separate cluster more related to bacterial than to eukaryotic proteins, suggesting a possible horizontal gene transfer event. A somatic knockout of
DES24
revealed that the gene encodes a protein, Des24p, which is involved in the dealkylation of phytosterols. Knocked-out mutants were unable to eliminate the C-24 ethyl group from C
29
sterols, whereas the ability to introduce other modifications, such as desaturations at positions C-5(6), C-7(8), and C-22(23), were not altered. Although C-24 dealkylations have been described in other organisms, such as insects, neither the enzymes nor the corresponding genes have been identified to date. Therefore, this is the first identification of a gene involved in sterol dealkylation. Moreover, the knockout mutant and wild-type strain differed significantly in growth and morphology only when cultivated with C
29
sterols; under this culture condition, a change from the typical pear-like shape to a round shape and an alteration in the regulation of tetrahymanol biosynthesis were observed. Sterol analysis upon culture with various substrates and inhibitors indicate that the removal of the C-24 ethyl group in
Tetrahymena
may proceed by a mechanism different from the one currently known.
Corynebacterium glutamicum
as a Host for Synthesis and Export of
d
-Amino Acids
Authors: Stäbler Norma , Oikawa Tadao , Bott Michael , Eggeling Lothar 
Published: January 2011

ABSTRACT

A number of
d
-amino acids occur in nature, and there is growing interest in their function and metabolism, as well as in their production and use. Here we use the well-established
l
-amino-acid-producing bacterium
Corynebacterium glutamicum
to study whether
d
-amino acid synthesis is possible and whether mechanisms for the export of these amino acids exist. In contrast to
Escherichia coli
,
C. glutamicum
tolerates
d
-amino acids added extracellularly. Expression of
argR
(encoding the broad-substrate-specific racemase of
Pseudomonas taetrolens
) with its signal sequence deleted results in cytosolic localization of ArgR in
C. glutamicum
. The isolated enzyme has the highest activity with lysine (100%) but also exhibits activity with serine (2%). Upon overexpression of
argR
in an
l
-arginine,
l
-ornithine, or
l
-lysine producer, equimolar mixtures of the
d
- and
l
-enantiomers accumulated extracellularly. Unexpectedly,
argR
overexpression in an
l
-serine producer resulted in extracellular accumulation of a surplus of
d
-serine (81 mM
d
-serine and 37 mM
l
-serine) at intracellular concentrations of 125 mM
d
-serine plus 125 mM
l
-serine. This points to a nonlimiting ArgR activity for intracellular serine racemization and to the existence of a specific export carrier for
d
-serine. Export of
d
-lysine relies fully on the presence of
lysE
, encoding the exporter for
l
-lysine, which is apparently promiscuous with respect to the chirality of lysine. These data show that
d
-amino acids can also be produced with
C. glutamicum
and that in special cases, due to specific carriers, even a preferential extracellular accumulation of this enantiomer is possible.
The ColR/ColS Two-Component System Plays Multiple Roles in the Pathogenicity of the Citrus Canker Pathogen
Xanthomonas citri
subsp.
citri
Authors: Yan Qing , Wang Nian 
Published: January 2011

ABSTRACT

Bacterial citrus canker disease, which is caused by
Xanthomonas citri
subsp.
citri
, is one of the most devastating diseases of citrus plants. In this study, we characterized the role of the two-component regulatory system ColR/ColS in the pathogenicity of
X. citri
subsp.
citri. colS
mutants (256A10 and 421E7),
colR
mutants (386C6 and 417E10), and a
colR colS
double mutant (306DSR) all lost pathogenicity and produced no symptoms on grapefruit leaves inoculated by either pressure infiltration or the spray method. The pathogenicity defect of the
colS
,
colR
, and
colR colS
mutants could be complemented using the wild-type
colS
,
colR
, and
colR colS
genes, respectively. Mutation of
colS
or
colR
significantly reduced
X. citri
subsp.
citri
growth
in planta
. The ColR/ColS system also played important roles in bacterial biofilm formation in glass tubes and on leaf surfaces, lipopolysaccharide (LPS) production, catalase activity, and tolerance of environmental stress, including phenol, copper, and hydrogen peroxide. Furthermore, quantitative reverse transcription-PCR assays demonstrated that the ColR/ColS system positively regulated the expression of important virulence genes, including
hrpD
6,
hpaF
, the O-antigen LPS synthesis gene
rfbC
, and the catalase gene
katE
. Overall, our data indicate that the two-component regulatory system ColR/ColS is critical for
X. citri
subsp.
citri
virulence, growth
in planta
, biofilm formation, catalase activity, LPS production, and resistance to environmental stress.
The influence of game scheduling on medical encounters at the USA Cup soccer tournament
Authors: Waibel Nathan G , Roberts William O , Lunos Scott 
Published: January 2011

ObjectiveTo investigate the influence of playing multiple games on multiple days on youth soccer medical encounter rates.DesignProspective cohort survey study.SettingMedical facility at the 2008 Schwan's USA Cup soccer tournament.ParticipantsPlayers presenting to the medical facility for game-related medical evaluation.Assessment of risk factorsDate, game and half of game for each medical encounter.Main outcome measuresGame play-related medical encounters per 1000 match hours (MH).Results211 players surveyed with 195 eligible and completed questionnaires. There were 4.06, 5.14 and 3.92 medical encounters/1000 MH on 11, 12 and 13 July, respectively, with no significant difference in injury incidence. There was no difference in medical encounter rates of second games compared with first games of the day (p=0.126). Daily medical encounter rates were 5.65, 8.95, 7.83, 6.94 and 4.62/1000 MH on 15, 16, 17, 18 and 19 July, respectively, with statistically significant differences on 16 July (p<0.001) and 17 July (p=0.022) compared with 15 July. Encounter rates of second games compared with first games of the day showed no difference (p=0.385). A linear test for trend from 15 to 19 July was not significant (p=0.092).ConclusionsThe USA Cup format did not show either increased medical encounter rates from the cumulative total of games played or a consistently increased rate in the second game of the day compared with the first. Players, coaches, parents and administrators can feel confident that this tournament format does not pose an additional risk of injury.
Clinical risk scores to guide perioperative management
Authors: Barnett Sarah , Moonesinghe Suneetha Ramani 
Published: January 2011

ABSTRACT
Perioperative morbidity is associated with reduced long term survival. Comorbid disease, cardiovascular illness, and functional capacity can predispose patients to adverse surgical outcomes. Accurate risk stratification would facilitate informed patient consent and identify those individuals who may benefit from specific perioperative interventions. The ideal clinical risk scoring system would be objective, accurate, economical, simple to perform, based entirely on information available preoperatively, and suitable for patients undergoing both elective and emergency surgery. The POSSUM (Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity) scoring systems are the most widely validated perioperative risk predictors currently utilised; however, their inclusion of intra- and postoperative variables precludes validation for preoperative risk prediction. The Charlson Index has the advantage of consisting exclusively of preoperative variables; however, its validity varies in different patient cohorts. Risk models predicting cardiac morbidity have been extensively studied, despite the relatively uncommon occurrence of postoperative cardiac events. Probably the most widely used cardiac risk score is the Lee Revised Cardiac Risk Index, although it has limited validity in some patient populations and for non-cardiac outcomes. Bespoke clinical scoring systems responding to dynamic changes in population characteristics over time, such as those developed by the American College of Surgeons National Surgical Quality Improvement Program, are more precise, but require considerable resources to implement. The combination of objective clinical variables with information from novel techniques such as cardiopulmonary exercise testing and biomarker assays, may improve the predictive precision of clinical risk scores used to guide perioperative management.
Acute presentations of HIV are still missed in low prevalence areas
Authors: Ratcliffe L , Thomas S , Beeching N J , Phillips-Howard P A , Taegtmeyer M 
Published: January 2011

ABSTRACT

Objectives
To evaluate missed opportunities and delays in the diagnosis of HIV in a low prevalence setting over a 24 year period.

Methods
Patients with acute presentations of HIV were included in a retrospective note based review. Data were compared from acute presentations in 1985–2001 (88/241 new patients) with 2005–2007 (99/136 new patients). The number of recorded clinical and laboratory clues to infection and subsequent time delays to diagnosis of HIV were evaluated.

Results
The findings reflect the shifting demographics of HIV in the UK over the past two decades, exemplified by an eightfold increase in tuberculosis at presentation. Despite recording clinical stigmata of HIV (clues) in the notes, the number of missed clues increased, and many clinicians failed to request HIV testing. The median delay between presentation and diagnosis reduced from 5 to 1 day (p&lt;0.001), and mortality dropped from 14% to 4% among patients presenting with acute symptoms. However, there was still a delay of more than 30 days before diagnosis for almost one in five patients.

Conclusions
Despite some improvement and better awareness, there are still significant delays before hospital doctors consider the diagnosis of HIV for patients in low prevalence areas, even among some patient groups with high risk. Hospitals should consider moving to opt-out routine HIV testing of all medical admissions.
Image segmentation and classification of Landsat Thematic Mapper data using a sampling approach for forest cover assessmentThis article is one of a selection of papers from Extending Forest Inventory and Monitoring over Space and Time.
Authors: Hirata Yasumasa , Takahashi Tomoaki 
Published: January 2011

Remote sensing surveys for estimating forest cover may be divided into two approaches: wall-to-wall and sampling. Sampling approaches offer a practical alternative to wall-to-wall mapping, but estimates of forest cover may be affected by the sampling rate of the estimation area. This study aimed to obtain stable estimates of forest cover from satellite data using object-oriented classification at the national level. We investigated a suitable value for the scale parameter in object-oriented classification using eCognition software to identify land cover types, and we evaluated the sampling rate for estimating forest cover at the national level. We used eight different scale parameters when applying object-oriented classification to Landsat data for a set of forty-six 10 km × 10 km sampling tiles centered at each degree of latitude and longitude in Japan. The scale parameter of 10 or less was found suitable for obtaining objects with areas of about 5 ha. Overall accuracy in classification was greater than 75% and greatest when the scale parameter was between 6 and 10. We then analyzed the entire land area of Japan using 10 km × 10 km tiles to evaluate the optimum sampling rate for estimating forest cover. A sampling rate greater than 20% was required to stably estimate forest cover in Japan.
Novel Role for STAT3 in Transcriptional Regulation of NK Immune Cell Targeting Receptor MICA on Cancer Cells
Authors: Bedel Romain , Thiery-Vuillemin Antoine , Grandclement Camille , Balland Jeremy , Remy-Martin Jean-Paul , Kantelip Bernadette , Pallandre Jean-René , Pivot Xavier , Ferrand Christophe , Tiberghien Pierre , Borg Christophe 
Published: January 2011

Abstract
The role of natural killer group 2, member D receptor (NKG2D)–expressing natural killer (NK) cells in tumor immunosurveillance is now well established. Nevertheless, tumor progression occurs despite tumor immunosurveillance, leading to cancer persistence in immunocompetent hosts. STAT3 plays a pivotal role both in oncogenic functions and in immunosuppression. In this study, we investigated the role of STAT3 in suppressing NK cell–mediated immunosurveillance. Using a colorectal cancer cell line (HT29) that can poorly activate NK, we neutralized STAT3 with pharmacologic inhibitors or siRNA and found that this led to an increase in NK degranulation and IFN-γ production in a TGF-β1–independent manner. Exposure to NKG2D-neutralizing antibodies partially restored STAT3 activity, suggesting that it prevented NKG2D-mediated NK cell activation. On this basis, we investigated the expression of NKG2D ligands after STAT3 activation in HT29, mesenchymal stem cells, and activated lymphocytes. The NK cell recognition receptor MHC class I chain–related protein A (MICA) was upregulated following STAT3 neutralization, and a direct interaction between STAT3 and the MICA promoter was identified. Because cross-talk between DNA damage repair and NKG2D ligand expression has been shown, we assessed the influence of STAT3 on MICA expression under conditions of genotoxic stress. We found that STAT3 negatively regulated MICA expression after irradiation or heat shock, including in lymphocytes activated by CD3/CD28 ligation. Together, our findings reveal a novel role for STAT3 in NK cell immunosurveillance by modulating the MICA expression in cancer cells. Cancer Res; 71(5); 1615–26. ©2011 AACR.
Enhancement of T-cell–Mediated Antitumor Response: Angiostatic Adjuvant to Immunotherapy against Cancer
Authors: Dings Ruud P.M. , Vang Kieng B. , Castermans Karolien , Popescu Flavia , Zhang Yan , oude Egbrink Mirjam G.A. , Mescher Matthew F. , Farrar Michael A. , Griffioen Arjan W. , Mayo Kevin H. 
Published: January 2011

AbstractPurpose: Tumor-released proangiogenic factors suppress endothelial adhesion molecule (EAM) expression and prevent leukocyte extravasation into the tumor. This is one reason why immunotherapy has met with limited success in the clinic. We hypothesized that overcoming EAM suppression with angiogenesis inhibitors would increase leukocyte extravasation and subsequently enhance the effectiveness of cellular immunotherapy.Experimental Design: Intravital microscopy, multiple color flow cytometry, immunohistochemistry, and various tumor mouse (normal and T-cell deficient) models were used to investigate the temporal dynamics of cellular and molecular events that occur in the tumor microenvironment during tumor progression and angiostatic intervention.Results: We report that while EAM levels and T-cell infiltration are highly attenuated early on in tumor growth, angiostatic therapy modulates these effects. In tumor models with normal and T-cell–deficient mice, we show the active involvement of the adaptive immune system in cancer and differentiate antiangiogenic effects from antiangiogenic mediated enhancement of immunoextravasation. Our results indicate that a compromised immune response in tumors can be obviated by the use of antiangiogenic agents. Finally, with adoptive transfer studies in mice, we show that a phased combination of angiostatic therapy and T-cell transfer significantly (P &lt; 0.0013) improves tumor growth inhibition.Conclusions: This research contributes to understand the cellular mechanism of action of angiostatic agents and the immune response within the tumor microenvironment, in particular as a consequence of the temporal dynamics of EAM levels. Moreover, our results suggest that adjuvant therapy with angiogenesis inhibitors holds promise for cellular immunotherapy in the clinic. Clin Cancer Res; 17(10); 3134–45. ©2011 AACR.
sFLT01: A Novel Fusion Protein with Antiangiogenic Activity
Authors: Bagley Rebecca G. , Kurtzberg Leslie , Weber William , Nguyen Tri-Hung , Roth Stephanie , Krumbholz Roy , Yao Min , Richards Brenda , Zhang Mindy , Pechan Peter , Schmid Steve , Scaria Abraham , Kaplan Johanne , Teicher Beverly A. 
Published: January 2011

Abstract
sFLT01 is a novel fusion protein that consists of the VEGF/PlGF (placental growth factor) binding domain of human VEGFR1/Flt-1 (hVEGFR1) fused to the Fc portion of human IgG1 through a polyglycine linker. It binds to both human VEGF (hVEGF) and human PlGF (hPlGF) and to mouse VEGF (mVEGF) and mouse PlGF (mPlGF). In vitro, sFLT01 inhibited the proliferation of human umbilical vein endothelial cells and pericytes stimulated by either hVEGF or hPlGF. In vivo, sFLT01 had robust and significant antitumor activity in numerous preclinical subcutaneous tumor models including H460 non–small cell lung carcinoma, HT29 colon carcinoma, Karpas 299 lymphoma, MOLM-13 AML (acute myeloid leukemia), 786-O, and RENCA renal cell carcinoma (RCC). sFLT01 also increased median survival in the orthotopic RENCA RCC model. sFLT01 had strong antiangiogenic activity and altered intratumoral microvessel density, blood vessel lumen size and perimeter, and vascular and vessel areas in RCC models. sFLT01 treatment resulted in fewer endothelial cells and pericytes within the tumor microenvironment. sFLT01 in combination with cyclophosphamide resulted in greater inhibition of tumor growth than either agent used alone as a monotherapy in the A673 Ewing's sarcoma model. Gene expression profiling indicated that the molecular changes in the A673 sarcoma tumors are similar to changes observed under hypoxic conditions. sFLT01 is an innovative fusion protein that possessed robust antitumor and antiangiogenic activities in preclinical cancer models. It is a dual targeting agent that neutralizes both VEGF and PlGF and, therefore, has potential as a next generation antiangiogenic therapeutic for oncology. Mol Cancer Ther; 10(3); 404–15. ©2011 AACR.
Worsening of Diet-Induced Atherosclerosis in a New Model of Transgenic Rabbit Expressing the Human Plasma Phospholipid Transfer Protein
Authors: Masson David , Deckert Valérie , Gautier Thomas , Klein Alexis , Desrumaux Catherine , Viglietta Céline , Pais de Barros Jean-Paul , Le Guern Naig , Grober Jacques , Labbé Jérôme , Ménétrier Franck , Ripoll Pierre-Jean , Leroux-Coyau Mathieu , Jolivet Geneviève , Houdebine Louis-Marie , Lagrost Laurent 
Published: January 2011

Objective—
Plasma phospholipid transfer protein (PLTP) is involved in intravascular lipoprotein metabolism. PLTP is known to act through 2 main mechanisms: by remodeling high-density lipoproteins (HDL) and by increasing apolipoprotein (apo) B–containing lipoproteins. The aim of this study was to generate a new model of human PLTP transgenic (HuPLTPTg) rabbit and to determine whether PLTP expression modulates atherosclerosis in this species that, unlike humans and mice, displays naturally very low PLTP activity.

Methods and Results—
In HuPLTPTg rabbits, the human PLTP cDNA was placed under the control of the human eF1-α gene promoter, resulting in a widespread tissue expression pattern and in increased plasma PLTP. The HuPLTPTg rabbits showed a significant increase in the cholesterol content of the plasma apoB-containing lipoprotein fractions, with a more severe trait when animals were fed a cholesterol-rich diet. In contrast, HDL cholesterol level was not modified in HuPLTPTg rabbits. Formation of aortic fatty streaks was increased in hypercholesterolemic HuPLTPTg animals as compared with nontransgenic littermates.

Conclusion—
Human PLTP expression in HuPLTPTg rabbit worsens atherosclerosis as a result of increased levels of atherogenic apoB-containing lipoproteins but not of alterations in their antioxidative protection or in cholesterol content of plasma HDL.