bluuebunny/crossref_metadata_2025 huggingface dataset:
Deletion of the Aconitase Gene in Corynebacterium glutamicum Causes Strong Selection Pressure for Secondary Mutations Inactivating Citrate Synthase
Authors: Baumgart Meike , Mustafi Nurije , Krug Andreas , Bott Michael
Published: October 2011

The aconitase gene
acn
of
Corynebacterium glutamicum
is regulated by four transcriptional regulators, indicating that the synthesis of this enzyme is carefully controlled. To understand the causes for this elaborate regulation, the properties of the Δ
acn
-1 deletion mutant were analyzed in detail. The mutant was glutamate auxotrophic in glucose minimal medium, showed a strong growth defect, and secreted large amounts of acetate. None of these phenotypes could be complemented by plasmid-encoded aconitase, suggesting the presence of a secondary mutation. In fact, a point mutation within the
gltA
gene encoding citrate synthase was identified that caused the instability of the protein and an almost complete lack of its enzymatic activity. Subsequently, 27 further, independent Δ
acn
clones were isolated, and 15 of them were found to contain distinct mutations in
gltA
, causing the loss of citrate synthase activity. A similar result was observed for mutants lacking the isocitrate dehydrogenase gene
icd
. In this case, 8 of 24 Δ
icd
clones contained additional mutations in
gltA
. Indirect evidence was obtained that elevated intracellular citrate concentrations could be the cause of this selection pressure. Accordingly, the careful control of aconitase synthesis might have evolved due to the necessity to avoid inhibitory cytoplasmic citrate levels on the one hand and to prevent the excessive synthesis of an oxygen-sensitive protein requiring both iron and sulfur on the other hand.
Mycobacterium smegmatis RoxY Is a Repressor ofoxySand Contributes to Resistance to Oxidative Stress and Bactericidal Ubiquitin-Derived Peptides
Authors: Daugherty Aaron , Powers Katelyn M. , Standley Melissa S. , Kim Cathy S. , Purdy Georgiana E.
Published: October 2011

The mycobactericidal properties of macrophages include the generation of reactive oxygen intermediates and the delivery of bacteria to a hydrolytic lysosome enriched in bactericidal ubiquitin-derived peptides (Ub-peptides). To better understand the interactions of ubiquitin-derived peptides with mycobacteria and identify putative mycobacterial intrinsic resistance mechanisms, we screened for transposon mutants with increased susceptibility to the bactericidal Ub-peptide Ub2. We isolated 27Mycobacterium smegmatismutants that were hypersusceptible to Ub2. Two mutants were isolated that possessed mutations in themsmeg_0166gene, which encodes a transcriptional regulator. Themsmeg_0166mutants were also hypersusceptible to other host antimicrobial peptides and oxidative stress. In characterizingmsmeg_0166, we found that it encodes arepressor ofoxyS, and therefore we have renamed the generoxY. We demonstrate that RoxY and OxyS contribute toM. smegmatisresistance to oxidative stress. AnahpDtransposon mutant was also isolated in our screen for Ub-peptide hypersusceptibility. Overexpression ofoxySinM. smegmatisreduced transcription of theahpCDgenes, which encode a peroxide detoxification system. Our data indicate that RoxY, OxyS, and AhpD play a role in the mycobacterial oxidative stress response and are important for resistance to host antimicrobial peptides.
Deletion of One Nucleotide within the Homonucleotide Tract Present in the
hsdS
Gene Alters the DNA Sequence Specificity of Type I Restriction-Modification System NgoAV
Authors: Adamczyk-Poplawska Monika , Lower Michal , Piekarowicz Andrzej
Published: October 2011

As a result of a frameshift mutation, the
hsdS
locus of the NgoAV type IC restriction and modification (RM) system comprises two genes,
hsdS
NgoAV1
and
hsdS
NgoAV2
. The specificity subunit, HsdS
NgoAV
, the product of the
hsdS
NgoAV1
gene, is a naturally truncated form of an archetypal specificity subunit (208 N-terminal amino acids instead of 410). The presence of a homonucleotide tract of seven guanines (poly[G]) at the 3′ end of the
hsdS
NgoAV1
gene makes the NgoAV system a strong candidate for phase variation, i.e., stochastic addition or reduction in the guanine number. We have constructed mutants with 6 guanines instead of 7 and demonstrated that the deletion of a single nucleotide within the 3′ end of the
hsdS
NgoAV1
gene restored the fusion between the
hsdS
NgoAV1
and
hsdS
NgoAV2
genes. We have demonstrated that such a contraction of the homonucleotide tract may occur
in vivo
: in a
Neisseria gonorrhoeae
population, a minor subpopulation of cells appeared to have only 6 guanines at the 3′ end of the
hsdS
NgoAV1
gene.
Escherichia coli
cells carrying the fused gene and expressing the NgoAVΔ RM system were able to restrict λ phage at a level comparable to that for the wild-type NgoAV system. NgoAV recognizes the quasipalindromic interrupted sequence 5′-GCA(N
8
)TGC-3′ and methylates both strands. NgoAVΔ recognizes DNA sequences 5′-GCA(N
7
)GTCA-3′ and 5′-GCA(N
7
)CTCA-3′, although the latter sequence is methylated only on the complementary strand within the 5′-CTCA-3′ region of the second recognition target sequence.
Fine-Tuning Control ofphoBRExpression in Vibrio cholerae by Binding of PhoB to Multiple Pho Boxes
Authors: Diniz Michelle Menezes Passos , Goulart Carolina Lage , Barbosa Livia Carvalho , Farache Júlia , Lery Letícia Miranda Santos , Pacheco Ana Beatriz Furlanetto , Bisch Paulo Mascarello , von Krüger Wanda Maria de Almeida
Published: October 2011

The control ofVibrio choleraephoBRexpression by PhoB involves its binding to Pho boxes at −35 (box 1), −60 (box 2), and −80 (box 3) from the putativephoBtranslation start site. These loci were located in the sense (box 1) and antisense (boxes 2 and 3) strands of thephoBRregulatory region, and PhoB binds to these individual boxes with distinct affinities. Fusions of sequences containing different combinations of these boxes upstream of thelacZreporter in a plasmid demonstrated that only those carrying boxes 1, 2, and 3, or 1 alone, activated transcription under inorganic phosphate (Pi) limitation. When a fragment, including only boxes 1 and 2, was fused tolacZ, expression was no longer induced by low Pi, suggesting a repressive role for PhoB∼box2 (PhoB bound to box 2) over the transcriptional activity induced by PhoB∼box1. The similarity betweenlacZexpression levels from promoter fragments containing the three boxes or box 1 alone showed that PhoB∼box3 eliminated the repressive effect imposed by PhoB∼box2 onphoBRtranscription. Complementation assays with aphoBR-containing plasmid demonstrated that the 234-bp promoter fragment carrying the three boxes is absolutely required for operon expression inVibrio choleraeΔphoBRcells. This was observed under Piabundance, whenphoBRwas expressed at a basal level and, also in low Piconditions, when Pho regulon genes were fully expressed. Thus, under Pilimitation, PhoB exerts dual regulatory functions by binding sequentially distinct Pho boxes to enable the fine-tuning and precise control ofphoBRexpression inV. choleraecells.
Organization and Evolution of the
cotG
and
cotH
Genes of Bacillus subtilis
Authors: Giglio Rosa , Fani Renato , Isticato Rachele , De Felice Maurilio , Ricca Ezio , Baccigalupi Loredana
Published: October 2011

The
cotG
and
cotH
genes of
Bacillus subtilis
encode two previously characterized spore coat proteins. The two genes are adjacent on the chromosome and divergently transcribed by σ
K
, a sporulation-specific σ factor of the RNA polymerase. We report evidence that the
cotH
promoter maps 812 bp upstream of the beginning of its coding region and that the divergent
cotG
gene is entirely contained between the promoter and the coding part of
cotH
. A bioinformatic analysis of all entirely sequenced prokaryotic genomes showed that such chromosomal organization is not common in spore-forming bacilli. Indeed, CotG is present only in
B. subtilis
,
B. amyloliquefaciens
, and
B. atrophaeus
and in two
Geobacillus
strains. When present,
cotG
always encodes a modular protein composed of tandem repeats and is always close to but divergently transcribed with respect to
cotH
. Bioinformatic and phylogenic data suggest that such genomic organizations have a common evolutionary origin and that the modular structure of the extant
cotG
genes is the outcome of multiple rounds of gene elongation events of an ancestral minigene.
Hfq Virulence Regulation in Enterohemorrhagic Escherichia coli O157:H7 Strain 86-24
Authors: Kendall Melissa M. , Gruber Charley C. , Rasko David A. , Hughes David T. , Sperandio Vanessa
Published: October 2011

Enterohemorrhagic
Escherichia coli
O157:H7 (EHEC) causes bloody diarrhea and hemolytic-uremic syndrome. EHEC encodes the sRNA chaperone Hfq, which is important in posttranscriptional regulation. In EHEC strain EDL933, Hfq acts as a negative regulator of the locus of enterocyte effacement (LEE), which encodes most of the proteins involved in type III secretion and attaching and effacing (AE) lesions. Here, we deleted
hfq
in the EHEC strain 86-24 and compared global transcription profiles of the
hfq
mutant and wild-type (WT) strains in exponential growth phase. Deletion of
hfq
affected transcription of genes common to nonpathogenic and pathogenic strains of
E. coli
as well as pathogen-specific genes. Downregulated genes in the
hfq
mutant included
ler
, the transcriptional activator of all the LEE genes, as well as genes encoded in the
LEE2
to
-5
operons. Decreased expression of the LEE genes in the
hfq
mutant occurred at middle, late, and stationary growth phases. We also confirmed decreased regulation of the LEE genes by examining the proteins secreted and AE lesion formation by the
hfq
mutant and WT strains. Deletion of
hfq
also caused decreased expression of the two-component system
qseBC
, which is involved in interkingdom signaling and virulence gene regulation in EHEC, as well as an increase in expression of
stx
2AB
, which encodes the deadly Shiga toxin. Altogether, these data indicate that Hfq plays a regulatory role in EHEC 86-24 that is different from what has been reported for EHEC strain EDL933 and that the role of Hfq in EHEC virulence regulation extends beyond the LEE.
The Same Periplasmic ExbD Residues Mediate
In Vivo
Interactions between ExbD Homodimers and ExbD-TonB Heterodimers
Authors: Ollis Anne A. , Postle Kathleen
Published: October 2011

The TonB system couples cytoplasmic membrane proton motive force to TonB-gated outer membrane transporters for active transport of nutrients into the periplasm. In
Escherichia coli
, cytoplasmic membrane proteins ExbB and ExbD promote conformational changes in TonB, which transmits this energy to the transporters. The only known energy-dependent interaction occurs between the periplasmic domains of TonB and ExbD. This study identified sites of
in vivo
homodimeric interactions within ExbD periplasmic domain residues 92 to 121. ExbD was active as a homodimer (ExbD
2
) but not through all Cys substitution sites, suggesting the existence of conformationally dynamic regions in the ExbD periplasmic domain. A subset of homodimeric interactions could not be modeled on the nuclear magnetic resonance (NMR) structure without significant distortion. Most importantly, the majority of ExbD Cys substitutions that mediated homodimer formation also mediated ExbD-TonB heterodimer formation with TonB A150C. Consistent with the implied competition, ExbD homodimer formation increased in the absence of TonB. Although ExbD D25 was not required for their formation, ExbD dimers interacted
in vivo
with ExbB. ExbD-TonB interactions required ExbD transmembrane domain residue D25. These results suggested a model where ExbD
2
assembled with ExbB undergoes a transmembrane domain-dependent transition and exchanges partners in localized homodimeric interfaces to form an ExbD
2
-TonB heterotrimer. The findings here were also consistent with our previous hypothesis that ExbD guides the conformation of the TonB periplasmic domain, which itself is conformationally dynamic.
Computed tomographic examination of South American sea lions (Otaria flavescens) with suspected Mycobacterium pinnipedii infection
Authors: Jurczynski K. , Scharpegge J. , Ley‐Zaporozhan J. , Ley S. , Cracknell J. , Lyashchenko K. , Greenwald R. , Schenk J. P.
Published: October 2011

Ten South American sea lions (Otaria flavescens) were presented for clinical evaluation and diagnosis of tuberculosis following known exposure to Mycobacterium pinnipedii. CT was used to determine whether foci of calcification in mediastinal lymph nodes, typically associated with pinniped tuberculosis, could be detected and whether CT was a useful diagnostic modality, in conjunction with other tests, for the diagnosis of tuberculosis in this species. Blood was collected from the caudal gluteal vein of each animal for serological testing using commercially available serological tests (ElephantTB STAT‐PAK and DPP Vet; Chembio Diagnostic Systems) and a multiantigen print immunoassay (MAPIA), carried out at Chembio to verify the in‐house kits. In four of nine animals that underwent CT scanning, lesions consistent with pinniped tuberculosis were apparent and these were confirmed at subsequent postmortem examination. The five remaining animals did not show any abnormalities on CT, with three being negative on serological tests, which were considered to be normal and potentially used as reference images for healthy sea lions. One animal could not be CT scanned due to its large size and weight (510 kg).
Wall structures of myocardial precapillary arterioles and postcapillary venules reexamined and reconstructed in vitro for studies on barrier functions
Authors: Nees Stephan , Juchem Gerd , Eberhorn Nicola , Thallmair Martin , Förch Stefan , Knott Maria , Senftl Anton , Fischlein Theodor , Reichart Bruno , Weiss Dominik R.
Published: October 2011

The barrier functions of myocardial precapillary arteriolar and postcapillary venular walls (PCA or PCV, respectively) are of considerable scientific and clinical interest (regulation of blood flow and recruitment of immune defense). Using enzyme histochemistry combined with confocal microscopy, we reexamined the cell architecture of human PCA and PVC and reconstructed appropriate in vitro models for studies of their barrier functions. Contrary to current opinion, the PCA endothelial tube is encompassed not by smooth muscle cells but rather by a concentric layer of pericytes cocooned in a thick, microparticle-containing extracellular matrix (ECM) that contributes substantially to the tightness of the arteriolar wall. This core tube extends upstream into the larger arterioles, there additionally enwrapped by smooth muscle. PCV consist of an inner layer of large, contractile endothelial cells encompassed by a fragile, wide-meshed pericyte network with a weakly developed ECM. Pure pericyte and endothelial cell preparations were isolated from PCA and PCV and grown in sandwich cultures. These in vitro models of the PCA and PCV walls exhibited typical histological and functional features. In both plasma-like (PLM) and serum-containing (SCM) media, the PCA model (including ECM) maintained its low hydraulic conductivity ( LP= 3.24 ± 0.52·10−8cm·s−1·cmH2O−1) and a high selectivity index for transmural passage of albumin (SIAlb= 0.95 ± 0.02). In contrast, LPand SIAlbin the PCV model (almost no ECM) were 2.55 ± 0.32·10−7cm·s−1·cmH2O−1and 0.88 ± 0.03, respectively, in PLM, and 1.39 ± 0.10·10−6cm·s−1·cmH2O−1and 0.49 ± 0.04 in SCM. With the use of these models, systematic, detailed studies on the regulation of microvascular barrier properties now appear to be feasible.
Increased basal coronary blood flow as a cause of reduced coronary flow reserve in diabetic patients
Authors: Picchi Andrea , Limbruno Ugo , Focardi Marta , Cortese Bernardo , Micheli Andrea , Boschi Letizia , Severi Silva , De Caterina Raffaele
Published: October 2011

A reduced coronary flow reserve (CFR) has been demonstrated in diabetes, but the underlying mechanisms are unknown. We assessed thermodilution-derived CFR after 5-min intravenous adenosine infusion through a pressure-temperature sensor-tipped wire in 30 coronary arteries without significant lumen reduction in 30 patients: 13 with and 17 without a history of diabetes. We determined CFR as the ratio of basal and hyperemic mean transit times (Tmn); fractional flow reserve (FFR) as the ratio of distal and proximal pressures at maximal hyperemia to exclude local macrovascular disease; and an index of microvascular resistance (IMR) as the distal coronary pressure at maximal hyperemia divided by the inverse of the hyperemic Tmn. We also assessed insulin resistance by the homeostasis model assessment (HOMA) index. FFR was normal in all investigated arteries. CFR was significantly lower in diabetic vs. nondiabetic patients [median (interquartile range): 2.2 (1.4–3.2) vs. 4.1 (2.7–4.4); P = 0.02]. Basal Tmn was lower in diabetic vs. nondiabetic subjects [median (interquartile range): 0.53 (0.25–0.71) vs. 0.64 (0.50–1.17); P = 0.04], while hyperemic Tmn and IMR were similar. We found significant correlations at linear regression analysis between logCFR and the HOMA index ( r2 = 0.35; P = 0.0005) and between basal Tmn and the HOMA index ( r2 = 0.44; P < 0.0001). In conclusion, compared with nondiabetic subjects, CFR is lower in patients with diabetes and epicardial coronary arteries free of severe stenosis, because of increased basal coronary flow, while hyperemic coronary flow is similar. Basal coronary flow relates to insulin resistance, suggesting a key role of cellular metabolism in the regulation of coronary blood flow.
Arachidonic acid- and prostaglandin E2-induced cerebral vasodilation is mediated by carbon monoxide, independent of reactive oxygen species in piglets
Authors: Kanu Alie , Leffler Charles W.
Published: October 2011

Arachidonic acid (AA) and prostaglandin (PG) E2 stimulate carbon monoxide (CO) production, and AA metabolism is known to be associated with the generation of reactive oxygen species (ROS). This study was conducted to address the hypothesis that CO and/or ROS mediate cerebrovascular dilation in newborn pigs. Experiments were performed on anesthetized newborn pigs with closed cranial windows. Different concentrations of AA (10−8-10−6 M), PGE2 (10−8-10−6 M), iloprost (10−8-10−6 M), and their vehicle (artificial cerebrospinal fluid) were given. Piglets with PGE2 and iloprost received indomethacin (5 mg/kg iv) to inhibit cyclooxygenase. AA, PGE2, and iloprost caused concentration-dependent increases in pial arteriolar diameter. The effects of both AA and PGE2 in producing cerebral vascular dilation and associated CO production were blocked by the heme oxygenase inhibitor chromium mesoporphyrin (2 × 10−5 M), but not by the prostacyclin analog, iloprost. ROS inhibitor tempol (SOD mimetic) (1 × 10−5 M) and the H2O2 scavenger catalase (1,000 U/ml) also do not block these vasodilator effects of AA and PGE2. Heme-l-lysinate-induced cerebrovascular dilation and CO production was blocked by chromium mesoporphyrin. Hypoxanthine plus xanthine oxidase, a combination that is known to generate ROS, caused pial arteriolar dilation and CO production that was inhibited by tempol and catalase. These data suggest that AA- and PGE2-induced cerebral vascular dilation is mediated by CO, independent of ROS.
Mechanism of prolonged electromechanical delay in late activated myocardium during left bundle branch block
Authors: Russell Kristoffer , Smiseth Otto A. , Gjesdal Ola , Qvigstad Eirik , Norseng Per Andreas , Sjaastad Ivar , Opdahl Anders , Skulstad Helge , Edvardsen Thor , Remme Espen W.
Published: October 2011

During left bundle branch block (LBBB), electromechanical delay (EMD), defined as time from regional electrical activation (REA) to onset shortening, is prolonged in the late-activated left ventricular lateral wall compared with the septum. This leads to greater mechanical relative to electrical dyssynchrony. The aim of this study was to determine the mechanism of the prolonged EMD. We investigated this phenomenon in an experimental LBBB dog model ( n = 7), in patients ( n = 9) with biventricular pacing devices, in an in vitro papillary muscle study ( n = 6), and a mathematical simulation model. Pressures, myocardial deformation, and REA were assessed. In the dogs, there was a greater mechanical than electrical delay (82 ± 12 vs. 54 ± 8 ms, P = 0.002) due to prolonged EMD in the lateral wall vs. septum (39 ± 8 vs.11 ± 9 ms, P = 0.002). The prolonged EMD in later activated myocardium could not be explained by increased excitation-contraction coupling time or increased pressure at the time of REA but was strongly related to dP/d t at the time of REA ( r = 0.88). Results in humans were consistent with experimental findings. The papillary muscle study and mathematical model showed that EMD was prolonged at higher dP/d t because it took longer for the segment to generate active force at a rate superior to the load rise, which is a requirement for shortening. We conclude that, during LBBB, prolonged EMD in late-activated myocardium is caused by a higher dP/d t at the time of activation, resulting in aggravated mechanical relative to electrical dyssynchrony. These findings suggest that LV contractility may modify mechanical dyssynchrony.
Group X secretory PLA2in neutrophils plays a pathogenic role in abdominal aortic aneurysms in mice
Authors: Watanabe Kazuhiro , Fujioka Daisuke , Saito Yukio , Nakamura Takamitsu , Obata Jun-ei , Kawabata Kenichi , Watanabe Yosuke , Mishina Hideto , Tamaru Shun , Hanasaki Kohji , Kugiyama Kiyotaka
Published: October 2011

Group X secretory PLA2(sPLA2-X) is expressed in neutrophils and plays a role in the pathogenesis of neutrophil-mediated tissue inflammation and injury. This study tested the hypothesis that sPLA2-X in neutrophils may contribute to the pathogenesis of abdominal aortic aneurysms (AAA) using sPLA2-X−/−mice. AAA was created by application of CaCl2to external surface of aorta. As a result, the aortas of sPLA2-X−/−mice had smaller diameters (percent increase from baseline; 24.8 ± 3.5% vs. 49.9 ± 9.1%, respectively; P < 0.01), a reduced grade of elastin degradation, and lower activities of elastase and gelatinase (26% and 19% lower, respectively) after CaCl2treatment compared with sPLA2-X+/+mice. In sPLA2-X+/+mice, immunofluorescence microscopic images showed that the immunoreactivity of sPLA2-X was detected only in neutrophils within aortic walls 3 days, 1, 2, and 6 wk after CaCl2treatment, whereas the immunoreactivity was not detected in macrophages or mast cells in aortic walls. sPLA2-X immunoreactivity also was colocalized in cells expressing matrix metalloproteinase (MMP)-9. Neutrophils isolated from sPLA2-X−/−mice had lower activities of elastase, gelatinase, and MMP-9 in response to stimuli compared with sPLA2-X+/+mice. The attenuated release of elastase and gelatinase from sPLA2-X−/−neutrophils was reversed by exogenous addition of mouse sPLA2-X protein. The adoptive transfer of sPLA2-X+/+neutrophils days 0 and 3 after CaCl2treatment reversed aortic diameters and elastin degradation grades in the lethally irradiated sPLA2-X+/+mice reconstituted with sPLA2-X−/−bone marrow to an extent similar to that seen in sPLA2-X+/+mice. In conclusion, sPLA2-X in neutrophils plays a pathogenic role in AAA in a mice model.
Synchronicity of systolic deformation in healthy pediatric and young adult subjects: a two-dimensional strain echocardiography study
Authors: Marcus Karen A. , Janoušek Jan , Barends Marlieke E. , Weijers Gert , de Korte Chris L. , Kapusta Livia
Published: October 2011

Two-dimensional speckle tracking echocardiography (2DSTE) offers valuable information in the echocardiographic assessment of ventricular myocardial function. It enables the quantification and timing of systolic ventricular myocardial deformation. In addition, 2DSTE can be used to identify mechanical dyssynchrony, which is an important parameter in predicting the response to cardiac resynchronization therapy for heart failure. Detailed knowledge of normal timing of systolic deformation and its degree of synchronicity in children is lacking. We aimed to establish the normal timing of left ventricular myocardial systolic deformation using 2DSTE in a large cohort of healthy children and young adults. Transthoracic echocardiograms were acquired in 195 healthy subjects (139 children and 56 young adult <40 yr of age) and were retrospectively analyzed. Time to peak systolic longitudinal, circumferential, and radial strain was determined by means of speckle tracking. Strong, statistically significant relations between age as well as various anthropometric variables (e.g., heart rate) and timing of systolic deformation ( P < 0.0001) were present. The extent of dyssynchronous deformation increased with age. This is the first report that establishes reference values per cardiac segment for time to peak systolic myocardial strain values in all three directions assessed with 2DSTE in a large pediatric and young adult cohort. We emphasize the need for using age-specific reference values as well as heart rate correction for the adequate interpretation of 2DSTE measurements.
Allergic inflammation induces a persistent mechanistic switch in thromboxane-mediated airway constriction in the mouse
Authors: Cyphert Jaime M. , Allen Irving C. , Church Rachel J. , Latour Anne M. , Snouwaert John N. , Coffman Thomas M. , Koller Beverly H.
Published: October 2011

Actions of thromboxane (TXA2) to alter airway resistance were first identified over 25 years ago. However, the mechanism underlying this physiological response has remained largely undefined. Here we address this question using a novel panel of mice in which expression of the thromboxane receptor (TP) has been genetically manipulated. We show that the response of the airways to TXA2is complex: it depends on expression of other G protein-coupled receptors but also on the physiological context of the signal. In the healthy airway, TXA2-mediated airway constriction depends on expression of TP receptors by smooth muscle cells. In contrast, in the inflamed lung, the direct actions of TXA2on smooth muscle cell TP receptors no longer contribute to bronchoconstriction. Instead, in allergic lung disease, TXA2-mediated airway constriction depends on neuronal TP receptors. Furthermore, this mechanistic switch persists long after resolution of pulmonary inflammation. Our findings demonstrate the powerful ability of lung inflammation to modify pathways leading to airway constriction, resulting in persistent changes in mechanisms of airway reactivity to key bronchoconstrictors. Such alterations are likely to shape the pathogenesis of asthmatic lung disease.
Programmatic change: lung disease research in the era of induced pluripotency
Authors: Ikonomou Laertis , Hemnes Anna R. , Bilousova Ganna , Hamid Rizwan , Loyd James E. , Hatzopoulos Antonis K. , Kotton Darrell N. , Majka Susan M. , Austin Eric D.
Published: October 2011

Human lung research has made remarkable progress over the last century largely through the use of animal models of disease. The challenge for the future is to translate these findings into human disease and bring about meaningful disease modification or even cure. The ability to generate transformative therapies in the future will require human tissue, currently scarce under the best of circumstances. Unfortunately, patient-derived somatic cells are often poorly characterized and have a limited life span in culture. Moreover, these cells are frequently obtained from patients with end-stage disease exposed to multiple drug therapies, leaving researchers with questions about whether their findings recapitulate disease-initiating processes or are simply the result of pharmacological intervention or subsequent host responses. The goal of studying early disease in multiple cell and tissue types has driven interest in the use of induced pluripotent stem cells (iPSCs) to model lung disease. These cells provide an alternative model for relevant lung research and hold promise in particular for studying the initiation of disease processes in genetic conditions such as heritable pulmonary arterial hypertension as well as other lung diseases. In this Perspective, we focus on potential iPSC use in pulmonary vascular disease research as a model for iPSC use in many types of advanced lung disease.
Multiple Stress Signals Activate Mutant p53 In Vivo
Authors: Suh Young-Ah , Post Sean M. , Elizondo-Fraire Ana C. , Maccio Daniela R. , Jackson James G. , El-Naggar Adel K. , Van Pelt Carolyn , Terzian Tamara , Lozano Guillermina
Published: October 2011

p53 levels are tightly regulated in normal cells, and thus, the wild-type p53 protein is nearly undetectable until stimulated through a variety of stresses. In response to stress, p53 is released from its negative regulators, mainly murine double minute 2 (Mdm2), allowing p53 to be stabilized to activate cell-cycle arrest, senescence, and apoptosis programs. Many of the upstream signals that regulate wild-type p53 are known; however, limited information for the regulation of mutant p53 exists. Previously, we showed that wild-type and mutant p53R172H are regulated in a similar manner in the absence of Mdm2 or p16. In addition, this stabilization of mutant p53 is responsible for the gain-of-function metastatic phenotype observed in the mouse. In this report, we examined the role of oncogenes, DNA damage, and reactive oxygen species, signals that stabilize wild-type p53, on the stabilization of mutant p53 in vivo and the consequences of this expression on tumor formation and survival. These factors stabilized mutant p53 protein which oftentimes contributed to exacerbated tumor phenotypes. These findings, coupled with the fact that patients carry p53 mutations without stabilization of p53, suggest that personalized therapeutic schemes may be needed for individual patients depending on their p53 status. Cancer Res; 71(23); 7168–75. ©2011 AACR.
Volumetric and Angiogenic Evaluation of Antitumor Effects with Acoustic Liposome and High-Frequency Ultrasound
Authors: Kodama Tetsuya , Tomita Noriko , Yagishita Yoko , Horie Sachiko , Funamoto Kenichi , Hayase Toshiyuki , Sakamoto Maya , Mori Shiro
Published: October 2011

Acoustic liposomes (AL) have their inherent echogenicity and can add functionality in serving as drug carriers with tissue specificity. Nonuniform vascular structures and vascular branches/bends are evaluated by imaging the intravascular movement locus of ALs with high-frequency ultrasound (HF-US) imaging. However, the evaluation of antitumor effects on angiogenesis by ALs and HF-US imaging has not been reported. Here, we show that the combination of ALs and an HF-US imaging system is capable of noninvasively evaluating antitumor volumetric and angiogenic effects in preclinical mouse models of various cancers. In this study, the antitumor effects of cisplatin on tumor growth and angiogenesis in mice bearing two different types of tumor cells were assessed. By tracking each AL flowing in the vessel and transferring the images to personal computers, microvessel structures were mapped and reconstructed using the color difference based on SD method. The antitumor effects were confirmed with an in vivo bioluminescence imaging system and immunohistochemical analysis. Our results show that cisplatin inhibits tumor growth by decreasing intratumoral vessel area but does not affect the angiogenesis ratio in the tumor. The vascular occupancy in the outer region of the tumor was larger than that in the inner region; however, both occupancies were similar to those of the control tumor. We propose that this method of mapping microvessels with ALs and an HF-US system can serve as a new molecular imaging method for the assessment of angiogenesis and can be applied to evaluate the antitumor effects by various therapeutic agents. Cancer Res; 71(22); 6957–64. ©2011 AACR.
Interaction of HIF and USF Signaling Pathways in Human Genes Flanked by Hypoxia-Response Elements and E-box Palindromes
Authors: Hu Junmin , Stiehl Daniel P. , Setzer Claudia , Wichmann Daniela , Shinde Dheeraj A. , Rehrauer Hubert , Hradecky Pavel , Gassmann Max , Gorr Thomas A.
Published: October 2011

Rampant activity of the hypoxia-inducible factor (HIF)-1 in cancer is frequently associated with the malignant progression into a harder-to-treat, increasingly aggressive phenotype. Clearly, anti-HIF strategies in cancer cells are of considerable clinical interest. One way to fine-tune, or inhibit, HIF's transcriptional outflow independently of hydroxylase activities could be through competing transcription factors. A CACGTG-binding activity in human hepatoma cells was previously found to restrict HIF's access to hypoxia response cis-elements (HRE) in a Daphnia globin gene promoter construct (phb2). The CACGTG factor, and its impact on hypoxia-responsive human genes, was analyzed in this study by genome-wide computational scans as well as gene-specific quantitative PCR, reporter and DNA-binding assays in hepatoma (Hep3B), cervical carcinoma (HeLa), and breast carcinoma (MCF7) cells. Among six basic helix-loop-helix transcription factors known to target CACGTG palindromes, we identified upstream stimulatory factor (USF)-1/2 as predominant phb2 CACGTG constituents in Hep3B, HeLa, and MCF7 cells. Human genes with adjacent or overlapping HRE and CACGTG motifs included with lactate dehydrogenase A (LDHA) and Bcl-2/E1B 19 kDa interacting protein 3 (BNIP3) hypoxia-induced HIF-1 targets. Parallel recruitment of HIF-1α and USF1/2a to the respective promoter chromatin was verified for all cell lines investigated. Mutual complementing (LDHA) or moderating (BNIP3) cross-talk was seen upon overexpression or silencing of HIF-1α and USF1/2a. Distinct (LDHA) or overlapping (BNIP3) promoter-binding sites for HIF-1 and USFs were subsequently characterized. We propose that, depending on abundance or activity of its protein constituents, O2-independent USF signaling can function to fine-tune or interfere with HIF-mediated transcription in cancer cells. Mol Cancer Res; 9(11); 1520–36. ©2011 AACR.
αB-Crystallin, an Effector of Unfolded Protein Response, Confers Anti-VEGF Resistance to Breast Cancer via Maintenance of Intracrine VEGF in Endothelial Cells
Authors: Ruan Qing , Han Song , Jiang Wen G. , Boulton Michael E. , Chen Zhi J. , Law Brian K. , Cai Jun
Published: October 2011

Effective inhibition of angiogenesis targeting the tumor endothelial cells requires identification of key cellular and molecular mechanisms associated with survival of vasculatures within the tumor microenvironment. Intracellular autocrine (intracrine) VEGF production by endothelial cells plays a critical role on the vasculature homeostasis. In vitro breast cancer cell–stimulated activation of the unfolded protein response (UPR) of the endothelial cells contributes to maintenance of the intracrine VEGF levels in the endothelial cells through the upregulation of a previous undescribed downstream effector- αB-crystallin (CRYAB). siRNA-mediated knockdown of two major UPR proteins—inositol requiring kinase 1 and ATF6, led to attenuated CRYAB expression of the endothelial cells. Finally, inhibition of CRYAB blocked the breast cancer cell–stimulated increase in the endogenous VEGF levels of the endothelial cells. A VEGF limited proteolysis assay further revealed that CRYAB protected VEGF for proteolytic degradation. Here, we report that the molecular chaperone-CRYAB was significantly increased and colocalized with tumor vessels in a breast cancer xenograft. Specifically, neutralization of VEGF induced higher levels of CRYAB expression in the endothelial cells cocultured with MDA-MB-231 or the breast cancer xenograft with a significant survival benefit. However, knockdown of CRYAB had a greater inhibitory effect on endothelial survival. These findings underscore the importance of defining a role for intracrine VEGF signaling in sustaining aberrant tumor angiogenesis and strongly implicate UPR/CRYAB as dichotomous parts of a crucial regulation pathway for maintaining intracrine VEGF signaling. Mol Cancer Res; 9(12); 1632–43. ©2011 AACR.
Modulation of Gene Expression and Cell-Cycle Signaling Pathways by the EGFR Inhibitor Gefitinib (Iressa) in Rat Urinary Bladder Cancer
Authors: Lu Yan , Liu Pengyuan , Van den Bergh Francoise , Zellmer Victoria , James Michael , Wen Weidong , Grubbs Clinton J. , Lubet Ronald A. , You Ming
Published: October 2011

The epidermal growth factor receptor inhibitor Iressa has shown strong preventive efficacy in the N-butyl-N-(4-hydroxybutyl)-nitrosamine (OH-BBN) model of bladder cancer in the rat. To explore its antitumor mechanism, we implemented a systems biology approach to characterize gene expression and signaling pathways in rat urinary bladder cancers treated with Iressa. Eleven bladder tumors from control rats, seven tumors from rats treated with Iressa, and seven normal bladder epithelia were profiled by the Affymetrix Rat Exon 1.0 ST Arrays. We identified 713 downregulated and 641 upregulated genes in comparing bladder tumors versus normal bladder epithelia. In addition, 178 genes were downregulated and 96 genes were upregulated when comparing control tumors versus Iressa-treated tumors. Two coexpression modules that were significantly correlated with tumor status and treatment status were identified [r = 0.70, P = 2.80 × 10−15 (bladder tumor vs. normal bladder epithelium) and r = 0.63, P = 2.00 × 10−42 (Iressa-treated tumor vs. control tumor), respectively]. Both tumor module and treatment module were enriched for genes involved in cell-cycle processes. Twenty-four and twenty-one highly connected hub genes likely to be key drivers in cell cycle were identified in the tumor module and treatment module, respectively. Analysis of microRNA genes on the array chips showed that tumor module and treatment module were significantly associated with expression levels of let-7c (r = 0.54, P = 3.70 × 10−8 and r = 0.73, P = 1.50 × 10−65, respectively). These results suggest that let-7c downregulation and its regulated cell-cycle pathway may play an integral role in governing bladder tumor suppression or collaborative oncogenesis and that Iressa exhibits its preventive efficacy on bladder tumorigenesis by upregulating let-7 and inhibiting the cell cycle. Cell culture study confirmed that the increased expression of let-7c decreases Iressa-treated bladder tumor cell growth. The identified hub genes may also serve as pharmacodynamic or efficacy biomarkers in clinical trials of chemoprevention in human bladder cancer. Cancer Prev Res; 5(2); 248–59. ©2011 AACR.
Association of Known Loci With Lipid Levels Among Children and Prediction of Dyslipidemia in Adults
Authors: Tikkanen Emmi , Tuovinen Tarja , Widén Elisabeth , Lehtimäki Terho , Viikari Jorma , Kähönen Mika , Peltonen Leena , Raitakari Olli T. , Ripatti Samuli
Published: October 2011

Background—

Recent genome-wide association studies have found 95 distinct genetic loci associated with high-density (HDL-C) and low-density (LDL-C) lipoprotein cholesterol, total cholesterol (TC), and triglycerides (TG), using adult samples. It is not known if these variants are associated with lipid levels in children and adolescents and if the genetic risk score (GRS), based on these variants, could improve adulthood dyslipidemia prediction over the childhood lipid measurements.

Methods and Results—

We used 2443 participants of the Cardiovascular Risk in Young Finns study cohort with up to 5 measurements of serum lipids taken between ages 3 and 45 years to estimate the effect of individual single-nucleotide polymorphisms and the GRS on lipids. The GRSs were strongly associated with lipids in all age groups (1.5×10
−20
<
P
<8.7×10
−12
for HDL-C, 3.5×10
−27
<
P
<5.6×10
−09
for LDL-C, 2.0×10
−25
<
P
<5.2×10
−09
for TC, and 4.1×10
−20
<
P
<8.4×10
−05
for TG). Jointly, the lipid loci explained 11.8–26.7% of the total variance in lipids among 3- to 6-year-old children, and the proportion dropped over age, except for TG. The discrimination of adult hypertriglyceridemia improved when GRS was added to childhood lipid measurement (
C
statistic=0.04,
P
=0.01).

Conclusions—

Previously identified lipid loci are associated with lipid levels in children and adolescents and explain up to more than 2 times of the lipid variation in children compared with adults. The TG-GRS improves the risk discrimination over childhood lipid measurement for adult hypertriglyceridemia.
International social workers in England: Factors influencing supply and demand
Authors: Moriarty Jo , Hussein Shereen , Manthorpe Jill , Stevens Martin
Published: October 2011

Recent years have seen considerable increases in the number of internationally-qualified social workers in England. This article presents trends in the international labour mobility of social workers migrating to work in England alongside information on the supply of UK-trained social workers. It concludes that demographic changes and policy imperatives have accentuated structural issues making it difficult to ensure an adequate supply in the number of domestically-trained social workers. We suggest that more cross-national research is needed to achieve a better understanding of the factors influencing social workers’ decisions to work in international settings and the extent to which this reflects permanent or temporary migration between countries.
Integrating cultural competency in South Korean social work education
Authors: Hong Jun Sung , Stokes Charu , Byoun Soo-Jung , Furuto Sharlene B.C.L. , Kim Young Sook
Published: October 2011

Multiculturalism in South Korea in recent years necessitates inclusion of cultural competency in South Korean social work education and practice. We examine the demographics of South Korea’s ‘diverse’ population, followed by a theoretical framework of cultural competency and whether and to what degree cultural competency training can be effectively incorporated in South Korean social work education. Educational implications are also discussed.
Devolution: Discontinuity and dissonance
Authors: Yu Nilan G.
Published: October 2011

This article examines the devolution of social welfare services in the Philippines, focusing on its ideological underpinnings and implications for social welfare. It argues that the devolution resulted in a policy environment that allows for varying levels of social support across municipalities and, consequently, the fragmentation of Filipino citizenship.
The Global Gag Rule: Impacts of conservative ideology on women’s health
Authors: Gezinski Lindsay B.
Published: October 2011

This article will outline the legislative history of the Global Gag Rule and will describe the key stakeholders responsible for the policy’s passage and promotion. The negative effects associated with the policy’s implementation will be discussed, as well as its implications for human rights discourse and political activism.
Bmp2 Is Required for Odontoblast Differentiation and Pulp Vasculogenesis
Authors: Yang W. , Harris M.A. , Cui Y. , Mishina Y. , Harris S.E. , Gluhak-Heinrich J.
Published: October 2011

Using the Bmp2 floxed/3.6Col1a1-Cre (Bmp2-cKOod) mouse model, we have observed severe defects in odontogenesis and dentin formation with the removal of the Bmp2 gene in early-polarizing odontoblasts. The odontoblasts in the Bmp2-cKOod do not mature properly and fail to form proper dentin with normal dentinal tubules and activate terminal differentiation, as reflected by decreased Osterix, Col1a1, and Dspp expression. There is less dentin, and the dentin is hypomineralized and patchy. We also describe an indirect effect of the Bmp2 gene in odontoblasts on formation of the vascular bed and associated pericytes in the pulp. This vascular niche and numbers of CD146+ pericytes are likely controlled by odontogenic and Bmp2-dependent VegfA production in odontoblasts. The complex roles of Bmp2, postulated to be both direct and indirect, lead to permanent defects in the teeth throughout life, and result in teeth with low quantities of dentin and dentin of poor quality.
Racist Events and Individual Coping Styles as Predictors of African American Activism
Authors: Szymanski Dawn M.
Published: October 2011

The purpose of this study was to examine racist events and three individual coping styles (reflective, suppressive, and reactive) as predictors of involvement in African American activism in a sample of 269 African American women and men. In addition, it examined the moderating roles of individual coping styles in the racist events-African American activism link. Results indicated that racist events, reflective coping, and the interaction of racist events and reflective coping uniquely and significantly predicted involvement in African American activism, accounting for 33% of the variance. Racist events and reflective individual coping styles were related to involvement in African American activism. Results also supported a moderating role of individual reflective coping styles in the link between frequency of racist events and involvement in African American activism. That is, participants with high reflective coping engaged in more African American activism than participants with low reflective coping when experiences of racist events were low, but a larger number of racist events mitigated this effect.
Theoretical analysis and application of Kalman filters for ultra-tight global position system/inertial navigation system integration
Authors: Chen Xi-Yuan , Yu Jing , Zhu Xue-Fen
Published: October 2011

When a global position system (GPS) is combined with an inertial navigation system (INS) in the ultra-tight GPS/INS integrated navigation system, their performances are both optimized. However, different from loose and tight integration, in the ultra-tight integration, the non-linearity of Kalman measurements will seriously affect the filtering result. As the performance of the Kalman filter is radically affected by the modelling strategies, this paper will discuss it in depth. Firstly, the modelling of a traditional Kalman filter for ultra-tight integration is introduced by derivation and simulation experiments based on a single-frequency GPS software receiver. Then, the theoretical analysis of its performances on observability, controllability and stability is given. According to that, a novel extended Kalman filter for the ultra-tight integration is presented, using a Q (quadrature) signal from the GPS receiver correlator and a position and velocity from both the GPS and INS to form the measurements of the extended Kalman filter. New simulation experiments under the same initial conditions are carried out, and the comparison results show that the new method can provide better precision of all navigation parameters. However, it is noted that the curves of position and velocity errors have slight oscillation; the reason for this will be studied in the future.
Resistance exercise in cardiac rehabilitation
Authors: Wise Frances M , Patrick Jennifer M
Published: October 2011

This series of articles for rehabilitation in practice aims to cover a knowledge element of the rehabilitation medicine curriculum. Nevertheless they are intended to be of interest to a multidisciplinary audience. The competency addressed in this article is ‘The trainee consistently demonstrates a knowledge of basic exercise physiology and is able to advise individuals about the risks and benefits of specific exercise programmes.’

Cardiovascular disease is the leading cause of death in developed nations, and there is a clear link with physical inactivity. The benefits of resistance training in patients with coronary heart disease are well documented and can contribute to secondary prevention of heart disease with corresponding improvements in patient survival. This review describes the benefits of resistance exercise for cardiac patients, details of its prescription in this group, and considers safety and contraindications.