bluuebunny/crossref_metadata_2025_split huggingface dataset:
Population‐Based Study of Risk Factors for Severe Maternal Morbidity
Authors: Gray Kristen E. , Wallace Erin R. , Nelson Kailey R. , Reed Susan D. , Schiff Melissa A. 
Published: October 2012

AbstractBackground:  Severe maternal morbidity (SMM) is a serious health condition potentially resulting in death without immediate medical attention, including organ failure, obstetric shock and eclampsia. SMM affects 20 000 US women every year; however, few population‐based studies have examined SMM risk factors.Methods:  We conducted a population‐based case–control study linking birth certificate and hospital discharge data from Washington State (1987–2008), identifying 9485 women with an antepartum, intrapartum or postpartum SMM with ≥3‐day hospitalisation or transfer from another facility and 41 112 random controls. Maternal age, race, smoking during pregnancy, parity, pre‐existing medical condition, multiple birth, prior caesarean delivery, and body mass index were assessed as risk factors with logistic regression to estimate odds ratios (OR) and 95% confidence intervals [CI], adjusted for education and delivery payer source.Results:  Older women (35–39: OR 1.65 [CI 1.52, 1.79]; 40+: OR 2.48 [CI 2.16, 2.81]), non‐White women (Black: OR 1.82 [CI 1.64, 2.01]; American Indian: OR 1.52 [CI 1.32, 1.73]; Asian/Pacific Islander: OR 1.30 [CI 1.19, 1.41]; Hispanic: OR 1.17 [CI 1.07, 1.27]) and women at parity extremes (nulliparous: OR 1.83 [CI 1.72, 1.95]; parity 3+: OR 1.34 [CI 1.23, 1.45]) were at greater risk of SMM. Women with a pre‐existing medical condition (OR 2.10 [CI 1.88, 2.33]), a multiple birth (OR 2.54 [CI 2.26, 2.82]) and a prior caesarean delivery (OR 2.08 [CI 1.93, 2.23]) were also at increased risk.Conclusion:  The risk factors identified are not modifiable at the individual level; therefore, provider and system‐level factors may be the most appropriate target for preventing SMM.
Consequentialism and the World in Time
Authors: Fiocco M. Oreste 
Published: October 2012

AbstractConsequentialism is a general approach to understanding the nature of morality that seems to entail a certain view of the world in time. This entailment raises specific problems for the approach. The first seems to lead to the conclusion that every actual act is right – an unacceptable result for any moral theory. The second calls into question the idea that consequentialism is an approach to morality, for it leads to the conclusion that this approach produces a theory whose truth does not depend in any way on the nature of rational beings or value.
Comparative metabolic profiling between desiccation‐sensitive and desiccation‐tolerant species of Selaginella reveals insights into the resurrection trait
Authors: Yobi Abou , Wone Bernard W. M. , Xu Wenxin , Alexander Danny C. , Guo Lining , Ryals John A. , Oliver Melvin J. , Cushman John C. 
Published: October 2012

SummarySpike mosses (Selaginellaceae) represent an ancient lineage of vascular plants in which some species have evolved desiccation tolerance (DT). A sister‐group contrast to reveal the metabolic basis of DT was conducted between a desiccation‐tolerant species, Selaginella lepidophylla, and a desiccation‐sensitive species, Selaginella moellendorffii, at 100% relative water content (RWC) and 50% RWC using non‐biased, global metabolomics profiling technology, based on GC/MS and UHLC/MS/MS2 platforms. A total of 301 metabolites, including 170 named (56.5%) and 131 (43.5%) unnamed compounds, were characterized across both species. S.  lepidophylla retained significantly higher abundances of sucrose, mono‐ and polysaccharides, and sugar alcohols than did S. moellendorffii. Aromatic amino acids, the well‐known osmoprotectant betaine and flavonoids were also more abundant in S. lepidophylla. Notably, levels of γ‐glutamyl amino acid, linked with glutathione metabolism in the detoxification of reactive oxygen species, and with possible nitrogen remobilization following rehydration, were markedly higher in S. lepidophylla. Markers for lipoxygenase activity were also greater in S. lepidophylla, especially at 50% RWC. S. moellendorffii contained more than twice the number of unnamed compounds, with only a slightly greater abundance than in S. lepidophylla. In contrast, S. lepidophylla contained 14 unnamed compounds of fivefold or greater abundance than in S. moellendorffii, suggesting that these compounds might play critical roles in DT. Overall, S. lepidophylla appears poised to tolerate desiccation in a constitutive manner using a wide range of metabolites with some inducible components, whereas S. moellendorffii mounts only limited metabolic responses to dehydration stress.
Mutations in two non‐canonical Arabidopsis SWI2/SNF2 chromatin remodeling ATPases cause embryogenesis and stem cell maintenance defects
Authors: Sang Yi , Silva‐Ortega Claudia O. , Wu Shuang , Yamaguchi Nobutoshi , Wu Miin‐Feng , Pfluger Jennifer , Gillmor C. Stewart , Gallagher Kimberly L. , Wagner Doris 
Published: October 2012

SummarySWI2/SNF2 chromatin remodeling ATPases play important roles in plant and metazoan development. Whereas metazoans generally encode one or two SWI2/SNF2 ATPase genes, Arabidopsis encodes four such chromatin regulators: the well‐studied BRAHMA and SPLAYED ATPases, as well as two closely related non‐canonical SWI2/SNF2 ATPases, CHR12 and CHR23. No developmental role has as yet been described for CHR12 and CHR23. Here, we show that although strong single chr12 or chr23 mutants are morphologically indistinguishable from the wild type, chr12 chr23 double mutants cause embryonic lethality. The double mutant embryos fail to initiate root and shoot meristems, and display few and aberrant cell divisions. Weak double mutant embryos give rise to viable seedlings with dramatic defects in the maintenance of both the shoot and the root stem cell populations. Paradoxically, the stem cell defects are correlated with increased expression of the stem cell markers WUSCHEL and WOX5. During subsequent development, the meristem defects are partially overcome to allow for the formation of very small, bushy adult plants. Based on the observed morphological defects, we named the two chromatin remodelers MINUSCULE 1 and 2. Possible links between minu1 minu2 defects and defects in hormone signaling and replication‐coupled chromatin assembly are discussed.
The tyrosine‐sulfated peptide receptors PSKR1 and PSY1R modify the immunity of Arabidopsis to biotrophic and necrotrophic pathogens in an antagonistic manner
Authors: Mosher Stephen , Seybold Heike , Rodriguez Patricia , Stahl Mark , Davies Kelli A. , Dayaratne Sajeewani , Morillo Santiago A. , Wierzba Michael , Favery Bruno , Keller Harald , Tax Frans E. , Kemmerling Birgit 
Published: October 2012

SummaryThe tyrosine‐sulfated peptides PSKα and PSY1 bind to specific leucine‐rich repeat surface receptor kinases and control cell proliferation in plants. In a reverse genetic screen, we identified the phytosulfokine (PSK) receptor PSKR1 as an important component of plant defense. Multiple independent loss‐of‐function mutants in PSKR1 are more resistant to biotrophic bacteria, show enhanced pathogen‐associated molecular pattern responses and less lesion formation after infection with the bacterial pathogen Pseudomonas syringae pv. tomato DC3000. By contrast, pskr1 mutants are more susceptible to necrotrophic fungal infection with Alternaria brassicicola, show more lesion formation and fungal growth which is not observed on wild‐type plants. The antagonistic effect on biotrophic and necrotrophic pathogen resistance is reflected by enhanced salicylate and reduced jasmonate responses in the mutants, suggesting that PSKR1 suppresses salicylate‐dependent defense responses. Detailed analysis of single and multiple mutations in the three paralogous genes PSKR1, ‐2 and PSY1‐receptor (PSY1R) determined that PSKR1 and PSY1R, but not PSKR2, have a partially redundant effect on plant immunity. In animals and plants, peptide sulfation is catalyzed by a tyrosylprotein sulfotransferase (TPST). Mutants lacking TPST show increased resistance to bacterial infection and increased susceptibility to fungal infection, mimicking the triple receptor mutant phenotypes. Feeding experiments with PSKα in tpst‐1 mutants partially restore the defense‐related phenotypes, indicating that perception of the PSKα peptide has a direct effect on plant defense. These results suggest that the PSKR subfamily integrates growth‐promoting and defense signals mediated by sulfated peptides and modulates cellular plasticity to allow flexible adjustment to environmental changes.
Algebraic boundaries of Hilbert’s SOS cones
Authors: Blekherman Grigoriy , Hauenstein Jonathan , Ottem John Christian , Ranestad Kristian , Sturmfels Bernd 
Published: October 2012

AbstractWe study the geometry underlying the difference between non-negative polynomials and sums of squares (SOS). The hypersurfaces that discriminate these two cones for ternary sextics and quaternary quartics are shown to be Noether–Lefschetz loci of K3 surfaces. The projective duals of these hypersurfaces are defined by rank constraints on Hankel matrices. We compute their degrees using numerical algebraic geometry, thereby verifying results due to Maulik and Pandharipande. The non-SOS extreme rays of the two cones of non-negative forms are parametrized, respectively, by the Severi variety of plane rational sextics and by the variety of quartic symmetroids.
Advancements in pressure–volume catheter technology – stress remodelling after infarction
Authors: Clark James E. , Marber Michael S. 
Published: October 2012

New Findings
What is the topic of this review?The gold standards for assessing heart function in experimental animals are magnetic resonance imaging or high‐frequency ultrasound; however, these are not accessible in many laboratories. We review here the use of the new microconductance catheter technologies to assess cardiac function in rodent models of the diseased heart.
What advances does it highlight?Recent advances in the technology of conductance and admittance catheter systems provide an inexpensive, readily available method to assess cardiac function in rodents. We discuss the common pitfalls in using this technique and present evidence showing that its reliability and reproducibility are similar to ultrasound.
Microconductance catheters have been successfully applied to measure left ventricular (LV) function in the mouse to assess cardiac or pharmacological interventions for a number of years. New complex admittance methods produce an estimate of the parallel admittance of cardiac muscle that can be used to correct the measurement in real time. This contrasts with existing conductance technologies that require in vivo calibration using a bolus of hypertonic saline. Here, we report the application of this emerging technology in the context of myocardial infarction and LV remodelling. Using a combination of high‐resolution ultrasound and LV conductance catheters, we compared measures of LV function using an admittance system and a traditional conductance‐derived pressure–volume (PV) system. We subjected C57BL/6 mice to focal myocardial ischaemia–reperfusion by transient ligation of the left anterior descending coronary artery and assessed cardiac function with different systems to determine the reliability and accuracy of these methods to distinguish between normal and dysfunctional ventricle. We demonstrate that the admittance PV system, in our hands, provides a straightforward solution for assessing LV function in mice. Using this technique in combination with other established methods, we measured LV dysfunction following coronary artery occlusion and reperfusion, which can be ameliorated using a known preconditioning agent (CORM‐3), and found that functional read‐outs are representative of other methods. We have found that, especially in diseased tissue, LV pressure–volume loops derived from complex admittance provide a reproducible and reliable method of determining LV function without the need for technically challenging calibration. Our data suggest that admittance records accurate/physiological LV cavity volumes when compared with other invasive methods in the same animal. This emerging technology is both effective and reproducible for measuring LV function and dysfunction in the mouse, without the need for complicated interventions to calibrate the measurements or training in a new technology. This may mark the way towards a fast and accurate assessment of murine cardiac function in normal animals and disease models.
The pulmonary vascular response to combined activation of the muscle metaboreflex and mechanoreflex
Authors: White Michael J. , Lykidis Christos K. , Balanos George M. 
Published: October 2012

New Findings
What is the central question of this study?It is currently unknown whether there is a pulmonary vascular response to the combined activation of the muscle and the muscle mechanoreflex in man.
What is the main finding and its importance?For the first time, we show that activation of the muscle mechanoreflex attenuated the increases in pulmonary vascular resistance caused by metaboreflex activation.
Muscle metabo‐ and mechanoreflexes are known to influence systemic cardiovascular responses to exercise. Whether interplay between these reflexes is operant in the control of the pulmonary vascular response to exercise is unknown. The aim of this study was to assess the pulmonary vascular response to the combined activation of the two muscle reflexes. Nine healthy subjects performed a bout of isometric calf plantarflexion exercise during local circulatory occlusion, which was continued for 9 min postexercise (PECO). At 5 min into PECO the calf muscle was passively stretched for 180 s. A control (no exercise) protocol was also undertaken. Heart rate, blood pressure measurements and echocardiographically determined estimates of systolic pulmonary artery pressure (SPAP) and cardiac output () were obtained at intervals throughout the two protocols. Elevations in SPAP (by 22.51 ± 2.61%), (by 26.92 ± 2.99%) and mean arterial pressure (by 15.38 ± 2.29%) were noted during isometric exercise in comparison to baseline (all P < 0.05). Increases in SPAP and mean arterial pressure persisted during PECO (All P < 0.05), whereas returned to resting levels. These increases in mean arterial pressure and SPAP were sustained during stretch which significantly elevated (All P < 0.05). These data suggest that activation of the muscle mechanoreflex attenuated the increases in pulmonary vascular resistance caused by metaboreflex activation. This finding has important implications for the regulation of pulmonary haemodynamics during human exercise.
Environment-Dependent Distribution of the Sediment
nifH
-Harboring Microbiota in the Northern South China Sea
Authors: Dang Hongyue , Yang Jinying , Li Jing , Luan Xiwu , Zhang Yunbo , Gu Guizhou , Xue Rongrong , Zong Mingyue , Klotz Martin G. 
Published: October 2012

ABSTRACT

The South China Sea (SCS), the largest marginal sea in the Western Pacific Ocean, is a huge oligotrophic water body with very limited influx of nitrogenous nutrients. This suggests that sediment microbial N
2
fixation plays an important role in the production of bioavailable nitrogen. To test the molecular underpinning of this hypothesis, the diversity, abundance, biogeographical distribution, and community structure of the sediment diazotrophic microbiota were investigated at 12 sampling sites, including estuarine, coastal, offshore, deep-sea, and methane hydrate reservoirs or their prospective areas by targeting
nifH
and some other functional biomarker genes. Diverse and novel
nifH
sequences were obtained, significantly extending the evolutionary complexity of extant
nifH
genes. Statistical analyses indicate that sediment
in situ
temperature is the most significant environmental factor influencing the abundance, community structure, and spatial distribution of the sediment
nifH
-harboring microbial assemblages in the northern SCS (nSCS). The significantly positive correlation of the sediment pore water NH
4
+
concentration with the
nifH
gene abundance suggests that the nSCS sediment
nifH
-harboring microbiota is active in N
2
fixation and NH
4
+
production. Several other environmental factors, including sediment pore water PO
4
3−
concentration, sediment organic carbon, nitrogen and phosphorus levels, etc., are also important in influencing the community structure, spatial distribution, or abundance of the
nifH
-harboring microbial assemblages. We also confirmed that the
nifH
genes encoded by archaeal diazotrophs in the ANME-2c subgroup occur exclusively in the deep-sea methane seep areas, providing for the possibility to develop ANME-2c
nifH
genes as a diagnostic tool for deep-sea methane hydrate reservoir discovery.
Expression and Characterization of a Bifidobacterium adolescentis Beta-Mannanase Carrying Mannan-Binding and Cell Association Motifs
Authors: Kulcinskaja Evelina , Rosengren Anna , Ibrahim Romany , Kolenová Katarína , Stålbrand Henrik 
Published: October 2012

ABSTRACTThe gene encoding β-mannanase (EC 3.2.1.78) BaMan26A from the bacteriumBifidobacterium adolescentis(living in the human gut) was cloned and the gene product characterized. The enzyme was found to be modular and to contain a putative signal peptide. It possesses a catalytic module of the glycoside hydrolase family 26, a predicted immunoglobulin-like module, and two putative carbohydrate-binding modules (CBMs) of family 23. The enzyme is likely cell attached either by the sortase mechanism (LPXTG motif) or via a C-terminal transmembrane helix. The gene was expressed inEscherichia coliwithout the native signal peptide or the cell anchor. Two variants were made: one containing all four modules, designated BaMan26A-101K, and one truncated before the CBMs, designated BaMan26A-53K. BaMan26A-101K, which contains the CBMs, showed an affinity to carob galactomannan having a dissociation constant of 0.34 μM (8.8 mg/liter), whereas BaMan26A-53K did not bind, showing that at least one of the putative CBMs of family 23 is mannan binding. For BaMan26A-53K,kcatwas determined to be 444 s−1andKm21.3 g/liter using carob galactomannan as the substrate at the optimal pH of 5.3. Both of the enzyme variants hydrolyzed konjac glucomannan, as well as carob and guar gum galactomannans to a mixture of oligosaccharides. The dominant product from ivory nut mannan was found to be mannotriose. Mannobiose and mannotetraose were produced to a lesser extent, as shown by high-performance anion-exchange chromatography. Mannobiose was not hydrolyzed, and mannotriose was hydrolyzed at a significantly lower rate than the longer oligosaccharides.
Functional γ-Aminobutyrate Shunt in Listeria monocytogenes: Role in Acid Tolerance and Succinate Biosynthesis
Authors: Feehily Conor , O'Byrne Conor P. , Karatzas Kimon Andreas G. 
Published: October 2012

ABSTRACT

Listeria monocytogenes
, the causative agent of human listeriosis, is known for its ability to withstand severe environmental stresses. The glutamate decarboxylase (GAD) system is one of the principal systems utilized by the bacterium to cope with acid stress, a reaction that produces γ-aminobutyrate (GABA) from glutamate. Recently, we have shown that GABA can accumulate intracellularly under acidic conditions, even under conditions where no extracellular glutamate-GABA exchange is detectable. The GABA shunt, a pathway that metabolizes GABA to succinate, has been described for several other bacterial genera, and the present study sought to determine whether
L. monocytogenes
has this metabolic capacity, which, if present, could provide a possible route for succinate biosynthesis in
L. monocytogenes
. Using crude protein extracts from
L. monocytogenes
EGD-e, we show that this strain exhibits activity for the two main enzyme reactions in the GABA shunt, GABA aminotransferase (GABA-AT) and succinic semialdehyde dehydrogenase (SSDH). Two genes were identified as candidates for encoding these enzyme activities,
argD
(GABA-AT) and
lmo0913
(SSDH). Crude protein extracts prepared from a mutant lacking a functional
argD
gene significantly reduced GABA-AT activity, while an
lmo0913
mutant lost all detectable SSDH activity. The deletion of
lmo0913
increased the acid tolerance of EGD-e and showed an increased accumulation of intracellular GABA, suggesting that this pathway plays a significant role in the survival of this pathogen under acidic conditions. This is the first report of such a pathway in the genus
Listeria
, which highlights an important link between metabolism and acid tolerance and also presents a possible compensatory pathway to partially overcome the incomplete tricarboxylic acid cycle of
Listeria
.
Lineage-Specific Responses of Microbial Communities to Environmental Change
Authors: Youngblut Nicholas D. , Shade Ashley , Read Jordan S. , McMahon Katherine D. , Whitaker Rachel J. 
Published: October 2012

ABSTRACT

A great challenge facing microbial ecology is how to define ecologically relevant taxonomic units. To address this challenge, we investigated how changing the definition of operational taxonomic units (OTUs) influences the perception of ecological patterns in microbial communities as they respond to a dramatic environmental change. We used pyrosequenced tags of the bacterial V2 16S rRNA region, as well as clone libraries constructed from the cytochrome oxidase C gene
ccoN
, to provide additional taxonomic resolution for the common freshwater genus
Polynucleobacter
. At the most highly resolved taxonomic scale, we show that distinct genotypes associated with the abundant
Polynucleobacter
lineages exhibit divergent spatial patterns and dramatic changes over time, while the also abundant
Actinobacteria
OTUs are highly coherent. This clearly demonstrates that different bacterial lineages demand different taxonomic definitions to capture ecological patterns. Based on the temporal distribution of highly resolved taxa in the hypolimnion, we demonstrate that change in the population structure of a single genotype can provide additional insight into the mechanisms of community-level responses. These results highlight the importance and feasibility of examining ecological change in microbial communities across taxonomic scales while also providing valuable insight into the ecological characteristics of ecologically coherent groups in this system.
Tetrathionate-Forming Thiosulfate Dehydrogenase from the Acidophilic, Chemolithoautotrophic Bacterium Acidithiobacillus ferrooxidans
Authors: Kikumoto Mei , Nogami Shohei , Kanao Tadayoshi , Takada Jun , Kamimura Kazuo 
Published: October 2012

ABSTRACT

Thiosulfate dehydrogenase is known to play a significant role in thiosulfate oxidation in the acidophilic, obligately chemolithoautotroph,
Acidithiobacillus ferrooxidans
. Enzyme activity measured using ferricyanide as the electron acceptor was detected in cell extracts of
A. ferrooxidans
ATCC 23270 grown on tetrathionate or sulfur, but no activity was detected in ferrous iron-grown cells. The enzyme was enriched 63-fold from cell extracts of tetrathionate-grown cells. Maximum enzyme activity (13.8 U mg
−1
) was observed at pH 2.5 and 70°C. The end product of the enzyme reaction was tetrathionate. The enzyme reduced neither ubiquinone nor horse heart cytochrome
c
, which serves as an electron acceptor. A major protein with a molecular mass of ∼25 kDa was detected in the partially purified preparation. Heme was not detected in the preparation, according to the results of spectroscopic analysis and heme staining. The open reading frame of AFE_0042 was identified by BLAST by using the N-terminal amino acid sequence of the protein. The gene was found within a region that was previously noted for sulfur metabolism-related gene clustering. The recombinant protein produced in
Escherichia coli
had a molecular mass of ∼25 kDa and showed thiosulfate dehydrogenase activity, with maximum enzyme activity (6.5 U mg
−1
) observed at pH 2.5 and 50°C.