bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transfusion of recently donated (fresh) red blood cells (RBCs) does not improve survival in comparison with current practice, while safety of the oldest stored units is yet to be established: a meta‐analysis
Authors: Remy K. E. , Sun J. , Wang D. , Welsh J. , Solomon S. B. , Klein H. G. , Natanson C. , Cortés‐Puch I. 
Published: February 2016

Background and ObjectivesPreclinical studies generated the hypothesis that older stored red blood cells (RBCs) can increase transfusion risks. To examine the most updated and complete clinical evidence and compare results between two trial designs, we assessed both observational studies and randomized controlled trials (RCTs) studying the effect of RBC storage age on mortality.Materials and MethodsFive databases were searched through December 2014 for studies comparing mortality using transfused RBCs having longer and shorter storage times.ResultsAnalysis of six RCTs found no significant differences in survival comparing current practice (average storage age of 2 to 3 weeks) to transfusion of 1‐ to 10‐day‐old RBCs (OR 0·91, 95% CI 0·77‐1·07). RBC storage age was lower in RCTs vs. observational studies (P = 0·01). The 31 observational studies found an increased risk of death (OR 1·13, 95% CI 1·03–1·24) (P = 0·01) with increasing age of RBCs, a different mortality effect than RCTs (P = 0·02).ConclusionRCTs established that transfusion of 1‐ to 10‐day‐old stored RBCs is not superior to current practice. The apparent discrepancy in mortality between analyses of RCTs and observational studies may in part relate to differences in hypotheses tested and ages of stored RBCs studied. Further trials investigating 1‐ to 10‐day‐old stored RBC benefits would seem of lower priority than studies to determine whether 4‐ to 6‐week stored units have safety and efficacy equivalent to the 2‐ to 3‐week‐old stored RBCs commonly transfused today.
Structural studies of the C‐terminal tail of polycystin‐2 (PC2) reveal insights into the mechanisms used for the functional regulation of PC2
Authors: Yang Yifei , Ehrlich Barbara E. 
Published: February 2016

AbstractMutations in polycystin‐2 (PC2) lead to autosomal dominant polycystic kidney disease (ADPKD). The molecular mechanism linking mutations in PC2 and the pathogenesis of ADPKD is not well understood. Therefore, understanding the functional regulation of PC2 and its interaction with other proteins under both physiological and pathogenic conditions is important for elucidating the disease mechanism and identifying potential molecular targets for treatment. Normally, PC2 functions as a calcium‐permeable channel whose activity is regulated by calcium binding to the C‐terminal domain of PC2 (PC2 Cterm). The PC2 Cterm is also involved in the PC2 channel assembly and hetero‐oligomerization with other binding partners in cells. Different functional domains of the PC2 Cterm have been studied using structural approaches. Within the PC2 Cterm, there is a calcium‐binding EF‐hand domain, crucial for the calcium‐dependent activity of the PC2 channel. Downstream of the EF‐hand domain lies a coiled‐coil region, which is involved in the assembly and hetero‐interaction of the PC2 protein. The PC2 Cterm can form an oligomer, mediated by the coiled‐coil region. Although PC2 Cterm has been extensively studied for its relationship with ADPKD and its importance in PC2 regulation, there are misunderstandings with respect to the definition of the domain topology within the PC2 Cterm and the functional role of each domain. Here, we review previous studies that connect the molecular properties of the domains of PC2 Cterm to distinct aspects of PC2 functions and regulation.
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Relevance of Damped Harmonic Oscillation for Modeling the Training Effects on Daily Physical Performance Capacity in Team Sport
Authors: Morin Stéphane , Ahmaïdi Saïd , Leprêtre Pierre-Marie 
Published: February 2016

Context:Positive and negative effects of training induce apparent oscillations of performance, suggesting that the delayed cumulative effects of training on daily performance capacity (DPC) are best fitted by sine waves damped over time.Purpose:To compare the criterion validity of the impulse-response (IR) model of Banister et al and the damped harmonic oscillation (DHO) model for quantifying the training load (TL)–DPC relationship.Methods:Six female professional volleyball players (20.8 ± 2.4 y) were monitored using the session rating of perceived exertion (sRPE) for 9 mo to quantify TL. Countermovement-jump (CMJ) and 4-step-approach-CMJ (4sCMJ) performances were recorded once a month. Parameters of models were determined by minimizing residual-sum squares between predicted and real performances with a nonlinear regression.Results:DPC was best fitted by the DHO model rather than the IR model (CMJ, R2 = .80 ±.08 and.69 ±.20, respectively; 4sCMJ, R2 = .86 ± .09 and .67 ± .29, respectively). The damping parameter θ and the period T were positively correlated with age (ρ = 0.81, P < .05, and ρ = 0.86, P < .02, respectively).Conclusions:The DHO model is a useful tool for modeling DPC as the sum of the delayed DPCs from the consecutive training and recovery days. DPC could be considered the expression of the individual process of accumulation and dissipation of fatigue induced by training. DHO-model parameters were correlated with age, which prompts one to postulate that expertise has a major influence on DPC. The DHO model will help coaches develop a greater understanding of training effects and make monitoring of the training process more effective.
Two Weeks of Repeated-Sprint Training in Soccer: To Turn or Not to Turn?
Authors: Taylor Jonathan M. , Macpherson Tom W. , McLaren Shaun J. , Spears Iain , Weston Matthew 
Published: February 2016

Purpose:To compare the effects of 2 repeated-sprint training programs on fitness in soccer.
Methods:Fifteen semiprofessional soccer players (age: 24 ± 4 y; body mass: 77 ± 8 kg) completed 6 repeated-sprint training sessions over a 2-week period. Players were assigned to a straight-line (STR) (n = 8; 3–4 sets of 7 × 30 m) or change of direction (CoD) (n = 7; 3–4 sets of 7 × 20-m) repeated-sprint training group. Performance measures included 5-, 10-, and 20-m sprints, countermovement jump, Illinois agility, and Yo-Yo Intermittent Recovery Test level 1 (YYIRTL1) performance. Internal (heart rate) and external (global positioning system-derived measures) training loads were monitored throughout. Data were analyzed using magnitude-based inferences.
Results:Internal and external loads were higher in the STR group than in the CoD group with large differences in maximum velocity (28.7%; ±90% confidence limits, 3.3%), moderate differences in mean heart rates (7.0%; ±1.4%) and PlayerLoad (17.6%; ±8.6%), and small differences in peak heart rates (3.0%; ±1.6%). Large improvements in 5-m (STR: 9.6%; ±7.0% and CoD: 9.4%; ±3.3%), 10-m (STR: 6.6%; ±4.6% and CoD: 6.7%; ±2.2%), and 20-m (STR: 3.6; ±4.0% and CoD: 4.0; ±1.7%) sprints were observed. Large and moderate improvements in YYIRTL1 performance were observed in the STR (24.0%; ±9.3%) and CoD (31.0%; ±7.5%), respectively. Between-groups differences in outcome measures were unclear.
Conclusions:Two weeks of repeated-sprint training stimulates improvements in acceleration, speed, and high-intensity running performance in soccer players. Despite STR inducing higher internal and external training loads, training adaptations were unclear between training modes, indicating a need for further research.
Energetics of Table Tennis and Table Tennis–Specific Exercise Testing
Authors: Zagatto Alessandro Moura , Leite Jorge Vieira de Mello , Papoti Marcelo , Beneke Ralph 
Published: February 2016

Purpose:To test the hypotheses that the metabolic profile of table tennis is dominantly aerobic, anaerobic energy is related to the accumulated duration and intensity of rallies, and activity and metabolic profile are interrelated with the individual fitness profile determined via table tennis–specific tests.
Methods:Eleven male experienced table tennis players (22 ± 3 y, 77.6 ± 18.9 kg, 177.1 ± 8.1 cm) underwent 2 simulated table tennis matches to analyze aerobic (WOXID) energy, anaerobic glycolytic (WBLC) energy, and phosphocreatine breakdown (WPCr); a table tennis–specific graded exercise test to measure ventilatory threshold and peak oxygen uptake; and an exhaustive supramaximal table tennis effort to determine maximal accumulated deficit of oxygen.
Results:WOXID, WBLC, and WPCr corresponded to 96.5% ± 1.7%, 1.0% ± 0.7%, and 2.5% ± 1.4%, respectively. WOXID was interrelated with rally duration (r = .81) and number of shots per rally (r = .77), whereas match intensity was correlated with WPCr (r = .62) and maximal accumulated oxygen deficit (r = .58).
Conclusions:The metabolic profile of table tennis is predominantly aerobic and interrelated with the individual fitness profile determined via table tennis–specific tests. Table tennis–specific ventilatory threshold determines the average oxygen uptake and overall WOXID, whereas table tennis–specific maximal accumulated oxygen deficit indicates the ability to use and sustain slightly higher blood lactate concentration and WBLC during the match.
Kinetic Study of Laboratory Mutants of NDM-1 Metallo-β-Lactamase and the Importance of an Isoleucine at Position 35
Authors: Marcoccia Francesca , Bottoni Carlo , Sabatini Alessia , Colapietro Martina , Mercuri Paola Sandra , Galleni Moreno , Kerff Frédéric , Matagne André , Celenza Giuseppe , Amicosante Gianfranco , Perilli Mariagrazia 
Published: February 2016

ABSTRACT

Two laboratory mutants of NDM-1 were generated by replacing the isoleucine at position 35 with threonine and serine residues: the NDM-1
I35T
and NDM-1
I35S
enzymes. These mutants were well characterized, and their kinetic parameters were compared with those of the NDM-1 wild type. The
k
cat
,

K
m

, and
k
cat
/

K
m

values calculated for the two mutants were slightly different from those of the wild-type enzyme. Interestingly, the
k
cat
/

K
m

of NDM-1
I35S
for loracarbef was about 14-fold higher than that of NDM-1. Far-UV circular dichroism (CD) spectra of NDM-1 and NDM-1
I35T
and NDM-1
I35S
enzymes suggest local structural rearrangements in the secondary structure with a marked reduction of α-helix content in the mutants.
VraH Is the Third Component of the Staphylococcus aureus VraDEH System Involved in Gallidermin and Daptomycin Resistance and Pathogenicity
Authors: Popella Peter , Krauss Sophia , Ebner Patrick , Nega Mulugeta , Deibert Julia , Götz Friedrich 
Published: February 2016

ABSTRACTIn bacteria, extracellular signals are transduced into the cell predominantly by two-component systems (TCSs) comprising a regulatory unit triggered by a specific signal. Some of the TCSs control executing units such as ABC transporters involved in antibiotic resistance. For instance, inStaphylococcus aureus, activation of BraSR leads to the upregulation ofvraDEexpression that encodes an ABC transporter playing a role in bacitracin and nisin resistance. In this study, we show that the small staphylococcal transmembrane protein VraH forms, together with VraDE, a three-component system. Although the expression ofvraHin the absence ofvraDEwas sufficient to mediate low-level resistance, only this VraDEH entity conferred high-level resistance against daptomycin and gallidermin. In most staphylococcal genomes,vraHis located immediately downstream ofvraDE, forming an operon, whereas in some species it is localized differently. In an invertebrate infection model, VraDEH significantly enhancedS. aureuspathogenicity. In analogy to the TCS connectors, VraH can be regarded as an ABC connector that modulates the activity of ABC transporters involved in antibiotic resistance.
Lead Selection of a New Aminomethylphenol, JPC-3210, for Malaria Treatment and Prevention
Authors: Chavchich Marina , Birrell Geoffrey W. , Ager Arba L. , MacKenzie Donna O. , Heffernan Gavin D. , Schiehser Guy A. , Jacobus Laura R. , Shanks G. Dennis , Jacobus David P. , Edstein Michael D. 
Published: February 2016

ABSTRACT

Structure-activity relationship studies of trifluoromethyl-substituted pyridine and pyrimidine analogues of 2-aminomethylphenols (JPC-2997, JPC-3186, and JPC-3210) were conducted for preclinical development for malaria treatment and/or prevention. Of these compounds, JPC-3210 [4-(
tert
-butyl)-2-((
tert
-butylamino)methyl)-6-(5-fluoro-6-(trifluoromethyl)pyridin-3-yl)phenol] was selected as the lead compound due to superior
in vitro
antimalarial activity against multidrug-resistant
Plasmodium falciparum
lines, lower
in vitro
cytotoxicity in mammalian cell lines, longer plasma elimination half-life, and greater
in vivo
efficacy against murine malaria.
Enhancing the α-Cyclodextrin Specificity of Cyclodextrin Glycosyltransferase from Paenibacillus macerans by Mutagenesis Masking Subsite −7
Authors: Wang Lei , Duan Xuguo , Wu Jing 
Published: February 2016

ABSTRACT

Cyclodextrin glycosyltransferases (CGTases) (EC 2.4.1.19) catalyze the conversion of starch or starch derivates into mixtures of α-, β-, and γ-cyclodextrins. Because time-consuming and expensive purification procedures hinder the widespread application of single-ingredient cyclodextrins, enzymes with enhanced specificity are needed. In this study, we tested the hypothesis that the α-cyclodextrin selectivity of
Paenibacillus macerans
α-CGTase could be augmented by masking subsite −7 of the active site, blocking the formation of larger cyclodextrins, particularly β-cyclodextrin. Five single mutants and three double mutants designed to remove hydrogen-bonding interactions between the enzyme and substrate at subsite −7 were constructed and characterized in detail. Although the rates of α-cyclodextrin formation varied only modestly, the rate of β-cyclodextrin formation decreased dramatically in these mutants. The increase in α-cyclodextrin selectivity was directly proportional to the increase in the ratio of their
k
cat
values for α- and β-cyclodextrin formation. The R146A/D147P and R146P/D147A double mutants exhibited ratios of α-cyclodextrin to total cyclodextrin production of 75.1% and 76.1%, approximately one-fifth greater than that of the wild-type enzyme (63.2%), without loss of thermostability. Thus, these double mutants may be more suitable for the industrial production of α-cyclodextrin than the wild-type enzyme. The production of β-cyclodextrin by these mutants was almost identical to their production of γ-cyclodextrin, which was unaffected by the mutations in subsite −7, suggesting that subsite −7 was effectively blocked by these mutations. Further increases in α-cyclodextrin selectivity will require identification of the mechanism or mechanisms by which these small quantities of larger cyclodextrins are formed.
Global Transcriptional Regulation of Backbone Genes in Broad-Host-Range Plasmid RA3 from the IncU Group Involves Segregation Protein KorB (ParB Family)
Authors: Kulinska Anna , Godziszewska Jolanta , Wojciechowska Anna , Ludwiczak Marta , Jagura-Burdzy Grazyna 
Published: February 2016

ABSTRACT

The KorB protein of the broad-host-range conjugative plasmid RA3 from the IncU group belongs to the ParB family of plasmid and chromosomal segregation proteins. As a partitioning DNA-binding factor, KorB specifically recognizes a 16-bp palindrome which is an essential motif in the centromere-like sequence
parS
RA3
, forms a segrosome, and together with its partner IncC (ParA family) participates in active DNA segregation ensuring stable plasmid maintenance. Here we show that by binding to this palindromic sequence, KorB also acts as a repressor for the adjacent
mobC
promoter driving expression of the
mobC-nic
operon, which is involved in DNA processing during conjugation. Three other promoters, one buried in the conjugative transfer module and two divergent promoters located at the border between the replication and stability regions, are regulated by KorB binding to additional KorB operators (O
B
s). KorB acts as a repressor at a distance, binding to O
B
s separated from their cognate promoters by between 46 and 1,317 nucleotides. This repressor activity is facilitated by KorB spreading along DNA, since a polymerization-deficient KorB variant with its dimerization and DNA-binding abilities intact is inactive in transcriptional repression. KorB may act as a global regulator of RA3 plasmid functions in
Escherichia coli
, since its overexpression in
trans
negatively interferes with mini-RA3 replication and stable maintenance of RA3.
High-Throughput Single-Cell Cultivation on Microfluidic Streak Plates
Authors: Jiang Cheng-Ying , Dong Libing , Zhao Jian-Kang , Hu Xiaofang , Shen Chaohua , Qiao Yuxin , Zhang Xinyue , Wang Yapei , Ismagilov Rustem F. , Liu Shuang-Jiang , Du Wenbin 
Published: February 2016

ABSTRACT

This paper describes the microfluidic streak plate (MSP), a facile method for high-throughput microbial cell separation and cultivation in nanoliter sessile droplets. The MSP method builds upon the conventional streak plate technique by using microfluidic devices to generate nanoliter droplets that can be streaked manually or robotically onto petri dishes prefilled with carrier oil for cultivation of single cells. In addition, chemical gradients could be encoded in the droplet array for comprehensive dose-response analysis. The MSP method was validated by using single-cell isolation of
Escherichia coli
and antimicrobial susceptibility testing of
Pseudomonas aeruginosa
PAO1. The robustness of the MSP work flow was demonstrated by cultivating a soil community that degrades polycyclic aromatic hydrocarbons. Cultivation in droplets enabled detection of the richest species diversity with better coverage of rare species. Moreover, isolation and cultivation of bacterial strains by MSP led to the discovery of several species with high degradation efficiency, including four
Mycobacterium
isolates and a previously unknown fluoranthene-degrading
Blastococcus
species.
Biofilm and Planktonic Bacterial and Fungal Communities Transforming High-Molecular-Weight Polycyclic Aromatic Hydrocarbons
Authors: Folwell Benjamin D. , McGenity Terry J. , Whitby Corinne 
Published: February 2016

ABSTRACT

High-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs) are natural components of fossil fuels that are carcinogenic and persistent in the environment, particularly in oil sands process-affected water (OSPW). Their hydrophobicity and tendency to adsorb to organic matter result in low bioavailability and high recalcitrance to degradation. Despite the importance of microbes for environmental remediation, little is known about those involved in HMW-PAH transformations. Here, we investigated the transformation of HMW-PAHs using samples of OSPW and compared the bacterial and fungal community compositions attached to hydrophobic filters and in suspension. It was anticipated that the hydrophobic filters with sorbed HMW-PAHs would select for microbes that specialize in adhesion. Over 33 days, more pyrene was removed (75% ± 11.7%) than the five-ring PAHs benzo[
a
]pyrene (44% ± 13.6%) and benzo[
b
]fluoranthene (41% ± 12.6%). For both bacteria and fungi, the addition of PAHs led to a shift in community composition, but thereafter the major factor determining the fungal community composition was whether it was in the planktonic phase or attached to filters. In contrast, the major determinant of the bacterial community composition was the nature of the PAH serving as the carbon source. The main bacteria enriched by HMW-PAHs were
Pseudomonas
,
Bacillus
, and
Microbacterium
species. This report demonstrates that OSPW harbors microbial communities with the capacity to transform HMW-PAHs. Furthermore, the provision of suitable surfaces that encourage PAH sorption and microbial adhesion select for different fungal and bacterial species with the potential for HMW-PAH degradation.
Host Plant Determines the Population Size of an Obligate Symbiont (Buchnera aphidicola) in Aphids
Authors: Zhang Yuan-Chen , Cao Wen-Jie , Zhong Le-Rong , Godfray H. Charles J. , Liu Xiang-Dong 
Published: February 2016

ABSTRACT

Buchnera aphidicola
is an obligate endosymbiont that provides aphids with several essential nutrients. Though much is known about aphid-
Buchnera
interactions, the effect of the host plant on
Buchnera
population size remains unclear. Here we used quantitative PCR (qPCR) techniques to explore the effects of the host plant on
Buchnera
densities in the cotton-melon aphid,
Aphis gossypii
.
Buchnera
titers were significantly higher in populations that had been reared on cucumber for over 10 years than in populations maintained on cotton for a similar length of time. Aphids collected in the wild from hibiscus and zucchini harbored more
Buchnera
symbionts than those collected from cucumber and cotton. The effect of aphid genotype on the population size of
Buchnera
depended on the host plant upon which they fed. When aphids from populations maintained on cucumber or cotton were transferred to novel host plants, host survival and
Buchnera
population size fluctuated markedly for the first two generations before becoming relatively stable in the third and later generations. Host plant extracts from cucumber, pumpkin, zucchini, and cowpea added to artificial diets led to a significant increase in
Buchnera
titers in the aphids from the population reared on cotton, while plant extracts from cotton and zucchini led to a decrease in
Buchnera
titers in the aphids reared on cucumber. Gossypol, a secondary metabolite from cotton, suppressed
Buchnera
populations in populations from both cotton and cucumber, while cucurbitacin from cucurbit plants led to higher densities. Together, the results suggest that host plants influence
Buchnera
population processes and that this may provide phenotypic plasticity in host plant use for clonal aphids.
XoxF Acts as the Predominant Methanol Dehydrogenase in the Type I Methanotroph Methylomicrobium buryatense
Authors: Chu Frances , Lidstrom Mary E. 
Published: February 2016

ABSTRACT

Many methylotrophic taxa harbor two distinct methanol dehydrogenase (MDH) systems for oxidizing methanol to formaldehyde: the well-studied calcium-dependent MxaFI type and the more recently discovered lanthanide-containing XoxF type. MxaFI has traditionally been accepted as the major functional MDH in bacteria that contain both enzymes. However, in this study, we present evidence that, in a type I methanotroph,
Methylomicrobium buryatense
, XoxF is likely the primary functional MDH in the environment. The addition of lanthanides increases
xoxF
expression and greatly reduces
mxa
expression, even under conditions in which calcium concentrations are almost 100-fold higher than lanthanide concentrations. Mutations in genes encoding the MDH enzymes validate our finding that XoxF is the major functional MDH, as XoxF mutants grow more poorly than MxaFI mutants under unfavorable culturing conditions. In addition, mutant and transcriptional analyses demonstrate that the lanthanide-dependent MDH switch operating in methanotrophs is mediated in part by the orphan response regulator MxaB, whose gene transcription is itself lanthanide responsive.

IMPORTANCE
Aerobic methanotrophs, bacteria that oxidize methane for carbon and energy, require a methanol dehydrogenase enzyme to convert methanol into formaldehyde. The calcium-dependent enzyme MxaFI has been thought to primarily carry out methanol oxidation in methanotrophs. Recently, it was discovered that XoxF, a lanthanide-containing enzyme present in most methanotrophs, can also oxidize methanol. In a methanotroph with both MxaFI and XoxF, we demonstrate that lanthanides transcriptionally control genes encoding the two methanol dehydrogenases, in part by controlling expression of the response regulator MxaB. Lanthanides are abundant in the Earth's crust, and we demonstrate that micromolar amounts of lanthanides are sufficient to suppress MxaFI expression. Thus, we present evidence that XoxF acts as the predominant methanol dehydrogenase in a methanotroph.