bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduction of Legionella spp. in Water and in Soil by a Citrus Plant Extract Vapor
Authors: Laird Katie , Kurzbach Elena , Score Jodie , Tejpal Jyoti , Chi Tangyie George , Phillips Carol 
Published: July 2014

ABSTRACT

Legionnaires' disease is a severe form of pneumonia caused by
Legionella
spp., organisms often isolated from environmental sources, including soil and water.
Legionella
spp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred,
Legionella
is particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml
−1
on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor against
Legionella
spp. in water and in soil systems. Reductions of viable cells of
Legionella pneumophila
,
Legionella longbeachae
,
Legionella bozemanii
, and an intra-amoebal culture of
Legionella pneumophila
(water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and β-pinene) was conducted. There was up to a 5-log cells ml
−1
reduction in
Legionella
spp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water was
L. pneumophila
, with a 4-log cells ml
−1
reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controlling
Legionella
spp. from environmental sources.
Urea Uptake and Carbon Fixation by Marine Pelagic Bacteria and Archaea during the Arctic Summer and Winter Seasons
Authors: Connelly Tara L. , Baer Steven E. , Cooper Joshua T. , Bronk Deborah A. , Wawrik Boris 
Published: July 2014

ABSTRACT

How Arctic climate change might translate into alterations of biogeochemical cycles of carbon (C) and nitrogen (N) with respect to inorganic and organic N utilization is not well understood. This study combined
15
N uptake rate measurements for ammonium, nitrate, and urea with
15
N- and
13
C-based DNA stable-isotope probing (SIP). The objective was to identify active bacterial and archeal plankton and their role in N and C uptake during the Arctic summer and winter seasons. We hypothesized that bacteria and archaea would successfully compete for nitrate and urea during the Arctic winter but not during the summer, when phytoplankton dominate the uptake of these nitrogen sources. Samples were collected at a coastal station near Barrow, AK, during August and January. During both seasons, ammonium uptake rates were greater than those for nitrate or urea, and nitrate uptake rates remained lower than those for ammonium or urea. SIP experiments indicated a strong seasonal shift of bacterial and archaeal N utilization from ammonium during the summer to urea during the winter but did not support a similar seasonal pattern of nitrate utilization. Analysis of 16S rRNA gene sequences obtained from each SIP fraction implicated marine group I
Crenarchaeota
(MGIC) as well as
Betaproteobacteria
,
Firmicutes
, SAR11, and SAR324 in N uptake from urea during the winter. Similarly,
13
C SIP data suggested dark carbon fixation for MGIC, as well as for several proteobacterial lineages and the
Firmicutes
. These data are consistent with urea-fueled nitrification by polar archaea and bacteria, which may be advantageous under dark conditions.
Galactosyl-Lactose Sialylation Using Trypanosoma cruzi trans-Sialidase as the Biocatalyst and Bovine κ-Casein-Derived Glycomacropeptide as the Donor Substrate
Authors: Wilbrink Maarten H. , ten Kate Geert A. , van Leeuwen Sander S. , Sanders Peter , Sallomons Erik , Hage Johannes A. , Dijkhuizen Lubbert , Kamerling Johannis P. 
Published: July 2014

ABSTRACT

trans
-Sialidase (TS) enzymes catalyze the transfer of sialyl (Sia) residues from Sia(α2-3)Gal(β1-
x
)-glycans (sialo-glycans) to Gal(β1-
x
)-glycans (asialo-glycans). Aiming to apply this concept for the sialylation of linear and branched (Gal)

n

Glc oligosaccharide mixtures (GOS) using bovine κ-casein-derived glycomacropeptide (GMP) as the sialic acid donor, a kinetic study has been carried out with three components of GOS, i.e., 3′-galactosyl-lactose (β3′-GL), 4′-galactosyl-lactose (β4′-GL), and 6′-galactosyl-lactose (β6′-GL). This prebiotic GOS is prepared from lactose by incubation with suitable β-galactosidases, whereas GMP is a side-stream product of the dairy industry. The
trans
-sialidase from
Trypanosoma cruzi
(TcTS) was expressed in
Escherichia coli
and purified. Its temperature and pH optima were determined to be 25°C and pH 5.0, respectively. GMP [sialic acid content, 3.6% (wt/wt);
N
-acetylneuraminic acid (Neu5Ac), >99%; (α2-3)-linked Neu5Ac, 59%] was found to be an efficient sialyl donor, and up to 95% of the (α2-3)-linked Neu5Ac could be transferred to lactose when a 10-fold excess of this acceptor substrate was used. The products of the TcTS-catalyzed sialylation of β3′-GL, β4′-GL, and β6′-GL, using GMP as the sialic acid donor, were purified, and their structures were elucidated by nuclear magnetic resonance spectroscopy. Monosialylated β3′-GL and β4′-GL contained Neu5Ac connected to the terminal Gal residue; however, in the case of β6′-GL, TcTS was shown to sialylate the 3 position of both the internal and terminal Gal moieties, yielding two different monosialylated products and a disialylated structure. Kinetic analyses showed that TcTS had higher affinity for the GL substrates than lactose, while the
V
max
and
k
cat
values were higher in the case of lactose.
GH51 Arabinofuranosidase and Its Role in the Methylglucuronoarabinoxylan Utilization System in Paenibacillus sp. Strain JDR-2
Authors: Sawhney Neha , Preston James F. 
Published: July 2014

ABSTRACT

Methylglucuronoarabinoxylan (MeGAX

n

) from agricultural residues and energy crops is a significant yet underutilized biomass resource for production of biofuels and chemicals. Mild thermochemical pretreatment of bagasse yields MeGAX

n

requiring saccharifying enzymes for conversion to fermentable sugars. A xylanolytic bacterium,
Paenibacillus
sp. strain JDR-2, produces an extracellular cell-associated GH10 endoxylanse (XynA
1
) which efficiently depolymerizes methylglucuronoxylan (MeGX

n

) from hardwoods coupled with assimilation of oligosaccharides for further processing by intracellular GH67 α-glucuronidase, GH10 endoxylanase, and GH43 β-xylosidase. This process has been ascribed to genes that comprise a xylan utilization regulon that encodes XynA
1
and includes a gene cluster encoding transcriptional regulators, ABC transporters, and intracellular enzymes that convert assimilated oligosaccharides to fermentable sugars. Here we show that
Paenibacillus
sp. JDR-2 utilized MeGAX

n

without accumulation of oligosaccharides in the medium. The
Paenibacillus
sp. JDR-2 growth rate on MeGAX

n

was 3.1-fold greater than that on oligosaccharides generated from MeGAX

n

by XynA
1
. Candidate genes encoding GH51 arabinofuranosidases with potential roles were identified. Following growth on MeGAX

n

, quantitative reverse transcription-PCR identified a cluster of genes encoding a GH51 arabinofuranosidase (AbfB) and transcriptional regulators which were coordinately expressed along with the genes comprising the xylan utilization regulon. The action of XynA
1
on MeGAX

n

generated arabinoxylobiose, arabinoxylotriose, xylobiose, xylotriose, and methylglucuronoxylotriose. Recombinant AbfB processed arabinoxylooligosaccharides to xylooligosaccharides and arabinose. MeGAX

n

processing by
Paenibacillus
sp. JDR-2 may be achieved by extracellular depolymerization by XynA
1
coupled to assimilation of oligosaccharides and further processing by intracellular enzymes, including AbfB.
Paenibacillus
sp. JDR-2 provides a GH10/GH67 system complemented with genes encoding intracellular GH51 arabinofuranosidases for efficient utilization of MeGAX

n

.
Acetoin Synthesis Acquisition Favors Escherichia coli Growth at Low pH
Authors: Vivijs Bram , Moons Pieter , Aertsen Abram , Michiels Chris W. 
Published: July 2014

ABSTRACT

Some members of the family
Enterobacteriaceae
ferment sugars via the mixed-acid fermentation pathway. This yields large amounts of acids, causing strong and sometimes even lethal acidification of the environment. Other family members employ the 2,3-butanediol fermentation pathway, which generates comparatively less acidic and more neutral end products, such as acetoin and 2,3-butanediol. In this work, we equipped
Escherichia coli
MG1655 with the
budAB
operon, encoding the acetoin pathway, from
Serratia plymuthica
RVH1 and investigated how this affected the ability of
E. coli
to cope with acid stress during growth. Acetoin fermentation prevented lethal medium acidification by
E. coli
in lysogeny broth (LB) supplemented with glucose. It also supported growth and higher stationary-phase cell densities in acidified LB broth with glucose (pH 4.10 to 4.50) and in tomato juice (pH 4.40 to 5.00) and reduced the minimal pH at which growth could be initiated. On the other hand, the acetoin-producing strain was outcompeted by the nonproducer in a mixed-culture experiment at low pH, suggesting a fitness cost associated with acetoin production. Finally, we showed that acetoin production profoundly changes the appearance of
E. coli
on several diagnostic culture media. Natural
E. coli
strains that have laterally acquired
budAB
genes may therefore have escaped detection thus far. This study demonstrates the potential importance of acetoin fermentation in the ecology of
E. coli
in the food chain and contributes to a better understanding of the microbiological stability and safety of acidic foods.
Lactobacillus reuteri 100-23 Modulates Urea Hydrolysis in the Murine Stomach
Authors: Wilson Charlotte M. , Loach Diane , Lawley Blair , Bell Tracey , Sims Ian M. , O'Toole Paul W. , Zomer Aldert , Tannock Gerald W. 
Published: July 2014

ABSTRACT

Comparisons of
in vivo
(mouse stomach) and
in vitro
(laboratory culture) transcriptomes of
Lactobacillus reuteri
strain 100-23 were made by microarray analysis. These comparisons revealed the upregulation of genes associated with acid tolerance, including urease production, in the mouse stomach. Inactivation of the
ureC
gene reduced the acid tolerance of strain 100-23
in vitro
, and the mutant was outcompeted by the wild type in the gut of ex-
Lactobacillus
-free mice. Urine analysis showed that stable isotope-labeled urea, administered by gavage, was metabolized to a greater extent in
Lactobacillus
-free mice than animals colonized by strain 100-23. This surprising observation was associated with higher levels of urease activity and fecal-type bacteria in the stomach digesta of
Lactobacillus
-free mice. Despite the modulation of urea hydrolysis in the stomach, recycling of urea nitrogen in the murine host was not affected since the essential amino acid isoleucine, labeled with a stable isotope, was detected in the livers of both
Lactobacillus
-free and 100-23-colonized animals. Therefore, our experiments reveal a new and unexpected impact of
Lactobacillus
colonization on urea hydrolysis in the murine gut.
Polyamine Transporters and Polyamines Increase Furfural Tolerance during Xylose Fermentation with Ethanologenic Escherichia coli Strain LY180
Authors: Geddes Ryan D. , Wang Xuan , Yomano Lorraine P. , Miller Elliot N. , Zheng Huabao , Shanmugam Keelnatham T. , Ingram Lonnie O. 
Published: July 2014

ABSTRACT

Expression of genes encoding polyamine transporters from plasmids and polyamine supplements increased furfural tolerance (growth and ethanol production) in ethanologenic
Escherichia coli
LY180 (in AM1 mineral salts medium containing xylose). This represents a new approach to increase furfural tolerance and may be useful for other organisms. Microarray comparisons of two furfural-resistant mutants (EMFR9 and EMFR35) provided initial evidence for the importance of polyamine transporters. Each mutant contained a single polyamine transporter gene that was upregulated over 100-fold (microarrays) compared to that in the parent LY180, as well as a mutation that silenced the expression of
yqhD
. Based on these genetic changes, furfural tolerance was substantially reconstructed in the parent, LY180. Deletion of
potE
in EMFR9 lowered furfural tolerance to that of the parent. Deletion of
potE
and
puuP
in LY180 also decreased furfural tolerance, indicating functional importance of the native genes. Of the 8 polyamine transporters (18 genes) cloned and tested, half were beneficial for furfural tolerance (PotE, PuuP, PlaP, and PotABCD). Supplementing AM1 mineral salts medium with individual polyamines (agmatine, putrescine, and cadaverine) also increased furfural tolerance but to a smaller extent. In pH-controlled fermentations, polyamine transporter plasmids were shown to promote the metabolism of furfural and substantially reduce the time required to complete xylose fermentation. This increase in furfural tolerance is proposed to result from polyamine binding to negatively charged cellular constituents such as nucleic acids and phospholipids, providing protection from damage by furfural.
PafR, a Novel Transcription Regulator, Is Important for Pathogenesis in Uropathogenic Escherichia coli
Authors: Baum Mordechai , Watad Mobarak , Smith Sara N. , Alteri Christopher J. , Gordon Noa , Rosenshine Ilan , Mobley Harry L. , Amster-Choder Orna 
Published: July 2014

ABSTRACT

The
metV
genomic island in the chromosome of uropathogenic
Escherichia coli
(UPEC) encodes a putative transcription factor and a sugar permease of the phosphotransferase system (PTS), which are predicted to compose a Bgl-like sensory system. The presence of these two genes, hereby termed
pafR
and
pafP
, respectively, has been previously shown to correlate with isolates causing clinical syndromes. We show here that deletion of both genes impairs the ability of the resulting mutant to infect the CBA/J mouse model of ascending urinary tract infection compared to that of the parent strain, CFT073. Expressing the two genes in
trans
in the two-gene knockout mutant complemented full virulence. Deletion of either gene individually generated the same phenotype as the double knockout, indicating that both
pafR
and
pafP
are important to pathogenesis. We screened numerous environmental conditions but failed to detect expression from the promoter that precedes the
paf
genes
in vitro
, suggesting that they are
in vivo
induced (ivi). Although PafR is shown here to be capable of functioning as a transcriptional antiterminator, its targets in the UPEC genome are not known. Using microarray analysis, we have shown that expression of PafR from a heterologous promoter in CFT073 affects expression of genes related to bacterial virulence, biofilm formation, and metabolism. Expression of PafR also inhibits biofilm formation and motility. Taken together, our results suggest that the
paf
genes are implicated in pathogenesis and that PafR controls virulence genes, in particular biofilm formation genes.
Overlapping Functionality of the Pht Proteins in Zinc Homeostasis of Streptococcus pneumoniae
Authors: Plumptre Charles D. , Hughes Catherine E. , Harvey Richard M. , Eijkelkamp Bart A. , McDevitt Christopher A. , Paton James C. 
Published: July 2014

ABSTRACT

Streptococcus pneumoniae
is a globally significant pathogen that causes a range of diseases, including pneumonia, sepsis, meningitis, and otitis media. Its ability to cause disease depends upon the acquisition of nutrients from its environment, including transition metal ions such as zinc. The pneumococcus employs a number of surface proteins to achieve this, among which are four highly similar polyhistidine triad (Pht) proteins. It has previously been established that these proteins collectively aid in the delivery of zinc to the ABC transporter substrate-binding protein AdcAII. Here we have investigated the contribution of each individual Pht protein to pneumococcal zinc homeostasis by analyzing mutant strains expressing only one of the four
pht
genes. Under conditions of low zinc availability, each of these mutants showed superior growth and zinc accumulation profiles relative to a mutant strain lacking all four genes, indicating that any of the four Pht proteins are able to facilitate delivery of zinc to AdcAII. However, optimal growth and zinc accumulation
in vitro
and pneumococcal survival and proliferation
in vivo
required production of all four Pht proteins, indicating that, despite their overlapping functionality, the proteins are not dispensable without incurring a fitness cost. We also show that surface-attached forms of the Pht proteins are required for zinc recruitment and that they do not contribute to defense against extracellular zinc stress.
Distinct Contributions of Interleukin-1α (IL-1α) and IL-1β to Innate Immune Recognition of Pseudomonas aeruginosa in the Lung
Authors: Al Moussawi Khatoun , Kazmierczak Barbara I. 
Published: July 2014

ABSTRACTThe bacterial pathogenPseudomonas aeruginosacauses acute infections associated with significant morbidity and mortality.P. aeruginosaelicits strong innate immune responses in immunocompetent hosts, and the resulting recruitment of neutrophils to the site of infection is necessary for bacterial clearance.P. aeruginosalipopolysaccharide and flagellin are recognized by extracellular Toll-like receptors, but the most rapid responses to infection occur when cytosolic receptors sense flagellin or type 3 secretion system (T3SS) structural proteins. The subsequent activation of the NLRC4 inflammasome and caspase-1 generates an interleukin-1β (IL-1β) signal that is required for the rapid neutrophilic response. A T3SS effector, exotoxin U (ExoU), can inhibit activation of the NLRC4 inflammasome and caspase-1. Thus, our observation that IL-1 receptor (IL-1R)-mediated signals were still required to initiate a response to ExoU-producing bacteria was unexpected. As both IL-1α and IL-1β signal via the IL-1R, we examined immune responses in mice lacking either of these cytokines. IL-1β-deficient mice responded to ExoU-producingP. aeruginosabacteria similarly to wild-type animals; however, IL-1α-deficient mice had an attenuated immune response. The situation was reversed following infections by ExoU-negative bacteria: here, IL-1α was dispensable for neutrophil recruitment, while IL-1β was required. IL-1α secretion by macrophages infected with ExoU-producingP. aeruginosaisolates was independent of both caspase-1 and caspase-11. This study documents distinct roles for IL-1α and IL-1β in the response toP. aeruginosainfection as a function of the T3SS effectors produced by the infecting strain. The redundancy of these two cytokines nonetheless allows the infected host to mount a response to ExoU-positive and -negative bacterial isolates.
Endovascular therapy of extracranial carotid artery pseudoaneurysms: case series and literature review
Authors: Seward Christopher J , Dumont Travis M , Levy Elad I 
Published: July 2014

BackgroundExperience with endovascular therapy of extracranial carotid artery pseudoaneurysm (ECAP) has been growing, and various results suggest it as a suitable treatment option. We present a consecutive case series of patients with ECAPs treated with endovascular therapy, and a pertinent literature review.MethodsA prospectively maintained database of neuroendovascular procedures was retrospectively reviewed for cases of ECAP treated between January 2007 and December 2012. The primary outcome of interest was incidence of periprocedural (within 30 days) neurologic and cardiopulmonary complications. PubMed was searched for relevant endovascular studies from 2000 to 2012 for the review.ResultsIn our series, 12 patients with 14 ECAPs received stents, with or without coils. No perioperative neurologic or cardiopulmonary complications occurred. Median duration of clinical follow-up was 6.25 months (range 0–50 months), and median duration of imaging follow-up was 6.25 months (range 0–50 months), with eight patients asymptomatic and three showing improved symptoms (one patient with two lesions was lost to follow-up). Literature review revealed an overall primary outcome of 8.6% and no procedure related deaths.ConclusionsEndovascular treatment of ECAP is safe and effective at improving symptoms. There were no perioperative or permanent neurologic sequelae in the 11 patients with follow-up, and all symptomatology related to ECAP improved or resolved with treatment.
O-010 Radiation Safety in Neurointervention: Is it Time for Dose Reference Levels?
Authors: Slater L , Hadley C , Soufan C , Yu H , Holt M , Chong W , Maroulis H , Stuckey S , Chandra R 
Published: July 2014

BackgroundTherapeutic neurointerventional (NI) procedures have become a significant source of radiation exposure during the treatment of cerebrovascular disease. While there are well-established radiation dose reference levels (DRLs) for diagnostic imaging, no similar NI DRLs are available. We analyzed the patient radiation dose for therapeutic NI procedures at a tertiary teaching hospital, with an aim to develop local DRLs that could form the foundation for developing national NI radiation safety guidelines.MethodRetrospective analysis of radiation dose area product (DAP) in Gy. Cm2for consecutive patients undergoing therapeutic NI procedures between July 2011 and April 2014 was performed. NI procedures were categorized into arteriovenous malformation (AVM) embolization, cerebral aneurysm embolization (primarily coiling vs balloon/stent assisted) and cerebral vasospasm procedures. Median and inter-quartile radiation dose levels were calculated for each NI category. The 75thpercentile was deemed to be the local DRL. Wilcoxon signed-rank test was performed for statistical correlation.ResultsA total of 303 NI procedures were included. Patients undergoing AVM embolization received a significantly higher radiation dose (n = 44; median 338 Gy. Cm2[IQR 225–528 Gy. Cm2]) than patients undergoing cerebral aneurysm embolization (n = 188; median 211 Gy. Cm2[IQR 130–328 Gy. Cm2]; p = 0.003). Patients treated with primary coiling received a significantly lower radiation dose (n = 96; median 170 Gy. Cm2[IQR 125–282 Gy. Cm2]) than patients undergoing stent/balloon assisted aneurysm embolization (n = 92; median 241 Gy. Cm2[IQR 145–369 Gy. Cm2]); p = 0.0002). Patients undergoing cerebral vasospasm procedures (n = 71) received median 161 Gy. Cm2[IQR 106–219 Gy. Cm2] of radiation.ConclusionTherapeutic NI procedures are a significant source of radiation exposure, particularly for AVM embolization. Proposed NI radiation DRLs based on the 75thpercentile for DAP were 528 Gy. Cm2, 328 Gy. Cm2and 219 Gy. Cm2for AVM embolization, cerebral aneurysm embolization and cerebral vasospasm procedures respectively.DisclosuresL. Slater: None. C. Hadley: None. C. Soufan: None. H. Yu: None. M. Holt: None. W. Chong: None. H. Maroulis: None. S. Stuckey: None. R. Chandra: None.