bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of acute moderate exercise on induced inflammation and arterial function in older adults
Authors: Ranadive Sushant Mohan , Kappus Rebecca Marie , Cook Marc D. , Yan Huimin , Lane Abbi Danielle , Woods Jeffrey A. , Wilund Kenneth R. , Iwamoto Gary , Vanar Vishwas , Tandon Rudhir , Fernhall Bo 
Published: January 2014

New Findings
What is the central question of this study?
The aim of the study was to evaluate the effect of acute induced systemic inflammation on endothelial function, wave reflection and arterial function in older adults.
What is the main finding and its importance?
Acute inflammation induced by influenza vaccination did not affect endothelial function in older adults. These findings have never been shown in older adults, and they emphasize the importance of vascular function during systemic arterial inflammation.
Acute inflammation reduces flow‐mediated vasodilatation and increases arterial stiffness in young healthy individuals. However, this response has not been studied in older adults. The aim of this study, therefore, was to evaluate the effect of acute induced systemic inflammation on endothelial function and wave reflection in older adults. Furthermore, an acute bout of moderate‐intensity aerobic exercise can be anti‐inflammatory. Taken together, we tested the hypothesis that acute moderate‐intensity endurance exercise, immediately preceding induced inflammation, would be protective against the negative effects of acute systemic inflammation on vascular function. Fifty‐nine healthy volunteers between 55 and 75 years of age were randomized to an exercise or a control group. Both groups received a vaccine (induced inflammation) and sham (saline) injection in a counterbalanced crossover design. Inflammatory markers, endothelial function (flow‐mediated vasodilatation) and measures of wave reflection and arterial stiffness were evaluated at baseline and at 24 and 48 h after injections. There were no significant differences in endothelial function and arterial stiffness between the exercise and control group after induced inflammation. The groups were then analysed together, and we found significant differences in the inflammatory markers 24 and 48 h after induction of acute inflammation compared with sham injection. However, flow‐mediated vasodilatation, augmentation index normalized for heart rate (AIx75) and β‐stiffness did not change significantly. Our results suggest that acute inflammation induced by influenza vaccination did not affect endothelial function in older adults.
Cell Growth Models Using Reaction Schemes: Batch Cultivation
Authors: Markov Svetoslav Marinov 
Published: January 2014

Simple structured mathematical models of bacterial cell growth are proposed. The modelsВ involve fractions of bacterial cells relatedВ toВ their physiological phases. Reaction schemes involving the biomass of theВ cell fractions, the substrate and the product are proposed in analogy to reaction schemes in enzyme kinetics. Applying the mass action law these reaction schemesВ lead toВ dynamical models represented byВ systems of ODE's. All parameters of the modelsВ are rate constants with clear biological or biochemical meaning.В The proposed models generalizeВ classical bacterial growth models and offer more flexible tools for modelling and control of biotechnological processes. In this paper the study is focused on batch cultivation models.
Assessment of Giardia and Cryptosporidium spp. as a Microbial Source Tracking Tool for Surface Water: Application in a Mixed-Use Watershed
Authors: Prystajecky Natalie , Huck Peter M. , Schreier Hans , Isaac-Renton Judith L. 
Published: January 2014

ABSTRACT

Knowledge of host specificity, combined with genomic sequencing of
Giardia
and
Cryptosporidium
spp., has demonstrated a microbial source tracking (MST) utility for these common waterborne microbes. To explore the source attribution potential of these pathogens, water samples were collected in a mixed rural-urban watershed in the Township of Langley, in southwestern British Columbia (BC), Canada, over a 2-year period.
Cryptosporidium
was detected in 63% of surface water samples at concentrations ranging from no positive detection (NPD) to 20,600 oocysts per 100 liters.
Giardia
was detected in 86% of surface water samples at concentrations ranging from NPD to 3,800 cysts per 100 liters of water. Sequencing at the 18S rRNA locus revealed that 50% of
Cryptosporidium
samples and 98% of
Giardia
samples contained species/genotypes (
Cryptosporidium
) or assemblages (
Giardia
) that are capable of infecting humans, based on current knowledge of host specificity and taxonomy.
Cryptosporidium
genotyping data were more promising for source tracking potential, due to the greater number of host-adapted (i.e., narrow-host-range) species/genotypes compared to
Giardia
, since 98% of
Giardia
isolates were zoonotic and the potential host could not be predicted. This report highlights the benefits of parasite genomic sequencing to complement Method 1623 (U.S. Environmental Protection Agency) and shows that
Cryptosporidium
subtyping for MST purposes is superior to the use of
Giardia
subtyping, based on better detection limits for
Cryptosporidium
-positive samples than for
Giardia
-positive samples and on greater host specificity among
Cryptosporidium
species. These additional tools could be used for risk assessment in public health and watershed management decisions.
Phylogenetic Differences in Attached and Free-Living Bacterial Communities in a Temperate Coastal Lagoon during Summer, Revealed via High-Throughput 16S rRNA Gene Sequencing
Authors: Mohit Vani , Archambault Philippe , Toupoint Nicolas , Lovejoy Connie 
Published: January 2014

ABSTRACT

Most of what is known about coastal free-living and attached bacterial diversity is based on open coasts, with high particulate and nutrient riverine supply, terrestrial runoffs, and anthropogenic activities. The Magdalen Islands in the Gulf of St. Lawrence (Canada) are dominated by shallow lagoons with small, relatively pristine catchments and no freshwater input apart from rain. Such conditions provided an opportunity to investigate coastal free-living and attached marine bacterial diversity in the absence of confounding effects of steep freshwater gradients. We found significant differences between the two communities and marked temporal patterns in both. Taxonomic richness and diversity were greater in the attached than in the free-living community, increasing over summer, especially within the least abundant bacterial phyla. The highest number of reads fell within the SAR 11 clade (
Pelagibacter
,
Alphaproteobacteria
), which dominated free-living communities. The attached communities had deeper phylum-level diversity than the free-living fraction. Distance-based redundancy analysis indicated that the particulate organic matter (POM) concentration was the main variable separating early and late summer samples with salinity and temperature changes also significantly correlated to bacterial community structure. Our approach using high-throughput sequencing detected differences in free-living versus attached bacteria in the absence of riverine input, in keeping with the concept that marine attached communities are distinct from cooccurring free-living taxa. This diversity likely reflects the diverse microhabitats of available particles, implying that the total bacterial diversity in coastal systems is linked to particle supply and variability, with implications for understanding microbial biodiversity in marine systems.
Two New Xylanases with Different Substrate Specificities from the Human Gut Bacterium Bacteroides intestinalis DSM 17393
Authors: Hong Pei-Ying , Iakiviak Michael , Dodd Dylan , Zhang Meiling , Mackie Roderick I. , Cann Isaac 
Published: January 2014

ABSTRACT

Xylan is an abundant plant cell wall polysaccharide and is a dominant component of dietary fiber. Bacteria in the distal human gastrointestinal tract produce xylanase enzymes to initiate the degradation of this complex heteropolymer. These xylanases typically derive from glycoside hydrolase (GH) families 10 and 11; however, analysis of the genome sequence of the xylan-degrading human gut bacterium
Bacteroides intestinalis
DSM 17393 revealed the presence of two putative GH8 xylanases. In the current study, we demonstrate that the two genes encode enzymes that differ in activity. The
xyn8A
gene encodes an endoxylanase (Xyn8A), and
rex8A
encodes a reducing-end xylose-releasing exo-oligoxylanase (Rex8A). Xyn8A hydrolyzed both xylopentaose (X
5
) and xylohexaose (X
6
) to a mixture of xylobiose (X
2
) and xylotriose (X
3
), while Rex8A hydrolyzed X
3
through X
6
to a mixture of xylose (X
1
) and X
2
. Moreover,
rex8A
is located downstream of a GH3 gene (
xyl3A
) that was demonstrated to exhibit β-xylosidase activity and would be able to further hydrolyze X
2
to X
1
. Mutational analyses of putative active site residues of both Xyn8A and Rex8A confirm their importance in catalysis by these enzymes. Recent genome sequences of gut bacteria reveal an increase in GH8 Rex enzymes, especially among the
Bacteroidetes
, indicating that these genes contribute to xylan utilization in the human gut.
A Link between Arabinose Utilization and Oxalotrophy in Bradyrhizobium japonicum
Authors: Koch Marion , Delmotte Nathanaël , Ahrens Christian H. , Omasits Ulrich , Schneider Kathrin , Danza Francesco , Padhi Barnali , Murset Valérie , Braissant Olivier , Vorholt Julia A. , Hennecke Hauke , Pessi Gabriella 
Published: January 2014

ABSTRACT

Rhizobia have a versatile catabolism that allows them to compete successfully with other microorganisms for nutrients in the soil and in the rhizosphere of their respective host plants. In this study,
Bradyrhizobium japonicum
USDA 110 was found to be able to utilize oxalate as the sole carbon source. A proteome analysis of cells grown in minimal medium containing arabinose suggested that oxalate oxidation extends the arabinose degradation branch via glycolaldehyde. A mutant of the key pathway genes
oxc
(for oxalyl-coenzyme A decarboxylase) and
frc
(for formyl-coenzyme A transferase) was constructed and shown to be (i) impaired in growth on arabinose and (ii) unable to grow on oxalate. Oxalate was detected in roots and, at elevated levels, in root nodules of four different
B. japonicum
host plants. Mixed-inoculation experiments with wild-type and
oxc-frc
mutant cells revealed that oxalotrophy might be a beneficial trait of
B. japonicum
at some stage during legume root nodule colonization.
Thermostability Improvement of a Streptomyces Xylanase by Introducing Proline and Glutamic Acid Residues
Authors: Wang Kun , Luo Huiying , Tian Jian , Turunen Ossi , Huang Huoqing , Shi Pengjun , Hua Huifang , Wang Caihong , Wang Shuanghe , Yao Bin 
Published: January 2014

ABSTRACT

Protein engineering is commonly used to improve the robustness of enzymes for activity and stability at high temperatures. In this study, we identified four residues expected to affect the thermostability of
Streptomyces
sp. strain S9 xylanase XynAS9 through multiple-sequence analysis (MSA) and molecular dynamic simulations (MDS). Site-directed mutagenesis was employed to construct five mutants by replacing these residues with proline or glutamic acid (V81P, G82E, V81P/G82E, D185P/S186E, and V81P/G82E/D185P/S186E), and the mutant and wild-type enzymes were expressed in
Pichia pastoris
. Compared to the wild-type XynAS9, all five mutant enzymes showed improved thermal properties. The activity and stability assays, including circular dichroism and differential scanning calorimetry, showed that the mutations at positions 81 and 82 increased the thermal performance more than the mutations at positions 185 and 186. The mutants with combined substitutions (V81P/G82E and V81P/G82E/D185P/S186E) showed the most pronounced shifts in temperature optima, about 17°C upward, and their half-lives for thermal inactivation at 70°C and melting temperatures were increased by >9 times and approximately 7.0°C, respectively. The mutation combination of V81P and G82E in adjacent positions more than doubled the effect of single mutations. Both mutation regions were at the end of long secondary-structure elements and probably rigidified the local structure. MDS indicated that a long loop region after positions 81 and 82 located at the end of the inner β-barrel was prone to unfold. The rigidified main chain and filling of a groove by the mutations on the bottom of the active site canyon may stabilize the mutants and thus improve their thermostability.
Vibrio coralliilyticus Strain OCN008 Is an Etiological Agent of Acute Montipora White Syndrome
Authors: Ushijima Blake , Videau Patrick , Burger Andrew H. , Shore-Maggio Amanda , Runyon Christina M. , Sudek Mareike , Aeby Greta S. , Callahan Sean M. 
Published: January 2014

ABSTRACT

Identification of a pathogen is a critical first step in the epidemiology and subsequent management of a disease. A limited number of pathogens have been identified for diseases contributing to the global decline of coral populations. Here we describe
Vibrio coralliilyticus
strain OCN008, which induces acute
Montipora
white syndrome (aMWS), a tissue loss disease responsible for substantial mortality of the coral
Montipora capitata
in Kāne‘ohe Bay, Hawai‘i. OCN008 was grown in pure culture, recreated signs of disease in experimentally infected corals, and could be recovered after infection. In addition, strains similar to OCN008 were isolated from diseased coral from the field but not from healthy
M. capitata
. OCN008 repeatedly induced the loss of healthy
M. capitata
tissue from fragments under laboratory conditions with a minimum infectious dose of between 10
7
and 10
8
CFU/ml of water. In contrast,
Porites compressa
was not infected by OCN008, indicating the host specificity of the pathogen. A decrease in water temperature from 27 to 23°C affected the time to disease onset, but the risk of infection was not significantly reduced. Temperature-dependent bleaching, which has been observed with the
V. coralliilyticus
type strain BAA-450, was not observed during infection with OCN008. A comparison of the OCN008 genome to the genomes of pathogenic
V. coralliilyticus
strains BAA-450 and P1 revealed similar virulence-associated genes and quorum-sensing systems. Despite this genetic similarity, infections of
M. capitata
by OCN008 do not follow the paradigm for
V. coralliilyticus
infections established by the type strain.
Environmental Survival of Mycobacterium avium subsp. paratuberculosis in Different Climatic Zones of Eastern Australia
Authors: Eppleston Jeffrey , Begg Douglas J. , Dhand Navneet K. , Watt Bruce , Whittington Richard J. 
Published: January 2014

ABSTRACT

The duration of survival of both the S and C strains of
Mycobacterium avium
subsp.
paratuberculosis
in feces was quantified in contrasting climatic zones of New South Wales, Australia, and detailed environmental temperature data were collected. Known concentrations of S and C strains in feces placed on soil in polystyrene boxes were exposed to the environment with or without the provision of shade (70%) at Bathurst, Armidale, Condobolin, and Broken Hill, and subsamples taken every 2 weeks were cultured for the presence of
M. avium
subsp.
paratuberculosis
. The duration of survival ranged from a minimum of 1 week to a maximum of 16 weeks, and the provision of 70% shade was the most important factor in extending the survival time. The hazard of death for exposed compared to shaded samples was 20 and 9 times higher for the S and C strains, respectively. Site did not affect the survival of the C strain, but for the S strain, the hazard of death was 2.3 times higher at the two arid zone sites (Broken Hill and Condobolin) than at the two temperate zone sites (Bathurst and Armidale). Temperature measurements revealed maximum temperatures exceeding 60°C and large daily temperature ranges at the soil surface, particularly in exposed boxes.
Distribution of Sequence-Based Types of Legionella pneumophila Serogroup 1 Strains Isolated from Cooling Towers, Hot Springs, and Potable Water Systems in China
Authors: Qin Tian , Zhou Haijian , Ren Hongyu , Guan Hong , Li Machao , Zhu Bingqing , Shao Zhujun 
Published: January 2014

ABSTRACT

Legionella pneumophila
serogroup 1 causes Legionnaires' disease. Water systems contaminated with
Legionella
are the implicated sources of Legionnaires' disease. This study analyzed
L. pneumophila
serogroup 1 strains in China using sequence-based typing. Strains were isolated from cooling towers (
n
= 96), hot springs (
n
= 42), and potable water systems (
n
= 26). Isolates from cooling towers, hot springs, and potable water systems were divided into 25 sequence types (STs; index of discrimination [IOD], 0.711), 19 STs (IOD, 0.934), and 3 STs (IOD, 0.151), respectively. The genetic variation among the potable water isolates was lower than that among cooling tower and hot spring isolates. ST1 was the predominant type, accounting for 49.4% of analyzed strains (
n
= 81), followed by ST154. With the exception of two strains, all potable water isolates (92.3%) belonged to ST1. In contrast, 53.1% (51/96) and only 14.3% (6/42) of cooling tower and hot spring, respectively, isolates belonged to ST1. There were differences in the distributions of clone groups among the water sources. The comparisons among
L. pneumophila
strains isolated in China, Japan, and South Korea revealed that similar clones (ST1 complex and ST154 complex) exist in these countries. In conclusion, in China, STs had several unique allelic profiles, and ST1 was the most prevalent sequence type of environmental
L. pneumophila
serogroup 1 isolates, similar to its prevalence in Japan and South Korea.
New
In Situ
Capture Quantitative (Real-Time) Reverse Transcription-PCR Method as an Alternative Approach for Determining Inactivation of Tulane Virus
Authors: Wang Dapeng , Xu Shuxia , Yang David , Young Glenn M. , Tian Peng 
Published: January 2014

ABSTRACT

Human noroviruses (HuNoVs) are the major cause of epidemic nonbacterial gastroenteritis. Although quantitative (real-time) reverse transcription-PCR (qRT-PCR) is widely used for detecting HuNoVs, it only detects the presence of viral RNA and does not indicate viral infectivity. Human blood group antigens (HBGAs) have been identified as receptors/co-receptors for both HuNoVs and Tulane virus (TV) and are crucial for viral infection. We propose that viral infectivity can be evaluated with a molecular assay based on receptor-captured viruses. In this study, we employed TV as an HuNoV surrogate to validate the HBGA-based capture qRT-PCR method against the 50% tissue culture infectious dose (TCID
50
) method. We employed type B HBGA on an immuno-well module to concentrate TV, followed by amplification of the captured viral genome by
in situ
qRT-PCR. We first demonstrated that this
in situ
capture qRT-PCR (ISC-qRT-PCR) method could effectively concentrate and detect TV. We then treated TV under either partial or full inactivation conditions and measured the remaining infectivity by ISC-qRT-PCR and a tissue culture-based amplification method (TCID
50
). We found that the ISC-qRT-PCR method could be used to evaluate virus inactivation deriving from damage to the capsid and study interactions between the capsid and viral receptor. Heat, chlorine, and ethanol treatment primarily affect the capsid structure, which in turns affects the ability of the capsid to bind to viral receptors. Inactivation of the virus by these methods could be reflected by the ISC-qRT-PCR method and confirmed by TCID
50
assay. However, the loss of the infectivity caused by damage to the viral genome (such as that from UV irradiation) could not be effectively reflected by this method. Despite this limitation, the ISC-qRT-PCR provides an alternative approach to determine inactivation of Tulane virus. A particular advantage of the ISC-qRT-PCR method is that it is also a faster and easier method to effectively recover and detect the viruses, as there is no need to extract viral RNA or to transfer the captured virus from magnetic beads to PCR tubes for further amplification. Therefore, ISC-qRT-PCR can be easily adapted for use in automated systems for multiple samples.
Transcription Factor RFX1 Is Crucial for Maintenance of Genome Integrity in Fusarium graminearum
Authors: Min Kyunghun , Son Hokyoung , Lim Jae Yun , Choi Gyung Ja , Kim Jin-Cheol , Harris Steven D. , Lee Yin-Won 
Published: January 2014

ABSTRACT

The survival of cellular organisms depends on the faithful replication and transmission of DNA. Regulatory factor X (RFX) transcription factors are well conserved in animals and fungi, but their functions are diverse, ranging from the DNA damage response to ciliary gene regulation. We investigated the role of the sole RFX transcription factor, RFX1, in the plant-pathogenic fungus
Fusarium graminearum
. Deletion of
rfx1
resulted in multiple defects in hyphal growth, conidiation, virulence, and sexual development. Deletion mutants of
rfx1
were more sensitive to various types of DNA damage than the wild-type strain. Septum formation was inhibited and micronuclei were produced in the
rfx1
deletion mutants. The results of the neutral comet assay demonstrated that disruption of
rfx1
function caused spontaneous DNA double-strand breaks (DSBs). The transcript levels of genes involved in DNA DSB repair were upregulated in the
rfx1
deletion mutants. DNA DSBs produced micronuclei and delayed septum formation in
F. graminearum
. Green fluorescent protein (GFP)-tagged RFX1 localized in nuclei and exhibited high expression levels in growing hyphae and conidiophores, where nuclear division was actively occurring. RNA-sequencing-based transcriptomic analysis revealed that RFX1 suppressed the expression of many genes, including those required for the repair of DNA damage. Taken together, these findings indicate that the transcriptional repressor
rfx1
performs crucial roles during normal cell growth by maintaining genome integrity.
Regulation of Acetate Kinase Isozymes and Its Importance for Mixed-Acid Fermentation in Lactococcus lactis
Authors: Puri Pranav , Goel Anisha , Bochynska Agnieszka , Poolman Bert 
Published: January 2014

ABSTRACT

Acetate kinase (ACK) converts acetyl phosphate to acetate along with the generation of ATP in the pathway for mixed-acid fermentation in
Lactococcus lactis
. The reverse reaction yields acetyl phosphate for assimilation purposes. Remarkably,
L. lactis
has two ACK isozymes, and the corresponding genes are present in an operon. We purified both enzymes (AckA1 and AckA2) from
L. lactis
MG1363 and determined their oligomeric state, specific activities, and allosteric regulation. Both proteins form homodimeric complexes, as shown by size exclusion chromatography and static light-scattering measurements. The turnover number of AckA1 is about an order of magnitude higher than that of AckA2 for the reaction in either direction. The

K
m

values for acetyl phosphate, ATP, and ADP are similar for both enzymes. However, AckA2 has a higher affinity for acetate than does AckA1, suggesting an important role under acetate-limiting conditions despite the lower activity. Fructose-1,6-bisphosphate, glyceraldehyde-3-phosphate, and phospho-
enol
-pyruvate inhibit the activities of AckA1 and AckA2 to different extents. The allosteric regulation of AckA1 and AckA2 and the pool sizes of the glycolytic intermediates are consistent with a switch from homolactic to mixed-acid fermentation upon slowing of the growth rate.