bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydroxyapatite-Mediated Separation of Double-Stranded DNA, Single-Stranded DNA, and RNA Genomes from Natural Viral Assemblages
Authors: Andrews-Pfannkoch Cynthia , Fadrosh Douglas W. , Thorpe Joyce , Williamson Shannon J.
Published: June 2010

Metagenomics can be used to determine the diversity of complex, often unculturable, viral communities with various nucleic acid compositions. Here, we report the use of hydroxyapatite chromatography to efficiently fractionate double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), dsRNA, and ssRNA genomes from known bacteriophages. Linker-amplified shotgun libraries were constructed to generate sequencing reads from each hydroxyapatite fraction. Greater than 90% of the reads displayed significant similarity to the expected genomes at the nucleotide level. These methods were applied to marine viruses collected from the Chesapeake Bay and the Dry Tortugas National Park. Isolated nucleic acids were fractionated using hydroxyapatite chromatography followed by linker-amplified shotgun library construction and sequencing. Taxonomic analysis demonstrated that the majority of environmental sequences, regardless of their source nucleic acid, were most similar to dsDNA viruses, reflecting the bias of viral metagenomic sequence databases.
Alteration of Microbial Communities Colonizing Leaf Litter in a Temperate Woodland Stream by Growth of Trees under Conditions of Elevated Atmospheric CO
2
Authors: Kelly John J. , Bansal Amit , Winkelman Jonathan , Janus Lori R. , Hell Shannon , Wencel Marie , Belt Patricia , Kuehn Kevin A. , Rier Steven T. , Tuchman Nancy C.
Published: June 2010

Elevated atmospheric CO
2
can cause increased carbon fixation and altered foliar chemical composition in a variety of plants, which has the potential to impact forested headwater streams because they are detritus-based ecosystems that rely on leaf litter as their primary source of organic carbon. Fungi and bacteria play key roles in the entry of terrestrial carbon into aquatic food webs, as they decompose leaf litter and serve as a source of nutrition for invertebrate consumers. This study tested the hypothesis that changes in leaf chemistry caused by elevated atmospheric CO
2
would result in changes in the size and composition of microbial communities colonizing leaves in a woodland stream. Three tree species,
Populus tremuloides
,
Salix alba
, and
Acer saccharum
, were grown under ambient (360 ppm) or elevated (720 ppm) CO
2
, and their leaves were incubated in a woodland stream. Elevated-CO
2
treatment resulted in significant increases in the phenolic and tannin contents and C/N ratios of leaves. Microbial effects, which occurred only for
P. tremuloides
leaves, included decreased fungal biomass and decreased bacterial counts. Analysis of fungal and bacterial communities on
P. tremuloides
leaves via terminal restriction fragment length polymorphism (T-RFLP) and clone library sequencing revealed that fungal community composition was mostly unchanged by the elevated-CO
2
treatment, whereas bacterial communities showed a significant shift in composition and a significant increase in diversity. Specific changes in bacterial communities included increased numbers of alphaproteobacterial and cytophaga-flavobacter-bacteroides (CFB) group sequences and decreased numbers of betaproteobacterial and firmicutes sequences, as well as a pronounced decrease in overall Gram-positive bacterial sequences.
Association of the Melioidosis AgentBurkholderia pseudomalleiwith Water Parameters in Rural Water Supplies in Northern Australia
Authors: Draper A. D. K. , Mayo M. , Harrington G. , Karp D. , Yinfoo D. , Ward L. , Haslem A. , Currie B. J. , Kaestli M.
Published: June 2010

We analyzed water parameters and the occurrence of the melioidosis agentBurkholderia pseudomalleiin 47 water bores in Northern Australia.B. pseudomalleiwas associated with soft, acidic bore water of low salinity but high iron levels. This finding aids in identifying water supplies at risk of contamination with this pathogenic bacterium.
Distribution of Shiga-Toxigenic
Escherichia coli
O157 in the Gastrointestinal Tract of Naturally O157-Shedding Cattle at Necropsy
Authors: Keen James E. , Laegreid William W. , Chitko-McKown Carol G. , Durso Lisa M. , Bono James L.
Published: June 2010

Shiga-toxigenic
Escherichia coli
(STEC) O157 occurrence was determined along the entire gastrointestinal tract (GIT) of each of four naturally shedding cattle and at three sites in 61 slaughter cattle. STEC O157 was distributed along the entire GIT, though interanimal distribution was variable. Neither feces nor rectoanal-junction samples accurately predicted the STEC O157-negative status of any particular animal.
Improved Molecular Detection ofAngiostrongylus cantonensisin Mollusks and Other Environmental Samples with a Species-Specific Internal Transcribed Spacer 1-Based TaqMan Assay
Authors: Qvarnstrom Yvonne , da Silva Ana Cristina Aramburu , Teem John L. , Hollingsworth Robert , Bishop Henry , Graeff-Teixeira Carlos , da Silva Alexandre J.
Published: June 2010

Angiostrongylus cantonensisis the most common cause of human eosinophilic meningitis. Humans become infected by ingesting food items contaminated with third-stage larvae that develop in mollusks. We report the development of a real-time PCR assay for the species-specific identification ofA. cantonensisin mollusk tissue.
Decreasing Trend of Overlapping Multilocus Sequence Types between Human and Chicken
Campylobacter jejuni
Isolates over a Decade in Finland
Authors: de Haan C. P. A. , Kivistö R. , Hakkinen M. , Rautelin H. , Hänninen M. L.
Published: June 2010

We describe the long-term multilocus sequence typing (MLST) analysis of the population structure and dynamics of 454 Finnish human
Campylobacter jejuni
isolates, as well as 208 chicken isolates, collected during the mid-1990s to 2007. The sequence type clonal complexes (ST CC) ST-45 CC, ST-21 CC, and ST-677 CC were the most common ones found among all isolates, and they covered 73.9% of all isolates. The ST-283 CC also was found frequently among chicken isolates (8.2%). The predominant STs among all isolates were ST-45, ST-50, and ST-677. ST-137 and ST-230 were common among human isolates, and ST-267 was found more frequently among chicken isolates than human isolates. The ST-45 CC was significantly associated with chicken isolates (
P
< 0.01), whereas the ST-21 CC was associated with human isolates (
P
< 0.001). The ST-677 CC was not associated with any host (
P
= 0.5), and an opposite temporary trend of this complex was seen among chicken and human isolates, with an increase in the former and a decrease in the latter during the study period. Furthermore, the ST-22 and ST-48 CCs were significantly associated with human isolates (
P
< 0.01), but neither of the CCs was found in chicken isolates. The annual overlap between STs from human and chicken isolates decreased from 76% at the beginning of the study to 58% at the end. Our results suggest that the importance of chicken as a reservoir for strains associated with human infections has declined despite the consumption of domestic chicken meat increasing during the follow-up period by 83%.
Biochemical Properties of Pectate Lyases Produced by Three Different
Bacillus
Strains Isolated from Fermenting Cocoa Beans and Characterization of Their Cloned Genes
Authors: Ouattara Honoré G. , Reverchon Sylvie , Niamke Sébastien L. , Nasser William
Published: June 2010

Pectinolytic enzymes play an important role in cocoa fermentation. In this study, we characterized three extracellular pectate lyases (Pels) produced by bacilli isolated from fermenting cocoa beans. These enzymes, named Pel-22, Pel-66, and Pel-90, were synthesized by
Bacillus pumilus
BS22,
Bacillus subtilis
BS66, and
Bacillus fusiformis
BS90, respectively. The three Pels were produced under their natural conditions and purified from the supernatants using a one-step chromatography method. The purified enzymes exhibited optimum activity at 60°C, and the half-time of thermoinactivation at this temperature was approximately 30 min. Pel-22 had a low specific activity compared with the other two enzymes. However, it displayed high affinity for the substrate, about 2.5-fold higher than those of Pel-66 and Pel-90. The optimum pHs were 7.5 for Pel-22 and 8.0 for Pel-66 and Pel-90. The three enzymes
trans
-eliminated polygalacturonate in a random manner to generate two long oligogalacturonides, as well as trimers and dimers. A synergistic effect was observed between Pel-22 and Pel-66 and between Pel-22 and Pel-90, but not between Pel-90 and Pel-66. The Pels were also strongly active on highly methylated pectins (up to 60% for Pel-66 and Pel-90 and up to 75% for Pel-22). Fe
2+
was found to be a better cofactor than Ca
2+
for Pel-22 activity, while Ca
2+
was the best cofactor for Pel-66 and Pel-90. The amino acid sequences deduced from the cloned genes showed the characteristics of Pels belonging to Family 1. The
pel
-
66
and
pel
-
90
genes appear to be very similar, but they are different from the
pe
l-
22
gene. The characterized enzymes form two groups, Pel-66/Pel-90 and Pel-22; members of the different groups might cooperate to depolymerize pectin during the fermentation of cocoa beans.
Characterization of a
gne
::IS
629
O Rough:H7
Escherichia coli
Strain from a Hemorrhagic Colitis Patient
Authors: Rump Lydia V. , Beutin Lothar , Fischer Markus , Feng Peter C. H.
Published: June 2010

Shiga-toxigenic
Escherichia coli
strains that are O rough:H7 due to
gne
::IS
629
were thought to be rare and to have unknown pathogenic potential. Recently, an O rough:H7 strain caused by
gne
::IS
629
was isolated from a hemorrhagic colitis patient, suggesting that these strains are pathogenic and may not be as rare as anticipated.
Redirecting Reductant Flux into Hydrogen Production via Metabolic Engineering of Fermentative Carbon Metabolism in a Cyanobacterium
Authors: McNeely Kelsey , Xu Yu , Bennette Nick , Bryant Donald A. , Dismukes G. Charles
Published: June 2010

Some aquatic microbial oxygenic photoautotrophs (AMOPs) make hydrogen (H
2
), a carbon-neutral, renewable product derived from water, in low yields during autofermentation (anaerobic metabolism) of intracellular carbohydrates previously stored during aerobic photosynthesis. We have constructed a mutant (the
ldhA
mutant) of the cyanobacterium
Synechococcus
sp. strain PCC 7002 lacking the enzyme for the NADH-dependent reduction of pyruvate to
d
-lactate, the major fermentative reductant sink in this AMOP. Both nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS) metabolomic methods have shown that autofermentation by the
ldhA
mutant resulted in no
d
-lactate production and higher concentrations of excreted acetate, alanine, succinate, and hydrogen (up to 5-fold) compared to that by the wild type. The measured intracellular NAD(P)(H) concentrations demonstrated that the NAD(P)H/NAD(P)
+
ratio increased appreciably during autofermentation in the
ldhA
strain; we propose this to be the principal source of the observed increase in H
2
production via an NADH-dependent, bidirectional [NiFe] hydrogenase. Despite the elevated NAD(P)H/NAD(P)
+
ratio, no decrease was found in the rate of anaerobic conversion of stored carbohydrates. The measured energy conversion efficiency (ECE) from biomass (as glucose equivalents) converted to hydrogen in the
ldhA
mutant is 12%. Together with the unimpaired photoautotrophic growth of the
ldhA
mutant, these attributes reveal that metabolic engineering is an effective strategy to enhance H
2
production in AMOPs without compromising viability.
Control of the Type 3 Secretion System in
Vibrio harveyi
by Quorum Sensing through Repression of ExsA
Authors: Waters Christopher M. , Wu Julie T. , Ramsey Meghan E. , Harris Rebecca C. , Bassler Bonnie L.
Published: June 2010

The type 3 secretion system (T3SS) genes of
Vibrio harveyi
are activated at low cell density and repressed at high cell density by quorum sensing (QS). Repression requires LuxR, the master transcriptional regulator of QS-controlled genes. Here, we determine the mechanism underlying the LuxR repression of the T3SS system. Using a fluorescence-based cell sorting approach, we isolated
V. harveyi
mutants that are unable to express T3SS genes at low cell density and identified two mutations in the
V. harveyi exsBA
operon. While LuxR directly represses the expression of
exsBA
, complementation and epistasis analyses reveal that it is the repression of
exsA
expression, but not
exsB
expression, that is responsible for the QS-mediated repression of T3SS genes at high cell density. The present work further defines the genes in the
V. harveyi
QS regulon and elucidates a mechanism demonstrating how multiple regulators can be linked in series to direct the expression of QS target genes specifically at low or high cell density.
Recombineering Using RecTE from
Pseudomonas syringae
Authors: Swingle Bryan , Bao Zhongmeng , Markel Eric , Chambers Alan , Cartinhour Samuel
Published: June 2010

In this report, we describe the identification of functions that promote genomic recombination of linear DNA introduced into
Pseudomonas
cells by electroporation. The genes encoding these functions were identified in
Pseudomonas syringae
pv. syringae B728a based on similarity to the lambda Red Exo/Beta and RecET proteins encoded by the lambda and Rac bacteriophages of
Escherichia coli
. The ability of the pseudomonad-encoded proteins to promote recombination was tested in
P. syringae
pv. tomato DC3000 using a quantitative assay based on recombination frequency. The results show that the
Pseudomonas
RecT homolog is sufficient to promote recombination of single-stranded DNA oligonucleotides and that efficient recombination of double-stranded DNA requires the expression of both the RecT and RecE homologs. Additionally, we illustrate the utility of this recombineering system to make targeted gene disruptions in the
P. syringae
chromosome.
Occurrence and Molecular Characteristics of Methicillin-Resistant
Staphylococcus aureus
and Methicillin-Resistant
Staphylococcus pseudintermedius
in an Academic Veterinary Hospital
Authors: Ishihara Kanako , Shimokubo Natsumi , Sakagami Akie , Ueno Hiroshi , Muramatsu Yasukazu , Kadosawa Tsuyoshi , Yanagisawa Chie , Hanaki Hideaki , Nakajima Chie , Suzuki Yasuhiko , Tamura Yutaka
Published: June 2010

Recently, methicillin-resistant
Staphylococcus aureus
(MRSA) and methicillin-resistant
Staphylococcus pseudintermedius
(MRSP) have been increasingly isolated from veterinarians and companion animals. With a view to preventing the spread of MRSA and MRSP, we evaluated the occurrence and molecular characteristics of each in a veterinary college. MRSA and MRSP were isolated from nasal samples from veterinarians, staff members, and veterinary students affiliated with a veterinary hospital. Using stepwise logistic regression, we identified two factors associated with MRSA carriage: (i) contact with an identified animal MRSA case (odds ratio [OR], 6.9; 95% confidence interval [95% CI], 2.2 to 21.6) and (ii) being an employee (OR, 6.2; 95% CI, 2.0 to 19.4). The majority of MRSA isolates obtained from individuals affiliated with the veterinary hospital and dog patients harbored
spa
type t002 and a type II staphylococcal cassette chromosome
mec
(SCC
mec
), similar to the hospital-acquired MRSA isolates in Japan. MRSA isolates harboring
spa
type t008 and a type IV SCC
mec
were obtained from one veterinarian on three different sampling occasions and also from dog patients. MRSA carriers can also be a source of MRSA infection in animals. The majority of MRSP isolates (85.2%) carried hybrid SCC
mec
type II-III, and almost all the remaining MRSP isolates (11.1%) carried SCC
mec
type V. MRSA and MRSP were also isolated from environmental samples collected from the veterinary hospital (5.1% and 6.4%, respectively). The application of certain disinfection procedures is important for the prevention of nosocomial infection, and MRSA and MRSP infection control strategies should be adopted in veterinary medical practice.
Specific and Rapid Enumeration of Viable but Nonculturable and Viable-Culturable Gram-Negative Bacteria by Using Flow Cytometry
Authors: Khan Mohiuddin M. Taimur , Pyle Barry H. , Camper Anne K.
Published: June 2010

An issue of critical concern in microbiology is the ability to detect viable but nonculturable (VBNC) and viable-culturable (VC) cells by methods other than existing approaches. Culture methods are selective and underestimate the real population, and other options (direct viable count and the double-staining method using epifluorescence microscopy and inhibitory substance-influenced molecular methods) are also biased and time-consuming. A rapid approach that reduces selectivity, decreases bias from sample storage and incubation, and reduces assay time is needed. Flow cytometry is a sensitive analytical technique that can rapidly monitor physiological states of bacteria. This report outlines a method to optimize staining protocols and the flow cytometer (FCM) instrument settings for the enumeration of VBNC and VC bacterial cells within 70 min. Experiments were performed using the FCM to quantify VBNC and VC
Escherichia coli
O157:H7,
Pseudomonas aeruginosa
,
Pseudomonas syringae
, and
Salmonella enterica
serovar Typhimurium cells after staining with different fluorescent probes: SYTO 9, SYTO 13, SYTO 17, SYTO 40, and propidium iodide (PI). The FCM data were compared with those for specific standard nutrient agar to enumerate the number of cells in different states. By comparing results from cultures at late log phase, 1 to 64% of cells were nonculturable, 40 to 98% were culturable, and 0.7 to 4.5% had damaged cell membranes and were therefore theoretically dead. Data obtained using four different Gram-negative bacteria exposed to heat and stained with PI also illustrate the usefulness of the approach for the rapid and unbiased detection of dead versus live organisms.
Using Chemobiosynthesis and Synthetic Mini-Polyketide Synthases To Produce Pharmaceutical Intermediates in
Escherichia coli
Authors: Menzella Hugo G. , Carney John R. , Li Yong , Santi Daniel V.
Published: June 2010

Recombinant microbial whole-cell biocatalysis is a valuable approach for producing enantiomerically pure intermediates for the synthesis of complex molecules. Here, we describe a method to produce polyketide intermediates possessing multiple stereogenic centers by combining chemobiosynthesis and engineered mini-polyketide synthases (PKSs). Chemobiosynthesis allows the introduction of unnatural moieties, while a library of synthetic bimodular PKSs expressed from codon-optimized genes permits the introduction of a variety of ketide units. To validate the approach, intermediates for the synthesis of
trans
-9,10-dehydroepothilone D were generated. The designer molecules obtained have the potential to greatly reduce the manufacturing cost of epothilone analogues, thus facilitating their commercial development as therapeutic agents.
Complementation ofListeria monocytogenesNull Mutants with SelectedListeria seeligeriVirulence Genes Suggests Functional Adaptation of Hly and PrfA and Considerable Diversification ofprfARegulation inL. seeligeri
Authors: Lucas Stelling Courtney R. , Orsi Renato H. , Wiedmann Martin
Published: June 2010

WhileListeria seeligeriandL. monocytogenescontain the mainListeriavirulence gene cluster, onlyL. monocytogenesis considered an intracellular pathogen. Initial evolutionary analyses showed that the virulence genesprfA,hly, andplcAare conserved inL. seeligeri, with specific Hly and PrfA amino acid residues showing evidence for positive selection inL. seeligeri. Our data also show that temperature-dependent transcript patterns forprfA, which encodes a transcriptional regulator of virulence genes, differed betweenL. monocytogenesandL. seeligeri. To further investigate the divergence of virulence gene function and regulation,L. seeligeri prfA(prfALS),hly(hlyLS), andplcA(plcALS), as well asprfALSconstructs with differentprfApromoter regions, were introduced into appropriateL. monocytogenesnull mutants. Only whenprfALSwas under the control of theL. monocytogenes prfApromoters (P1- and P2prfA) (P1P2LMprfALS) wasprfALSable to fully complement the ΔprfALMdeletion.hlyLSintroduced into anL. monocytogenesbackground under its native promoter showed transcript levels similar to those ofhlyLMand was able to partially restoreL. monocytogeneswild-type-level hemolysis and intracellular growth, even though HlyLMand HlyLSshowed distinct patterns of cell- and supernatant-associated hemolytic activities. Our data indicate that (i) regulation ofprfAexpression differs betweenL. monocytogenesandL. seeligeri, althoughhlytranscription is temperature dependent in both species, and (ii) PrfA and Hly functions are largely, but not fully, conserved betweenL. seeligeriandL. monocytogenes. Virulence gene homologues and their expression thus appear to have adapted to distinct but possibly related functions in these two species.
Methylenetetrahydrofolate Reductase Activity Is Involved in the Plasma Membrane Redox System Required for Pigment Biosynthesis in Filamentous Fungi
Authors: Frandsen Rasmus J. N. , Albertsen Klaus Selk , Stougaard Peter , Sørensen Jens L. , Nielsen Kristian F. , Olsson Stefan , Giese Henriette
Published: June 2010

Methylenetetrahydrofolate reductases (MTHFRs) play a key role in biosynthesis of methionine and
S
-adenosyl-
l
-methionine (SAM) via the recharging methionine biosynthetic pathway. Analysis of 32 complete fungal genomes showed that fungi were unique among eukaryotes by having two MTHFRs, MET12 and MET13. The MET12 type contained an additional conserved sequence motif compared to the sequences of MET13 and MTHFRs from other eukaryotes and bacteria. Targeted gene replacement of either of the two MTHFR encoding genes in
Fusarium graminearum
showed that they were essential for survival but could be rescued by exogenous methionine. The
F. graminearum
strain with a mutation of MET12 (FgΔ
MET12
) displayed a delay in the production of the mycelium pigment aurofusarin and instead accumulated nor-rubrofusarin and rubrofusarin. High methionine concentrations or prolonged incubation eventually led to production of aurofusarin in the MET12 mutant. This suggested that the chemotype was caused by a lack of SAM units for the methylation of nor-rubrofusarin to yield rubrofusarin, thereby imposing a rate-limiting step in aurofusarin biosynthesis. The FgΔ
MET13
mutant, however, remained aurofusarin deficient at all tested methionine concentrations and instead accumulated nor-rubrofusarin and rubrofusarin. Analysis of MET13 mutants in
F. graminearum
and
Aspergillus nidulans
showed that both lacked extracellular reduction potential and were unable to complete mycelium pigment biosynthesis. These results are the first to show that MET13, in addition to its function in methionine biosynthesis, is required for the generation of the extracellular reduction potential necessary for pigment production in filamentous fungi.
Nuclear Dynamics during Germination, Conidiation, and Hyphal Fusion of Fusarium oxysporum
Authors: Ruiz-Roldán M. Carmen , Köhli Michael , Roncero M. Isabel G. , Philippsen Peter , Di Pietro Antonio , Espeso Eduardo A.
Published: June 2010

In many fungal pathogens, infection is initiated by conidial germination. Subsequent stages involve germ tube elongation, conidiation, and vegetative hyphal fusion (anastomosis). Here, we used live-cell fluorescence to study the dynamics of green fluorescent protein (GFP)- and cherry fluorescent protein (ChFP)-labeled nuclei in the plant pathogen
Fusarium oxysporum
. Hyphae of
F. oxysporum
have uninucleated cells and exhibit an acropetal nuclear pedigree, where only the nucleus in the apical compartment is mitotically active. In contrast, conidiation follows a basopetal pattern, whereby mononucleated microconidia are generated by repeated mitotic cycles of the subapical nucleus in the phialide, followed by septation and cell abscission. Vegetative hyphal fusion is preceded by directed growth of the fusion hypha toward the receptor hypha and followed by a series of postfusion nuclear events, including mitosis of the apical nucleus of the fusion hypha, migration of a daughter nucleus into the receptor hypha, and degradation of the resident nucleus. These previously unreported patterns of nuclear dynamics in
F. oxysporum
could be intimately related to its pathogenic lifestyle.
Two Components of a
velvet
-Like Complex Control Hyphal Morphogenesis, Conidiophore Development, and Penicillin Biosynthesis in Penicillium chrysogenum
Authors: Hoff Birgit , Kamerewerd Jens , Sigl Claudia , Mitterbauer Rudolf , Zadra Ivo , Kürnsteiner Hubert , Kück Ulrich
Published: June 2010

Penicillium chrysogenum
is the industrial producer of the antibiotic penicillin, whose biosynthetic regulation is barely understood. Here, we provide a functional analysis of two major homologues of the
velvet
complex in
P. chrysogenum
, which we have named
P. chrysogenum
velA
(
PcvelA
) and
PclaeA
. Data from array analysis using a Δ
PcvelA
deletion strain indicate a significant role of PcVelA on the expression of biosynthesis and developmental genes, including
PclaeA
. Northern hybridization and high-performance liquid chromatography quantifications of penicillin titers clearly show that both PcVelA and PcLaeA play a major role in penicillin biosynthesis in a producer strain that underwent several rounds of UV mutagenesis during a strain improvement program. Both regulators are further involved in different developmental processes. While
PcvelA
deletion leads to light-independent conidial formation, dichotomous branching of hyphae, and pellet formation in shaking cultures, a Δ
PclaeA
strain shows a severe impairment in conidiophore formation under both light and dark conditions. Bimolecular fluorescence complementation assays provide evidence for a
velvet
-like complex in
P. chrysogenum
, with structurally conserved components that have distinct developmental roles, illustrating the functional plasticity of these regulators in genera other than
Aspergillus
.
A Novel Spore Protein, ExsM, Regulates Formation of the Exosporium in
Bacillus cereus
and
Bacillus anthracis
and Affects Spore Size and Shape
Authors: Fazzini Monica M. , Schuch Raymond , Fischetti Vincent A.
Published: June 2010

Bacillus cereus
spores are assembled with a series of concentric layers that protect them from a wide range of environmental stresses. The outermost layer, or exosporium, is a bag-like structure that interacts with the environment and is composed of more than 20 proteins and glycoproteins. Here, we identified a new spore protein, ExsM, from a β-mercaptoethanol extract of
B. cereus
ATCC 4342 spores. Subcellular localization of an ExsM-green fluorescent protein (GFP) protein revealed a dynamic pattern of fluorescence that follows the site of formation of the exosporium around the forespore. Under scanning electron microscopy,
exsM
null mutant spores were smaller and rounder than wild-type spores, which had an extended exosporium (spore length for the wt, 2.40 ± 0.56 μm, versus that for the
exsM
mutant, 1.66 ± 0.38 μm [
P
< 0.001]). Thin-section electron microscopy revealed that
exsM
mutant spores were encased by a double-layer exosporium, both layers of which were composed of a basal layer and a hair-like nap. Mutant
exsM
spores were more resistant to lysozyme treatment and germinated with higher efficiency than wild-type spores, and they had a delay in outgrowth. Insertional mutagenesis of
exsM
in
Bacillus anthracis
ΔSterne resulted in a partial second exosporium and in smaller spores. In all, these findings suggest that ExsM plays a critical role in the formation of the exosporium.
Genomic Identification of a Novel Mutation in
hfq
That Provides Multiple Benefits in Evolving Glucose-Limited Populations of
Escherichia coli
Authors: Maharjan Ram , Zhou Zhemin , Ren Yan , Li Yang , Gaffé Joël , Schneider Dominique , McKenzie Christopher , Reeves Peter R. , Ferenci Thomas , Wang Lei
Published: June 2010

Beneficial mutations in diversifying glucose-limited
Escherichia coli
populations are mostly unidentified. The genome of an evolved isolate with multiple differences from that of the ancestor was fully assembled. Remarkably, a single mutation in
hfq
was responsible for the multiple benefits under glucose limitation through changes in at least five regulation targets.
The Importance of the Small RNA Chaperone Hfq for Growth of EpidemicYersinia pestis, but NotYersinia pseudotuberculosis, with Implications for Plague Biology
Authors: Bai Guangchun , Golubov Andrey , Smith Eric A. , McDonough Kathleen A.
Published: June 2010

Yersinia pestis, the etiologic agent of plague, has only recently evolved fromYersinia pseudotuberculosis. hfqdeletion caused severe growth restriction at 37°C inY. pestisbut not inY. pseudotuberculosis. Strains from all epidemic plague biovars were similarly affected, implicating Hfq, and likely small RNAs (sRNAs), in the unique biology of the plague bacillus.
Gender influences: the role of leg dominance in ACL injury among soccer players: Table 1
Authors: Brophy Robert , Silvers Holly Jacinda , Gonzales Tyler , Mandelbaum Bert R
Published: June 2010

Objective

This study intends to look at the role of leg dominance in anterior cruciate ligament (ACL) injury risk among soccer (football) athletes. The purpose of this study was to test the hypothesis that soccer players rupture the ACL of their preferred support leg more frequently than the ACL in their preferred kicking leg, particularly in non-contact injuries, despite differences in gender.

Design

Retrospective observational study.

Setting

Outpatient orthopaedic practice.

Patients

Subjects who had sustained an ACL injury due to direct participation in soccer. N=93 (41 male, 52 female).

Interventions

These noncontact injuries were sustained while playing soccer.

Results

For non-contact injuries, roughly half of the injuries occurred in the preferred kicking leg (30) and the contralateral leg (28). However, by gender, there was a significant difference in the distribution of non-contact injury, as 74.1% of males (20/27) were injured on the dominant kicking leg compared with 32% (10/31) of females (p<0.002).

Conclusions

When limited to a non-contact injury mechanism, females are more likely to injure the ACL in their supporting leg, whereas males tend to injure their kicking leg. This research suggests that limb dominance does serve as an aetiological factor with regard to ACL injuries sustained while playing soccer. If follow-up studies confirm that females are more likely to injure their preferred supporting leg, future research should investigate the cause for this discrepancy, which could result from underlying gender-based anatomical differences as well as differences in neuromuscular patterns during cutting manoeuvres or kicking.
Allez Hop, a nationwide programme for the promotion of physical activity in Switzerland: what is the evidence for a population impact after one decade of implementation?
Authors: Wanner Miriam , Martin-Diener Eva , Bauer Georg F , Stamm Hanspeter , Martin Brian W
Published: June 2010

Objectives

To present evidence for a population impact of a national physical activity promotion programme after a decade of implementation.

Methods

The programme Allez Hop offered local physical activity courses (mainly walking and Nordic walking) once a week over 12 weeks. Data from a pretest posttest survey in 2005 course participants (N=2157 at baseline (of 4130, 52.2%), 1587 at first follow-up (73.6%); smaller subsample with second follow-up) and from repeated cross-sectional national surveys have been analysed regarding changes in physical activity behaviour.

Results

The total number of Allez Hop courses was 18 684 between 1997 and 2008. 89.2% of participants were women, the mean age was 48.5 years. The proportion meeting the physical activity recommendations was 31.7% at baseline, in participants with first follow-up data it increased from 33.1% to 42.3% (p<0.001). On the population level in the main user group of Allez Hop (middle-aged women) the proportion not engaging in any sport decreased from 50.1% (1997) to 47.2% (2002) and to 43.1% (2007) (p<0.01). Walking/hiking was the second most frequently performed sport (33.7%) in 2007, with the most remarkable increase since 2000 (+11.1%).

Conclusions

Allez Hop was successfully implemented for more than a decade, reached middle-aged women and a high proportion of insufficiently active individuals. Changes in participants' physical activity behaviour must be interpreted cautiously because of low response rates and short follow-up. However, indications for behavioural changes were observed at the population level, even though these data do not allow a causal link to Allez Hop.
Does a 3-month multidisciplinary intervention improve pain, body composition and physical fitness in women with fibromyalgia?
Authors: Carbonell-Baeza Ana , Aparicio Virginia A , Ortega Francisco B , Cuevas Ana M , Alvarez Inmaculada C , Ruiz Jonatan R , Delgado-Fernandez Manuel
Published: June 2010

Objective

To determine the effects of a 3-month multidisciplinary intervention on pain (primary outcome), body composition and physical fitness (secondary outcomes) in women with fibromyalgia (FM).

Methods

75 women with FM were allocated to a low-moderate intensity 3-month (three times/week) multidisciplinary (pool, land-based and psychological sessions) programme (n=33) or to a usual care group (n=32). The outcome variables were pain threshold, body composition (body mass index and estimated body fat percentage) and physical fitness (30 s chair stand, handgrip strength, chair sit and reach, back scratch, blind flamingo, 8 feet up and go and 6 min walk test).

Results

The authors observed a significant interaction effect (group*time) for the left (L) and right (R) side of the anterior cervical (p<0.001) and the lateral epicondyle R (p=0.001) tender point. Post hoc analysis revealed that pain threshold increased in the intervention group (positive) in the anterior cervical R (p<0.001) and L (p=0.012), and in the lateral epicondyle R (p=0.010), whereas it decreased (negative) in the anterior cervical R (p<0.001) and L (p=0.002) in the usual care group. There was also a significant interaction effect for chair sit and reach. Post hoc analysis revealed improvement in the intervention group (p=0.002). No significant improvement attributed to the training was observed in the rest of physical fitness or body composition variables.

Conclusions

A 3-month multidisciplinary intervention three times/week had a positive effect on pain threshold in several tender points in women with FM. Though no overall improvements were observed in physical fitness or body composition, the intervention had positive effects on lower-body flexibility.
Practice management of musculoskeletal injuries in active children
Authors: Boudier-Revéret Mathieu , Mazer Barbara , Feldman Debbie Ehrmann , Shrier Ian
Published: June 2010

Background

Although increasing participation in physical activities has significant health benefits, there are no guidelines to help professionals decide when it is safe to return to activity after injury.

Objective

To examine the specific criteria (eg, strength, pain) that expert sport medicine clinicians use for return to activity decisions in children with musculoskeletal injuries.

Methods

The authors conducted an online cross-sectional survey of certified Canadian sport medicine doctors (MDs) and sport rehabilitation specialists (physiotherapists (PTs) or athletic therapists (ATs)). The authors asked how they would measure each of the following signs in the context of a knee injury: sport-specific skills, pain, swelling, strength, range of motion (ROM) and balance. Clinicians also ranked the importance of each sign with respect to influencing their recommendations for each of five clinical vignettes.

Results

The overall response rate was 33.6% (464/1380) with similar rates for each profession. For each clinical sign, all three professions preferred the same measure to determine readiness to return to play: standardised testing for sport-specific skills, impact on function for pain, palpation for swelling, manual muscle testing for strength, visual inspection for ROM and standing on one leg with eyes closed for balance. Regarding importance of specific signs for return to activity, all professions had similar responses for one vignette, but MDs differed from PTs and ATs for the remaining four. Finally, pain was ranked as the no 1 or 2 most important sign in all five vignettes by 41.0% of MDs, 18.1% of ATs and 11.3% of PTs, whereas sport-specific skills was chosen by 9.6% MDs, 12.0% ATs and 16.1% PTs.

Conclusion

Our results provide the foundation for future work leading towards the development of interdisciplinary consensus guidelines.
Mitochondrial haplogroups associated with elite Japanese athlete status
Authors: Mikami Eri , Fuku Noriyuki , Takahashi Hideyuki , Ohiwa Nao , Scott Robert A , Pitsiladis Yannis P , Higuchi Mitsuru , Kawahara Takashi , Tanaka Masashi
Published: June 2010

Purpose

It has been hypothesised that certain mitochondrial haplogroups, which are defined by the presence of a characteristic cluster of tightly linked mitochondrial DNA polymorphisms, would be associated with elite Japanese athlete status. To examine this hypothesis, the frequencies of mitochondrial haplogroups found in elite Japanese athletes were compared with those in the general Japanese population.

Methods

Subjects comprised 139 Olympic athletes (79 endurance/middle-power athletes (EMA), 60 sprint/power athletes (SPA)) and 672 controls (CON). Two mitochondrial DNA fragments containing the hypervariable sequence I (m16024–m16383) of the major non-coding region and the polymorphic site at m.5178C>A within the NADH dehydrogenase subunit 2 gene were sequenced, and subjects were classified into 12 major mitochondrial haplogroups (ie, F, B, A, N9a, N9b, M7a, M7b, M*, G2, G1, D5 or D4). The mitochondrial haplogroup frequency differences among EMA, SPA and CON were then examined.

Results

EMA showed an excess of haplogroup G1 (OR 2.52, 95% CI 1.05 to 6.02, p=0.032), with 8.9% compared with 3.7% in CON, whereas SPA displayed a greater proportion of haplogroup F (OR 2.79, 95% CI 1.28 to 6.07, p=0.007), with 15.0% compared with 6.0% in CON.

Conclusions

The results suggest that mitochondrial haplogroups G1 and F are associated with elite EMA and SPA status in Japanese athletes, respectively.
Motor responses to experimental Achilles tendon pain
Authors: Henriksen Marius , Aaboe Jens , Graven-Nielsen Thomas , Bliddal Henning , Langberg Henning
Published: June 2010

Background

Achilles tendinopathies are characterised by pain and reduced function, and heavy-load exercises have been shown to be effective in the treatment of painful chronic Achilles tendinopathies. However, basic information is needed on how the biomechanics and neuromuscular control of the exercise are affected by Achilles tendon pain.

Objective

The authors aimed to determine the effects of experimental Achilles tendon pain on motor function during one-legged weight bearing ankle plantar and dorsal flexion exercises.

Methods

In a crossover study, with 16 healthy subjects tested on two different days separated by 1 week, three-dimensional ground reaction forces, ankle joint kinematics and surface electromyography (EMG) of the lower leg muscles were recorded during one-legged full weight-bearing ankle plantar (concentric) and dorsal (eccentric) flexion exercises. Measurements were done before, during and after either experimental Achilles tendon pain or a non-painful control condition. Pain was induced by intratendinous injections of hypertonic saline with isotonic saline injections as control. Joint kinematics, ground reaction force frequency contents and average EMG amplitudes were calculated.

Results

Compared with the control condition experimental Achilles tendon pain reduced the EMG activity in agonistic, synergistic and antagonistic muscles, and increased the ground reaction force frequency content around 10 Hz, during both eccentric and concentric movement phases.

Conclusions

These data show that experimental Achilles tendon pain causes widespread and reduced motor responses with functional effects on the ground reaction force.
Cognition and performance: anxiety, mood and perceived exertion among Ironman triathletes
Authors: Parry David , Chinnasamy Camilla , Papadopoulou Eleni , Noakes Timothy , Micklewright Dominic
Published: June 2010

Objective

The authors examined the changing patterns of mood before and after an Ironman triathlon, and the relationships between expected performance outcomes, perception of effort and pacing.

Design

Twelve participants in the 2008 Ironman Austria triathlon competition were studied before, during and after the event. Each participant completed measures of mood, anxiety and perceived exertion, while pacing was calculated from official race timings at various points on the course.

Results

Positive correlations were found between distance covered and rating of perceived exertion (RPE) during each of the individual disciplines, and also between RPE and the percentage of overall race time completed (r=0.826, p<0.001). A negative correlation was found between average speed and distance covered during the run segment (r=−0.911, p<0.005) with pace gradually declining. Differences occurred in the profile of mood states mood subscales of tension and fatigue between the baseline, prerace and postrace trials. Somatic anxiety was higher before the race compared with baseline measures.

Discussion

RPE followed a linear progression of RPE during each discipline followed by a re-setting of the perception of effort at the start of the next discipline. The increase in RPE for the entire event followed a linear increase. The linear decline in run pace is consistent with a recent model in which expected RPE is used to modulate pacing. Anxiety and mood responses of participants in this study indicate that the emotional response of athletes before and after ultra-endurance exercise is closely aligned with their conscious thoughts.
Comparison of sports medicine, public health and exercise promotion between bidding countries for the FIFA World Cup in 2018
Authors: Orchard Jessica Joan , Orchard John William , Driscoll Timothy R
Published: June 2010

Objective

To ascertain whether it is possible to assess countries bidding for international sporting events based on public health and sports medicine criteria. In particular, the authors undertook this exercise for countries bidding for the 2018 Fédération Internationale de Football Association (FIFA) Football World Cup (2018 World Cup).

Design

A scorecard framework approach to pose and answer nine relevant questions. Questions were answered using Medline-listed references (where possible) and internet research.

Results

England scored the highest overall, largely due to its sports medicine training programme and recognition, and funding of treatment for sports injuries. The Netherlands/Belgium scored highly in the questions relating to public health expenditure, Australia was very strong in sports medicine research, and Japan was the best of the bidding countries in terms of having a lower prevalence of overweight and obese people.

Conclusions

It is possible to assess countries bidding for international sporting events based on their performance with respect to sports medicine, physical activity and health promotion criteria. Bodies organising major sporting events such as FIFA and the International Olympic Committee may wish to consider making public health measures part of the bidding criteria for hosting these events.
Surgonomics of unruptured intracranial aneurysms
Authors: Drazin Doniel , Dalfino John C , Donovan Mark , Friedlich Daniel , Feustel Paul J , Popp A John , Boulos Alan S
Published: June 2010

Background/Aims

A comparison of reimbursement for endovascular coil embolization and surgical clipping of unruptured aneurysms has not been previously reported. The aim of this study is to assess the reimbursement to physicians and hospitals for each of these two unruptured aneurysm treatments with long-term follow-up.

Methods

Hospital and physician payents were determined for 14 patients treated with coil embolization or surgical clipping of a single unruptured aneurysm per patient from 2004 to 2005, retrospectively. For this analysis, each considered hospital and physician payment encompassed one clipping or coiling procedure plus all pre- and post-operative diagnostic angiograms performed through 2007 to evaluate the treated aneurysm. Reimbursements were analyzed in three categories: physician payments, hospital payments and total payments.

Results

Average physician payments were significantly lower for coil embolization ($3422) than surgical clipping ($5645). Average length of stay after coil embolization was 2.6 days (range: 1–7) and after surgical clipping was 4.7 days (range: 2–11). The length of hospital stay directly affected hospital and total payments only, but was not significantly altered by which procedure was performed.

Conclusion

This study suggests that physician payment for an unruptured aneurysm coil embolization treatment was statistically lower than for a surgical clip treatment. Although physicians were compensated at a lower rate for performing a coil embolization, there was no significant difference in the hospital or total payments between coil or clip treatment modalities.
Complete angiographic obliteration of intracranial AVMs with endovascular embolization: incomplete embolic nidal opacification is associated with AVM recurrence
Authors: Reig Adam S , Rajaram Ravi , Simon Scott , Mericle Robert A
Published: June 2010

Background

Embolization of intracranial arteriovenous malformations (AVMs) is generally a preoperative adjunctive procedure in the USA. However, sometimes embolization can result in complete angiographic obliteration of the AVM. There is significant controversy regarding the best management strategy for this subset of patients. There is a scarcity of literature predicting which embolized, angiographically obliterated AVMs are likely to recur and which ones are cured. We present our series of patients with complete obliteration of their AVMs from embolization.

Methods

A prospectively maintained database identified 122 patients who underwent embolization of an intracerebral pial AVM with liquid embolics. Eighteen patients (15%) achieved complete angiographic obliteration of the AVM with embolization. We followed several parameters to assess possible predictors of recurrence.

Results

Fifteen of 18 patients (83%) had angiographic/anatomical follow-up to assess for AVM recurrence and 3 (17%) refused angiographic follow-up. Three patients underwent surgical resection with intraoperative angiography despite complete AVM obliteration with embolization alone. Thirteen of the 15 (87%) patients with follow-up remained obliterated at time of follow-up, and all of these patients had an embolic cast that had a similar morphology to the AVM nidus. Two of 15 patients (13%) had AVM recurrence, both of whom had incomplete embolic nidal opacification (proximal pedicle embolization).

Conclusions

A minority of intracranial AVMs can be safely obliterated with stand-alone embolization. Proximal occlusion of feeding arteries appears to be associated with recurrence. Prospective studies with longer follow-up and larger patient numbers are necessary.