bluuebunny/crossref_metadata_2025 huggingface dataset:
Solubility Behavior of Cyanophycin Depending on Lysine Content
Authors: Wiefel Lars , Steinbüchel Alexander
Published: November 2013

Study of the synthesis of cyanophycin (CGP) in recombinant organisms focused for a long time mostly on the insoluble form of CGP, due to its easy purification and its putative use as a precursor for biodegradable chemicals. Recently, another form of CGP, which, in contrast to the insoluble form, was soluble at neutral pH, became interesting due to its high lysine content, which was also assumed to be the reason for the solubility of the polymer. In this study, we demonstrate that lysine incorporated into insoluble CGP affected the solubility of the polymer in relation to its lysine content. Insoluble CGP can be separated along a temperature gradient of 90°C to 30°C, where CGP showed an increasing lysine content corresponding to a decreasing temperature needed for solubilization. CGP with less than 3 to 4 mol% lysine did not become soluble even at 90°C, while CGP with 31 mol% lysine was soluble at 30°C. In lysine fractions at higher than 31 mol%, CGP was soluble. The temperature separation will be suitable for improving the downstream processing of CGP synthesized in large-scale fermentations, including faster and more efficient purification of CGP, as well as enrichment and separation of dipeptides and CGP with specific amino acid compositions.
Restoration of Bioactive Lantibiotic Suicin from a Remnant
lan
Locus of Pathogenic Streptococcus suis Serotype 2
Authors: Wang Jian , Gao Yong , Teng Kunling , Zhang Jie , Sun Shutao , Zhong Jin
Published: November 2013

Lantibiotics are ribosomally synthesized, posttranslationally modified antimicrobial peptides. Their biosynthesis genes are usually organized in gene clusters, which are mainly found in Gram-positive bacteria, including pathogenic streptococci. Three highly virulent
Streptococcus suis
serotype 2 strains (98HAH33, 05ZYH33, and SC84) have been shown to contain an 89K pathogenicity island. Here, on these islands, we unveiled and reannotated a putative lantibiotic locus designated
sui
which contains a virulence-associated two-component regulator,
suiK-suiR. In silico
analysis revealed that the putative lantibiotic modification gene
suiM
was interrupted by a 7.9-kb integron and that other biosynthesis-related genes contained various frameshift mutations. By reconstituting the intact
suiM
in
Escherichia coli
together with a semi-
in vitro
biosynthesis system, a putative lantibiotic named suicin was produced with bactericidal activities against a variety of Gram-positive strains, including pathogenic streptococci and vancomycin-resistant enterococci. Ring topology dissection indicated that the 34-amino-acid lantibiotic contained two methyllanthionine residues and one disulfide bridge, which render suicin in an N-terminal linear and C-terminal globular shape. To confirm the function of
suiK-suiR
, SuiR was overexpressed and purified.
In vitro
analysis showed that SuiR could specifically bind to the
suiA
gene promoter. Its coexpression with
suiK
could activate
suiA
gene promoter in
Lactococcus lactis
NZ9000. Conclusively, we obtained a novel lantibiotic suicin by restoring its production from the remnant
sui
locus and demonstrated that virulence-associated SuiK-SuiR regulates its production.
Potential Role of Nitrite for Abiotic Fe(II) Oxidation and Cell Encrustation during Nitrate Reduction by Denitrifying Bacteria
Authors: Klueglein Nicole , Zeitvogel Fabian , Stierhof York-Dieter , Floetenmeyer Matthias , Konhauser Kurt O. , Kappler Andreas , Obst Martin
Published: November 2013

Microorganisms have been observed to oxidize Fe(II) at neutral pH under anoxic and microoxic conditions. While most of the mixotrophic nitrate-reducing Fe(II)-oxidizing bacteria become encrusted with Fe(III)-rich minerals, photoautotrophic and microaerophilic Fe(II) oxidizers avoid cell encrustation. The Fe(II) oxidation mechanisms and the reasons for encrustation remain largely unresolved. Here we used cultivation-based methods and electron microscopy to compare two previously described nitrate-reducing Fe(II) oxidizers (
Acidovorax
sp. strain BoFeN1 and
Pseudogulbenkiania
sp. strain 2002) and two heterotrophic nitrate reducers (
Paracoccus denitrificans
ATCC 19367 and
P. denitrificans
Pd 1222). All four strains oxidized ∼8 mM Fe(II) within 5 days in the presence of 5 mM acetate and accumulated nitrite (maximum concentrations of 0.8 to 1.0 mM) in the culture media. Iron(III) minerals, mainly goethite, formed and precipitated extracellularly in close proximity to the cell surface. Interestingly, mineral formation was also observed within the periplasm and cytoplasm; intracellular mineralization is expected to be physiologically disadvantageous, yet acetate consumption continued to be observed even at an advanced stage of Fe(II) oxidation. Extracellular polymeric substances (EPS) were detected by lectin staining with fluorescence microscopy, particularly in the presence of Fe(II), suggesting that EPS production is a response to Fe(II) toxicity or a strategy to decrease encrustation. Based on the data presented here, we propose a nitrite-driven, indirect mechanism of cell encrustation whereby nitrite forms during heterotrophic denitrification and abiotically oxidizes Fe(II). This work adds to the known assemblage of Fe(II)-oxidizing bacteria in nature and complicates our ability to delineate microbial Fe(II) oxidation in ancient microbes preserved as fossils in the geological record.
Functional Screening and
In Vitro
Analysis Reveal Thioesterases with Enhanced Substrate Specificity Profiles That Improve Short-Chain Fatty Acid Production in Escherichia coli
Authors: McMahon Matthew D. , Prather Kristala L. J.
Published: November 2013

Short-chain fatty acid (SCFA) biosynthesis is pertinent to production of biofuels, industrial compounds, and pharmaceuticals from renewable resources. To expand on
Escherichia coli
SCFA products, we previously implemented a coenzyme A (CoA)-dependent pathway that condenses acetyl-CoA to a diverse group of short-chain fatty acyl-CoAs. To increase product titers and reduce premature pathway termination products, we conducted
in vivo
and
in vitro
analyses to understand and improve the specificity of the acyl-CoA thioesterase enzyme, which releases fatty acids from CoA. A total of 62 putative bacterial thioesterases, including 23 from the cow rumen microbiome, were inserted into a pathway that condenses acetyl-CoA to an acyl-CoA molecule derived from exogenously provided propionic or isobutyric acid. Functional screening revealed thioesterases that increase production of saturated (valerate), unsaturated (
trans
-2-pentenoate), and branched (4-methylvalerate) SCFAs compared to overexpression of
E. coli
thioesterase
tesB
or native expression of endogenous thioesterases. To determine if altered thioesterase acyl-CoA substrate specificity caused the increase in product titers, six of the most promising enzymes were analyzed
in vitro
. Biochemical assays revealed that the most productive thioesterases rely on promiscuous activity but have greater specificity for product-associated acyl-CoAs than for precursor acyl-CoAs. In this study, we introduce novel thioesterases with improved specificity for saturated, branched, and unsaturated short-chain acyl-CoAs, thereby expanding the diversity of potential fatty acid products while increasing titers of current products. The growing uncertainty associated with protein database annotations denotes this study as a model for isolating functional biochemical pathway enzymes in situations where experimental evidence of enzyme function is absent.
The Pine Bark Adelgid, Pineus strobi, Contains Two Novel Bacteriocyte-Associated Gammaproteobacterial Symbionts
Authors: Toenshoff Elena R. , Szabó Gitta , Gruber Daniela , Horn Matthias
Published: November 2013

Bacterial endosymbionts of the pine bark adelgid,
Pineus strobi
(Insecta: Hemiptera: Adelgidae), were investigated using transmission electron microscopy, 16S and 23S rRNA-based phylogeny, and fluorescence
in situ
hybridization. Two morphologically different symbionts affiliated with the
Gammaproteobacteria
were present in distinct bacteriocytes. One of them (“
Candidatus
Annandia pinicola”) is most closely related to an endosymbiont of
Adelges tsugae
, suggesting that they originate from a lineage already present in ancient adelgids before the hosts diversified into the two major clades,
Adelges
and
Pineus
. The other
P. strobi
symbiont (“
Candidatus
Hartigia pinicola”) represents a novel symbiont lineage in members of the Adelgidae. Our findings lend further support for a complex evolutionary history of the association of adelgids with a phylogenetically diverse set of bacterial symbionts.
An
N
-Acyl Homoserine Lactone Synthase in the Ammonia-Oxidizing Bacterium Nitrosospira multiformis
Authors: Gao Jie , Ma Anzhou , Zhuang Xuliang , Zhuang Guoqiang
Published: November 2013

The chemolithoautotrophic bacterium
Nitrosospira multiformis
is involved in affecting the process of nitrogen cycling. Here we report the existence and characterization of a functional quorum sensing signal synthase in
N. multiformis
. One gene (
nmuI
) playing a role in generating a protein with high levels of similarity to
N
-acyl homoserine lactone (AHL) synthase protein families was identified. Two AHLs (C
14
-AHL and 3-oxo-C
14
-AHL) were detected using an AHL biosensor and liquid chromatography-mass spectrometry (LC-MS) when
nmuI
, producing a LuxI homologue, was introduced into
Escherichia coli
. However, by extracting
N. multiformis
culture supernatants with acidified ethyl acetate, no AHL product was obtained that was capable of activating the biosensor or being detected by LC-MS. According to reverse transcription-PCR, the
nmuI
gene is transcribed in
N. multiformis
, and a LuxR homolog (NmuR) in this ammonia-oxidizing strain showed great sensitivity to long-chain AHL signals by solubility assay. A degradation experiment demonstrated that the absence of AHL signals might be attributed to the possible AHL-inactivating activities of this strain. To summarize, an AHL synthase gene (
nmuI
) acting as a long-chain AHL producer has been found in a chemolithotrophic ammonia-oxidizing microorganism, and the results provide an opportunity to complete the knowledge of the regulatory networks in
N. multiformis
.
3-Hydroxybutyrate Oligomer Hydrolase and 3-Hydroxybutyrate Dehydrogenase Participate in Intracellular Polyhydroxybutyrate and Polyhydroxyvalerate Degradation in Paracoccus denitrificans
Authors: Lu Jing , Takahashi Akira , Ueda Shunsaku
Published: November 2013

Genes encoding 3-hydroxybutyrate oligomer hydrolase (PhaZc) and 3-hydroxybutyrate dehydrogenase (Hbd) were isolated from
Paracoccus denitrificans
. PhaZc and Hbd were overproduced as His-tagged proteins in
Escherichia coli
and purified by affinity and gel filtration chromatography. Purified His-tagged proteins had molecular masses of 31 kDa and 120 kDa (a tetramer of 29-kDa subunits). The His-tagged PhaZc hydrolyzed not only 3-hydroxybutyrate oligomers but also 3-hydroxyvalerate oligomers. The His-tagged Hbd catalyzed the dehydrogenation of 3-hydroxyvalerate as well as 3-hydroxybutyrate. When both enzymes were included in the same enzymatic reaction system with 3-hydroxyvalerate dimer, sequential reactions occurred, suggesting that PhaZc and Hbd play an important role in the intracellular degradation of poly(3-hydroxyvalerate). When the
phaZc
gene was disrupted in
P. denitrificans
by insertional inactivation, the mutant strain lost PhaZc activity. When the
phaZc
-disrupted
P. denitrificans
was complemented with
phaZc
, PhaZc activity was restored. These results suggest that
P. denitrificans
carries a single
phaZc
gene. Disruption of the
phaZc
gene in
P. denitrificans
affected the degradation rate of PHA.
Corexit 9500 Inactivates Two Enveloped Viruses of Aquatic Animals but Enhances the Infectivity of a Nonenveloped Fish Virus
Authors: Pham P. H. , Huang Y. J. , Chen C. , Bols N. C.
Published: November 2013

The effects of Corexit 9500, a dispersant used to clean up oil spills, on invertebrates, lower vertebrates, birds, and human health have been examined, but there is a significant lack of study of the effect of this dispersant on aquatic viruses. In this study, the effects of Corexit 9500 on four aquatic viruses of differing structural composition were examined. Corexit 9500 reduced the titer of the enveloped viral hemorrhagic septicemia virus (VHSV) at all concentrations (10% to 0.001%) examined. The titer of frog virus 3 (FV3), a virus with both enveloped and nonenveloped virions, was reduced only at the high Corexit 9500 concentrations (10% to 0.1%). Corexit 9500 was unable to reduce the titer of nonenveloped infectious pancreatic necrosis virus (IPNV) but enhanced the titer of chum salmon reovirus (CSV) by 2 to 4 logs. With the ability to inactivate enveloped viruses and possibly enhance some nonenveloped viruses, Corexit 9500 has the potential to alter the aquatic virosphere.
Discovery and Characterization of a 5-Hydroxymethylfurfural Oxidase from Methylovorus sp. Strain MP688
Authors: Dijkman Willem P. , Fraaije Marco W.
Published: November 2013

In the search for useful and renewable chemical building blocks, 5-hydroxymethylfurfural (HMF) has emerged as a very promising candidate, as it can be prepared from sugars. HMF can be oxidized to 2,5-furandicarboxylic acid (FDCA), which is used as a substitute for petroleum-based terephthalate in polymer production. On the basis of a recently identified bacterial degradation pathway for HMF, candidate genes responsible for selective HMF oxidation have been identified. Heterologous expression of a protein from
Methylovorus
sp. strain MP688 in
Escherichia coli
and subsequent enzyme characterization showed that the respective gene indeed encodes an efficient HMF oxidase (HMFO). HMFO is a flavin adenine dinucleotide-containing oxidase and belongs to the glucose-methanol-choline-type flavoprotein oxidase family. Intriguingly, the activity of HMFO is not restricted to HMF, as it is active with a wide range of aromatic primary alcohols and aldehydes. The enzyme was shown to be relatively thermostable and active over a broad pH range. This makes HMFO a promising oxidative biocatalyst that can be used for the production of FDCA from HMF, a reaction involving both alcohol and aldehyde oxidations.
The FtsZ-Like Protein FtsZm of Magnetospirillum gryphiswaldense Likely Interacts with Its Generic Homolog and Is Required for Biomineralization under Nitrate Deprivation
Authors: Müller Frank D. , Raschdorf Oliver , Nudelman Hila , Messerer Maxim , Katzmann Emanuel , Plitzko Jürgen M. , Zarivach Raz , Schüler Dirk
Published: November 2013

Midcell selection, septum formation, and cytokinesis in most bacteria are orchestrated by the eukaryotic tubulin homolog FtsZ. The alphaproteobacterium
Magnetospirillum gryphiswaldense
(MSR-1) septates asymmetrically, and cytokinesis is linked to splitting and segregation of an intracellular chain of membrane-enveloped magnetite crystals (magnetosomes). In addition to a generic, full-length
ftsZ
gene, MSR-1 contains a truncated
ftsZ
homolog (
ftsZm
) which is located adjacent to genes controlling biomineralization and magnetosome chain formation. We analyzed the role of FtsZm in cell division and biomineralization together with the full-length MSR-1 FtsZ protein. Our results indicate that loss of FtsZm has a strong effect on microoxic magnetite biomineralization which, however, could be rescued by the presence of nitrate in the medium. Fluorescence microscopy revealed that FtsZm-mCherry does not colocalize with the magnetosome-related proteins MamC and MamK but is confined to asymmetric spots at midcell and at the cell pole, coinciding with the FtsZ protein position. In
Escherichia coli
, both FtsZ homologs form distinct structures but colocalize when coexpressed, suggesting an FtsZ-dependent recruitment of FtsZm.
In vitro
analyses indicate that FtsZm is able to interact with the FtsZ protein. Together, our data suggest that FtsZm shares key features with its full-length homolog but is involved in redox control for magnetite crystallization.
Repression of Flagellar Genes in Exponential Phase by CsgD and CpxR, Two Crucial Modulators of Escherichia coli Biofilm Formation
Authors: Dudin Omaya , Geiselmann Johannes , Ogasawara Hiroshi , Ishihama Akira , Lacour Stéphan
Published: November 2013

Escherichia coli
adapts its lifestyle to the variations of environmental growth conditions, swapping between swimming motility or biofilm formation. The stationary-phase sigma factor RpoS is an important regulator of this switch, since it stimulates adhesion and represses flagellar biosynthesis. By measuring the dynamics of gene expression, we show that RpoS inhibits the transcription of the flagellar sigma factor, FliA, in exponential growth phase. RpoS also partially controls the expression of CsgD and CpxR, two transcription factors important for bacterial adhesion. We demonstrate that these two regulators repress the transcription of
fliA
,
flgM
, and
tar
and that this regulation is dependent on the growth medium. CsgD binds to the
flgM
and
fliA
promoters around their −10 promoter element, strongly suggesting direct repression. We show that CsgD and CpxR also affect the expression of other known modulators of cell motility. We propose an updated structure of the regulatory network controlling the choice between adhesion and motility.
Cyclic Di-AMP Impairs Potassium Uptake Mediated by a Cyclic Di-AMP Binding Protein in Streptococcus pneumoniae
Authors: Bai Yinlan , Yang Jun , Zarrella Tiffany M. , Zhang Yang , Metzger Dennis W. , Bai Guangchun
Published: November 2013

Cyclic di-AMP (c-di-AMP) has been shown to play important roles as a second messenger in bacterial physiology and infections. However, understanding of how the signal is transduced is still limited. Previously, we have characterized a diadenylate cyclase and two c-di-AMP phosphodiesterases in
Streptococcus pneumoniae
, a Gram-positive pathogen. In this study, we identified a
c
-di-
A
MP
b
inding
p
rotein (CabP) in
S. pneumoniae
using c-di-AMP affinity chromatography. We demonstrated that CabP specifically bound c-di-AMP and that this interaction could not be interrupted by competition with other nucleotides, including ATP, cAMP, AMP, phosphoadenylyl adenosine (pApA), and cyclic di-GMP (c-di-GMP). By using a bacterial two-hybrid system and genetic mutagenesis, we showed that CabP directly interacted with a potassium transporter (SPD_0076) and that both proteins were required for pneumococcal growth in media with low concentrations of potassium. Interestingly, the interaction between CabP and SPD_0076 and the efficiency of potassium uptake were impaired by elevated c-di-AMP in pneumococci. These results establish a direct c-di-AMP-mediated signaling pathway that regulates pneumococcal potassium uptake.
Identification of FkpA as a Key Quality Control Factor for the Biogenesis of Outer Membrane Proteins under Heat Shock Conditions
Authors: Ge Xi , Lyu Zhi-Xin , Liu Yang , Wang Rui , Zhao Xin Sheng , Fu Xinmiao , Chang Zengyi
Published: November 2013

The outer membrane proteins (OMPs) of Gram-negative bacterial cells, as well as the mitochondrion and chloroplast organelles, possess unique and highly stable β-barrel structures. Biogenesis of OMPs in
Escherichia coli
involves such periplasmic chaperones as SurA and Skp. In this study, we found that the Δ
surA
Δ
skp
double-deletion strain of
E. coli
, although lethal and defective in the biogenesis of OMPs at the normal growth temperature, is viable and effective at the heat shock temperature. We identified FkpA as the multicopy suppressor for the lethal phenotype of the Δ
surA
Δ
skp
strain. We also demonstrated that the deletion of
fkpA
from the Δ
surA
cells resulted in only a mild decrease in the levels of folded OMPs at the normal temperature but a severe decrease as well as lethality at the heat shock temperature, whereas the deletion of
fkpA
from the Δ
skp
cells had no detectable effect on OMP biogenesis at either temperature. These results strongly suggest a functional redundancy between FkpA and SurA for OMP biogenesis under heat shock stress conditions. Mechanistically, we found that FkpA becomes a more efficient chaperone for OMPs under the heat shock condition, with increases in both binding rate and affinity. In light of these observations and earlier reports, we propose a temperature-responsive OMP biogenesis mechanism in which the degrees of functional importance of the three chaperones are such that SurA > Skp > FkpA at the normal temperature but FkpA ≥ SurA > Skp at the heat shock temperature.
Identification of Legionella pneumophila Effectors Regulated by the LetAS-RsmYZ-CsrA Regulatory Cascade, Many of Which Modulate Vesicular Trafficking
Authors: Nevo Oded , Zusman Tal , Rasis Michal , Lifshitz Ziv , Segal Gil
Published: November 2013

Legionella pneumophila
, the causative agent of Legionnaires' disease, is an intracellular human pathogen that utilizes the Icm/Dot type IVB secretion system to translocate a large repertoire of effectors into host cells. To find coregulated effectors, we performed a bioinformatic genomic screen with the aim of identifying effector-encoding genes containing putative CsrA regulatory elements. The regulation of these genes by the LetAS-RsmYZ-CsrA regulatory cascade was experimentally validated by examining their levels of expression in deletion mutants of relevant regulators and by site-directed mutagenesis of the putative CsrA sites. These analyses resulted in the identification of 26 effector-encoding genes regulated by the LetAS-RsmYZ-CsrA regulatory cascade, all of which were expressed at higher levels during the stationary phase. To determine if any of these effectors is involved in modulating the secretory pathway, they were overexpressed in wild-type yeast as well as in a yeast
sec22
deletion mutant, which encodes an R-SNARE that participates in the endoplasmic reticulum (ER)-Golgi trafficking. This examination identified many novel LetAS-RsmYZ-CsrA regulated effectors which are involved in this process. To further characterize the role of these 26 effectors in vesicular trafficking, they were examined in yeast
arf
and
arl
deletion mutants, which encode small GTPases that regulate ER-Golgi trafficking. This analysis revealed that the effectors examined manipulate different processes of the secretory pathway. Collectively, our results demonstrate that several of the
L. pneumophila
effectors which are coregulated in the bacterial cell are involved in the modulation of the same eukaryotic pathway.
Coordinated Expression of
fdxD
and Molybdenum Nitrogenase Genes Promotes Nitrogen Fixation by Rhodobacter capsulatus in the Presence of Oxygen
Authors: Hoffmann Marie-Christine , Müller Alexandra , Fehringer Maria , Pfänder Yvonne , Narberhaus Franz , Masepohl Bernd
Published: November 2013

Rhodobacter capsulatus
is able to grow with N
2
as the sole nitrogen source using either a molybdenum-dependent or a molybdenum-free iron-only nitrogenase whose expression is strictly inhibited by ammonium. Disruption of the
fdxD
gene, which is located directly upstream of the Mo-nitrogenase genes,
nifHDK
, abolished diazotrophic growth via Mo-nitrogenase at oxygen concentrations still tolerated by the wild type, thus demonstrating the importance of FdxD under semiaerobic conditions. In contrast, FdxD was not beneficial for diazotrophic growth depending on Fe-nitrogenase. These findings suggest that the 2Fe2S ferredoxin FdxD specifically supports the Mo-nitrogenase system, probably by protecting Mo-nitrogenase against oxygen, as previously shown for its
Azotobacter vinelandii
counterpart, FeSII. Expression of
fdxD
occurred under nitrogen-fixing conditions, but not in the presence of ammonium. Expression of
fdxD
strictly required NifA1 and NifA2, the transcriptional activators of the Mo-nitrogenase genes, but not AnfA, the transcriptional activator of the Fe-nitrogenase genes. Expression of the
fdxD
and
nifH
genes, as well as the FdxD and NifH protein levels, increased with increasing molybdate concentrations. Molybdate induction of
fdxD
was independent of the molybdate-sensing regulators MopA and MopB, which repress
anfA
transcription at micromolar molybdate concentrations. In this report, we demonstrate the physiological relevance of an
fesII
-like gene,
fdxD
, and show that the cellular nitrogen and molybdenum statuses are integrated to control its expression.
SP10 Infectivity Is Aborted after Bacteriophage SP10 Infection Induces
nonA
Transcription on the Prophage SPβ Region of the Bacillus subtilis Genome
Authors: Yamamoto Tatsuya , Obana Nozomu , Yee Lii Mien , Asai Kei , Nomura Nobuhiko , Nakamura Kouji
Published: November 2013

Bacteria have developed various strategies for phage resistance. Infection with phage induces the transcription of part of the phage resistance gene, but the regulatory mechanisms of such transcription remain largely unknown. The phage resistance gene
nonA
is located on the SPβ prophage region of the
Bacillus subtilis
Marburg strain genome. The
nonA
transcript was detected at the late stage of SP10 infection but is undetectable in noninfected cells. The
nonA
transcript was detected after the induction of the sigma factor Orf199-Orf200 (σ
Orf199-200
), when sigma factors encoded in the SP10 genome were expressed from a xylose-inducible plasmid. Thus, the SP10 sigma factor is an activator of a set of SP10 genes and
nonA
. The
nonA
gene encodes a 72-amino-acid protein with a transmembrane motif and has no significant homology with any protein in any database. NonA overexpression halted cell growth and reduced the efficiency of
B. subtilis
colony formation and respiration activity. In addition, SP10 virion protein synthesis was inhibited in the
nonA
+
strain, and SP10 virion particles were scarce in it. These results indicate that NonA is a novel protein that can abort SP10 infection, and its transcription was regulated by SP10 sigma factor.
Juvenile rheumatic mitral stenosis in association with perimembranous ventricular septal defect in a 3-year old boy
Authors: Vijay Sudarshan Kumar , Tiwari Bhuwan , Misra Mukul , Vijaywargiya Taruna
Published: November 2013

Rheumatic mitral stenosis (MS) is a well-known entity in the developing world. Though rarely seem, MS can present at a very young age with severe symptoms. We describe here an unusual association of a large perimembranous ventricular septal defect with juvenile rheumatic MS leading to severe pulmonary hypertension and heart failure in a very young child.
Injury surveillance during a 2-day national female youth football tournament in Kenya
Authors: Lislevand Marianne , Andersen Thor Einar , Junge Astrid , Dvorak Jiri , Steffen Kathrin
Published: November 2013

Objective

To analyse the incidence, characteristics and circumstances of injuries during a female youth amateur football tournament in Kenya.

Design

14 injury recorders prospectively registered and classified all injuries during all matches. Four physiotherapists and two doctors supported the injury recorders.

Setting

A 2-day Mathare Youth Sports Association (MYSA) inter-provincial football tournament for female players in Nairobi, Kenya. The tournament is organised by a non-governmental organisation (NGO).

Participants

938 females divided into three age groups (under 13 years (U13), under 16 years (U16) and over 16 years (O16)).

Main outcome measurements

Overall injury incidence.

Results

123 injuries occurred in 106 matches. The incidence of all injuries was 93.3 injuries/1000 h. Players in the U13 (relative risk (RR)=2.16, 95% CI 1.3 to 3.5; p=0.002) and U16 (RR=2.17, 95% CI 1.3 to 3.5; p=0.002) age groups had an increased risk of injury compared to the O16 group. Most injuries allowed the players to continue to play (n=98 of 121; 81%). For 15 (12%) of the injuries the player did not continue to play but was expected to fully participate in the following match, and eight of the injuries (6.1 injuries/1000 h) were expected to result in the player's absence from play for 1–7 days. The injuries most commonly affected the lower limb (n=100; 82%); contusions to the ankle (n=15; 12%) and foot/toe (n=15; 12%) were the most common specific injury types. Most acute injuries (89 of 113, 79%) were caused by player contact.

Conclusions

The incidence of injuries among female youth football players in a national tournament in Kenya was high, but time-loss injuries were rare. Playing football in a tournament organised by an NGO at the inter-provincial level was safe.
Chronic traumatic encephalopathy: How serious a sports problem is it?
Authors: Tator Charles H
Published: November 2013

It is now recognised that there is a spectrum of concussion disorders ranging from acute concussion at one end to various forms of brain degeneration at the other end. The spectrum includes acute concussion, second impact syndrome or acute cerebral swelling, postconcussion syndrome, depression or anxiety, chronic traumatic encephalopathy (CTE) and possibly other forms of central nervous system degeneration. It is essential to carefully evaluate the clinical and neuropathological correlations of CTE that have been published. This has been accomplished in an excellent paper on this subject by Gardner and colleagues in this issue. There have been significant advances in our knowledge of the clinical and neuropathological features of CTE in athletes in the past 10 years. However, we are just at the beginning of our appreciation of this entity due to the paucity of research and the inability to diagnose CTE during life. At present, it is not possible to assess the validity of the proposed methods of classification and grading of the severity of the disease. Additional studies of large numbers of at-risk athletes are essential, especially prospective longitudinal studies. Obviously, such studies would be even more effective if reliable in vivo biomarkers were discovered, especially non-invasive ones such as advanced MRI or MR spectroscopy or invasive ones such as blood or cerebrospinal fluid tests. The major questions that remain unanswered include the frequency of CTE in various collision sports, the causal or otherwise relationship between concussions and CTE, the number of concussions that need to be involved and their management.
Change in objectively measured physical activity during the transition to adolescence
Authors: Corder Kirsten , Sharp Stephen J , Atkin Andrew J , Griffin Simon J , Jones Andrew P , Ekelund Ulf , van Sluijs Esther M F
Published: November 2013

Background

Physical activity (PA) declines during adolescence but change in different PA intensities across population subgroups is rarely explored. We describe change in sedentary (SED) time, light (LPA), moderate (MPA) and vigorous PA (VPA) assessed at three time points over 4 years.

Methods

Accelerometer-assessed PA (min) was obtained at baseline (N=2064), 1 and 4 years later among British children (baseline mean±SD 10.2±0.3-year-old; 42.5% male). Change in SED (<100 counts/min (cpm)), LPA (101–1999 cpm), MPA (2000–3999 cpm) and VPA (≥4000 cpm) was studied using three-level (age, individual and school) mixed-effects linear regression including participants with data at ≥2 time points (N=990). Differences in change by sex, home location and weight status were explored with interactions for SED, LPA and moderate and vigorous PA (MVPA).

Results

SED increased by 10.6 (95% CI 9.1 to 12.2) min/day/year. MPA and VPA decreased by 1.4 (1.0 to 1.8) and 1.5 (1.1 to 1.8) min/day/year, respectively. VPA decreased more than MPA as a percentage of the baseline value. MVPA declined more steeply among boys (3.9 (3.0 to 4.8)) versus girls (2.0 (1.2 to 2.7) min/day/year) despite lower MVPA among girls at all ages; rural (4.4 (3.5 to 5.2)) versus urban individuals (1.3 (0.4 to 2.3) min/day/year) and on weekends (6.7 (5.2 to 8.1)) versus weekdays (2.8 (1.9 to 3.7) min/day/year). MVPA was consistently lower among overweight/obese individuals (−17.5 (−3.9 to −2.5) min/day/year).

Conclusions

PA decreases and is replaced by SED during early adolescence in British youth. Results indicate the urgency of PA promotion among all adolescents but especially girls and in rural areas. Increasing VPA and targeting PA promotion during weekends appear important.
The orthopaedic error index: development and application of a novel national indicator for assessing the relative safety of hospital care using a cross-sectional approach
Authors: Panesar Sukhmeet S , Netuveli Gopalakrishnan , Carson-Stevens Andrew , Javad Sundas , Patel Bhavesh , Parry Gareth , Donaldson Liam J , Sheikh Aziz
Published: November 2013

Objective

The Orthopaedic Error Index for hospitals aims to provide the first national assessment of the relative safety of provision of orthopaedic surgery.

Design

Cross-sectional study (retrospective analysis of records in a database).

Setting

The National Reporting and Learning System is the largest national repository of patient-safety incidents in the world with over eight million error reports. It offers a unique opportunity to develop novel approaches to enhancing patient safety, including investigating the relative safety of different healthcare providers and specialties.

Participants

We extracted all orthopaedic error reports from the system over 1 year (2009–2010).

Outcome measures

The Orthopaedic Error Index was calculated as a sum of the error propensity and severity. All relevant hospitals offering orthopaedic surgery in England were then ranked by this metric to identify possible outliers that warrant further attention.

Results

155 hospitals reported 48 971 orthopaedic-related patient-safety incidents. The mean Orthopaedic Error Index was 7.09/year (SD 2.72); five hospitals were identified as outliers. Three of these units were specialist tertiary hospitals carrying out complex surgery; the remaining two outlier hospitals had unusually high Orthopaedic Error Indexes: mean 14.46 (SD 0.29) and 15.29 (SD 0.51), respectively.

Conclusions

The Orthopaedic Error Index has enabled identification of hospitals that may be putting patients at disproportionate risk of orthopaedic-related iatrogenic harm and which therefore warrant further investigation. It provides the prototype of a summary index of harm to enable surveillance of unsafe care over time across institutions. Further validation and scrutiny of the method will be required to assess its potential to be extended to other hospital specialties in the UK and also internationally to other health systems that have comparable national databases of patient-safety incidents.
The comparative risk of new-onset diabetes after prescription of drugs for cardiovascular risk prevention in primary care: a national cohort study
Authors: Currie Olivia , Mangin Dee , Williman Jonathan , McKinnon-Gee Bianca , Bridgford Paul
Published: November 2013

Objective

Recent studies suggest that statins increase the risk of subsequent diabetes with a clear dose response effect. However, patients prescribed statins have a higher background risk of diabetes. This national cohort study aims to provide an estimate of the comparative risks for subsequent development of new-onset diabetes in adults prescribed statins and in those with an already higher background risk on cardiovascular risk-modifying drugs and a control drug.

Design

Longitudinal cohort study.

Setting

Use of routinely collected data from a complete national primary care electronic prescription database in New Zealand.

Participants

32 086 patients aged between 40 and 60 years in 2005 were eligible and assigned to four non-overlapping groups receiving their first prescription for: (1) diclofenac (healthy population) n=7140; (2) antihypertensives thought likely to induce diabetes (thiazides and β-blockers) n=5769; (3) antihypertensives thought less likely to induce diabetes (ACE inhibitors, angiotensin II receptor blockers, calcium channel blocker) n=6565 and (4) statins n=12 612.

Outcome

Numbers of first metformin prescriptions were compared between these groups from 2006 to 2011.

Results

Patients prescribed statins have the highest risk of receiving a subsequent metformin prescription (HR 3.31; 95% CI 2.56 to 4.30; p<0.01), followed by patients prescribed antihypertensives thought less likely to induce diabetes (HR 2.32; 95% CI 1.74 to 3.09; p<0.01) and patients prescribed antihypertensives thought more likely to induce diabetes (HR 1.59; 95% CI 1.15 to 2.20; p<0.01) in the subsequent 6 years of follow-up, when compared to diclofenac.

Conclusions

These findings further support the link between statin use and new-onset diabetes and suggest that the understanding of diabetes risk associated with different antihypertensive drug classes may bear practice modification. This provides important information for future research, and for prescribers and patients when considering the risks and benefits of different types of cardiovascular risk-modifying drugs.
A three-year follow-up on the efficacy of psychosocial interventions for patients with mild dementia and their caregivers: the multicentre, rater-blinded, randomised Danish Alzheimer Intervention Study (DAISY)
Authors: Phung Kieu T T , Waldorff F B , Buss D V , Eckermann A , Keiding N , Rishøj S , Siersma V , Sørensen J , Søgaard R , Sørensen L V , Vogel A , Waldemar G
Published: November 2013

Objectives

To examine the long-term efficacy at the 36-month follow-up of an early psychosocial counselling and support programme lasting 8–12 months for community-dwelling patients with mild Alzheimer's disease and their caregivers.

Design

Multicentre, randomised, controlled, rater-blinded trial.

Setting

Primary care and memory clinics in five Danish districts.

Participants

330 home-dwelling patients with mild Alzheimer's disease and their primary caregivers (dyads).

Interventions

Dyads were randomised to receive intervention during the first year after diagnosis. Both intervention and control groups had follow-up visits at 3, 6, 12 and 36 months.

Main outcome measures

Primary outcomes for the patients assessed at 36-month follow-up were changes from baseline in global cognitive function (Mini-Mental State Examination), depressive symptoms (Cornell Depression Scale) and proxy-rated EuroQoL quality of life on visual analogue scale. The primary outcomes for the caregivers were changes from baseline in depressive symptoms (Geriatric Depression Scale) and self-rated EuroQoL quality of life on a visual analogue scale. The secondary outcome measures for the patient were proxy-rated Quality of Life Scale for Alzheimer's disease (QoL-AD), Neuropsychiatric Inventory-Questionnaire, Alzheimer's disease Cooperative Study Activities of Daily Living Scale, all-cause mortality and nursing home placement.

Results

At a 36-month follow-up, 2 years after the completion of the Danish Alzheimer Intervention Study (DAISY), the unadjusted positive effects previously detected at the 12-month follow-up in one patient primary outcome (Cornell depression score) and one patient secondary outcome (proxy-rated QoL-AD) disappeared (Cornell depression score, p=0.93; proxy-rated QoL-AD, p=0.81). No long-term effect of DAISY intervention on any other primary and secondary outcomes was found at the 36-month follow-up.

Conclusions

For patients with very mild Alzheimer's disease and their caregivers, an intensive, multi-component, semitailored psychosocial intervention programme with counselling, education and support during the first year after diagnosis did not show any positive long-term effect on primary and secondary outcomes.

Trial registration

The study was registered in the Clinical Trial Database (http://www.controlled-trials.com/ISRCTN74848736).
Improving the investigation of suspected deep vein thrombosis in the Emergency Department
Authors: Daum Peter
Published: November 2013

Deep vein thrombosis is an important medical condition that requires treatment to prevent further complications. However, diagnosing deep vein thrombosis is not straightforward because its symptoms can mimic a number of alternative diagnoses - often leading to unnecessary investigation. The latest NICE guidance published in June 2012 provides a clear evidence-based approach to diagnosis which helps to minimise this potential loss of valuable time and resources.

It was recognised that the Emergency Department was unaware of the latest guidance and demonstrated that it was often over and inadequately investigating suspected deep vein thromboses, unnecessarily using resources and putting patients at risk. To address this, a new investigation pathway and proforma were introduced into the department. It was placed onto the Trust website and incorporated into the departmental induction for new staff and trainees.

Following the introduction of these changes, a re-audit demonstrated that the department's investigation of deep vein thrombosis improved significantly. In addition to increased adherence to the latest guidelines and improved documentation there was a 21% reduction in the total number of ultrasound scans performed indicating a significant impact upon both the department and patient care.
Poverty's latent effect on adiposity during childhood: evidence from a Québec birth cohort
Authors: Kakinami Lisa , Séguin Louise , Lambert Marie , Gauvin Lise , Nikiema Béatrice , Paradis Gilles
Published: November 2013

Background

Childhood poverty heightens the risk of obesity in adulthood, but the age at which this risk appears is unclear. We analysed the association between poverty trajectories with body mass index (BMI) Z-scores or the risk of being overweight or obese across four ages (6 years, 8 years, 10 years and 12 years) in childhood.

Methods

Data were from the 1998–2010 ‘Quebec Longitudinal Study of Child Development’ cohort (n=698). Poverty was defined using Statistics Canada's thresholds, and trajectories were characterised with a Latent Class Growth Analysis. Multivariable linear and logistic regression models adjusted for sex, whether the mother was an immigrant, maternal education and birth weight.

Results

Four income trajectories were identified: a reference group (stable non-poor), and 3 higher exposure categories (increasing likelihood of poverty, decreasing likelihood of poverty or stable poor). Compared with children from stable non-poor households, children from stable poor households had BMI Z-scores that were 0.39 and 0.43 larger than children from stable non-poor households at age 10 years and 12 years, respectively (p<0.05). Compared with children from stable non-poor households, children from stable poor households were 2.22, 2.34, and 3.04 times more likely to be overweight or obese at age 8 years, 10 years and 12 years, respectively (p<0.05).

Conclusion

A latency period for the detrimental effects of child poverty on the risk of overweight or obesity was detected. Whether the effects continue to widen with increasing duration of exposure to poverty as the children age should be investigated.
Extreme temperatures and paediatric emergency department admissions
Authors: Xu Zhiwei , Hu Wenbiao , Su Hong , Turner Lyle R , Ye Xiaofang , Wang Jiajia , Tong Shilu
Published: November 2013

Background

Children are particularly vulnerable to the effects of extreme temperatures.

Objective

To examine the relationship between extreme temperatures and paediatric emergency department admissions (EDAs) in Brisbane, Australia, during 2003–2009.

Methods

A quasi-Poisson generalised linear model combined with a distributed lag non-linear model was used to examine the relationships between extreme temperatures and age-, gender- and cause-specific paediatric EDAs, while controlling for air pollution, relative humidity, day of the week, influenza epidemics, public holiday, season and long-term trends. The model residuals were checked to identify whether there was an added effect due to heat waves or cold spells.

Results

There were 131 249 EDAs among children during the study period. Both high (RR=1.27; 95% CI 1.12 to 1.44) and low (RR=1.81; 95% CI 1.66 to 1.97) temperatures were significantly associated with an increase in paediatric EDAs in Brisbane. Male children were more vulnerable to temperature effects. Children aged 0–4 years were more vulnerable to heat effects and children aged 10–14 years were more sensitive to both hot and cold effects. High temperatures had a significant impact on several paediatric diseases, including intestinal infectious diseases, respiratory diseases, endocrine, nutritional and metabolic diseases, nervous system diseases and chronic lower respiratory diseases. Low temperatures were significantly associated with intestinal infectious diseases, respiratory diseases and endocrine, nutritional and metabolic diseases. An added effect of heat waves on childhood chronic lower respiratory diseases was seen, but no added effect of cold spells was found.

Conclusions

As climate change continues, children are at particular risk of a variety of diseases which might be triggered by extremely high temperatures. This study suggests that preventing the effects of extreme temperature on children with respiratory diseases might reduce the number of EDAs.
How the Neoproterozoic S-isotope record illuminates the genesis of vein gold systems: an example from the Dalradian Supergroup in Scotland
Authors: Hill Nyree J. , Jenkin Gawen R. T. , Boyce Adrian J. , Sangster Christopher J. S. , Catterall David J. , Holwell David A. , Naden Jonathan , Rice Clive M.
Published: November 2013

The genesis of quartz vein-hosted gold mineralization in the Neoproterozoic–early Palaeozoic Dalradian Supergroup of Scotland remains controversial. An extensive new dataset of S-isotope analyses from the Tyndrum area, together with correlation of the global Neoproterozoic sedimentary S-isotope dataset to the Dalradian stratigraphy, demonstrates a mixed sedimentary and magmatic sulphur source for the mineralization. δ
34
S values for early molybdenite- and later gold-bearing mineralization range from −2 to +12‰, but show distinct populations related to mineralization type. Modelling of the relative input of magmatic and sedimentary sulphur into gold-bearing quartz veins with δ
34
S values of +12‰ indicates a maximum of 68% magmatic sulphur, and that S-rich, SEDEX-bearing, Easdale Subgroup metasedimentary rocks lying stratigraphically above the host rocks represent the
only
viable source of sedimentary sulphur in the Dalradian Supergroup. Consequently, the immediate host rocks were not a major source of sulphur to the mineralization, consistent with their low bulk sulphur and lack of metal enrichment. Recent structural models of the Tyndrum area suggest that Easdale Subgroup metasedimentary rocks, enriched in
34
S, sulphur and metals, are repeated at depth owing to folding, and it is suggested that these are the most likely source of sedimentary sulphur, and possibly metals, for the ore fluids.