bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Micro- and Nanoscale Topography on the Adhesion of Bacterial Cells to Solid Surfaces
Authors: Hsu Lillian C. , Fang Jean , Borca-Tasciuc Diana A. , Worobo Randy W. , Moraru Carmen I.
Published: February 2013

Attachment and biofilm formation by bacterial pathogens on surfaces in natural, industrial, and hospital settings lead to infections and illnesses and even death. Minimizing bacterial attachment to surfaces using controlled topography could reduce the spreading of pathogens and, thus, the incidence of illnesses and subsequent human and financial losses. In this context, the attachment of key microorganisms, including
Escherichia coli
,
Listeria innocua
, and
Pseudomonas fluorescens
, to silica and alumina surfaces with micron and nanoscale topography was investigated. The results suggest that orientation of the attached cells occurs preferentially such as to maximize their contact area with the surface. Moreover, the bacterial cells exhibited different morphologies, including different number and size of cellular appendages, depending on the topographical details of the surface to which they attached. This suggests that bacteria may utilize different mechanisms of attachment in response to surface topography. These results are important for the design of novel microbe-repellant materials.
Legionella pneumophila Transcriptional Response following Exposure to CuO Nanoparticles
Authors: Lu Jingrang , Struewing Ian , Buse Helen Y. , Kou Jiahui , Shuman Howard A. , Faucher Sébastien P. , Ashbolt Nicholas J.
Published: February 2013

Copper ions are an effective antimicrobial agent used to control Legionnaires' disease and Pontiac fever arising from institutional drinking water systems. Here, we present data on an alternative bactericidal agent, copper oxide nanoparticles (CuO-NPs), and its efficacy on
Legionella pneumophila
. In broth cultures, the CuO-NPs caused growth inhibition, which appeared to be concentration and exposure time dependent. The transcriptomic response of
L. pneumophila
to CuO-NP exposure was investigated by using a whole-genome microarray. The expression of genes involved in metabolism, transcription, translation, DNA replication and repair, and unknown/hypothetical proteins was significantly affected by exposure to CuO-NPs. In addition, expression of 21 virulence genes was also affected by exposure to CuO-NP and further evaluated by quantitative reverse transcription-PCR (qRT-PCR). Some virulence gene responses occurred immediately and transiently after addition of CuO-NPs to the cells and faded rapidly (
icmV
,
icmW
,
lepA
), while expression of other genes increased within 6 h (
ceg29
,
legLC8
,
legP
,
lem19
,
lem24
,
lpg1689
, and
rtxA
), 12 h (
cegC1
,
dotA
,
enhC
,
htpX
,
icmE
,
pvcA
, and
sidF
), and 24 h (
legP
,
lem19
, and
ceg19
), but for most of the genes tested, expression was reduced after 24 h of exposure. Genes like
ceg29
and
rtxA
appeared to be the most responsive to CuO-NP exposures and along with other genes identified in this study may prove useful to monitor and manage the impact of drinking water disinfection on
L. pneumophila
.
Phylogenetic and Molecular Analysis of Food-Borne Shiga Toxin-Producing Escherichia coli
Authors: Hauser Elisabeth , Mellmann Alexander , Semmler Torsten , Stoeber Helen , Wieler Lothar H. , Karch Helge , Kuebler Nikole , Fruth Angelika , Harmsen Dag , Weniger Thomas , Tietze Erhard , Schmidt Herbert
Published: February 2013

Seventy-five food-associated Shiga toxin-producing
Escherichia coli
(STEC) strains were analyzed by molecular and phylogenetic methods to describe their pathogenic potential. The presence of the locus of proteolysis activity (LPA), the chromosomal pathogenicity island (PAI) PAI I
CL3
, and the autotransporter-encoding gene
sabA
was examined by PCR. Furthermore, the occupation of the chromosomal integration sites of the locus of enterocyte effacement (LEE),
selC
,
pheU
, and
pheV
, as well as the Stx phage integration sites
yehV
,
yecE
,
wrbA
,
z2577
, and
ssrA
, was analyzed. Moreover, the antibiotic resistance phenotypes of all STEC strains were determined. Multilocus sequence typing (MLST) was performed, and sequence types (STs) and sequence type complexes (STCs) were compared with those of 42 hemolytic-uremic syndrome (HUS)-associated enterohemorrhagic
E. coli
(HUSEC) strains. Besides 59 STs and 4 STCs, three larger clusters were defined in this strain collection. Clusters A and C consist mostly of highly pathogenic
eae
-positive HUSEC strains and some related food-borne STEC strains. A member of a new O26 HUS-associated clone and the 2011 outbreak strain
E. coli
O104:H4 were found in cluster A. Cluster B comprises only
eae
-negative food-borne STEC strains as well as mainly
eae
-negative HUSEC strains. Although food-borne strains of cluster B were not clearly associated with disease, serotypes of important pathogens, such as O91:H21 and O113:H21, were in this cluster and closely related to the food-borne strains. Clonal analysis demonstrated eight closely related genetic groups of food-borne STEC and HUSEC strains that shared the same ST and were similar in their virulence gene composition. These groups should be considered with respect to their potential for human infection.
Kinetics of Ozone Inactivation of Infectious Prion Protein
Authors: Ding Ning , Neumann Norman F. , Price Luke M. , Braithwaite Shannon L. , Balachandran Aru , Mitchell Gordon , Belosevic Miodrag , Gamal El-Din Mohamed
Published: February 2013

The kinetics of ozone inactivation of infectious prion protein (PrP
Sc
, scrapie 263K) was investigated in ozone-demand-free phosphate-buffered saline (PBS). Diluted infectious brain homogenates (IBH) (0.01%) were exposed to a predetermined ozone dose (10.8 ± 2.0 mg/liter) at three pHs (pH 4.4, 6.0, and 8.0) and two temperatures (4°C and 20°C). The inactivation of PrP
Sc
was quantified by determining the
in vitro
destruction of PrP
Sc
templating properties using the protein misfolding cyclic amplification (PMCA) assay and bioassay, which were shown to correlate well. The inactivation kinetics were characterized by both Chick-Watson (CW) and efficiency factor Hom (EFH) models. It was found that the EFH model fit the experimental data more appropriately. The efficacy of ozone inactivation of PrP
Sc
was both pH and temperature dependent. Based on the EFH model,
CT
(disinfectant concentration multiplied by contact time) values were determined for 2-log
10
, 3-log
10
, and 4-log
10
inactivation at the conditions under which they were achieved. Our results indicated that ozone is effective for prion inactivation in ozone-demand-free water and may be applied for the inactivation of infectious prion in prion-contaminated water and wastewater.
Genetic Analysis of Capsular Polysaccharide Synthesis Gene Clusters from All Serotypes of Streptococcus suis: Potential Mechanisms for Generation of Capsular Variation
Authors: Okura Masatoshi , Takamatsu Daisuke , Maruyama Fumito , Nozawa Takashi , Nakagawa Ichiro , Osaki Makoto , Sekizaki Tsutomu , Gottschalk Marcelo , Kumagai Yumi , Hamada Shigeyuki
Published: February 2013

Streptococcus suis
strains are classified into 35 serotypes on the basis of the antigenicity of their capsular polysaccharides (CPs). CP synthesis genes are known to be clustered on the chromosome (
cps
gene cluster). The entire
cps
gene clusters of
S. suis
have so far been sequenced in 15 serotypes and found to be located between
orfZ
and
aroA
. In this study, to provide comprehensive information about
S. suis
CPs, we sequenced the entire
cps
gene clusters of the remaining serotypes and analyzed the complete set of
S. suis
cps
gene clusters. Among the 35
cps
gene clusters, 22 were located between
orfZ
and
aroA
, whereas the other 13 were flanked by other gene(s) on the chromosomes, and the chromosomal locus was classified into five patterns. By clustering analysis, the predicted products of
cps
genes found in the 35 serotypes were assigned into 291 homology groups, and all serotypes possessed a serotype-specific gene, except for serotypes 1, 2, 1/2, and 14. Because of the presence of genes encoding flippase (
wzx
) and polymerase (
wzy
), CPs of all serotypes were thought to be synthesized by the Wzx/Wzy pathway. Our data also implied the possibility of the transfer of the entire or partial
cps
gene clusters among
S. suis
strains, as well as the influence of spontaneous mutations in a single gene or a few genes on the antigenicity of some serotypes. Accumulation of these gene transfers and small-scale mutations may have generated the antigenic diversity of
S. suis
CPs.
New Constitutive Vectors: Useful Genetic Engineering Tools for Biocatalysis
Authors: Xu Youqiang , Tao Fei , Ma Cuiqing , Xu Ping
Published: February 2013

Constitutive vectors are useful tools for genetic engineering. Two constitutive vectors with high levels of expression and broad host ranges were developed and used in a range of
Pseudomonas
hosts. The vectors showed superior characteristics compared to the inducible vectors as well as the potential to be used as improved genetic tools for biocatalysis.
Rapid Microcystis Cyanophage Gene Diversification Revealed by Long- and Short-Term Genetic Analyses of the Tail Sheath Gene in a Natural Pond
Authors: Kimura Shigeko , Sako Yoshihiko , Yoshida Takashi
Published: February 2013

Viruses influence the abundance of host populations through virus-mediated host cell lysis. Viruses contribute to the generation and maintenance of host diversity, which also results in viral diversity throughout their coevolution. Here, to determine the phage gene diversification throughout the coevolution of host and phage in a natural environment, we investigated the genetic diversity and temporal changes in
Microcystis
cyanophage populations using a total of 810 sequences of the Ma-LMM01-type cyanophage tail sheath gene (
g91
) from 2006 to 2011 in a natural pond. The sequences obtained were highly diverse and assigned to 419 different genotypes (GT1 to GT419) clustered at 100% nucleotide sequence similarity. A maximum-parsimony network showed that the genotypes were largely divided into three sequence groups, which were dominated by major genotypes (more than 24 sequences: GT2, GT53, and GT163 in group I; GT25 in group II; and GT1 in group III). These major genotypes coexisted and oscillated throughout the sampling periods, suggesting that the
Microcystis
-cyanophage coevolution was partly driven by a negative frequency-dependent selection. Meanwhile, the high viral genetic diversity observed was derived from a large number of the variants of each major and moderately frequent genotype (including 7 to 18 sequences: GT7, GT26, GT56, GT149, and GT182 in group I; GT152 in group II) (1 or 2 nucleotide substitutions). The variants almost always co-occurred with their origin genotypes. This manner of variant emergence suggests that increased contact frequency within a host-phage population promotes rapid coevolution in a form of “arms race.”
CYP63A2, a Catalytically Versatile Fungal P450 Monooxygenase Capable of Oxidizing Higher-Molecular-Weight Polycyclic Aromatic Hydrocarbons, Alkylphenols, and Alkanes
Authors: Syed Khajamohiddin , Porollo Aleksey , Lam Ying Wai , Grimmett Paul E. , Yadav Jagjit S.
Published: February 2013

Cytochrome P450 monooxygenases (P450s) are known to oxidize hydrocarbons, albeit with limited substrate specificity across classes of these compounds. Here we report a P450 monooxygenase (CYP63A2) from the model ligninolytic white rot fungus
Phanerochaete chrysosporium
that was found to possess a broad oxidizing capability toward structurally diverse hydrocarbons belonging to mutagenic/carcinogenic fused-ring higher-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs), endocrine-disrupting long-chain alkylphenols (APs), and crude oil aliphatic hydrocarbon
n
-alkanes. A homology-based three-dimensional (3D) model revealed the presence of an extraordinarily large active-site cavity in CYP63A2 compared to the mammalian PAH-oxidizing (CYP3A4, CYP1A2, and CYP1B1) and bacterial aliphatic-hydrocarbon-oxidizing (CYP101D and CYP102A1) P450s. This structural feature in conjunction with ligand docking simulations suggested potential versatility of the enzyme. Experimental characterization using recombinantly expressed CYP63A2 revealed its ability to oxidize HMW-PAHs of various ring sizes, including 4 rings (pyrene and fluoranthene), 5 rings [benzo(
a
)pyrene], and 6 rings [benzo(
ghi
)perylene], with the highest enzymatic activity being toward the 5-ring PAH followed by the 4-ring and 6-ring PAHs, in that order. Recombinant CYP63A2 activity yielded monohydroxylated PAH metabolites. The enzyme was found to also act as an alkane ω-hydroxylase that oxidized
n
-alkanes with various chain lengths (C
9
to C
12
and C
15
to C
19
), as well as alkyl side chains (C
3
to C
9
) in alkylphenols (APs). CYP63A2 showed preferential oxidation of long-chain APs and alkanes. To our knowledge, this is the first P450 identified from any of the biological kingdoms that possesses such broad substrate specificity toward structurally diverse xenobiotics (PAHs, APs, and alkanes), making it a potent enzyme biocatalyst candidate to handle mixed pollution (e.g., crude oil spills).
SUP05 Dominates the Gammaproteobacterial Sulfur Oxidizer Assemblages in Pelagic Redoxclines of the Central Baltic and Black Seas
Authors: Glaubitz Sabine , Kießlich Katrin , Meeske Christian , Labrenz Matthias , Jürgens Klaus
Published: February 2013

Gammaproteobacterial sulfur oxidizers (GSOs), particularly SUP05-related sequences, have been found worldwide in numerous oxygen-deficient marine environments. However, knowledge regarding their abundance, distribution, and ecological role is scarce. In this study, on the basis of phylogenetic analyses of 16S rRNA gene sequences originating from a Baltic Sea pelagic redoxcline, the
in situ
abundances of different GSO subgroups were quantified by CARD-FISH (catalyzed reporter fluorescence
in situ
hybridization) with oligonucleotide probes developed specifically for this purpose. Additionally, ribulose bisphosphate carboxylase/oxygenase form II (
cbbM
) gene transcript clone libraries were used to detect potential active chemolithoautotrophic GSOs in the Baltic Sea. Taken together, the results obtained by these two approaches demonstrated the existence of two major phylogenetic subclusters embedded within the GSO, one of them affiliated with sequences of the previously described SUP05 subgroup. CARD-FISH analyses revealed that only SUP05 occurred in relatively high numbers, reaching 10 to 30% of the total prokaryotes around the oxic-anoxic interface, where oxygen and sulfide concentrations are minimal. The applicability of the oligonucleotide probes was confirmed with samples from the Black Sea redoxcline, in which the SUP05 subgroup accounted for 10 to 13% of the total prokaryotic abundance. The
cbbM
transcripts presumably originating from SUP05 cells support previous evidence for the chemolithoautotrophic activity of this phylogenetic group. Our findings on the vertical distribution and high abundance of SUP05 suggest that this group plays an important role in marine redoxcline biogeochemistry, probably as anaerobic or aerobic sulfur oxidizers.
Occurrence of Livestock-Associated Methicillin-Resistant Staphylococcus aureus in Turkey and Broiler Barns and Contamination of Air and Soil Surfaces in Their Vicinity
Authors: Friese A. , Schulz J. , Zimmermann K. , Tenhagen B.-A. , Fetsch A. , Hartung J. , Rösler U.
Published: February 2013

The emission of microorganisms, especially resistant bacteria such as methicillin-resistant
Staphylococcus aureus
(MRSA), from poultry farms is of public interest, and its occurrence and relevance are controversially discussed. So far, there are limited data on this issue. In this study, we investigated the occurrence of livestock-associated (LA)-MRSA inside and outside previously tested MRSA-positive poultry barns in Germany. In total, five turkey and two broiler fattening farms were investigated four and three times, respectively. In a longitudinal study during one fattening period, samples were collected from animals, the animals' environment inside the barn, including the air, and the barns' surroundings, such as ambient air and boot swabs of ground surfaces at different distances from the barn. Moreover, a cross-sectional study was carried out once inside the barns on five turkey and four broiler farms during the last third of the fatting period. In the cross-sectional study, LA-MRSA was detected in the air of most barns (7 of 9, 77.8%), as well as in many samples originating from animals, with detections levels of 50 to 54% in broiler and 62 to 77% in turkey farms. In the longitudinal study, LA-MRSA was found in the ambient air outside two turkey barns and on the ground surface on the downwind side of many (44.4%) turkey and broiler farms. The same
spa
types of isolates were observed inside and outside the barns. Transmission of MRSA within poultry farms, as well as emission via the airborne route, seems to be possible.
Nitrogen Removal by a Nitritation-Anammox Bioreactor at Low Temperature
Authors: Hu Ziye , Lotti Tommaso , de Kreuk Merle , Kleerebezem Robbert , van Loosdrecht Mark , Kruit Jans , Jetten Mike S. M. , Kartal Boran
Published: February 2013

Currently, nitritation-anammox (anaerobic ammonium oxidation) bioreactors are designed to treat wastewaters with high ammonium concentrations at mesophilic temperatures (25 to 40°C). The implementation of this technology at ambient temperatures for nitrogen removal from municipal wastewater following carbon removal may lead to more-sustainable technology with energy and cost savings. However, the application of nitritation-anammox bioreactors at low temperatures (characteristic of municipal wastewaters except in tropical and subtropical regions) has not yet been explored. To this end, a laboratory-scale (5-liter) nitritation-anammox sequencing batch reactor was adapted to 12°C in 10 days and operated for more than 300 days to investigate the feasibility of nitrogen removal from synthetic pretreated municipal wastewater by the combination of aerobic ammonium-oxidizing bacteria (AOB) and anammox. The activities of both anammox and AOB were high enough to remove more than 90% of the supplied nitrogen. Multiple aspects, including the presence and activity of anammox, AOB, and aerobic nitrite oxidizers (NOB) and nitrous oxide (N
2
O) emission, were monitored to evaluate the stability of the bioreactor at 12°C. There was no nitrite accumulation throughout the operational period, indicating that anammox bacteria were active at 12°C and that AOB and anammox bacteria outcompeted NOB. Moreover, our results showed that sludge from wastewater treatment plants designed for treating high-ammonium-load wastewaters can be used as seeding sludge for wastewater treatment plants aimed at treating municipal wastewater that has a low temperature and low ammonium concentrations.
Transcriptome Profiling of Botrytis cinerea Conidial Germination Reveals Upregulation of Infection-Related Genes during the Prepenetration Stage
Authors: Leroch Michaela , Kleber Astrid , Silva Evelyn , Coenen Tina , Koppenhöfer Dieter , Shmaryahu Amir , Valenzuela Pablo D. T. , Hahn Matthias
Published: February 2013

Botrytis cinerea
causes gray mold on a great number of host plants. Infection is initiated by airborne conidia that invade the host tissue, often by penetration of intact epidermal cells. To mimic the surface properties of natural plant surfaces, conidia were incubated on apple wax-coated surfaces, resulting in rapid germination and appressorium formation. Global changes in gene expression were analyzed by microarray hybridization between conidia incubated for 0 h (dormant), 1 h (pregermination), 2.5 h (postgermination), 4 h (appressoria), and 15 h (early mycelium). Considerable changes were observed, in particular between 0 h and 1 h. Genes induced during germination were enriched in those genes encoding secreted proteins, including lytic enzymes. Comparison of wild-type and a nonpathogenic MAP kinase mutant (
bmp1
) revealed marked differences in germination-related gene expression, in particular related to secretory proteins. Using promoter-GFP reporter strains, we detected a strictly germination-specific expression pattern of a putative chitin deacetylase gene (
cda1
). In contrast, a cutinase gene (
cutB
) was found to be expressed only in the presence of plant lipids, in a developmentally less stringent pattern. We also identified a coregulated gene cluster possibly involved in secondary metabolite synthesis which was found to be controlled by a transcription factor also encoded in this cluster. Our data demonstrate that early conidial development in
B. cinerea
is accompanied by rapid shifts in gene expression that prepare the fungus for germ tube outgrowth and host cell invasion.
Nucleosome Assembly Factors CAF-1 and HIR Modulate Epigenetic Switching Frequencies in an H3K56 Acetylation-Associated Manner in Candida albicans
Authors: Stevenson John S. , Liu Haoping
Published: February 2013

CAF-1 and HIR are highly conserved histone chaperone protein complexes that function in the assembly of nucleosomes onto chromatin. CAF-1 is characterized as having replication-coupled nucleosome activity, whereas the HIR complex can assemble nucleosomes independent of replication. Histone H3K56 acetylation, controlled by the acetyltransferase Rtt109 and deacetylase Hst3, also plays a significant role in nucleosome assembly. In this study, we generated a set of deletion mutants to genetically characterize pathway-specific and overlapping functions of CAF-1 and HIR in
C. albicans
. Their roles in epigenetic maintenance of cell type were examined by using the white-opaque switching system in
C. albicans
. We show that CAF-1 and HIR play conserved roles in UV radiation recovery, repression of histone gene expression, correct chromosome segregation, and stress responses. Unique to
C. albicans
, the
cac2Δ/Δ
mutant shows increased sensitivity to the Hst3 inhibitor nicotinamide, while the
rtt109Δ/Δ cac2Δ/Δ
and
hir1Δ/Δ cac2Δ/Δ
mutants are resistant to nicotinamide. CAF-1 plays a major role in maintaining cell types, as the
cac2Δ/Δ
mutant exhibited increased switching frequencies in both directions and switched at a high frequency to opaque in response to nicotinamide. Like the
rtt109Δ/Δ
mutant, the
hir1Δ/Δ cac2Δ/Δ
double mutant is defective in maintaining the opaque cell fate and blocks nicotinamide-induced opaque formation, and the defects are suppressed by ectopic expression of the master white-opaque regulator Wor1. Our data suggest an overlapping function of CAF-1 and HIR in epigenetic regulation of cell fate determination in an H3K56 acetylation-associated manner.
Factors Supporting Cysteine Tolerance and Sulfite Production in Candida albicans
Authors: Hennicke Florian , Grumbt Maria , Lermann Ulrich , Ueberschaar Nico , Palige Katja , Böttcher Bettina , Jacobsen Ilse D. , Staib Claudia , Morschhäuser Joachim , Monod Michel , Hube Bernhard , Hertweck Christian , Staib Peter
Published: February 2013

The amino acid cysteine has long been known to be toxic at elevated levels for bacteria, fungi, and humans. However, mechanisms of cysteine tolerance in microbes remain largely obscure. Here we show that the human pathogenic yeast
Candida albicans
excretes sulfite when confronted with increasing cysteine concentrations. Mutant construction and phenotypic analysis revealed that sulfite formation from cysteine in
C. albicans
relies on cysteine dioxygenase Cdg1, an enzyme with similar functions in humans. Environmental cysteine induced not only the expression of the
CDG1
gene in
C. albicans
, but also the expression of
SSU1
, encoding a putative sulfite efflux pump. Accordingly, the deletion of
SSU1
resulted in enhanced sensitivity of the fungal cells to both cysteine and sulfite. To study the regulation of sulfite/cysteine tolerance in more detail, we screened a
C. albicans
library of transcription factor mutants in the presence of sulfite. This approach and subsequent independent mutant analysis identified the zinc cluster transcription factor Zcf2 to govern sulfite/cysteine tolerance, as well as cysteine-inducible
SSU1
and
CDG1
gene expression.
cdg1
Δ and
ssu1
Δ mutants displayed reduced hypha formation in the presence of cysteine, indicating a possible role of the newly proposed mechanisms of cysteine tolerance and sulfite secretion in the pathogenicity of
C. albicans
. Moreover,
cdg1
Δ mutants induced delayed mortality in a mouse model of disseminated infection. Since sulfite is toxic and a potent reducing agent, its production by
C. albicans
suggests diverse roles during host adaptation and pathogenicity.
Draft Genome Sequence of a Clinical Strain of Yersinia enterocolitica (IP10393) of Bioserotype 4/O:3 from France
Authors: Savin Cyril , Frangeul Lionel , Ma Laurence , Bouchier Christiane , Moszer Ivan , Carniel Elisabeth
Published: February 2013

We sequenced the genome of a clinical isolate of
Yersinia enterocolitica
(IP10393) from France. This strain belongs to bioserotype 4/O:3, which is the most common pathogenic subgroup worldwide. The draft genome has a size of 4,463,212 bp and a G+C content of 47.0%, and it is predicted to contain 4,181 coding sequences.
Molecular Kinetics of Reviving Bacterial Spores
Authors: Segev Einat , Rosenberg Alex , Mamou Gideon , Sinai Lior , Ben-Yehuda Sigal
Published: February 2013

Bacterial spores can remain dormant for years, yet they possess a remarkable potential to rapidly resume a vegetative life form. Here, we identified a distinct phase at the onset of spore outgrowth, designated the ripening period. This transition phase is exploited by the germinating spore for molecular reorganization toward elongation and subsequent cell division. We have previously shown that spores of different ages, kept under various temperatures, harbor dissimilar molecular reservoirs (E. Segev, Y. Smith, and S. Ben-Yehuda, Cell
148:
139–149, 2012). Utilizing this phenomenon, we observed that the length of the ripening period can vary according to the spore molecular content. Importantly, the duration of the ripening period was found to correlate with the initial spore rRNA content and the kinetics of rRNA accumulation upon exiting dormancy. Further, the synthesis of the ribosomal protein RplA and the degradation of the spore-specific protein SspA also correlated with the duration of the ripening period. Our data suggest that the spore molecular cargo determines the extent of the ripening period, a potentially crucial phase for a germinating spore in obtaining limited resources during revival.
Growth Inhibition of Sporomusa ovata by Incorporation of Benzimidazole Bases into Cobamides
Authors: Mok Kenny C. , Taga Michiko E.
Published: February 2013

Phenolyl cobamides are unique members of a class of cobalt-containing cofactors that includes vitamin B
12
(cobalamin). Cobamide cofactors facilitate diverse reactions in prokaryotes and eukaryotes. Phenolyl cobamides are structurally and chemically distinct from the more commonly used benzimidazolyl cobamides such as cobalamin, as the lower axial ligand is a phenolic group rather than a benzimidazole. The functional significance of this difference is not well understood. Here we show that in the bacterium
Sporomusa ovata
, the only organism known to synthesize phenolyl cobamides, several cobamide-dependent acetogenic metabolisms have a requirement or preference for phenolyl cobamides. The addition of benzimidazoles to
S. ovata
cultures results in a decrease in growth rate when grown on methanol, 3,4-dimethoxybenzoate, H
2
plus CO
2
, or betaine. Suppression of native
p
-cresolyl cobamide synthesis and production of benzimidazolyl cobamides occur upon the addition of benzimidazoles, indicating that benzimidazolyl cobamides are not functionally equivalent to the phenolyl cobamide cofactors produced by
S. ovata
. We further show that
S. ovata
is capable of incorporating other phenolic compounds into cobamides that function in methanol metabolism. These results demonstrate that
S. ovata
can incorporate a wide range of compounds as cobamide lower ligands, despite its preference for phenolyl cobamides in the metabolism of certain energy substrates. To our knowledge,
S. ovata
is unique among cobamide-dependent organisms in its preferential utilization of phenolyl cobamides.
Characterizing the Hexose-6-Phosphate Transport System of Vibrio cholerae, a Utilization System for Carbon and Phosphate Sources
Authors: Moisi Manuel , Lichtenegger Sabine , Tutz Sarah , Seper Andrea , Schild Stefan , Reidl Joachim
Published: February 2013

The facultative human pathogen
Vibrio cholerae
transits between the gastrointestinal tract of its host and aquatic reservoirs.
V. cholerae
adapts to different situations by the timely coordinated expression of genes during its life cycle. We recently identified a subclass of genes that are induced at late stages of infection. Initial characterization demonstrated that some of these genes facilitate the transition of
V. cholerae
from host to environmental conditions. Among these genes are uptake systems lacking detailed characterization or correct annotation. In this study, we comprehensively investigated the function of the VCA0682-to-VCA0687 gene cluster, which was previously identified as
in vivo
induced. The results presented here demonstrate that the operon encompassing open reading frames VCA0685 to VCA0687 encodes an ABC transport system for hexose-6-phosphates with

K
m

values ranging from 0.275 to 1.273 μM for glucose-6P and fructose-6P, respectively. Expression of the operon is induced by the presence of hexose-6P controlled by the transcriptional activator VCA0682, representing a UhpA homolog. Finally, we provide evidence that the operon is essential for the utilization of hexose-6P as a C and P source. Thereby, a physiological role can be assigned to hexose-6P uptake, which correlates with increased fitness of
V. cholerae
after a transition from the host into phosphate-limiting environments.
Characterization of a Novel Rieske-Type Alkane Monooxygenase System in Pusillimonas sp. Strain T7-7
Authors: Li Ping , Wang Lei , Feng Lu
Published: February 2013

The cold-tolerant bacterium
Pusillimonas
sp. strain T7-7 is able to utilize diesel oils (C
5
to C
30
alkanes) as a sole carbon and energy source. In the present study, bioinformatics, proteomics, and real-time reverse transcriptase PCR approaches were used to identify the alkane hydroxylation system present in this bacterium. This system is composed of a Rieske-type monooxygenase, a ferredoxin, and an NADH-dependent reductase. The function of the monooxygenase, which consists of one large (46.711 kDa) and one small (15.355 kDa) subunit, was further studied using
in vitro
biochemical analysis and
in vivo
heterologous functional complementation tests. The purified large subunit of the monooxygenase was able to oxidize alkanes ranging from pentane (C
5
) to tetracosane (C
24
) using NADH as a cofactor, with greatest activity on the C
15
substrate. The large subunit also showed activity on several alkane derivatives, including nitromethane and methane sulfonic acid, but it did not act on any aromatic hydrocarbons. The optimal reaction condition of the large subunit is pH 7.5 at 30°C. Fe
2+
can enhance the activity of the enzyme evidently. This is the first time that an alkane monooxygenase system belonging to the Rieske non-heme iron oxygenase family has been identified in a bacterium.
FtsH-Mediated Coordination of Lipopolysaccharide Biosynthesis in Escherichia coli Correlates with the Growth Rate and the Alarmone (p)ppGpp
Authors: Schäkermann Michael , Langklotz Sina , Narberhaus Franz
Published: February 2013

The outer membrane is the first line of defense for Gram-negative bacteria and serves as a major barrier for antibiotics and other harmful substances. The biosynthesis of lipopolysaccharides (LPS), the essential component of the outer membrane, must be tightly controlled as both too much and too little LPS are toxic. In
Escherichia coli
, the cellular level of the key enzyme LpxC, which catalyzes the first committed step in LPS biosynthesis, is adjusted by proteolysis carried out by the essential and membrane-bound protease FtsH. Here, we demonstrate that LpxC is degraded in a growth rate-dependent manner with half-lives between 4 min and >2 h. According to the cellular demand for LPS biosynthesis, LpxC is degraded during slow growth but stabilized when cells grow rapidly. Disturbing the balance between LPS and phospholipid biosynthesis in favor of phospholipid production in an
E. coli
strain encoding a hyperactive FabZ protein abolishes growth rate dependency of LpxC proteolysis. Lack of the alternative sigma factor RpoS or inorganic polyphosphates, which are known to mediate growth rate-dependent gene regulation in
E. coli
, did not affect proteolysis of LpxC. In contrast, absence of RelA and SpoT, which synthesize the alarmone (p)ppGpp, deregulated LpxC degradation resulting in rapid proteolysis in fast-growing cells and stabilization during slow growth. Our data provide new insights into the essential control of LPS biosynthesis in
E. coli
.
A Rex Family Transcriptional Repressor Influences H
2
O
2
Accumulation by Enterococcus faecalis
Authors: Vesić Dušanka , Kristich Christopher J.
Published: February 2013

Rex factors are bacterial transcription factors thought to respond to the cellular NAD
+
/NADH ratio in order to modulate gene expression by differentially binding DNA. To date, Rex factors have been implicated in regulating genes of central metabolism, oxidative stress response, and biofilm formation. The genome of
Enterococcus faecalis
, a low-GC Gram-positive opportunistic pathogen, encodes
EF2638
, a putative Rex factor. To study the role of
E. faecalis
Rex, we purified EF2638 and evaluated its DNA binding activity
in vitro
. EF2638 was able to bind putative promoter segments of several
E. faecalis
genes in an NADH-responsive manner, indicating that it represents an authentic Rex factor. Transcriptome analysis of a Δ
EF2638
mutant revealed that genes likely to be involved in anaerobic metabolism were upregulated during aerobic growth, and the mutant exhibited an altered NAD
+
/NADH ratio. The Δ
EF2638
mutant also exhibited a growth defect when grown with aeration on several carbon sources, suggesting an impaired ability to cope with oxidative stress. Inclusion of catalase in the medium alleviated the growth defect. H
2
O
2
measurements revealed that the mutant accumulates significantly more H
2
O
2
than wild-type
E. faecalis
. In summary, EF2638 represents an authentic Rex factor in
E. faecalis
that influences the production or detoxification of H
2
O
2
in addition to its more familiar role as a regulator of anaerobic gene expression.
High Hydrostatic Pressure Induces Counterclockwise to Clockwise Reversals of the Escherichia coli Flagellar Motor
Authors: Nishiyama Masayoshi , Sowa Yoshiyuki , Kimura Yoshifumi , Homma Michio , Ishijima Akihiko , Terazima Masahide
Published: February 2013

The bacterial flagellar motor is a reversible rotary machine that rotates a left-handed helical filament, allowing bacteria to swim toward a more favorable environment. The direction of rotation reverses from counterclockwise (CCW) to clockwise (CW), and vice versa, in response to input from the chemotaxis signaling circuit. CW rotation is normally caused by binding of the phosphorylated response regulator CheY (CheY-P), and strains lacking CheY are typically locked in CCW rotation. The detailed mechanism of switching remains unresolved because it is technically difficult to regulate the level of CheY-P within the concentration range that produces flagellar reversals. Here, we demonstrate that high hydrostatic pressure can induce CW rotation even in the absence of CheY-P. The rotation of single flagellar motors in
Escherichia coli
cells with the
cheY
gene deleted was monitored at various pressures and temperatures. Application of >120 MPa pressure induced a reversal from CCW to CW at 20°C, although at that temperature, no motor rotated CW at ambient pressure (0.1 MPa). At lower temperatures, pressure-induced changes in direction were observed at pressures of <120 MPa. CW rotation increased with pressure in a sigmoidal fashion, as it does in response to increasing concentrations of CheY-P. Application of pressure generally promotes the formation of clusters of ordered water molecules on the surfaces of proteins. It is possible that hydration of the switch complex at high pressure induces structural changes similar to those caused by the binding of CheY-P.
Multidimensional View of the Bacterial Cytoskeleton
Authors: Celler Katherine , Koning Roman I. , Koster Abraham J. , van Wezel Gilles P.
Published: February 2013

The perspective of the cytoskeleton as a feature unique to eukaryotic organisms was overturned when homologs of the eukaryotic cytoskeletal elements were identified in prokaryotes and implicated in major cell functions, including growth, morphogenesis, cell division, DNA partitioning, and cell motility. FtsZ and MreB were the first identified homologs of tubulin and actin, respectively, followed by the discovery of crescentin as an intermediate filament-like protein. In addition, new elements were identified which have no apparent eukaryotic counterparts, such as the deviant Walker A-type ATPases, bactofilins, and several novel elements recently identified in streptomycetes, highlighting the unsuspected complexity of cytostructural components in bacteria.In vivomultidimensional fluorescence microscopy has demonstrated the dynamics of the bacterial intracellular world, and yet we are only starting to understand the role of cytoskeletal elements. Elucidating structure-function relationships remains challenging, because core cytoskeletal protein motifs show remarkable plasticity, with one element often performing various functions and one function being performed by several types of elements. Structural imaging techniques, such as cryo-electron tomography in combination with advanced light microscopy, are providing the missing links and enabling scientists to answer many outstanding questions regarding prokaryotic cellular architecture. Here we review the recent advances made toward understanding the different roles of cytoskeletal proteins in bacteria, with particular emphasis on modern imaging approaches.
Subarachnoid haemorrhage with bilateral intracranial vertebral artery dissecting aneurysms treated by staged endovascular stenting
Authors: Wilkinson David Andrew , Wilson Thomas J , Stetler William R , Pandey Aditya S
Published: February 2013

Bilateral vertebral artery dissecting aneurysms (VADAs) presenting with subarachnoid haemorrhage (SAH) are an exceedingly rare and deadly clinical dilemma. Prompt intervention in the case of unilateral VADAs is advocated to prevent rebleed; however, in the case of bilateral VADAs, the optimal therapeutic intervention is unclear. We describe the case of a patient presenting with SAH with bilateral VADAs treated by staged endovascular stenting. This led to resolution of the aneurysms with patency of both vertebral arteries.

Stent-based therapy of the symptomatic aneurysm followed by staged stenting of the asymptomatic, contralateral aneurysm appears to be a viable treatment option. This method allows the ability to preserve flow in both vertebral arteries with minimal changes in flow characteristics that may threaten the contralateral, asymptomatic VADA, and appears to be the ideal treatment in these rare cases.
Bilateral peripapillary serous retinal detachment in association with congenital optic disc pits
Authors: Shafi Aabgina , Twaij Suhair , Ibraheim A
Published: February 2013

A middle-aged asymptomatic patient was referred to the eye clinic by her optician because of unusual optic nerve heads. She was found to have optic disc pits with bilateral serous retinal detachments which were non-progressive. She did not need any treatment and was safely followed up in the community. This uncommon condition is discussed along with possible pathophysiology and treatment.
Primary mucinous carcinoma of the periocular region: successful management with local resections over 30 years
Authors: Burris Christopher Keith , Rajan K D Anand , Iliff Nicholas T
Published: February 2013

Primary mucinous carcinoma of the skin is a rare malignant neoplasm, often with periocular involvement, believed to originate from eccrine sweat glands. It is slow growing and locally destructive, at times forming tumour satellites. We present a case with six local recurrences treated with surgical resections over a period of 30 years. We have not been able to find longer follow-up in the literature, and believe this case may offer insight into the management of these uniquely indolent malignancies.
Dyshidrotic eczema associated with the use of IVIg
Authors: Kotan Dilcan , Erdem Teoman , Acar Bilgehan Atilgan , Boluk Ayhan
Published: February 2013

Intravenous immunoglobulin (IVIg) treatment is highly effective for autoimmune diseases including myasthenia gravis. Recovery is observed at approximately. 75% of myasthenia gravis patients through IVIg treatment. As a result of many clinical studies, the recommended dose is determined as 0.4 g/kg for 5 days (maximum total dose at 2 g/kg body weight). If an additional immunomodulatory treatment is not administered, IVIg maintenance treatment is needed mostly. However, some side effects may inhibit long-term treatment. For this reason, it is important to know the effect profile well and when the treatment should be discontinued. A female myasthenia gravis patient case is presented here, where dyshidrotic eczema has occurred after the second dose of  intravenous Ig medication and whose treatment is despite further IVIg therapy.
Granular cell breast tumour mimicking infiltrating carcinoma
Authors: Gavriilidis Paschalis , Michalopoulou Ilektra , Baliaka Aggeliki , Nikolaidou Anastasia
Published: February 2013

Granular cell tumour (GCT) is a rare, usually benign neoplasm that can mimic carcinoma on breast imaging. GCT can originate anywhere in the body but is most frequently found in the head and neck region, particularly in the tongue. Of the reported cases, 6% have occurred in the breast, most commonly in the upper inner quadrant. We report a case of GCT of the breast presenting as a spiculated mass infiltrating the greater thoracic muscle on breast screening mammogram.
Chronic eosinophilic pneumonia with persistent decreased diffusing capacity for carbon monoxide
Authors: Blanc Sibylle , Albertini Marc , Leroy Sylvie , Giovannini-Chami Lisa
Published: February 2013

We report a 15-year-old girl presenting with dry cough, exertional dyspnoea, weight loss, fever and night sweats for over 1 month. Blood tests revealed hypereosinophilia, high IgE and antinuclear antibodies levels. Chest x-rays showed bilateral peripheral infiltrates mostly in the right upper lobe which was confirmed by a chest CT. Bronchoalveolar lavage showed hypercellularity with 28% of eosinophils. Idiopathic chronic eosinophilic pneumonia was confirmed after exclusion of other causes of eosinophilic pneumonia and systemic disease. The patient responded dramatically to oral corticosteroids. Oral corticotherapy was stopped after 4 months. At 8 months of follow-up, diffusing capacity for carbon monoxide (DLCO) remained moderately low (58%) with persistent mild exertional dyspnoea. Cardiopulmonary exercise testing showed muscular peripheral limitation. Even if in our patient, mild exertional dyspnoea can be partly correlated to peripheral deconditioning, DLCO should be systematically evaluated to determine follow-up studies standards, to correlate with subclinical disease, relapse risk and to codify therapeutic options.
MRI-induced soft tissue pain: incidental finding of a 15-year-old foreign body
Authors: El Sayed Omar Theofilos , El-Khani Ussamah , Nehme Jean
Published: February 2013

We present the case of an 82-year-old woman who developed intense right middle finger pain during MRI scan This alerted the clinical team to the incidental finding of a 15-year-old metallic foreign body in the distal phalanx of the right middle finger. This case report is a reminder that the responsible clinician should be vigilant when screening for metallic foreign body on completion of the MRI checklist, and should adopt a low threshold for plain imaging prior to MRI.
Acute Marchiafava-Bignami disease presenting as reversible dementia in a chronic alcoholic
Authors: Sehgal Vineet , Kesav Praveen , Modi M , Ahuja Chirag K
Published: February 2013

Marchiafava-Bignami disease (MBD) is a rare complication of chronic alcoholism. Its clinical diagnosis has considerably changed during recent times, with MRI of the brain paving way for in life diagnosis. We believe that physicians need to have a high index of suspicion, because acute onset MBD is not always fatal and complete recovery is possible, provided the diagnosis is made early and treated appropriately. We report a case of MBD who was diagnosed early in the disease course with subsequent clinical and radiological recovery on institution of appropriate treatment.
Management of occupational hazards in healthcare: exposure to diphencyprone
Authors: Basu Subhashis , Adisesh Anil
Published: February 2013

Diphencyprone is a chemical agent used most commonly in the treatment of alopecia areata. Its mechanism of action is through the sensitisation (type IV immune reaction) of affected areas to stimulate hair follicle growth. The consequences of accidental occupational exposure, however, have not been widely recognised. This report describes the clinical presentation and management of two pharmacy technicians that presented to Sheffield Occupational Health Service (SOHS) centre in 2012. Exposure sources were identified through a workplace visit arranged between the SOHS centre and the hospital's pharmacy; a chemical analysis revealed concentrations of the chemical sufficient to induce sensitisation at several points during the manufacturing process. The case highlights the role of close liaison between specialist services (dermatology and occupational medicine) in managing individual patient cases and mitigating risk within relevant occupational groups.
Systemic arterial air embolism: positive pressure ventilation can be fatal in a patient with blunt trauma
Authors: Yadav Siddharth , Jain Shalabh , Aggarwal Puneet , Gupta Ritu
Published: February 2013

Systemic air embolism is a potentially fatal condition. Although venous embolism is commonly reported after deep sea diving or neurosurgical procedures, arterial embolism is rare. It usually occurs because of lung trauma after biopsy or lung resection but can rarely affect patients of blunt or penetrating trauma to chest managed on positive pressure ventilation. We report a case of road traffic accident with head injury, with normal primary survey of chest and abdomen who developed fatal systemic arterial air embolism immediately after intubation. Postmortem CT scan revealed huge amounts of air in left side of the heart, ascending aorta, arch of aorta, bilateral internal carotids and all right-sided intracranial arteries. In emergency departments of non-specialised centres, such complications are universally fatal. Thus, extreme caution needs to be exercised while managing patients of blunt trauma on mechanical ventilation even if the chest and abdominal examinations are normal.
Endovascular stent-associated infection withStaphylococcus lugdunensis
Authors: Morris Thomas C , Davies Olubanke , Bradlow William M , Jeffery Katie , Bowler Ian C J W
Published: February 2013

An elderly woman presented febrile 5 days after stenting of multiple coronary arteries. Echocardiography showed a thickening of the aortic root, raising the possibility of stent infection. Four  of four blood culture bottles grewStaphylococcus lugdunensisand repeat echo showed an aortic root abscess. Despite appropriate antibiotic treatment, the patient died. A 24-year-old man with a ventricular septal defect presented febrile 4 weeks after stenting of an aortic coarctation. Initial transoesophageal echo found no vegetations around the stent or elsewhere. Four of six blood culture bottles grewS lugdunensis. Following an episode of hypoxia, the imaging was repeated and a new large vegetation was seen on the pulmonary valve with two thin-walled cavities in the lungs on a CT pulmonary angiogram. The patient was treated with a long course of appropriate antibiotic therapy and discharged from hospital 6 weeks later.