bluuebunny/crossref_metadata_2025 huggingface dataset:
A Synthetic Reinforcement Patch in Repair of Challenging Two-Tendon Rotator Cuff Tears
Authors: Marberry Thomas A.
Published: September 2012

Background

The repair of chronic massive tendon tears may be a challenging procedure, especially with a frayed tendon caused by degeneration. The aim of this case series was to evaluate the outcome of a synthetic patch in the repair of complex rotator cuff tears, with regard to shoulder function, pain relief and quality of life.

Methods

A synthetic patch (Artelon® Tissue Reinforcement; Artimplant AB, Västra Frölunda, Sweden) was used in 17 patients with challenging repairs of chronic rotator cuff tears. The outcome of surgical treatment was evaluated after 3, 6 and 12 months by the Constant functional score and the Western Ontario Rotator Cuff (WORC) score.

Results

Significantly less pain and improved shoulder function, as evaluated by the Constant score, was seen 1 year after surgery, as well as an increased WORC score as a measure of improved disease-related quality of life. Re-operation was performed in one patient as a result of a re-tear. There were no complications related to the use of the reinforcement patch.

Conclusions

This case series showed satisfying results in technically challenging repairs of rotator cuff tears with the use of a synthetic reinforcement patch. Postoperatively, the patients showed less pain and improved shoulder function to the extent to perform better in daily life activities.
The Emerging Biology of Autism Spectrum Disorders
Authors: State Matthew W. , Šestan Nenad
Published: September 2012

Expression patterns of the diverse genes disrupted in autism spectrum disorders in the developing brain give a fresh perspective on the underlying biology.
Effects of Engineered Sinorhizobium meliloti on Cytokinin Synthesis and Tolerance of Alfalfa to Extreme Drought Stress
Authors: Xu Ji , Li Xiao-Lin , Luo Li
Published: September 2012

Cytokinin is required for the initiation of leguminous nitrogen fixation nodules elicited by rhizobia and the delay of the leaf senescence induced by drought stress. A few free-living rhizobia have been found to produce cytokinin. However, the effects of engineered rhizobia capable of synthesizing cytokinin on host tolerance to abiotic stresses have not yet been described. In this study, two engineered
Sinorhizobium
strains overproducing cytokinin were constructed. The tolerance of inoculated alfalfa plants to severe drought stress was assessed. The engineered strains, which expressed the
Agrobacterium ipt
gene under the control of different promoters, synthesized more zeatins than the control strain under free-living conditions, but their own growth was not affected. After a 4-week inoculation period, the effects of engineered strains on alfalfa growth and nitrogen fixation were similar to those of the control strain under nondrought conditions. After being subjected to severe drought stress, most of the alfalfa plants inoculated with engineered strains survived, and the nitrogenase activity in their root nodules showed no apparent change. A small elevation in zeatin concentration was observed in the leaves of these plants. The expression of antioxidant enzymes increased, and the level of reactive oxygen species decreased correspondingly. Although the
ipt
gene was transcribed in the bacteroids of engineered strains, the level of cytokinin in alfalfa nodules was identical to that of the control. These findings suggest that engineered
Sinorhizobium
strains synthesizing more cytokinin could improve the tolerance of alfalfa to severe drought stress without affecting alfalfa nodulation or nitrogen fixation.
Whole-Genome Microarray and Gene Deletion Studies Reveal Regulation of the Polyhydroxyalkanoate Production Cycle by the Stringent Response in Ralstonia eutropha H16
Authors: Brigham Christopher J. , Speth Daan R. , Rha ChoKyun , Sinskey Anthony J.
Published: September 2012

Poly(3-hydroxybutyrate) (PHB) production and mobilization in
Ralstonia eutropha
are well studied, but in only a few instances has PHB production been explored in relation to other cellular processes. We examined the global gene expression of wild-type
R. eutropha
throughout the PHB cycle: growth on fructose, PHB production using fructose following ammonium depletion, and PHB utilization in the absence of exogenous carbon after ammonium was resupplied. Our results confirm or lend support to previously reported results regarding the expression of PHB-related genes and enzymes. Additionally, genes for many different cellular processes, such as DNA replication, cell division, and translation, are selectively repressed during PHB production. In contrast, the expression levels of genes under the control of the alternative sigma factor σ
54
increase sharply during PHB production and are repressed again during PHB utilization. Global gene regulation during PHB production is strongly reminiscent of the gene expression pattern observed during the stringent response in other species. Furthermore, a ppGpp synthase deletion mutant did not show an accumulation of PHB, and the chemical induction of the stringent response with
dl
-norvaline caused an increased accumulation of PHB in the presence of ammonium. These results indicate that the stringent response is required for PHB accumulation in
R. eutropha
, helping to elucidate a thus-far-unknown physiological basis for this process.
Lack of Direct Effects of Agrochemicals on Zoonotic Pathogens and Fecal Indicator Bacteria
Authors: Staley Zachery R. , Senkbeil Jacob K. , Rohr Jason R. , Harwood Valerie J.
Published: September 2012

Agrochemicals, fecal indicator bacteria (FIB), and pathogens frequently contaminate water simultaneously. No significant direct effects of fertilizer, atrazine, malathion, and chlorothalonil on the survival of
Escherichia coli
,
Enterococcus faecalis
,
Salmonella enterica
, human polyomaviruses, and adenovirus were detected, supporting the assertion that previously observed effects of agrochemicals on FIB were indirect.
Fe(III) Reduction and U(VI) Immobilization by Paenibacillus sp. Strain 300A, Isolated from Hanford 300A Subsurface Sediments
Authors: Ahmed Bulbul , Cao Bin , McLean Jeffrey S. , Ica Tuba , Dohnalkova Alice , Istanbullu Ozlem , Paksoy Akin , Fredrickson Jim K. , Beyenal Haluk
Published: September 2012

A facultative iron-reducing [Fe(III)-reducing]
Paenibacillus
sp. strain was isolated from Hanford 300A subsurface sediment biofilms that was capable of reducing soluble Fe(III) complexes [Fe(III)-nitrilotriacetic acid and Fe(III)-citrate] but unable to reduce poorly crystalline ferrihydrite (Fh). However,
Paenibacillus
sp. 300A was capable of reducing Fh in the presence of low concentrations (2 μM) of either of the electron transfer mediators (ETMs) flavin mononucleotide (FMN) or anthraquinone-2,6-disulfonate (AQDS). Maximum initial Fh reduction rates were observed at catalytic concentrations (<10 μM) of either FMN or AQDS. Higher FMN concentrations inhibited Fh reduction, while increased AQDS concentrations did not. We also found that
Paenibacillus
sp. 300A could reduce Fh in the presence of natural ETMs from Hanford 300A subsurface sediments. In the absence of ETMs,
Paenibacillus
sp. 300A was capable of immobilizing U(VI) through both reduction and adsorption. The relative contributions of adsorption and microbial reduction to U(VI) removal from the aqueous phase were ∼7:3 in PIPES [piperazine-
N
,
N
′
-
bis(2-ethanesulfonic acid)] and ∼1:4 in bicarbonate buffer. Our study demonstrated that
Paenibacillus
sp. 300A catalyzes Fe(III) reduction and U(VI) immobilization and that these reactions benefit from externally added or naturally existing ETMs in 300A subsurface sediments.
Antimicrobial Resistance of Staphylococcus aureus Strains Acquired by Pig Farmers from Pigs
Authors: Oppliger Anne , Moreillon Philippe , Charrière Nicole , Giddey Marlyse , Morisset Delphine , Sakwinska Olga
Published: September 2012

Carriage of animal-associated methicillin-resistant
Staphylococcus aureus
(MRSA) clonal complex 398 (CC398) is common among pig farmers. This study was conducted (i) to investigate whether pig farmers are colonized with pig-specific
S. aureus
genotypes other than CC398 and (ii) to survey antimicrobial resistance of
S. aureus
isolates from pigs and pig farmers. Forty-eight
S. aureus
isolates from pig farmers and veterinarians and 130 isolates from pigs collected in Western Switzerland were genotyped by
spa
typing and amplified fragment length polymorphism (AFLP). Antimicrobial resistance profiles were determined for representative sample of the isolates. The data obtained earlier on healthy
S. aureus
carriers without exposure to agriculture were used for comparison. The genotype composition of
S. aureus
isolates from pig farmers and veterinarians was similar to isolates from pigs with predominant AFLP clusters CC398, CC9, and CC49. The resistance to tetracycline and macrolides (clarithromycin) was common among the isolates from farmers and veterinarians (52 and 21%, respectively) and similar to resistance levels in isolates from pigs (39 and 23%, respectively). This was in contrast to isolates from persons without contact with agriculture, where no (0/128) isolates were resistant to tetracycline and 3% of the isolates were resistant to clarithromycin. MRSA CC398 was isolated from pigs (
n
= 11) and pig farmers (
n
= 5). These data imply that zoonotic transmission of multidrug-resistant
S. aureus
from pigs to farmers is frequent, and well-known MRSA transmission merely represents the tip of the iceberg for this phenomenon. We speculate that the relatively low frequency of MRSA isolation is related to lower antimicrobial use in Switzerland compared to, for example, the Netherlands.
High Prevalence and Species Diversity of Helicobacter spp. Detected in Wild House Mice
Authors: Wasimuddin  , Čížková Dagmar , Bryja Josef , Albrechtová Jana , Hauffe Heidi C. , Piálek Jaroslav
Published: September 2012

PCR diagnostics detected 100% prevalence of
Helicobacter
in 425 wild house mice (
Mus musculus
) from across central Europe. Of seven species identified, the five most frequent were
Helicobacter rodentium
(78%),
H. typhlonius
(53%),
H. hepaticus
(41%),
H. bilis
(30%), and
H. muridarum
(1%). Double infections were more common (42%) than single (30%) and triple (21%) infections. Wild house mice could be considered potential reservoirs of
Helicobacter
strains for both humans and other vertebrates.
Intestinal Bacterium Eubacterium cellulosolvens Deglycosylates Flavonoid
C-
and
O-
Glucosides
Authors: Braune Annett , Blaut Michael
Published: September 2012

Eubacterium cellulosolvens
cleaved the flavone
C
-glucosides homoorientin and isovitexin to their aglycones luteolin and apigenin, respectively. The corresponding isomers, orientin and vitexin, or other polyphenolic
C
-glucosides were not deglycosylated.
E. cellulosolvens
also cleaved several
O
-coupled glucosides of flavones and isoflavones to their corresponding aglycones.
Different Roles for Lactococcal Aggregation Factor and Mucin Binding Protein in Adhesion to Gastrointestinal Mucosa
Authors: Lukić Jovanka , Strahinić Ivana , Jovčić Branko , Filipić Brankica , Topisirović Ljubiša , Kojić Milan , Begović Jelena
Published: September 2012

Adhesion of bacteria to mucosal surfaces and epithelial cells is one of the key features for the selection of probiotics. In this study, we assessed the adhesion property of
Lactococcus lactis
subsp.
lactis
BGKP1 based on its strong autoaggregation phenotype and the presence of the mucin binding protein (MbpL). Genes involved in aggregation (
aggL
) and possible interaction with mucin (
mbpL
), present on the same plasmid pKP1, were previously separately cloned in the plasmid pAZIL.
In vivo
and
in vitro
experiments revealed potentially different physiological roles of these two proteins in the process of adherence to the intestine during the passage of the strain through the gastrointestinal tract. We correlated the
in vitro
and
in vivo
aggregation of the BGKP1-20 carrying plasmid with
aggL
to binding to the colonic mucus through nonspecific hydrophobic interactions. The expression of AggL on the bacterial cell surface significantly increased the hydrophobicity of the strain. On the other hand, the presence of AggL in the strain reduced its ability to adhere to the ileum. Moreover, MbpL protein showed an affinity to bind gastric type mucin proteins such as MUC5AC. This protein did not contribute to the binding of the strain to the ileal or colonic part of the intestine. Different potential functions of lactococcal AggL and MbpL proteins in the process of adhesion to the gastrointestinal tract are proposed.
Pleiotropic Control of Secondary Metabolism and Morphological Development by KsbC, a Butyrolactone Autoregulator Receptor Homologue in Kitasatospora setae
Authors: Aroonsri Aiyada , Kitani Shigeru , Hashimoto Junko , Kosone Ikuko , Izumikawa Miho , Komatsu Mamoru , Fujita Nobuyuki , Takahashi Yoko , Shin-ya Kazuo , Ikeda Haruo , Nihira Takuya
Published: September 2012

The γ-butyrolactone autoregulator signaling cascades have been shown to control secondary metabolism and/or morphological development among many
Streptomyces
species. However, the conservation and variation of the regulatory systems among actinomycetes remain to be clarified. The genome sequence of
Kitasatospora setae
, which also belongs to the family
Streptomycetaceae
containing the genus
Streptomyces
, has revealed the presence of three homologues of the autoregulator receptor: KsbA, which has previously been confirmed to be involved only in secondary metabolism; KsbB; and KsbC. We describe here the characterization of
ksbC
, whose regulatory cluster closely resembles the
Streptomyces virginiae barA
locus responsible for the autoregulator signaling cascade. Deletion of the gene
ksbC
resulted in lowered production of bafilomycin and a defect of aerial mycelium formation, together with the early and enhanced production of a novel β-carboline alkaloid named kitasetaline. A putative kitasetaline biosynthetic gene cluster was identified, and its expression in a heterologous host led to the production of kitasetaline together with JBIR-133, the production of which is also detected in the
ksbC
disruptant, and JBIR-134 as novel β-carboline alkaloids, indicating that these genes were biosynthetic genes for β-carboline alkaloid and thus are the first such genes to be discovered in bacteria.
Differences in Colonization and Shedding Patterns after Oral Challenge of Cattle with Three Escherichia coli O157:H7 Strains
Authors: Kulow Megan J. , Gonzales Tina K. , Pertzborn Kelly M. , Dahm James , Miller Bret A. , Park Dongjin , Gautam Raju , Kaspar Charles W. , Ivanek Renata , Döpfer Dörte
Published: September 2012

Experimental oral challenge studies with three different genotypes ofEscherichia coliO157:H7 were conducted in cattle to determine the genotype-specific variability in shedding frequencies and concentrations and the frequency and extent of contamination of the environment. The results indicated that theE. coliO157:H7 genotype and ecological origin maybe important factors for the occurrence and concentration in the cattle host. Four groups of six young Holstein steers each were orally challenged with 106CFU of one of threeE. coliO157:H7 strains: FRIK 47 (groups 1 and 2), FRIK 1641 (group 3), and FRIK 2533 (group 4). Recto-anal mucosal swabs (RAMS) and environmental samples were taken on alternate days over 30 days. The numbers ofE. coliO157:H7 cells and genericE. colicells per sample were determined. Also, the presence and absence of 28 gene targets were determined for 2,411 isolates using high-throughput real-time PCR. Over the study period, strains FRIK 47, FRIK 1641, and FRIK 2533 were detected in 52%, 42%, and 2% of RAMS, respectively. Environmental detection of the challenge strains was found mainly in samples of the hides and pen floors, with strains FRIK 47, FRIK 1641, and FRIK 2533 detected in 22%, 27%, and 0% of environmental samples, respectively. Based on the panel of 28 gene targets, genotypes of enterohemorrhagicE. coli(EHEC) and genericE. colifrom the experimental samples were clustered into three subgroups. In conclusion, the results suggested that the type and intensity of measures to control this pathogen at the preharvest level may need to be strain specific.
Physiological Significance of Network Organization in Fungi
Authors: Simonin Anna , Palma-Guerrero Javier , Fricker Mark , Glass N. Louise
Published: September 2012

The evolution of multicellularity has occurred in diverse lineages and in multiple ways among eukaryotic species. For plants and fungi, multicellular forms are derived from ancestors that failed to separate following cell division, thus retaining cytoplasmic continuity between the daughter cells. In networked organisms, such as filamentous fungi, cytoplasmic continuity facilitates the long-distance transport of resources without the elaboration of a separate vascular system. Nutrient translocation in fungi is essential for nutrient cycling in ecosystems, mycorrhizal symbioses, virulence, and substrate utilization. It has been proposed that an interconnected mycelial network influences resource translocation, but the theory has not been empirically tested. Here we show, by using mutants that disrupt network formation in
Neurospora crassa
(Δ
so
mutant, no fusion; Δ
Prm-1
mutant, ∼50% fusion), that the translocation of labeled nutrients is adversely affected in homogeneous environments and is even more severely impacted in heterogeneous environments. We also show that the ability to share resources and genetic exchange between colonies (via hyphal fusion) is very limited in mature colonies, in contrast to in young colonies and germlings that readily share nutrients and genetic resources. The differences in genetic/resource sharing between young and mature colonies were associated with variations in colony architecture (hyphal differentiation/diameters, branching patterns, and angles). Thus, the ability to share resources and genetic material between colonies is developmentally regulated and is a function of the age of a colony. This study highlights the necessity of hyphal fusion for efficient nutrient translocation within an
N. crassa
colony but also shows that established
N. crassa
colonies do not share resources in a significant manner.
Insights into Glycogen Metabolism in Chemolithoautotrophic Bacteria from Distinctive Kinetic and Regulatory Properties of ADP-Glucose Pyrophosphorylase from Nitrosomonas europaea
Authors: Machtey Matías , Kuhn Misty L. , Flasch Diane A. , Aleanzi Mabel , Ballicora Miguel A. , Iglesias Alberto A.
Published: September 2012

Nitrosomonas europaeais a chemolithoautotroph that obtains energy by oxidizing ammonia in the presence of oxygen and fixes CO2via the Benson-Calvin cycle. Despite its environmental and evolutionary importance, very little is known about the regulation and metabolism of glycogen, a source of carbon and energy storage. Here, we cloned and heterologously expressed the genes coding for two major putative enzymes of the glycogen synthetic pathway inN. europaea, ADP-glucose pyrophosphorylase and glycogen synthase. In other bacteria, ADP-glucose pyrophosphorylase catalyzes the regulatory step of the synthetic pathway and glycogen synthase elongates the polymer. In starch synthesis in plants, homologous enzymes play similar roles. We purified to homogeneity the recombinant ADP-glucose pyrophosphorylase fromN. europaeaand characterized its kinetic, regulatory, and oligomeric properties. The enzyme was allosterically activated by pyruvate, oxaloacetate, and phosphoenolpyruvate and inhibited by AMP. It had a broad thermal and pH stability and used different divalent metal ions as cofactors. Depending on the cofactor, the enzyme was able to accept different nucleotides and sugar phosphates as alternative substrates. However, characterization of the recombinant glycogen synthase showed that only ADP-Glc elongates the polysaccharide, indicating that ATP and glucose-1-phosphate are the physiological substrates of the ADP-glucose pyrophosphorylase. The distinctive properties with respect to selectivity for substrates and activators of the ADP-glucose pyrophosphorylase were in good agreement with the metabolic routes operating inN. europaea, indicating an evolutionary adaptation. These unique properties place the enzyme in a category of its own within the family, highlighting the unique regulation in these organisms.
A Novel Component of the Rhodobacter sphaeroides Fla1 Flagellum Is Essential for Motor Rotation
Authors: Ramírez-Cabrera Victor , Poggio Sebastian , Domenzain Clelia , Osorio Aurora , Dreyfus Georges , Camarena Laura
Published: September 2012

Here we describe a novel component essential for flagellar rotation in
Rhodobacter sphaeroides
. This protein is encoded by
motF
(RSP_0067), the first gene of a predicted transcriptional unit which contains two hypothetical genes. Sequence analysis indicated that MotF is a bitopic membrane-spanning protein. Protease sensitivity assays and green fluorescent protein (GFP) fusions confirmed this prediction and allowed us to conclude that the C terminus of MotF is located in the periplasmic space. Wild-type cells expressing a functional GFP-MotF fusion show a single fluorescent focus per cell. The localization of this protein in different genetic backgrounds allowed us to determine that normal localization of MotF depends on the presence of FliL and MotB. Characterization of a Δ
motF
pseudorevertant strain revealed that a single nucleotide change in
motB
suppresses the Mot
−
phenotype of the
motF
mutant. Additionally, we show that MotF also becomes dispensable when other mutant alleles of
motB
previously isolated as second-site suppressors of Δ
fliL
were expressed in the
motF
mutant strain. These results show that MotF is a new component of the Fla1 flagellum, which together with FliL is required to promote flagellar rotation, possibly through MotB.
The Lysozyme-Induced Peptidoglycan
N
-Acetylglucosamine Deacetylase PgdA (EF1843) Is Required for Enterococcus faecalis Virulence
Authors: Benachour Abdellah , Ladjouzi Rabia , Le Jeune André , Hébert Laurent , Thorpe Simon , Courtin Pascal , Chapot-Chartier Marie-Pierre , Prajsnar Tomasz K. , Foster Simon J. , Mesnage Stéphane
Published: September 2012

Lysozyme is a key component of the innate immune response in humans that provides a first line of defense against microbes. The bactericidal effect of lysozyme relies both on the cell wall lytic activity of this enzyme and on a cationic antimicrobial peptide activity that leads to membrane permeabilization. Among Gram-positive bacteria, the opportunistic pathogen
Enterococcus faecalis
has been shown to be extremely resistant to lysozyme. This unusual resistance is explained partly by peptidoglycan
O
-acetylation, which inhibits the enzymatic activity of lysozyme, and partly by
d
-alanylation of teichoic acids, which is likely to inhibit binding of lysozyme to the bacterial cell wall. Surprisingly, combined mutations abolishing both peptidoglycan
O
-acetylation and teichoic acid alanylation are not sufficient to confer lysozyme susceptibility. In this work, we identify another mechanism involved in
E. faecalis
lysozyme resistance. We show that exposure to lysozyme triggers the expression of EF1843, a protein that is not detected under normal growth conditions. Analysis of peptidoglycan structure from strains with
EF1843
loss- and gain-of-function mutations, together with
in vitro
assays using recombinant protein, showed that EF1843 is a peptidoglycan
N
-acetylglucosamine deacetylase. EF1843-mediated peptidoglycan deacetylation was shown to contribute to lysozyme resistance by inhibiting both lysozyme enzymatic activity and, to a lesser extent, lysozyme cationic antimicrobial activity. Finally,
EF1843
mutation was shown to reduce the ability of
E. faecalis
to cause lethality in the
Galleria mellonella
infection model. Taken together, our results reveal that peptidoglycan deacetylation is a component of the arsenal that enables
E. faecalis
to thrive inside mammalian hosts, as both a commensal and a pathogen.
Alternative Excision Repair of Ultraviolet B- and C-Induced DNA Damage in Dormant and Developing Spores of Bacillus subtilis
Authors: Ramírez-Guadiana Fernando H. , Barraza-Salas Marcelo , Ramírez-Ramírez Norma , Ortiz-Cortés Mayte , Setlow Peter , Pedraza-Reyes Mario
Published: September 2012

The nucleotide excision repair (NER) and spore photoproduct lyase DNA repair pathways are major determinants of
Bacillus subtilis
spore resistance to UV radiation. We report here that a putative ultraviolet (UV) damage endonuclease encoded by
ywjD
confers protection to developing and dormant spores of
B. subtilis
against UV DNA damage. In agreement with its predicted function, a His
6
-YwjD recombinant protein catalyzed the specific incision of UV-irradiated DNA
in vitro
. The maximum expression of a reporter gene fusion to the
ywjD
opening reading frame occurred late in sporulation, and this maximal expression was dependent on the forespore-specific RNA polymerase sigma factor, σ
G
. Although the absence of YwjD and/or UvrA, an essential protein of the NER pathway, sensitized developing spores to UV-C, this effect was lower when these cells were treated with UV-B. In contrast, UV-B but not UV-C radiation dramatically decreased the survival of dormant spores deficient in both YwjD and UvrA. The distinct range of lesions generated by UV-C and UV-B and the different DNA photochemistry in developing and dormant spores may cause these differences. We postulate that in addition to the UvrABC repair system, developing and dormant spores of
B. subtilis
also rely on an alternative excision repair pathway involving YwjD to deal with the deleterious effects of various UV photoproducts.
Identification and Characterization of Five Intramembrane Metalloproteases in Anabaena variabilis
Authors: Chen Kangming , Gu Liping , Xiang Xianling , Lynch Michael , Zhou Ruanbao
Published: September 2012

Regulated intramembrane proteolysis (RIP) involves cleavage of a transmembrane segment of a protein, releasing the active form of a membrane-anchored transcription factor (MTF) or a membrane-tethered signaling protein in response to an extracellular or intracellular signal. RIP is conserved from bacteria to humans and governs many important signaling pathways in both prokaryotes and eukaryotes. Proteases that carry out these cleavages are named intramembrane cleaving proteases (I-CLips). To date, little is known about I-CLips in cyanobacteria. In this study, five putative site-2 type I-Clips (Ava_1070, Ava_1730, Ava_1797, Ava_3438, and Ava_4785) were identified through a genome-wide survey in
Anabaena variabilis
. Biochemical analysis demonstrated that these five putative
A. variabilis
site-2 proteases (S2Ps

Av

) have authentic protease activities toward an artificial substrate pro-σ
K
, a
Bacillus subtilis
MTF, in our reconstituted
Escherichia coli
system. The enzymatic activities of processing pro-σ
K
differ among these five S2Ps

Av

. Substitution of glutamic acid (E) by glutamine (Q) in the conserved HEXXH zinc-coordinated motif caused the loss of protease activities in these five S2Ps

Av

, suggesting that they belonged to the metalloprotease family. Further mapping of the cleaved peptides of pro-σ
K
by Ava_4785 and Ava_1797 revealed that Ava_4785 and Ava_1797 recognized the same cleavage site in pro-σ
K
as SpoIVFB, a cognate S2P of pro-σ
K
from
B. subtilis
. Taking these results together, we report here for the first time the identification of five metallo-intramembrane cleaving proteases in
Anabaena variabilis
. The experimental system described herein should be applicable to studies of other RIP events and amenable to developing
in vitro
assays for I-CLips.
Hyperosmotic Stress Response of Campylobacter jejuni
Authors: Cameron Andrew , Frirdich Emilisa , Huynh Steven , Parker Craig T. , Gaynor Erin C.
Published: September 2012

The diarrheal pathogen
Campylobacter jejuni
and other gastrointestinal bacteria encounter changes in osmolarity in the environment, through exposure to food processing, and upon entering host organisms, where osmotic adaptation can be associated with virulence. In this study, growth profiles, transcriptomics, and phenotypic, mutant, and single-cell analyses were used to explore the effects of hyperosmotic stress exposure on
C. jejuni
. Increased growth inhibition correlated with increased osmotic concentration, with both ionic and nonionic stressors inhibiting growth at 0.620 total osmol liter
−1
.
C. jejuni
adaptation to a range of osmotic stressors and concentrations was accompanied by severe filamentation in subpopulations, with microscopy indicating septum formation and phenotypic diversity between individual cells in a filament. Population heterogeneity was also exemplified by the bifurcation of colony morphology into small and large variants on salt stress plates. Flow cytometry of
C. jejuni
harboring green fluorescent protein (GFP) fused to the ATP synthase promoter likewise revealed bimodal subpopulations under hyperosmotic stress. We also identified frequent hyperosmotic stress-sensitive variants within the clonal wild-type population propagated on standard laboratory medium. Microarray analysis following hyperosmotic upshift revealed enhanced expression of heat shock genes and genes encoding enzymes for synthesis of potential osmoprotectants and cross-protective induction of oxidative stress genes. The capsule export gene
kpsM
was also upregulated, and an acapsular mutant was defective for growth under hyperosmotic stress. For
C. jejuni
, an organism lacking most conventional osmotic response factors, these data suggest an unusual hyperosmotic stress response, including likely “bet-hedging” survival strategies relying on the presence of stress-fit individuals in a heterogeneous population.
SurA Is Involved in the Targeting to the Outer Membrane of a Tat Signal Sequence-Anchored Protein
Authors: Rondelet Arnaud , Condemine Guy
Published: September 2012

The twin arginine translocation (Tat) pathway exports folded proteins from the cytoplasm to the periplasm of bacteria. The targeting of the exported proteins to the Tat pathway relies on a specific amino-terminal signal sequence, which is cleaved after exportation. In the phytopathogen
Dickeya dadantii
, the pectin lyase homologue PnlH is exported by the Tat pathway without cleavage of its signal sequence, which anchors PnlH into the outer membrane. In proteobacteria, the vast majority of outer membrane proteins consists of β-barrel proteins and lipoproteins. Thus, PnlH represents a new kind of outer membrane protein. In
Escherichia coli
, periplasmic chaperones SurA, Skp, and DegP work together with the β-barrel assembly machinery (Bam) to target and insert β-barrel proteins into the outer membrane. In this work, we showed that SurA is required for an efficient targeting of PnlH to the outer membrane. Moreover, we were able to detect an
in vitro
interaction between SurA and the PnlH signal sequence. Since the PnlH signal sequence contains a highly hydrophobic region, we propose that SurA protects it from the hydrophobic periplasm during targeting of PnlH to the outer membrane. We also studied the nature of the information carried by the PnlH signal sequence responsible for its targeting to the outer membrane after exportation by the Tat system.
Characterization of a Ferrous Iron-Responsive Two-Component System in Nontypeable Haemophilus influenzae
Authors: Steele Kendra H. , O'Connor Lauren H. , Burpo Nicole , Kohler Katharina , Johnston Jason W.
Published: September 2012

Nontypeable
Haemophilus influenzae
(NTHI), an opportunistic pathogen that is commonly found in the human upper respiratory tract, has only four identified two-component signal transduction systems. One of these, an ortholog to the QseBC (
q
uorum-
s
ensing

E

scherichia coli
) system, was characterized. This system, designated
firRS
, was found to be transcribed in an operon with a gene encoding a small, predicted periplasmic protein with an unknown function,
ygiW
. The
ygiW-firRS
operon exhibited a unique feature with an attenuator present between
ygiW
and
firR
that caused the
ygiW
transcript level to be 6-fold higher than the
ygiW-firRS
transcript level. FirRS induced expression of
ygiW
and
firR
, demonstrating that FirR is an autoactivator. Unlike the QseBC system of
E. coli
, FirRS does not respond to epinephrine or norepinephrine. FirRS signal transduction was stimulated when NTHI cultures were exposed to ferrous iron or zinc but was unresponsive to ferric iron. Notably, the ferrous iron-responsive activation only occurred when a putative iron-binding site in FirS and the key phosphorylation aspartate in FirR were intact. FirRS was also activated when cultures were exposed to cold shock. Mutants in
ygiW
,
firR
, and
firS
were attenuated during pulmonary infection, but not otitis media. These data demonstrate that the
H. influenzae
strain 2019 FirRS is a two-component regulatory system that senses ferrous iron and autoregulates its own operon.
RECENT RESULTS FROM THE LHCb EXPERIMENT
Authors:   (on behalf of the LHCb Collaboration), CAMPANA PIERLUIGI , LANFRANCHI GAIA
Published: September 2012

We present a review of the operation and of the most recent results from the LHCb experiment at the LHC collider, based on the analyses performed using the data collected in 2010 and 2011, which correspond to an integrated luminosity of ~ 1 fb-1. These measurements set stringent new limits on the contributions of New Physics processes in the field of rare b decays, and in the search for CP violation in B0 and [Formula: see text] mesons decays. In addition, a summary of results from studies of CP violation in the charm sector are presented, together with measurements in quarkonia production, in spectroscopy, in electroweak physics and in searches for exotica. The planned upgrade of LHCb is also briefly discussed.
Closed-End Funds: A Survey
Authors: Cherkes Martin
Published: September 2012

New theories have emerged over the past 10 years that reveal CEFs to be an important and efficient organizational device. This review surveys the old and current literature on closed-end funds (CEFs) in general and theories of discounts in particular. Among the topics reviewed are liquidity transformation, the effects of tax overhang, the importance of managerial fees, the provision of leverage services, the impact of the potential irrationality of small investors on discounts, and rationality of CEFs' initial public offering (IPO) process.
Left ventricular vortex formation is unaffected by diastolic impairment
Authors: Stewart Kelley C. , Charonko John C. , Niebel Casandra L. , Little William C. , Vlachos Pavlos P.
Published: September 2012

Normal left ventricular (LV) filling occurs rapidly early in diastole caused by a progressive pressure gradient within the ventricle and with a low left atrial pressure. This normal diastolic function is altered in patients with heart failure. Such impairment of diastolic filling is manifested as an abrupt deceleration of the early filling wave velocity. Although variations within the early filling wave have been observed previously, the underlying hydrodynamic mechanisms are not well understood. Previously, it was proposed that the mitral annulus vortex ring formation time was the total duration of early diastolic filling and provided a measure of the efficiency of diastolic filling. However, we found that the favorable LV pressure difference driving early diastolic filling becomes zero simultaneously with the deceleration of the early filling wave propagation velocity and pinch-off of the LV vortex ring. Thus we calculated the vortex ring formation time using the duration of the early diastolic filling wave from its initiation to the time of the early filling wave propagation velocity deceleration when pinch-off occurs. This formation time does not vary with decreasing intraventricular pressure difference or with degree of diastolic dysfunction. Thus we conclude the vortex ring pinch-off occurs before the completion of early diastole, and its formation time remains invariant to changes of diastolic function.
Selective V1aagonism attenuates vascular dysfunction and fluid accumulation in ovine severe sepsis
Authors: Rehberg Sebastian , Yamamoto Yusuke , Sousse Linda , Bartha Eva , Jonkam Collette , Hasselbach Anthony K. , Traber Lillian D. , Cox Robert A. , Westphal Martin , Enkhbaatar Perenlei , Traber Daniel L.
Published: September 2012

Vasopressin analogs are used as a supplement to norepinephrine in septic shock. The isolated effects of vasopressin agonists on sepsis-induced vascular dysfunction, however, remain controversial. Because V2-receptor stimulation induces vasodilation and procoagulant effects, a higher V1a- versus V2-receptor selectivity might be advantageous. We therefore hypothesized that a sole, titrated infusion of the selective V1a-agonist Phe2-Orn8-Vasotocin (POV) is more effective than the mixed V1a-/V2-agonist AVP for the treatment of vascular and cardiopulmonary dysfunction in methicillin resistant staphylococcus aureus pneumonia-induced, ovine sepsis. After the onset of hemodynamic instability, awake, chronically instrumented, mechanically ventilated, and fluid resuscitated sheep were randomly assigned to receive continuous infusions of either POV, AVP, or saline solution (control; each n = 6). AVP and POV were titrated to maintain mean arterial pressure above baseline − 10 mmHg. When compared with that of control animals, AVP and POV reduced neutrophil migration (myeloperoxidase activity, alveolar neutrophils) and plasma levels of nitric oxide, resulting in higher mean arterial pressures and a reduced vascular leakage (net fluid balance, chest and abdominal fluid, pulmonary bloodless wet-to-dry-weight ratio, alveolar and septal edema). Notably, POV stabilized hemodynamics at lower doses than AVP. In addition, POV, but not AVP, reduced myocardial and pulmonary tissue concentrations of 3-nitrotyrosine, VEGF, and angiopoietin-2, thereby leading to an abolishment of cumulative fluid accumulation (POV, 9 ± 15 ml/kg vs. AVP, 110 ± 13 ml/kg vs. control, 213 ± 16 ml/kg; P < 0.001 each) and an attenuated cardiopulmonary dysfunction (left ventricular stroke work index, PaO2-to-FiO2ratio) versus control animals. Highly selective V1a-agonism appears to be superior to unselective vasopressin analogs for the treatment of sepsis-induced vascular dysfunction.
Maternal high-altitude hypoxia and suppression of ryanodine receptor-mediated Ca2+ sparks in fetal sheep pulmonary arterial myocytes
Authors: Hadley Scott R. , Blood Quintin , Rubalcava Monica , Waskel Edith , Lumbard Britney , Le Petersen , Longo Lawrence D. , Buchholz John N. , Wilson Sean M.
Published: September 2012

Ca2+ sparks are fundamental Ca2+ signaling events arising from ryanodine receptor (RyR) activation, events that relate to contractile and dilatory events in the pulmonary vasculature. Recent studies demonstrate that long-term hypoxia (LTH) can affect pulmonary arterial reactivity in fetal, newborn, and adult animals. Because RyRs are important to pulmonary vascular reactivity and reactivity changes with ontogeny and LTH we tested the hypothesis that RyR-generated Ca2+ signals are more active before birth and that LTH suppresses these responses. We examined these hypotheses by performing confocal imaging of myocytes in living arteries and by performing wire myography studies. Pulmonary arteries (PA) were isolated from fetal, newborn, or adult sheep that lived at low altitude or from those that were acclimatized to 3,801 m for > 100 days. Confocal imaging demonstrated preservation of the distance between the sarcoplasmic reticulum, nucleus, and plasma membrane in PA myocytes. Maturation increased global Ca2+ waves and Ca2+ spark activity, with sparks becoming larger, wider, and slower. LTH preferentially depressed Ca2+ spark activity in immature pulmonary arterial myocytes, and these sparks were smaller, wider, and slower. LTH also suppressed caffeine-elicited contraction in fetal PA but augmented contraction in the newborn and adult. The influence of both ontogeny and LTH on RyR-dependent cell excitability shed new light on the therapeutic potential of these channels for the treatment of pulmonary vascular disease in newborns as well as adults.
Annexin V decreases PS-mediated macrophage efferocytosis and deteriorates elastase-induced pulmonary emphysema in mice
Authors: Yoshida S. , Minematsu N. , Chubachi S. , Nakamura H. , Miyazaki M. , Tsuduki K. , Takahashi S. , Miyasho T. , Iwabuchi T. , Takamiya R. , Tateno H. , Mouded M. , Shapiro S. D. , Asano K. , Betsuyaku T.
Published: September 2012

Efferocytosis is believed to be a key regulator for lung inflammation in chronic obstructive pulmonary disease. In this study we pharmacologically inhibited efferocytosis with annexin V and attempted to determine its impact on the progression of pulmonary emphysema in mouse. We first demonstrated in vitro and in vivo efferocytosis experiments using annexin V, an inhibitor for phosphatidylserine-mediated efferocytosis. We then inhibited efferocytosis in porcine pancreatic elastase (PPE)-treated mice. PPE-treated mice were instilled annexin V intranasally starting from day 8 until day 20. Mean linear intercept (Lm) was measured, and cell apoptosis was assessed in lung specimen obtained on day 21. Cell profile, apoptosis, and mRNA expression of matrix metalloproteinases (MMPs) and growth factors were evaluated in bronchoalveolar lavage (BAL) cells on day 15. Annexin V attenuated macrophage efferocytosis both in vitro and in vivo. PPE-treated mice had a significant higher Lm, and annexin V further increased that by 32%. More number of macrophages was found in BAL fluid in this group. Interestingly, cell apoptosis was not increased by annexin V treatment both in lung specimens and BAL fluid, but macrophages from mice treated with both PPE and annexin V expressed higher MMP-2 mRNA levels and had a trend for higher MMP-12 mRNA expression. mRNA expression of keratinocyte growth factor tended to be downregulated. We showed that inhibited efferocytosis with annexin V worsened elastase-induced pulmonary emphysema in mice, which was, at least partly, attributed to a lack of phenotypic change in macrophages toward anti-inflammatory one.
Decreases in manganese superoxide dismutase expression and activity contribute to oxidative stress in persistent pulmonary hypertension of the newborn
Authors: Afolayan Adeleye J. , Eis Annie , Teng Ru-Jeng , Bakhutashvili Ivane , Kaul Sushma , Davis Jonathan M. , Konduri Girija G.
Published: September 2012

A rapid increase in the synthesis and release of nitric oxide (NO) facilitates the pulmonary vasodilation that occurs during birth-related transition. Alteration of this transition in persistent pulmonary hypertension of the newborn (PPHN) is associated with impaired function of endothelial nitric oxide synthase (eNOS) and an increase in oxidative stress. We investigated the hypothesis that a decrease in expression and activity of mitochondrial localized manganese superoxide dismutase (MnSOD) in pulmonary artery endothelial cells (PAEC) increases oxidative stress and impairs eNOS function in PPHN. We isolated PAEC and pulmonary arteries from fetal lambs with PPHN induced by prenatal ductus arteriosus ligation or sham ligation (control). We investigated MnSOD expression and activity, tyrosine nitration of MnSOD, and mitochondrial O2−levels in PAEC from control and PPHN lambs. We introduced exogenous MnSOD via an adenoviral vector (ad-MnSOD) transduction into PAEC and pulmonary arteries of PPHN lambs. The effect of ad-MnSOD was investigated on: mitochondrial O2−levels, MnSOD and eNOS expression and activity, intracellular hydrogen peroxide (H2O2) levels, and catalase expression in PAEC. MnSOD mRNA and protein levels and activity were decreased and MnSOD tyrosine nitration was increased in PPHN-PAEC. ad-MnSOD transduction of PPHN-PAEC increased its activity two- to threefold, decreased mitochondrial O2−levels, and increased H2O2levels and catalase expression. ad-MnSOD transduction improved eNOS expression and function and the relaxation response of PPHN pulmonary arteries. Our observations suggest that decreased MnSOD expression and activity contribute to the endothelial dysfunction observed in PPHN.
Acute cigarette smoke exposure impairs proteasome function in the lung
Authors: van Rijt Sabine H. , Keller Ilona E. , John Gerrit , Kohse Kathrin , Yildirim Ali Ö. , Eickelberg Oliver , Meiners Silke
Published: September 2012

Cigarette smoke mediates DNA damage, lipid peroxidation, and modification and misfolding of proteins, thereby inducing severe cellular damage. The ubiquitin proteasome system serves as the major disposal system for modified and misfolded proteins and is thus essential for proper cellular function. Its role in cigarette smoke-induced cell damage, however, is largely unknown. We hypothesized that the ubiquitin-proteasome system is involved in the degradation of cigarette smoke-damaged proteins and that cigarette smoke exposure impairs the proteasome itself. Here, we show that treatment of human alveolar epithelial cells with cigarette smoke extract (CSE) induced time- and dose-dependent cell death, a rise in intracellular reactive oxygen species, and increased levels of carbonylated and polyubiquitinated proteins. While high doses of CSE severely impaired all three proteasomal activities, low CSE concentrations significantly inhibited only the trypsin-like activity of the proteasome in alveolar and bronchial epithelial cells. Moreover, acute exposure of mice to cigarette smoke significantly impaired the trypsin-like activity by 25% in the lungs. Reduced proteasome activity was not due to transcriptional regulation of the proteasome. Notably, cigarette smoke exposure induced accumulation of polyubiquitinated proteins in the soluble and insoluble protein fraction of the lung. We show for the first time that acute exposure to cigarette smoke directly impairs proteasome activity in the lungs of mice and in human epithelial cells at low doses without affecting proteasome expression. Our results indicate that defective proteasomal protein quality control may exacerbate the detrimental effects of cigarette smoke in the lung.
Diaphragm weakness in pulmonary arterial hypertension: role of sarcomeric dysfunction
Authors: Manders Emmy , de Man Frances S. , Handoko M. L. , Westerhof Nico , van Hees Hieronymus W. H. , Stienen Ger J. M. , Vonk-Noordegraaf Anton , Ottenheijm Coen A. C.
Published: September 2012

We previously demonstrated that diaphragm muscle weakness is present in experimental pulmonary arterial hypertension (PH). However, the nature of this diaphragm weakness is still unknown. Therefore, the aim of this study was to investigate whether changes at the sarcomeric level contribute to diaphragm weakness in PH. For this purpose, in control rats and rats with monocrotaline-induced PH, contractile performance and myosin heavy chain content of demembranated single diaphragm fibers were determined. We observed a reduced maximal tension of 20% ( P < 0.05), whereas tension cost was preserved in type 2X and 2B diaphragm fibers in PH compared with control. The reduced maximal tension was associated with a reduction of force generated per half-sarcomeric myosin heavy chain content. Additionally, reduced Ca2+ sensitivity of force generation was found in type 2X fibers compared with control, which could exacerbate diaphragm muscle weakness at submaximal activation. No changes in maximal tension and Ca2+ sensitivity of force generation were observed in fibers from the nonrespiratory extensor digitorum longus muscle. Together, these findings indicate that diaphragm weakness in PH is at least partly caused by sarcomeric dysfunction, which appears to be specific for the diaphragm.