bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling Approach for the Electrodynamics of Multilayer DE Stack-Transducers
Authors: Hoffstadt Thorben , Meier Philip , Maas Jürgen
Published: November 2016

In most cases the electrical behavior of dielectric elastomer (DE) transducers is modeled by an equivalent circuit with lumped electrical parameters. Here, the capacitance is obtained under consideration of the active area of the whole DE transducer, while additional parallel and series resistances model the losses in the dielectric and the electrode respectively. Since this represents a quite simple modeling approach it is very common. However, in general a DE transducer has a certain spatial distribution depending on the design of the considered transducer. Thus, a model with lumped parameters might be inaccurate and does not take into account the field-distribution within the DE transducer. Since no analytical expression of the field-distribution can be derived by solving the partial differential equations for diagonal-edge contacts, within this contribution an electrical network model for a multilayer DE stack-transducer is presented. This model takes into account the influence of the contacting of each single transducer film as well as the electrical interaction of these films and their spatial distribution. Based on this model the influence of different design parameters can be investigated, resulting in design rules for the considered transducers with both optimized transient and static behavior.
The Cosmopolitan Performers: Chinese–Indonesian Migrants in Perth, Australia
Authors: Winarnita Monika , Araujo Natalie
Published: November 2016

This paper will discuss the socio-cultural process of performance in relation to the cosmopolitan identity and imaginings of Chinese-Indonesian migrants in Perth, Western Australia. Representing the largest visible group of Indonesian migrants in Australia, the Chinese ‘descendants’ (keturunan) perform as Indonesian traditional dancers on the Australian multicultural stage, to "celebrate the institutions of the state(s) in which [they] live" (Appiah 1997, 633). Nevertheless and perhaps inevitably, this cosmopatriot identity is often tinted with uncertainty due to the ambiguity surrounding their positioning as a legally accepted ethnic group in Indonesia. When viewed as ‘ethnic’ dancers from Jakarta, these women are seen as ‘legitimate’ cultural representatives because the Indonesian migrant community accepts the discourse of Chinese historical settlement in Jakarta, creating a cultural syncretic influence. However, their own internal sense of belonging is disrupted, particularly due to the lingering memory of the violent ‘May 1998 riots’, which targeted Chinese Indonesians. For many, the uncertainty generated by this violent episode became the reason for migration and settlement in Perth. Migration, the Australian multicultural stage, and a cosmopolitan worldview thus provide the spaces for Chinese Indonesians to express a cosmopatriotic affiliation with Indonesia despite being in a neighbouring country.
Some Contemporary Critical Cosmopolitanisms and Anthropology.
Authors: Fitzgerald Ruth Patricia
Published: November 2016

This is a book review essay based on the following texts:

Caraus, T., and C.A. Parvu. eds. 2014. Cosmopolitanism and the Legacies of Dissent,
Florence: Taylor and Francis, 304 pages
ISBN 9781317645023 (hardback)
ISBN 9781315761381 (ebook)

Josephides, L., and A. Hall. eds. 2014. We The Cosmopolitans. Moral And Existential Conditions Of Being Human. Oxford: Berghahn Books 186 pages
ISBN 9781782382768 (hardback)
ISBN 9782782382775 (institutional ebook)

Schiller, N. Glick., and A. Irving. eds. 2015. Whose Cosmopolitanism? Critical Perspectives, Relationalities And Discontents. Oxford: Berghahn Books 253 pages
ISBN 9781782384458 (hardback)
ISBN 9781782384465 (ebook)

Bielsa, E. 2016. Cosmopolitanism And Translation: Investigations Into The Experience Of The Foreign. New York: Routledge. 188 pages
ISBN 9781138946385 (hardback)
ISBN 9781138946392 (paperback)
ISBN 9781315670843 (ebook)
Dynamic pre-BCR homodimers fine-tune autonomous survival signals in B cell precursor acute lymphoblastic leukemia
Authors: Erasmus M. Frank , Matlawska-Wasowska Ksenia , Kinjyo Ichiko , Mahajan Avanika , Winter Stuart S. , Xu Li , Horowitz Michael , Lidke Diane S. , Wilson Bridget S.
Published: November 2016

Homotypic interactions between pre–B cell receptors generate survival signals in human acute lymphoblastic leukemia cells.
Battling over mTORC1 in T
reg
cells
Authors: Foley John F.
Published: November 2016

Metabolism in T regulatory cells depends on the balance between inflammatory signals and the transcriptional regulator Foxp3.
Papers of note in
Science
Authors: VanHook Annalisa M.
Published: November 2016

This week’s papers report distinct signals for cell reprogramming, an effect of social status on immune responses, and a mechanism for degrading autophagosomal membranes.
Molecular Investigation of Resistance to Second-Line Injectable Drugs in Multidrug-Resistant Clinical Isolates of
Mycobacterium tuberculosi
s in France
Authors: Brossier Florence , Pham Anne , Bernard Christine , Aubry Alexandra , Jarlier Vincent , Veziris Nicolas , Sougakoff Wladimir ,   on behalf of the CNR-MyRMA
Published: November 2016

The second-line injectable drugs (SLID, i.e., amikacin, kanamycin, capreomycin) are key drugs for the treatment of multidrug-resistant tuberculosis. Mutations in
rrs
region 1400,
tlyA
, and
eis
promoter are associated with resistance to SLID, to capreomycin, and to kanamycin, respectively. In this study, the sequencing data of SLID resistance-associated genes were compared to the results of phenotypic drug susceptibility testing by the proportion method for the SLID in 206 multidrug-resistant clinical isolates of
Mycobacterium tuberculosis
collected in France. Among the 153 isolates susceptible to the 3 SLID, 145 showed no mutation, 1 harbored T1404C and G1473A mutations in
rrs
, and 7 had an
eis
promoter mutation. Among the 53 strains resistant to at least 1 of the SLID, mutations in
rrs
accounted for resistance to amikacin, capreomycin, and kanamycin for 81%, 75%, and 44% of the isolates, respectively, while mutations in
eis
promoter were detected in 44% of the isolates resistant to kanamycin. In contrast, no mutations in
tlyA
were observed in the isolates resistant to capreomycin. The discrepancies observed between the genotypic (on the primary culture) and phenotypic drug susceptibility testing were explained by (i) resistance to SLID with MICs close to the critical concentration used for routine DST and not detected by phenotypic testing (
n
= 8, 15% of SLID-resistant strains), (ii) low-frequency heteroresistance not detected by sequencing of drug resistance-associated genes on the primary culture (
n
= 8, 15% of SLID-resistant strains), and (iii) other resistance mechanisms not yet characterized (
n
= 7, 13% of SLID-resistant strains).
In Vitro
and
In Vivo
Activities of Sulfur-Containing Linear Bisphosphonates against Apicomplexan Parasites
Authors: Szajnman Sergio H. , Galaka Tamila , Li Zhu-Hong , Li Catherine , Howell Nathan M. , Chao María N. , Striepen Boris , Muralidharan Vasant , Moreno Silvia N. J. , Rodriguez Juan B.
Published: November 2016

We tested a series of sulfur-containing linear bisphosphonates against
Toxoplasma gondii
, the etiologic agent of toxoplasmosis. The most potent compound (compound 22; 1-[(
n
-decylsulfonyl)ethyl]-1,1-bisphosphonic acid) is a sulfone-containing compound, which had a 50% effective concentration (EC
50
) of 0.11 ± 0.02 μM against intracellular tachyzoites. The compound showed low toxicity when tested in tissue culture with a selectivity index of >2,000. Compound 22 also showed high activity
in vivo
in a toxoplasmosis mouse model. The compound inhibited the
Toxoplasma
farnesyl diphosphate synthase (
Tg
FPPS), but the concentration needed to inhibit 50% of the enzymatic activity (IC
50
) was higher than the concentration that inhibited 50% of growth. We tested compound 22 against two other apicomplexan parasites,
Plasmodium falciparum
(EC
50
of 0.6 ± 0.01 μM), the agent of malaria, and
Cryptosporidium parvum
(EC
50
of ∼65 μM), the agent of cryptosporidiosis. Our results suggest that compound 22 is an excellent novel compound that could lead to the development of potent agents against apicomplexan parasites.
The Plasmodium falciparum Cell-Traversal Protein for Ookinetes and Sporozoites as a Candidate for Preerythrocytic and Transmission-Blocking Vaccines
Authors: Espinosa Diego A. , Vega-Rodriguez Joel , Flores-Garcia Yevel , Noe Amy R. , Muñoz Christian , Coleman Russell , Bruck Torben , Haney Keith , Stevens Alex , Retallack Diane , Allen Jeff , Vedvick Thomas S. , Fox Christopher B. , Reed Steven G. , Howard Randall F. , Salman Ahmed M. , Janse Chris J. , Khan Shahid M. , Zavala Fidel , Gutierrez Gabriel M.
Published: November 2016

Recent studies have shown that immune responses against the cell-traversal protein for
Plasmodium
ookinetes and sporozoites (CelTOS) can inhibit parasite infection. While these studies provide important evidence toward the development of vaccines targeting this protein, it remains unknown whether these responses could engage the
Plasmodium falciparum
CelTOS
in vivo
. Using a newly developed rodent malaria chimeric parasite expressing the
P. falciparum
CelTOS (PfCelTOS), we evaluated the protective effect of
in vivo
immune responses elicited by vaccination and assessed the neutralizing capacity of monoclonal antibodies specific against PfCelTOS. Mice immunized with recombinant
P. falciparum
CelTOS in combination with the glucopyranosyl lipid adjuvant-stable emulsion (GLA-SE) or glucopyranosyl lipid adjuvant-liposome-QS21 (GLA-LSQ) adjuvant system significantly inhibited sporozoite hepatocyte infection. Notably, monoclonal antibodies against PfCelTOS strongly inhibited oocyst development of
P. falciparum
and
Plasmodium berghei
expressing PfCelTOS in
Anopheles gambiae
mosquitoes. Taken together, our results demonstrate that anti-CelTOS responses elicited by vaccination or passive immunization can inhibit sporozoite and ookinete infection and impair vector transmission.
The Predicted Lytic Transglycosylase HpaH from Xanthomonas campestris pv. vesicatoria Associates with the Type III Secretion System and Promotes Effector Protein Translocation
Authors: Hausner Jens , Hartmann Nadine , Jordan Michael , Büttner Daniela
Published: November 2016

The pathogenicity of the Gram-negative plant-pathogenic bacterium
Xanthomonas campestris
pv. vesicatoria depends on a type III secretion (T3S) system, which spans both bacterial membranes and translocates effector proteins into plant cells. The assembly of the T3S system presumably involves the predicted lytic transglycosylase (LT) HpaH, which is encoded adjacent to the T3S gene cluster. Bacterial LTs degrade peptidoglycan and often promote the formation of membrane-spanning macromolecular protein complexes. In the present study, we show that HpaH localizes to the bacterial periplasm and binds to peptidoglycan as well as to components of the T3S system, including the predicted periplasmic inner rod proteins HrpB1 and HrpB2 as well as the pilus protein HrpE.
In vivo
translocation assays revealed that HpaH promotes the translocation of various effector proteins and of early substrates of the T3S system, suggesting a general contribution of HpaH to type III-dependent protein export. Mutant studies and the analysis of reporter fusions showed that the N-terminal region of HpaH contributes to protein function and is proteolytically cleaved. The N-terminally truncated HpaH cleavage product is secreted into the extracellular milieu by a yet-unknown transport pathway, which is independent of the T3S system.
The Pathogenic Potential of Proteus mirabilis Is Enhanced by Other Uropathogens during Polymicrobial Urinary Tract Infection
Authors: Armbruster Chelsie E. , Smith Sara N. , Johnson Alexandra O. , DeOrnellas Valerie , Eaton Kathryn A. , Yep Alejandra , Mody Lona , Wu Weisheng , Mobley Harry L. T.
Published: November 2016

Urinary catheter use is prevalent in health care settings, and polymicrobial colonization by urease-positive organisms, such asProteus mirabilisandProvidencia stuartii, commonly occurs with long-term catheterization. We previously demonstrated that coinfection withP. mirabilisandP. stuartiiincreased overall urease activityin vitroand disease severity in a model of urinary tract infection (UTI). In this study, we expanded these findings to a murine model of catheter-associated UTI (CAUTI), delineated the contribution of enhanced urease activity to coinfection pathogenesis, and screened for enhanced urease activity with other common CAUTI pathogens. In the UTI model, mice coinfected with the two species exhibited higher urine pH values, urolithiasis, bacteremia, and more pronounced tissue damage and inflammation compared to the findings for mice infected with a single species, despite having a similar bacterial burden within the urinary tract. The presence ofP. stuartii, regardless of urease production by this organism, was sufficient to enhanceP. mirabilisurease activity and increase disease severity, and enhanced urease activity was the predominant factor driving tissue damage and the dissemination of both organisms to the bloodstream during coinfection. These findings were largely recapitulated in the CAUTI model. Other uropathogens also enhancedP. mirabilisurease activityin vitro, including recent clinical isolates ofEscherichia coli,Enterococcus faecalis,Klebsiella pneumoniae, andPseudomonas aeruginosa. We therefore conclude that the underlying mechanism of enhanced urease activity may represent a widespread target for limiting the detrimental consequences of polymicrobial catheter colonization, particularly byP. mirabilisand other urease-positive bacteria.
Starvation- and Stationary-phase-induced resistance to the antimicrobial peptide polymyxin B in Salmonella typhimurium is RpoS (sigma(S)) independent and occurs through both phoP-dependent and -independent pathways
Authors: McLeod G I , Spector M P
Published: November 2016

A common stress encountered by Salmonella serovars involves exposure to membrane-permeabilizing antimicrobial peptides and proteins such as defensins, cationic antibacterial proteins, and polymyxins. We wanted to determine if starvation induces cross-resistance to the membrane-permeabilizing antimicrobial peptide polymyxin B (PmB). We report here that starved and stationary-phase (Luria-Bertani [LB] medium) cells exhibited ca. 200- to 1,500-fold-higher (cross-)resistance to a 60-min PmB challenge than log-phase cells. Genetic analysis indicates that this PmB resistance involves both phoP-dependent and -independent pathways. Furthermore, both pathways were sigma(S) independent, indicating that they are different from other known sigma(S) -dependent cross-resistance mechanisms. Additionally, both pathways were important for PmB resistance early during C starvation and for cells in stationary phase in LB medium. However, only the phoP-independent pathway was important for P-starvation-induced PmB resistance and the sustained PmB resistance seen in 24-h-C-starved (and N-starved) or stationary-phase cells in LB medium. The results indicate the presence of an rpoS- and phoP-independent pathway important to starvation- and stationary-phase-induced resistance to membrane-permeabilizing antimicrobial agents.
Relative levels and fractionation properties of Bacillus subtilis sigma(B) and its regulators during balanced growth and stress
Authors: Dufour A , Voelker U , Voelker A , Haldenwang W G
Published: November 2016

sigma B is a secondary sigma factor that controls the general stress response in Bacillus subtilis. sigma B-dependent genes are activated when sigma B is released from an inhibitory complex with an anti-sigma B protein (RsbW) and becomes free to associate with RNA polymerase. Two separate pathways, responding either to a drop in intracellular ATP levels or to environmental stress (e.g., heat, ethanol, or salt), cause the release of sigma B from RsbW. rsbR, rsbS, rsbT, and rsbU are four genes now recognized as the upstream half of an operon that includes sigB (sigma B) and its principal regulators. Using reporter gene assays, we find that none of these four genes are essential for stationary-phase (i.e., ATP-dependent) activation of sigma B, but rsbU and one or more of the genes contained within an rsbR,S,T deletion are needed for stress induction of sigma B. In other experiments, Western blot (immunoblot) analyses showed that the levels of RsbR, RsbS, Rsb, and RsbU, unlike those of the sigB operon's four downstream gene products (RsbV, RsbW, RsbX and sigma B), are not elevated during sigma B activation. Gel filtration and immunoprecipitation studies did not reveal the formation of complexes between any of the four upstream sigB operon products and the products of the downstream half of the operon. Much of the detectable RsbR, RsbS, RsbT, and RsbU did, however, fractionate as a large-molecular-mass (approximately 600-kDa) aggregate which was excluded from our gel filtration matrix. The downstream sigB operon products were not present in this excluded material. The unaggregated RsbR, RsbS, and RsbU, which were retarded by the gel matrix, elated from the column earlier than expected from their molecular weights. The RsbR and RsbS fractionation profile was consistent with homodimers (60 and 30 kDa, respectively), while the RsbU appeared larger, suggesting a protein complex of approximately 90 to 100 kDa.
Polyamines decrease Escherichia coli outer membrane permeability
Authors: Dela Vega A L , Delcour A H
Published: November 2016

The permeability of the outer membranes of gram-negative bacteria to hydrophilic compounds is mostly due to the presence of porin channels. We tested the effects of four polyamines (putrescine, cadaverine, spermidine, and spermine) on two processes known to depend on intact porin function: fluxes of beta-lactam antibiotics in live cells and chemotaxis. In both cases, inhibition was observed. Measurements of the rate of permeation of cephaloridine and of chemotaxis in swarm plates and capillary assays were used to determine the concentration dependence of this modulation. The effective concentration ranges depended on the nature of the polyamine and varied from submillimolar for spermine to tens of millimolar for cadaverine. Both OmpC and OmpF porins were inhibited, although the effects on OmpC appeared to be milder. These results are in agreement with our observations that polyamines inhibit porin-mediated ion fluxes in electrophysiological experiments, and they suggest that a low-affinity polyamine binding site might exist in these porins. These results reveal the potential use of porins as targets for blocking agents and suggest that polyamines may act as endogenous modulators of outer membrane permeability.
Membrane insertion of the F-pilin subunit is Sec independent but requires leader peptidase B and the proton motive force
Authors: Majdalani N , Ippen-Ihler K
Published: November 2016

F pilin is the subunit required for the assembly of conjugative pili on the cell surface of Escherichia coli carrying the F plasmid. Maturation of the F-pilin precursor, propilin, involves three F plasmid transfer products: TraA, the propilin precursor; TraQ, which promotes efficient propilin processing; and TraX, which is required for acetylation of the amino terminus of the 7-kDa pilin polypeptide. The mature pilin begins at amino acid 52 of the TraA propilin sequence. We performed experiments to determine the involvement of host cell factors in propilin maturation. At the nonpermissive temperature in a LepBts (leader peptidase B) host, propilin processing was inhibited. Furthermore, under these conditions, only full-length precursor was observed, suggesting that LepB is responsible for the removal of the entire propilin leader peptide. Using propilin processing as a measure of propilin insertion into the plasma membrane, we found that inhibition or depletion of SecA and SecY does not affect propilin maturation. Addition of a general membrane perturbant such as ethanol also had no effect. However, dissipation of the proton motive force did cause a marked inhibition of propilin processing, indicating that membrane insertion requires this energy source. We propose that propilin insertion in the plasma membrane proceeds independently of the SecA-SecY secretion machinery but requires the proton motive force. These results present a model whereby propilin insertion leads to processing by leader peptidase B to generate the 7-kDa peptide, which is then acetylated in the presence of TraX.
Role of CodY in regulation of the Bacillus subtilis hut operon
Authors: Fisher S H , Rohrer K , Ferson A E
Published: November 2016

Bacillus subtilis mutants deficient in amino acid repression of the histidine utilization (hut) operon were isolated by transposon mutagenesis. Genetic characterization of these mutants indicated that they most likely contained transposon insertions within the codVWXY operon. The codY gene is required for nutritional regulation of the dipeptide permease (dpp) operon. An examination of hut expression in a delta codY mutant demonstrated that amino acid repression exerted at the hutOA operator, which lies immediately downstream of the hut promoter, was defective in a delta codY mutant. The codY gene product was not required for amino acid regulation of either hut induction or the expression of proline oxidase, the first enzyme in proline degradation. This indicates that more than one mechanism of amino acid repression is present in B. subtilis. An examination of dpp and hut expression in cells during exponential growth in various media revealed that the level of CodY-dependent regulation appeared to be related to the growth rate of the culture.
Changes in patterns of ADP-ribosylated proteins during differentiation of Streptomyces coelicolor A3(2) and its development mutants
Authors: Shima J , Penyige A , Ochi K
Published: November 2016

Mutants resistant to 3-aminobenzamide, a known inhibitor of ADP-ribosyltransferase, were obtained from Streptomyces coelicolor A3(2). One (strain 27) was analyzed in detail. Mutant 27 had a reduced ADP-ribosyl-transferase activity, exhibited substantial changes from the wild type in ADP-ribosylated protein profile during cell aging, and was defective in producing aerial mycelium and antibiotics. A 92-kDa ADP-ribosylated protein disappeared at the onset of differentiation in the parent strain but was present in mutant 27. Four ADP-ribosylated proteins (39, 41, 43, and 46 kDa) appeared at the onset of differentiation in the parent strain but were missing in mutant 27. Failure to ADP-ribosylate these four proteins was detected when the parent strain was grown in the presence of subinhibitory amounts of 3-aminobenzamide. Genetic analysis showed that the mutation, named brgA, conferring resistance to 3-aminobenzamide, cosegregated with the altered phenotypes (i.e., defects in ADP-ribosylation and aerial mycelium formation) and was mapped to a new locus near uraA. The brgA mutants were nonconditionally deficient in producing aerial mycelium and antibiotics, as determined by using various media, and had a morphological and physiological phenotype quite different from that of a bldG mutant carrying a mutation which was previously mapped near uraA. Among the known bld mutants, bldA, bldD, and bldG mutants exhibited a ADP-ribosylated protein profile similar to that of the wild type, while like mutant 27, bldB, bldC, and bldH mutants failed to ADP-ribosylate certain proteins.
Active efflux of fluoroquinolones in Mycobacterium smegmatis mediated by LfrA, a multidrug efflux pump
Authors: Liu J , Takiff H E , Nikaido H
Published: November 2016

The lfrA gene cloned from chromosomal DNA of quinolone-resistant Mycobacterium smegmatis mc2-552 conferred low-level resistance to fluoroquinolones when present on multicopy plasmids. Sequence analysis suggested that lfrA encodes a membrane efflux pump of the major facilitator family (H. E. Takiff, M. Cimino, M. C. Musso, T. Weisbrod, R. Martinez, M. B. Delgado, L Salazar, B. R. Bloom, and W. R. Jacbos, Jr., Proc. Natl. Acad. Sci. USA 93:362-366, 1996). In this work, we studied the role of LfrA in the accumulation of fluoroquinolones by M. smegmatis. The steady-state accumulation level of a hydrophilic quinolone, norfloxacin, by M. smegmatis harboring a plasmid carrying the lfrA gene was about 50% of that by the parent strain but was increased to the same level as that of the parent strain by addition of a proton conductor, carbonyl cyanide m-chorophenylhydrazone. Norfloxacin efflux mediated by LfrA was competed for strongly by ciprofloxacin but not by nalidixic acid. Furthermore, we showed that portions of norfloxacin accumulated by starved cells were pumped out upon reenergization of the cells, and the rates of this efflux showed evidence of saturation at higher intracellular concentrations of the drug. These results suggest that the LfrA polypeptide catalyzes the active efflux of several quinolones.
Two-component regulatory proteins ResD-ResE are required for transcriptional activation of fnr upon oxygen limitation in Bacillus subtilis
Authors: Nakano M M , Zuber P , Glaser P , Danchin A , Hulett F M
Published: November 2016

Bacillus subtilis can grow anaerobically in the presence of nitrate as a terminal electron acceptor. The two component regulatory proteins, ResD and ResE, and an anaerobic gene regulator, FNR, were previously shown to be indispensable for nitrate respiration in B. subtilis. Unlike Escherichia coli fnr, B. subtilis fnr transcription was shown to be highly induced by oxygen limitation. fnr is transcribed from its own promoter as well as from a promoter located upstream of narK, the first gene in the narK-fnr dicistronic operon. DNA fragments containing the narK promoter, the fnr promoter, and both of the promoters were used to construct three lacZ fusions to examine the transcriptional regulation of the narK-fnr operon. ResDE was found to be required for transcriptional activation of fnr from the fnr-specific promoter, and FNR was required for activation of narK-fnr transcription from the FNR-dependent narK operon promoter under anaerobiosis. In order to determine if the requirement for ResDE in nitrate respiration is solely to activate fnr transcription, fnr was placed under control of the IPTG (isopropyl-beta-D-thiogalactopyranoside)-inducible promoter, Pspac. The observed defect in anaerobic growth of a Pspac-fnr delta resDE mutant in the presence of IPTG indicated that resDE has an additional role in B. subtilis anaerobic gene regulation.
Identification of two genes with prepilin-like leader sequences involved in type 4 fimbrial biogenesis in Pseudomonas aeruginosa
Authors: Alm R A , Mattick J S
Published: November 2016

Type 4 fimbriae are surface filaments produced by a range of bacterial pathogens for colonization of host epithelial surfaces. In Pseudomonas aeruginosa, they are involved in adhesion as well as in a form of surface translocation called twitching motility, and sensitivity to infection by fimbria-specific bacteriophage. Analysis of the 2.5-kb intergenic region between the previously defined pilR and pilV genes on P. aeruginosa genomic SpeI fragment E has identified three new genes, fimT, fimU, and dadA*. The predicted 18.5-kDa products of the fimT and fimU genes contain prepilin-like leader sequences, whereas the third gene, dadA*, encodes a protein similar to the D-amino acid dehydrogenase of Escherichia coli. Isogenic mutants constructed by allelic exchange demonstrated that the fimU gene was required for fimbrial biogenesis and twitching motility, whereas the fimT and dada* mutants retained wild-type phenotypes. However, overexpression of the fimT gene was found to be able to functionally replace the lack of a fimU gene product, suggesting a subtle role in fimbrial biogenesis. The identification of these proteins increases the similarity between type 4 fimbrial biogenesis and the supersystems involved in macromolecular traffic, such as extracellular protein secretion and DNA uptake, all of which now possess multiple protein species that possess prepilin-like leader sequences.
The D-Alanyl carrier protein in Lactobacillus casei: cloning, sequencing, and expression of dltC
Authors: Debabov D V , Heaton M P , Zhang Q , Stewart K D , Lambalot R H , Neuhaus F C
Published: November 2016

The incorporation of D-alanine into membrane-associated D-alanyl-lipoteichoic acid in Lactobacillus casei requires the 56-kDa D-alanine-D-alanyl carrier protein ligase (Dcl) and the 8.9-kDa D-alanyl carrier protein (Dcp). To identify and isolate the gene encoding Dcp, we have cloned and sequenced a 4.3-kb chromosomal fragment that contains dcl (dltA). In addition to this gene, the fragment contains three other genes, dltB, d1tC, and a partial dltD gene. dltC (246 nucleotides) was subcloned from this region and expressed in Escherichia coli. The product was identified as apo-Dcp lacking the N-terminal methionine (8,787.9 Da). The in vitro conversion of the recombinant apo-Dcp to holo-Dcp by recombinant E. coli holo-ACP synthase provided Dcp which accepts activated D-alanine in the reaction catalyzed by Bcl. The recombinant D-alanyl-Dcp was functionally identical to native D-alanyl-Dcp in the incorporation of D-alanine into lipoteichoic acid. L. casei Dcp is 46% identical to the putative product of dltC in the Bacillus subtilis dlt operon (M. Perego, P. Glaser, A. Minutello, M. A. Strauch, K. Leopold, and W. Fischer, J. Biol. Chem. 270:15598-15606, 1995), and therefore, this gene also encodes Dcp. Comparisons of the primary sequences and predicted secondary structures of the L. casei and B. subtilis Dcps with that of the E. coli acyl carrier protein (ACP) were undertaken together with homology modeling to identify the functional determinants of the donor and acceptor specificities of Dcp. In the region of the phospho-pantetheine attachment site, significant similarity between Dcps and ACPs was observed. This similarity may account for the relaxed acceptor specificity of the Dcps and ACPs in the ligation Of D-alanine catalyzed by Dcl. In contrast, two Dcp consensus sequences, KXXVLDXLA and DXVKXNXD, share little identity with the rest of the ACP family and, thus, may determine the donor specificity of D-alanyl-Dcp in the D-alanylation of membrane-associated D-alanyl-lipoteichoic acid.
Cloning, sequencing, and characterization of the nucH gene encoding an extracellular nuclease from Aeromonas hydrophila JMP636
Authors: Dodd H N , Pemberton J M
Published: November 2016

An Escherichia coli clone expressing activity on DNase agar was obtained by cloning chromosomal DNA of Aeromonas hydrophila JMP636 into plasmid pUC19. Examination (of the clone's nuclease activity on a sodium dodecyl sulfate (SDS)-polyacrylamide gel containing DNA as a substrate revealed an activity band at approximately 100 kDa. Subsequently, subcloning localized the gene, designated nucH, to a 3.6-kb DNA fragment (pJP9521). Southern blotting of the nucH gene against chromosomal DNA of JMP636 confirmed that it had originated from this strain and demonstrated that it was present in a single copy, although additional faint bands were also detected. Analysis of the subclone using in vivo transcription and translation revealed only a single polypeptide of approximately 110 kDa. Sequencing of pJP9521 predicted an open reading frame of 3,213 bp encoding a protein of 1,070 amino acids and having a molecular mass of 114 kDa. Comparison of the deduced nucleotide sequence and the NucH predicted protein sequence with relevant databases indicated that no known homologs have previously been identified. A signal sequence was predicted from these data, and cellular fractionation of a nucH clone in E. coli indicated that the protein was able to be processed to the periplasm. An activity similar in size was detected in an extracellular protein sample of JMP636, while inactivation of the nucH gene resulted in loss of this activity band. By native SDS-polyacrylamide gel electrophoresis, NucH substrate specificity, cofactor requirements, and sensitivity to denaturing agents were assessed.
Caulobacter and Asticcacaulis stalk bands as indicators of stalk age
Authors: Poindexter J S , Staley J T
Published: November 2016

The prosthecae (stalks) of dimorphic caulobacters of the genera Caulobacter and Asticcacaulis are distinguished among such appendages by the presence of disk-like components known as stalk bands. Whether bands are added to a cell's stalk(s) as a regular event coordinated with the cell's reproductive cycle has not been settled by previous studies. Analysis of the frequency of stalks with i, i + 1, i + 2, etc. bands 'among more than 7,000 stalks of Caulobacter crescentus revealed that in finite (batch) cultures (in which all offspring accumulate), the proportion of stalks with i + 1 hands was regularly 50% of the proportion of stalks with i bands. This implied that the number of bands correlated with the number of reproductive cycles completed by a stalked cell. In chemostat-maintained perpetual cultures, the proportion was greater than 50% because stalked cells, with their shorter reproductive cycle times, contributed a larger proportion of offspring to the steady-state population than did their swarmer siblings. In Asticcacaulis biprosthecum cells, which bear twin prosthecae, the twins on a typical cell possessed the same number of bands. For both genera, stalk bands provide a unique morphological feature that could be employed in an assessment of age distribution and reproductive dynamics within natural populations of these caulobacters.
Cloning, characterization, and regulation of nifF from Rhodobacter capsulatus
Authors: Gennaro G , Hübner P , Sandmeier U , Yakunin A F , Hallenbeck P C
Published: November 2016

The Rhodobacter capsulatus nifF gene and upstream sequence were cloned by using a probe based on the N-terminal sequence of NifF. nifF was found to not be contained in the previously described nif regions I, II, and III. Comparison of the deduced amino acid sequence showed that it is highly similar to NifF from Azotobacter vinelandii and NifF from Klebsiella pneumoniae. Analysis of translational fusions demonstrated that the regulation of transcription was the same as previously reported at the protein level. Insertional mutagen esis showed that NifF contributes significantly to nitrogenase activity under normal nitrogen-fixing conditions and that it is absolutely required for nitrogen fixation under iron limitation.
Sulfate transport in Penicillium chrysogenum plasma membranes
Authors: Hillenga D J , Versantvoort H J , Driessen A J , Konings W N
Published: November 2016

Transport studies with Penicillium chrysogenum plasma membranes fused with cytochrome c oxidase liposomes demonstrate that sulfate uptake is driven by the transmembrane pH gradient and not by the transmembrane electrical potential. Ca2+ and other divalent cations are not required. It is concluded that the sulfate transport system catalyzes the symport of two protons with one sulfate anion.
The activity of the high-affinity K+ uptake system Kdp sensitizes cells of Escherichia coli to methylglyoxal
Authors: Ferguson G P , Chacko A D , Lee C H , Booth I R , Lee C
Published: November 2016

Expression of the Kdp system sensitizes cells to methylglyoxal (MG) whether this electrophile is added externally or is synthesized endogenously. The basis of this enhanced sensitivity is the maintenance of a higher cytoplasmic pH (pHi) in cells expressing Kdp. In such cells, MG elicits rapid cytoplasmic acidification via KefB and KefC, but the steady-state pHi attained is still too high to confer protection Lowering pHi further by incubation with acetate increases the sensitivity of cells to MG.
A glutamate-dependent acid resistance gene in Escherichia coli
Authors: Hersh B M , Farooq F T , Barstad D N , Blankenhorn D L , Slonczewski J L
Published: November 2016

Stationary-phase cultures of Escherichia coli can survive several hours or exposure to extreme acid (pH 2 to 3), a level well below the pH range for growth (pH 4.5 to 9). To identify the genes needed for survival in extreme acid, a microliter screening procedure was devised. Colonies from a Tn10 transposon pool in E. coli MC4100 were inoculated into buffered Luria broth, pH 7.0, in microtiter wells, grown overnight, and then diluted in Luria broth, pH 2.5, at 37 degrees C for 2 h. From 3,000 isolates screened, 3 Tet(r) strains were identified as extremely acid sensitive (<0.1% survival at pH 2.5 for 2 h). Flanking sequences of the Tn10 inserts were amplified by inverse PCR. The sequences encoded a hydrophobic partial peptide of 88 residues. A random-primer-generated probe hybridized to Kohara clones 279 and 280 at 32 min (33.7 min on the revised genomic map EcoMap7) near gadB (encoding glutamate decarboxylase). The gene was designated xasA for extreme acid sensitive. xasA::Tn10 strains grown at pH 7 to 8 showed 100-fold-less survival in acid than the parent strain. Growth in mild acid (pH 5 to 6) restored acid resistance; anaerobiosis was not required, as it is for acid resistance in rpoS strains. xasA::Tn10 eliminated enhancement of acid resistance by glutamic acid. xasA was found to be a homolog of gadC recently sequenced in Shigella flexneri, in which it appears to encode a permease for the decarboxylated product of GadB. These results suggest that GadC (XasA) participates in a glutamate decarboxylase alkalinization cycle to protect E. coli from cytoplasmic acidification. The role of the glutamate cycle is particularly important for cultures grown at neutral pH before exposure to extreme acid.
The binding site of the IclR repressor protein overlaps the promoter of aceBAK
Authors: Pan B , Unnikrishnan I , LaPorte D C
Published: November 2016

In Escherichia coli, repression of the aceBAK operon is mediated by the IclR protein. We used an in vitro oligonucleotide selection technique to determine the consensus recognition sequence for MR. Mutational analysis confirmed the contribution of this sequence to repression in vivo and identified the -35 element of the promoter.
Physical map of the Western X-disease phytoplasma chromosome
Authors: Firrao G , Smart C D , Kirkpatrick B C
Published: November 2016

A physical map of the chromosome of the western X-disease phytoplasma was constructed and represents the first physical map of a phytoplasma chromosome. The western X-disease phytoplasma is a nonculturable, plant-pathogenic member of the class Mollicutes and is the causal agent of a severe disease of fruit trees in North America. The map was generated by performing restriction digests of the chromosome and resolving the restriction fragments by pulsed-field gel electrophoresis. Southern blot analysis using cloned phytoplasma probes confirmed the arrangement of contiguous restriction fragments. The locations of 20 restriction sites for the enzymes SalI, XhoI, BssHII, RsrII, SmaI, and NotI were mapped on the chromosome, which is circular and comprises approximately 670 kb. The locations or the two rRNA operons and of four previously cloned fragments of chromosomal DNA were also placed on the map.
Shared drink and a soft punch: an almost deadly combination
Authors: Klingberg Karsten , Srivastava David , Bosbach Simon , Lehmann Beat
Published: November 2016

Injuries of the spleen in blunt abdominal trauma are common and can lead to fatal bleeding. The diagnostic of choice to determine severity and treatment is usually made in contrast-enhanced CT. In our case we used contrast-enhanced ultrasound to identify the origin of an intra-abdominal bleeding following a minor trauma in a patient with splenomegaly due to an Epstein-Barr virus infection.
Activation ofCytomegaloviruscorneal endotheliitis following laser in situ keratomileusis
Authors: Tan Tien-En , Cheung Chui Ming Gemmy , Mehta Jodhbir S
Published: November 2016

A case ofCytomegalovirus(CMV) corneal endotheliitis following laser in-situ keratomileusis (LASIK) is presented. A 32-year-old man presented 3 weeks after uncomplicated myopic LASIK with unilateral LASIK flap oedema, interface fluid accumulation, keratic precipitates, anterior uveitis and raised intraocular pressure. Despite treatment with topical corticosteroids, he had 3 further recurrent episodes. Specular microscopy showed decreased endothelial cell density and aqueous humour. Polymerase chain reaction (PCR) testing was positive for CMV DNA. He was treated with topical ganciclovir and ketorolac, and the inflammation and oedema resolved. Repeat aqueous humour PCR testing was negative for CMV DNA, and he remained well at last follow-up (3 months after stopping all medications). CMV corneal endotheliitis can be reactivated after LASIK, and CMV DNA PCR of aqueous humour samples can help in definitive diagnosis. Early recognition and treatment of this condition is important to prevent permanent endothelial cell loss and corneal decompensation.
Strategy to reduce bortezomib-induced paralytic ileus in patients with myeloma and impaired renal function
Authors: Keating Matthew , Dasanu Constantin A
Published: November 2016

While bortezomib is known to cause adverse effects involving the autonomic nervous system, gastrointestinal side effects are typically mild. We describe herein a series of patients with myeloma and impaired renal function who developed severe paralytic ileus secondary to bortezomib use. Our patients had other risk factors for paralytic ileus including electrolyte abnormalities and opiate use. The striking commonality in our patients is the development of paralytic ileus with intravenous bortezomib in the setting of reduced renal function, followed by ileus resolution with bortezomib dose reduction. We discuss the existing literature on this subject and propose a strategy in order to reduce the risk of paralytic ileus in these patients. Upfront bortezomib dose reduction to 1 mg/m2intravenously in patients with myeloma with a glomerular filtration rate (GFR) of <30 mL/min may prevent paralytic ileus, while not compromising the clinical outcomes. Our conclusions will have to be validated in larger studies.
Risk of obstructive sleep apnoea in patients with rheumatoid arthritis: a nationwide population-based retrospective cohort study
Authors: Shen Te-Chun , Hang Liang-Wen , Liang Shinn-Jye , Huang Chien-Chung , Lin Cheng-Li , Tu Chih-Yen , Hsia Te-Chun , Shih Chuen-Ming , Hsu Wu-Huei , Sung Fung-Chang
Published: November 2016

Objective

Sleep disorders are prevalent medical disorders in patients with rheumatoid arthritis (RA). However, whether patients with RA are at an increased risk of developing obstructive sleep apnoea (OSA) is unclear.

Design

Using population-based retrospective cohort study to examine the risk of OSA in patients with RA.

Setting

We used claims data of the National Health Insurance Research Database (NHIRD) of Taiwan.

Participants

We identified a RA cohort with 33 418 patients newly diagnosed in 2000–2010 and a randomly selected non-RA comparison cohort with 33 418 individuals frequency matched by sex, age and diagnosis year.

Primary and secondary outcome measures

Incident OSA was estimated by the end of 2011. The HRs of OSA were calculated using the Cox proportional hazards regression analysis.

Results

The overall incidence rate of OSA was 75% greater in the RA cohort than in the non-RA cohort (3.04 vs 1.73/10 000 person-years, p<0.001), with an adjusted HR (aHR) of 1.75 (95% CI 1.18 to 2.60). Stratified analyses by sex, age group and comorbidity revealed that the incidence rates of OSA associated with RA were higher in all subgroups.

Conclusions

This population-based retrospective cohort study suggested that patients with RA should be monitored for the risk of developing OSA.
Protocol of the Swiss Longitudinal Cohort Study (SWICOS) in rural Switzerland
Authors: Schoenenberger Andreas W , Muggli Franco , Parati Gianfranco , Gallino Augusto , Ehret Georg , Suter Paolo M , Schoenenberger-Berzins Renate , Resink Therese J , Erne Paul
Published: November 2016

Introduction

Increased longevity and consequent major changes in demographics and population lifestyles necessitate new approaches to reduce the burden of ageing-related diseases (including cardiovascular disease) and maintain an optimal quality of life. This study aims to examine and longitudinally follow health status and disease risk factors in a Swiss rural cohort, evaluating all health-related research and practice disciplines to assure development of new implementable and successful preventive strategies for healthy ageing.

Methods and objectives

Small Swiss villages with low migration rates will be selected for this study. 2 villages (Cama/Lostallo) have already been selected as initial study sites. All residents (age ≥6 years, no upper age limit) are eligible. The target enrolment number per village is 300. Examinations and measurements encompass medical history, anthropometry, cardiac and vascular health, pulmonary function, physical performance, nutritional, mental and emotional status, biochemical and molecular analyses. Follow-up examinations (identical to baseline) will be performed after 5 and 10 years, and in 10-year intervals thereafter. The major objective is to assess, and observe change in, health status over time in a prospective manner. Secondary objectives are to: (1) identify ‘hidden’ (asymptomatic and/or unrecognised) health problems which enhance risk for chronic diseases; (2) identify barriers to accessing healthcare and adapting health behaviours; (3) evaluate efficacy of present preventive strategies and recommendations; (4) evaluate knowledge and attitude towards ongoing health programmes and public health recommendations; (5) monitor change and progress towards the national health objectives; (6) formulate new preventive strategies and recommendations based on the findings and knowledge base of the past 10 years; (7) formulate models for successful prevention of chronic diseases and for healthy ageing.

Ethics and dissemination

The Ethics Committee of Nordwest-und Zentralschweiz approved this study (EKNZ 2014-209). It is registered at ClinicalTrials.gov (NCT02282748). Findings will be disseminated through scientific articles/presentations and public events.
Impact of a dedicated cancer-associated thrombosis service on clinical outcomes: a mixed-methods evaluation of a clinical improvement exercise
Authors: Noble Simon , Pease Nikki , Sui Jessica , Davies James , Lewis Sarah , Malik Usman , Alikhan Raza , Prout Hayley , Nelson Annmarie
Published: November 2016

Objectives

Cancer-associated thrombosis (CAT) complex condition, which may present to any healthcare professional and at any point during the cancer journey. As such, patients may be managed by a number of specialties, resulting in inconsistent practice and suboptimal care. We describe the development of a dedicated CAT service and its evaluation.

Setting

Specialist cancer centre, district general hospital and primary care.

Participants

Patients with CAT and their referring clinicians.

Intervention

A cross specialty team developed a dedicated CAT service , including clear referral pathways, consistent access to medicines, patient's information and a specialist clinic.

Primary and secondary outcome measures

The service was evaluated using a mixed-methods evaluation , including audits of clinical practice, clinical outcomes, staff surveys and qualitative interviewing of patients and healthcare professionals.

Results

Data from 457 consecutive referrals over an 18-month period were evaluated. The CAT service has led to an 88% increase in safe and consistent community prescribing of low-molecular-weight heparin, with improved access to specialist advice and information. Patients reported improved understanding of their condition, enabling better self-management as well as better access to support and information. Referring clinicians reported better care standards for their patients with improved access to expertise and appropriate management.

Conclusions

A dedicated CAT service improves overall standards of care and is viewed positively by patients and clinicians alike. Further health economic evaluation would enhance the case for establishing this as the standard model of care.