Estimation de la distensibilité aortique à partir de séquences d’images de résonance magnétique « steady-state free-precession » et « contraste de phase »

Objective

To investigate the accuracy in the estimation of the aortic lumen area and distensibility obtained from Steady-State Free-Precession (SSFP) and Phase Contrast (PC) MR sequences.

Subjects and methods

Systolic and diastolic aortic lumen of the ascending and descending aorta of 50 subjects, collected with both acquisition sequences, were extracted using a 2D + t automated segmentation method.

Results

While the statistical study indicated very similar lumen areas for SSFP and PC data (slope = 1, r = 0.99), the corresponding distensibility values were less correlated (r = 0.54). Comparison between distensibility values in the ascending and descending aorta and study of these values with aging indicated a greater coherence with expected physiological behavior of the aorta when using SSFP images.

Discussion

Flow artifacts were more severe in PC images and could explain the better results obtained when using SSFP sequences.

Conclusion

A more accurate local assessment of the aortic stiffness is obtained from SSFP image sequences than from PC image sequences.     

Herd prevalence of Enterobacteriaceae producing CTX‐M‐type and CMY‐2 β‐lactamases among Japanese dairy farms

Aims

To determine the herd prevalence of Enterobacteriaceae producing CTX‐M‐type extended‐spectrum β‐lactamases (ESBLs) among 381 dairy farms in Japan.

Methods and Results

Between 2007 and 2009, we screened 897 faecal samples using BTB lactose agar plates containing cefotaxime (2 μg ml^?1). Positive isolates were tested using ESBL confirmatory tests, PCR and sequencing for CTX‐M, AmpC, TEM and SHV. The incidence of Enterobacteriaceae producing CTX‐M‐15 (n = 7), CTX‐M‐2 (n = 12), CTX‐M‐14 (n = 3), CMY‐2 (n = 2) or CTX‐M‐15/2/14 and CMY‐2 (n = 4) in bovine faeces was 28/897 (3·1%) faecal samples. These genes had spread to Escherichia coli (n = 23) and three genera of Enterobacteriaceae (n = 5). Herd prevalence was found to be 20/381 (5·2%) dairy farms. The 23 E. coli isolates showed clonal diversity, as assessed by multilocus sequence typing and pulsed‐field gel electrophoresis. The pandemic E. coli strain ST131 producing CTX‐M‐15 or CTX‐M‐27 was not detected.

Conclusions

Three clusters of CTX‐M (CTX‐M‐15, CTX‐M‐2, CTX‐M‐14) had spread among Japanese dairy farms.

Significance and Impact of the Study

This is the first report on the prevalence of multidrug‐resistant CTX‐M‐15–producing E. coli among Japanese dairy farms.     

A <Emphasis Type="Italic">var2</Emphasis> leaf variegation suppressor locus, <Emphasis Type="Italic">SUPPRESSOR OF VARIEGATION3</Emphasis>, encodes a putative chloroplast translation elongation factor that is important for chloroplast development in the cold

Background  

The Arabidopsis var2 mutant displays a unique green and white/yellow leaf variegation phenotype and lacks VAR2, a chloroplast FtsH metalloprotease. We are characterizing second-site var2 genetic suppressors as means to better understand VAR2 function and to study the regulation of chloroplast biogenesis.     

Control of <Emphasis Type="Italic">gag-pol</Emphasis> gene expression in the <Emphasis Type="Italic">Candida albicans</Emphasis> retrotransposon Tca2

Background  

In the C. albicans retrotransposon Tca2, the gag and pol ORFs are separated by a UGA stop codon, 3' of which is a potential RNA pseudoknot. It is unclear how the Tca2 gag UGA codon is bypassed to allow pol expression. However, in other retroelements, translational readthrough of the gag stop codon can be directed by its flanking sequence, including a 3' pseudoknot.     

<Emphasis Type="Bold">Report from the 33rd</Emphasis><Emphasis Type="BoldItalic">Mycotoxin-Workshop</Emphasis><Emphasis Type="Bold">(Freising,Germany)</Emphasis>

Society for Mycotoxin Research – News and Announcements 2011/II

Report from the 33rd Mycotoxin-Workshop (Freising, Germany)     

Proceedings and papers published in <Emphasis Type="Italic">Japanese Journal of Ichthyology</Emphasis>

Editorial Notes and Announcements

Proceedings and papers published in Japanese Journal of Ichthyology     

<Emphasis Type="Italic">PGM2</Emphasis> overexpression improves anaerobic galactose fermentation in <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

Background  

In Saccharomyces cerevisiae galactose is initially metabolized through the Leloir pathway after which glucose 6-phosphate enters glycolysis. Galactose is controlled both by glucose repression and by galactose induction. The gene PGM2 encodes the last enzyme of the Leloir pathway, phosphoglucomutase 2 (Pgm2p), which catalyses the reversible conversion of glucose 1-phosphate to glucose 6-phosphate. Overexpression of PGM2 has previously been shown to enhance aerobic growth of S. cerevisiae in galactose medium.     

<Emphasis Type="Italic">Msx1</Emphasis> and <Emphasis Type="Italic">Msx2</Emphasis>are required for endothelial-mesenchymal transformation of the atrioventricular cushions and patterning of the atrioventricular myocardium

Background  

Msx1 and Msx2, which belong to the highly conserved Nk family of homeobox genes, display overlapping expression patterns and redundant functions in multiple tissues and organs during vertebrate development. Msx1 and Msx2 have well-documented roles in mediating epithelial-mesenchymal interactions during organogenesis. Given that both Msx1 and Msx2 are crucial downstream effectors of Bmp signaling, we investigated whether Msx1 and Msx2 are required for the Bmp-induced endothelial-mesenchymal transformation (EMT) during atrioventricular (AV) valve formation.     

The <Emphasis Type="Italic">MB2</Emphasis> gene family of <Emphasis Type="Italic">Plasmodium</Emphasis> species has a unique combination of S1 and GTP-binding domains

Background  

Identification and characterization of novel Plasmodium gene families is necessary for developing new anti-malarial therapeutics. The products of the Plasmodium falciparum gene, MB2, were shown previously to have a stage-specific pattern of subcellular localization and proteolytic processing.     

Functional characterization of O‐methyltransferases used to catalyse site‐specific methylation in the post‐tailoring steps of pradimicin biosynthesis

Aims

To identify the roles of the two O‐methyltransferase homologous genes pdmF and pdmT in the pradimicin biosynthetic gene cluster of Actinomadura hibisca P157‐2.

Methods and Results

Pradimicins are pentangular polyphenol antibiotics synthesized by bacterial type II polyketide synthases (PKSs) and tailoring enzymes. Pradimicins are naturally derivatized by combinatorial O‐methylation at two positions (i.e., 7‐OH and 11‐OH) of the benzo[α]naphthacenequinone structure. PdmF and PdmT null mutants (PFKO and PTKO) were generated. PFKO produced the 11‐O‐demethyl shunt metabolites 11‐O‐demethylpradimicinone II ( 1 ), 11‐O‐demethyl‐7‐methoxypradimicinone II ( 2 ), 11‐O‐demethylpradimicinone I ( 3 ) and 11‐O‐demethylpradimicin A ( 4 ), while PTKO generated the 7‐O‐demethyl derivatives pradimicinone II ( 5 ) and 7‐hydroxypradimicin A ( 6 ). Pradimicinones 1 , 2 , 3 , and 5 were fed to a heterologous host Escherichia coli harbouring expression plasmid pET‐22b::pdmF or pET‐28a::pdmT. PdmF catalysed 11‐O‐methylation of pradimicinones 1 , 2 , and 3 regardless of O‐methylation at the C‐7 position, while PdmT was unable to catalyse 7‐O‐methylation when the C‐11 hydroxyl group was methylated ( 5 ).

Conclusions

PdmF and PdmT were involved in 11‐O‐ and 7‐O‐methylations of the benzo[α]naphthacenequinone moiety of pradimicin, respectively. Methylation of the C‐7 hydroxyl group precedes methylation of the C‐11 hydroxyl group in pradimicin biosynthesis.

Significance and Impact of the Study

This is the first reported demonstration of the functions of PdmF and PdmT for regiospecific O‐methylation, which contributes to better understanding of the post‐PKS modifications in pradimicin biosynthesis as well as to rational engineering of the pradimicin biosynthetic machinery.     

Disruption of insulin signalling preserves bioenergetic competence of mitochondria in ageing <Emphasis Type="Italic">Caenorhabditis elegans</Emphasis>

Background  

The gene daf-2 encodes the single insulin/insulin growth factor-1-like receptor of Caenorhabditis elegans. The reduction-of-function allele e1370 induces several metabolic alterations and doubles lifespan.     

<Emphasis Type="Italic">Brucella abortus ure2</Emphasis> region contains an acid-activated urea transporter and a nickel transport system

Background  

Urease is a virulence factor that plays a role in the resistance of Brucella to low pH conditions, both in vivo and in vitro. Brucella contains two separate urease gene clusters, ure1 and ure2. Although only ure1 codes for an active urease, ure2 is also transcribed, but its contribution to Brucella biology is unknown.     

Remobilization of <Emphasis Type="Italic">Tol2</Emphasis> transposons in <Emphasis Type="Italic">Xenopus tropicalis</Emphasis>

Background  

The Class II DNA transposons are mobile genetic elements that move DNA sequence from one position in the genome to another. We have previously demonstrated that the naturally occurring Tol2 element from Oryzias latipes efficiently integrates its corresponding non-autonomous transposable element into the genome of the diploid frog, Xenopus tropicalis. Tol2 transposons are stable in the frog genome and are transmitted to the offspring at the expected Mendelian frequency.     

Inhibition of hydrogen uptake in <Emphasis Type="Italic">Escherichia coli</Emphasis> by expressing the hydrogenase from the cyanobacterium <Emphasis Type="Italic">Synechocystis</Emphasis>sp. PCC 6803

Background  

Molecular hydrogen is an environmentally-clean fuel and the reversible (bi-directional) hydrogenase of the cyanobacterium Synechocystis sp. PCC 6803 as well as the native Escherichia coli hydrogenase 3 hold great promise for hydrogen generation. These enzymes perform the simple reaction 2H⁺ + 2e^- ↔ H₂ (g).     

Functional dissection of the <Emphasis Type="Italic">ash2</Emphasis> and <Emphasis Type="Italic">ash1</Emphasis> transcriptomes provides insights into the transcriptional basis of wing phenotypes and reveals conserved protein interactions

Background  

The trithorax group (trxG) genes absent, small or homeotic discs 1 (ash1) and 2 (ash2) were isolated in a screen for mutants with abnormal imaginal discs. Mutations in either gene cause homeotic transformations but Hox genes are not their only targets. Although analysis of double mutants revealed that ash2 and ash1 mutations enhance each other's phenotypes, suggesting they are functionally related, it was shown that these proteins are subunits of distinct complexes.     

<Emphasis Type="Italic">Brucella suis</Emphasis> urease encoded by <Emphasis Type="Italic">ure</Emphasis> 1 but not <Emphasis Type="Italic">ure</Emphasis> 2 is necessary for intestinal infection of BALB/c mice

Background  

In prokaryotes, the ureases are multi-subunit, nickel-containing enzymes that catalyze the hydrolysis of urea to carbon dioxide and ammonia. The Brucella genomes contain two urease operons designated as ure1 and ure2. We investigated the role of the two Brucella suis urease operons on the infection, intracellular persistence, growth, and resistance to low-pH killing.     

Low‐intensity pulsed ultrasound induced enhanced adipogenesis of adipose‐derived stem cells

Objective

The aim of this study was to investigate effects of low‐intensity pulsed ultrasound (LIPUS) on differentiation of adipose‐derived stem cells (ASCs), in vitro.

Materials and methods

Murine ASCs were treated with LIPUS for either three or five days, immediately after adipogenic induction, or delayed for 2 days. Expression of adipogenic genes PPAR‐γ1, and APN, was examined by real‐time PCR. Immunofluorescence (IF) staining was performed to test for PPAR‐γ at the protein level.

Results

Our data revealed that specific patterns of LIPUS up‐regulated levels of both PPAR‐γ1 and APN mRNA, and PPAR‐γ protein.

Conclusions

In culture medium containing adipogenic reagents, LIPUS enhanced ASC adipogenesis.