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831.
Nathalie Crevier-Denoix Bérangère Ravary-Plumioën Delphine Evrard Philippe Pourcelot 《Journal of biomechanics》2009,42(13):2210-2213
A non-invasive ultrasonic (US) technique of tendon force measurement has been recently developed. It is based on the relationship demonstrated between the speed of sound (SOS) in a tendon and the traction force applied to it. The objectives of the present study were to evaluate the variability of this non-linear relationship among 7 equine superficial digital flexor (SDF) tendons, and the reproducibility of SOS measurements in these tendons over successive loading cycles and tests. Seven SDF tendons were equipped with an US probe (1 MHz), secured in contact with the skin overlying the tendon metacarpal part. The tendons were submitted to a traction test consisting in 5 cycles of loading/unloading between 50 and 4050 N. Four tendons out of the 7 were submitted to 5 additional cycles up to 5550 N. The SOS-tendon force relationships appeared similar in shape, although large differences in SOS levels were observed among the tendons. Reproducibility between cycles was evaluated from the root mean square of the standard deviations (RMS-SD) of SOS values observed every 100 N, and of force values every 2 m/s. Reproducibility of SOS measurements revealed high between successive cycles: above 500 N the RMS-SD was less than 2% of the corresponding traction force. Reproducibility between tests was lower, partly due to the experimental set-up; above 500 N the difference between the two tests stayed nevertheless below 15% of the corresponding mean traction force. The reproducibility of the US technique here demonstrated in vitro has now to be confirmed in vivo. 相似文献
832.
Ana M. Meireles Katherine H. Fisher Nathalie Colombié James G. Wakefield Hiroyuki Ohkura 《The Journal of cell biology》2009,184(6):777-784
The bipolar spindle forms without centrosomes naturally in female meiosis and by experimental manipulation in mitosis. Augmin is a recently discovered protein complex required for centrosome-independent microtubule generation within the spindle in Drosophila
melanogaster cultured cells. Five subunits of Augmin have been identified so far, but neither their organization within the complex nor their role in developing organisms is known. In this study, we report a new Augmin subunit, wee Augmin component (Wac). Wac directly interacts with another Augmin subunit, Dgt2, via its coiled-coil domain. Wac depletion in cultured cells, especially without functional centrosomes, causes severe defects in spindle assembly. We found that a wac deletion mutant is viable but female sterile and shows only a mild impact on somatic mitosis. Unexpectedly, mutant female meiosis showed robust microtubule assembly of the acentrosomal spindle but frequent chromosome misalignment. For the first time, this study establishes the role of an Augmin subunit in developing organisms and provides an insight into the architecture of the complex. 相似文献
833.
Robert J. Brown Andrew C. Edmondson Nathalie Griffon Theophelus B. Hill Ilia V. Fuki Karen O. Badellino Mingyao Li Megan L. Wolfe Muredach P. Reilly Daniel J. Rader 《Journal of lipid research》2009,50(9):1910-1916
Human endothelial lipase (EL) is a member of a family of lipases and phospholipases that are involved in the metabolism of plasma lipoproteins. EL displays a preference to hydrolyze lipids in HDL. We report here that a naturally occurring low frequency coding variant in the EL gene (LIPG), glycine-26 to serine (G26S), is significantly more common in African-American individuals with elevated HDL cholesterol (HDL-C) levels. To test the hypothesis that this variant results in reduced EL function, we extensively characterized and compared the catalytic and noncatalytic functions of the G26S variant and wild-type (WT) EL. While the catalytic-specific activity of G26S EL is similar to WT EL, its secretion is markedly reduced. Consistent with this observation, we found that carriers of the G26S variant had significantly reduced plasma levels of EL protein. Thus, this N-terminal variant results in reduced secretion of EL protein, plausibly leading to increased HDL-C levels. 相似文献
834.
Albano C. Meli Maria Kondratova Virginie Molle Laurent Coquet Andrey V. Kajava Nathalie Saint 《The Journal of membrane biology》2009,230(3):143-154
Attachment to host tissues is a critical step in the pathogenesis of most bacterial infections. Enterotoxigenic Escherichia coli (ETEC) remains one of the principal causes of infectious diarrhea in humans. The recent identification of additional ETEC
surface molecules suggests that new targets may be exploited in vaccine development. The EtpA protein identified in ETEC H10407
is a large glycosylated adhesin secreted via the two-partner secretion system. EtpA requires its putative partner EtpB for
translocation across the outer membrane (OM). We investigated the biochemical and electrophysiological properties of purified
EtpB. We showed that EtpB is 65-kDa heat-modifiable protein localized to the OM. Electrophysiological experiments indicated
that EtpB is able to form pores in planar lipid bilayer membranes with an asymmetric current, suggesting its functional asymmetry.
The pore of EtpB frequently assumes an opened conformation and fluctuates between three well-defined conductance states. In
silico analysis of the EtpB amino acid sequence and molecular modeling suggest that EtpB is similar to the well-known TpsB
protein FhaC from Bordetella pertussis and has a C-terminal transmembrane β-barrel domain that is occluded by an N-terminal α-helix, an extracellular loop, and
two periplasmic polypeptide-transport-associated (POTRA) domains. Together, these data confirm that EtpB is a pore-forming
protein mainly folded into a β-barrel conformation and indicate that EtpB presents typical features of the OM TpsB proteins. 相似文献
835.
Christopher T. Lefèvre Alain Bernadac Kui Yu‐Zhang Nathalie Pradel Long‐Fei Wu 《Environmental microbiology》2009,11(7):1646-1657
The widespread magnetotactic bacteria have the peculiar capacity of navigation along the geomagnetic field. Despite their ubiquitous distribution, only few axenic cultures have been obtained worldwide. In this study, we reported the first axenic culture of magnetotactic bacteria isolated from the Mediterranean Sea. This magneto‐ovoid strain MO‐1 grew in chemically defined O2 gradient minimal media at the oxic–anoxic transition zone. It is phylogenetically related to Magnetococcus sp. MC‐1 but might represent a novel genus of Proteobacteria. Pulsed‐field gel electrophoresis analysis indicated that the genome size of the MO‐1 strain is 5 ± 0.5 Mb, with four rRNA operons. Each cell synthesizes about 17 magnetosomes within a single chain, two phosphorous‐oxygen‐rich globules and one to seven lipid storage granules. The magnetosomes chain seems to divide in the centre during cell division giving rise to two daughter cells with an approximately equal number of magnetosomes. The MO‐1 cell possesses two bundles of seven individual flagella that were enveloped in a unique sheath. They swam towards the north pole with a velocity up to 300 μm per second with frequent change from right‐hand to left‐hand helical trajectory. Using a magneto‐spectrophotometry assay we showed that MO‐1 flagella were powered by both proton‐motive force and sodium ion gradient, which is a rare feature among bacteria. 相似文献
836.
Caroline Charpin Sandrine Guis Philippe Colson Patrick Borentain Jean-Pierre Mattéi Patrice Alcaraz Nathalie Balandraud Benoit Thomachot Jean Roudier René Gérolami 《Arthritis research & therapy》2009,11(6):R179-5
Introduction
Reactivation of hepatitis B virus (HBV) infection in patients with past infection has been described in 5% to 10% of individuals undergoing immunosuppressive therapies. No data are available to date on the outcome of patients treated by tumour necrosis factor-alpha (TNFα) inhibitors for chronic arthritis with a serological pattern of past HBV infection. The aim of our study was to monitor HBV markers in HBV surface antigen (HBsAg)-negative/anti-HBcAb-positive patients treated with a TNFα inhibitor for inflammatory arthritides. 相似文献837.
838.
Robertson BC Frauenfelder N Eason DK Elliott G Moorhouse R 《Molecular ecology resources》2009,9(2):664-666
Thirty polymorphic microsatellite loci were developed from the critically endangered kakapo (Strigops habroptilus), using an enriched genomic library. Characterization of loci using 90 kakapo revealed an average of 3.3 alleles per locus (range: 2–5) and an average expected heterozygosity of 0.47 (range: 0.17–0.70). The probability of identity (7.2 × 10?15) and probability of exclusion (0.999999) demonstrate that these loci are a highly informative marker set that can aid the genetic management of the kakapo. 相似文献
839.
Nathalie Droin Jean-Baptiste Hendra Patrick Ducoroy Eric Solary 《Journal of Proteomics》2009,72(6):918
Human defensins, which are small cationic peptides produced by neutrophils and epithelial cells, form two genetically distinct alpha and beta subfamilies. They are involved in innate immunity through killing microbial pathogens or neutralizing bacterial toxins and in adaptive immunity by serving as chemoattractants and activators of immune cells. α-defensins are mainly packaged in neutrophil granules (HNP1, HNP2, HNP3) or secreted by intestinal Paneth cells (HD5, HD6), while β-defensins are expressed in mucosa and epithelial cells. Using surface enhanced laser desorption/ionisation time-of-flight (SELDI-TOF) mass spectrometry (MS), α-defensins were found to be expressed in a variety of human tumours, either in tumour cells or at their surface. HNP1–3 peptides are also secreted and their accumulation in biological fluids was proposed as a tumour biomarker. Conversely, β-defensin-1 (HBD-1) is down-regulated in some tumour types in which it could behave as a tumour suppressor protein. Alpha-defensins promote tumour cell growth or, at higher concentration, provoke cell death. These peptides also inhibit angiogenesis, which, in addition to immunomodulation, indicates a complex role in tumour development. This review summarizes current knowledge of defensins to discuss their role in tumour growth, tumour monitoring and cancer treatment. 相似文献
840.
Sylvie Rodrigues-Ferreira Anne Di Tommaso Ariane Dimitrov Sylvie Cazaubon Nadège Gruel Hélène Colasson André Nicolas Nathalie Chaverot Vincent Molinié Fabien Reyal Brigitte Sigal-Zafrani Benoit Terris Olivier Delattre Fran?ois Radvanyi Franck Perez Anne Vincent-Salomon Clara Nahmias 《PloS one》2009,4(10)