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Purification and characterization of PBP4a, a new low-molecular-weight penicillin-binding protein from Bacillus subtilis
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Duez C Vanhove M Gallet X Bouillenne F Docquier J Brans A Frère J 《Journal of bacteriology》2001,183(5):1595-1599
Penicillin-binding protein 4a (PBP4a) from Bacillus subtilis was overproduced and purified to homogeneity. It clearly exhibits DD-carboxypeptidase and thiolesterase activities in vitro. Although highly isologous to the Actinomadura sp. strain R39 DD-peptidase (B. Granier, C. Duez, S. Lepage, S. Englebert, J. Dusart, O. Dideberg, J. van Beeumen, J. M. Frère, and J. M. Ghuysen, Biochem. J. 282:781-788, 1992), which is rapidly inactivated by many beta-lactams, PBP4a is only moderately sensitive to these compounds. The second-order rate constant (k(2)/K) for the acylation of the essential serine by benzylpenicillin is 300,000 M(-1) s(-1) for the Actinomadura sp. strain R39 peptidase, 1,400 M(-1) s(-1) for B. subtilis PBP4a, and 7,000 M(-1) s(-1) for Escherichia coli PBP4, the third member of this class of PBPs. Cephaloridine, however, efficiently inactivates PBP4a (k(2)/K = 46,000 M(-1) s(-1)). PBP4a is also much more thermostable than the R39 enzyme. 相似文献
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Olivia Lenoir Magali Jasiek Carole Hénique Léa Guyonnet Bj?rn Hartleben Tillmann Bork Anna Chipont Kathleen Flosseau Imane Bensaada Alain Schmitt Jean-Marc Massé Michèle Souyri Tobias B Huber Pierre-Louis Tharaux 《Autophagy》2015,11(7):1130-1145
The glomerulus is a highly specialized capillary tuft, which under pressure filters large amounts of water and small solutes into the urinary space, while retaining albumin and large proteins. The glomerular filtration barrier (GFB) is a highly specialized filtration interface between blood and urine that is highly permeable to small and midsized solutes in plasma but relatively impermeable to macromolecules such as albumin. The integrity of the GFB is maintained by molecular interplay between its 3 layers: the glomerular endothelium, the glomerular basement membrane and podocytes, which are highly specialized postmitotic pericytes forming the outer part of the GFB. Abnormalities of glomerular ultrafiltration lead to the loss of proteins in urine and progressive renal insufficiency, underlining the importance of the GFB. Indeed, albuminuria is strongly predictive of the course of chronic nephropathies especially that of diabetic nephropathy (DN), a leading cause of renal insufficiency. We found that high glucose concentrations promote autophagy flux in podocyte cultures and that the abundance of LC3B II in podocytes is high in diabetic mice. Deletion of Atg5 specifically in podocytes resulted in accelerated diabetes-induced podocytopathy with a leaky GFB and glomerulosclerosis. Strikingly, genetic alteration of autophagy on the other side of the GFB involving the endothelial-specific deletion of Atg5 also resulted in capillary rarefaction and accelerated DN. Thus autophagy is a key protective mechanism on both cellular layers of the GFB suggesting autophagy as a promising new therapeutic strategy for DN. 相似文献
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Emusu D Salihu HM Aliyu ZY Pierre-Louis BJ Druschel CM Kirby RS 《Birth defects research. Part A, Clinical and molecular teratology》2005,73(10):649-654
OBJECTIVE: To determine if the risk for fetal growth inhibition among gastroschisis-afflicted fetuses is heightened among younger gravidas (teen mothers). METHOD: This was a retrospective cohort study on live-born infants with isolated gastroschisis delivered in New York State from 1983 through 1999. We compared infants of mature (>20 years) mothers with those of younger (<20 years) mothers with respect to the following indices of fetal morbidity outcomes: low birth weight and very low birth weight, preterm and very pre-term, and small for gestational age. We used adjusted odds ratios to approximate relative risks. RESULTS: A total of 368 infants with isolated gastroschisis were analyzed. The two groups differed in terms of mean gestational age at delivery [Mean + standard deviation(SD) for infants with gastroschisis born to mature mothers = 37.2 weeks +/- 2.8 versus 36.3 weeks + 3.6 for those of teenage mothers(p = 0.01)], as well as mean birth weight [mean birth weight +/- SD for infants with gastroschisis born to mature mothers = 2562.4 grams +548.8 versus 2367.9 grams +/- 645.2 for those of younger mothers (p = 0.004)]. Infants of teen mothers were about twice as likely to be of low birth weight (OR = 1.70; 95% CI = 1.05-2.77) and about three times as likely to be born very preterm when compared to those of mature mothers (OR = 2.80; 95% Cl = 1.02-8.00). No significant differences were observed with respect to very low birth weight, pre-term and small for gestational age. CONCLUSION: Low maternal age appears to be a risk factor for low birth weight and very preterm birth among gastroschisis-affected fetuses. This information is potentially useful for planning by care providers and in counseling affected parents. 相似文献
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Sophie Vériter Wivine André Najima Aouassar Hélène Antoine Poirel Aurore Lafosse Pierre-Louis Docquier Denis Dufrane 《PloS one》2015,10(10)
Based on immunomodulatory, osteogenic, and pro-angiogenic properties of adipose-derived stem cells (ASCs), this study aims to assess the safety and efficacy of ASC-derived cell therapies for clinical indications. Two autologous ASC-derived products were proposed to 17 patients who had not experienced any success with conventional therapies: (1) a scaffold-free osteogenic three-dimensional graft for the treatment of bone non-union and (2) a biological dressing for dermal reconstruction of non-healing chronic wounds. Safety was studied using the quality control of the final product (genetic stability, microbiological/mycoplasma/endotoxin contamination) and the in vivo evaluation of adverse events after transplantation. Feasibility was assessed by the ability to reproducibly obtain the final ASC-based product with specific characteristics, the time necessary for graft manufacturing, the capacity to produce enough material to treat the lesion, the surgical handling of the graft, and the ability to manufacture the graft in line with hospital exemption regulations. For 16 patients (one patient did not undergo grafting because of spontaneous bone healing), in-process controls found no microbiological/mycoplasma/endotoxin contamination, no obvious deleterious genomic anomalies, and optimal ASC purity. Each type of graft was reproducibly obtained without significant delay for implantation and surgical handling was always according to the surgical procedure and the implantation site. No serious adverse events were noted for up to 54 months. We demonstrated that autologous ASC transplantation can be considered a safe and feasible therapy tool for extreme clinical indications of ASC properties and physiopathology of disease. 相似文献
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The use of massive bone allografts is increasing year by year and selection method remains unchanged. Superposition of patient’s
radiograph over allograft image and comparison of distances is the gold standard. Experiment was led to test selection procedure
of a major european tissue bank. Four observers were asked to select an allograft for 10 fictive recipients. Nine allografts
were provided. To simulate a perfect allograft, recipient himself was inserted in the pool of allografts (trap graft). The
10 potential bone transplants were classified in four categories (from adequate to unacceptable). In addition, observers were
asked to choose the three best grafts for a given recipient. Quadratic kappa measuring agreement on classification between
two observers ranged between 0.74 (substantial) and 0.47 (moderate). Trap graft was quoted by observers as adequate four times
(10%) and was cited eight times (20%) among the three best matching allografts. None of the observers discovered that recipient
was among allograft panel. This study demonstrates that current selection method is inaccurate for hemipelvic allograft selection.
New methods should be developed and tested to assist tissue banks in bone allograft selection. 相似文献