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1.
Co-aggregation of penicillin g acylase and polyionic polymers: an easy methodology to prepare enzyme biocatalysts stable in organic media 总被引:1,自引:0,他引:1
Wilson L Illanes A Abián O Pessela BC Fernández-Lafuente R Guisán JM 《Biomacromolecules》2004,5(3):852-857
A novel type of biocatalyst that combines the good properties of cross-linked enzyme aggregates (CLEAs) and hydrophilic microenvironments has been developed. Dextran sulfate- and polyethyleneimine-coated CLEAs of penicillin acylase (CLEA-GDP) were prepared by adding the polymers of different sizes before the precipitation stage of the enzyme. This study presents the development and optimization of a protocol to produce such a biocatalyst using penicillin acylase as a model. Experiments show that CLEA-GDPs have a highly increased stability in organic media. The average half-life of the preparations was much higher than standard CLEA without a microenvironment (CLEA-G), (e.g., more than 25-fold) in the presence of dioxane. However, their thermal stability was not increased, which leads to the conclusion that the stability of CLEA-GDPs in organic media is due to the hydrophilic microenvironment that surrounds the protein enzyme more than to a conformational stiffening effect. This is further supported by solvation experiments that show a preferential hydration of CLEA when polymers are used to coat the enzyme. CLEA-GDPs are clearly better than other biocatalysts in terms of solvent stability. 相似文献
2.
Juan Del Coso Javier Portillo Gloria Muñoz Javier Abián-Vicén Cristina Gonzalez-Millán Jesús Muñoz-Guerra 《Amino acids》2013,44(6):1511-1519
The aim of this study was to determine the effects of a caffeine-containing energy drink on physical performance during a rugby sevens competition. A second purpose was to investigate the post-competition urinary caffeine concentration derived from the energy drink intake. On two non-consecutive days of a friendly tournament, 16 women from the Spanish National rugby sevens Team (mean age and body mass = 23 ± 2 years and 66 ± 7 kg) ingested 3 mg of caffeine per kg of body mass in the form of an energy drink (Fure®, ProEnergetics) or the same drink without caffeine (placebo). After 60 min for caffeine absorption, participants performed a 15-s maximal jump test, a 6 × 30 m sprint test, and then played three rugby sevens games against another national team. Individual running pace and instantaneous speed during the games were assessed using global positioning satellite (GPS) devices. Urine samples were obtained pre and post-competition. In comparison to the placebo, the ingestion of the energy drink increased muscle power output during the jump series (23.5 ± 10.1 vs. 25.6 ± 11.8 kW, P = 0.05), running pace during the games (87.5 ± 8.3 vs. 95.4 ± 12.7 m/min, P < 0.05), and pace at sprint velocity (4.6 ± 3.3 vs. 6.1 ± 3.4 m/min, P < 0.05). However, the energy drink did not affect maximal running speed during the repeated sprint test (25.0 ± 1.5 vs. 25.0 ± 1.7 km/h). The ingestion of the energy drink resulted in a higher post-competition urine caffeine concentration than the placebo (3.3 ± 0.7 vs. 0.2 ± 0.1 μg/mL; P < 0.05). In summary, 3 mg/kg of caffeine in the form of a commercially available energy drink considerably enhanced physical performance during a women’s rugby sevens competition. 相似文献
3.
Inhaled nebulized nitrite is a hypoxia-sensitive NO-dependent selective pulmonary vasodilator 总被引:11,自引:0,他引:11
Hunter CJ Dejam A Blood AB Shields H Kim-Shapiro DB Machado RF Tarekegn S Mulla N Hopper AO Schechter AN Power GG Gladwin MT 《Nature medicine》2004,10(10):1122-1127
The blood anion nitrite contributes to hypoxic vasodilation through a heme-based, nitric oxide (NO)-generating reaction with deoxyhemoglobin and potentially other heme proteins. We hypothesized that this biochemical reaction could be harnessed for the treatment of neonatal pulmonary hypertension, an NO-deficient state characterized by pulmonary vasoconstriction, right-to-left shunt pathophysiology and systemic hypoxemia. To test this, we delivered inhaled sodium nitrite by aerosol to newborn lambs with hypoxic and normoxic pulmonary hypertension. Inhaled nitrite elicited a rapid and sustained reduction ( approximately 65%) in hypoxia-induced pulmonary hypertension, with a magnitude approaching that of the effects of 20 p.p.m. NO gas inhalation. This reduction was associated with the immediate appearance of NO in expiratory gas. Pulmonary vasodilation elicited by aerosolized nitrite was deoxyhemoglobin- and pH-dependent and was associated with increased blood levels of iron-nitrosyl-hemoglobin. Notably, from a therapeutic standpoint, short-term delivery of nitrite dissolved in saline through nebulization produced selective, sustained pulmonary vasodilation with no clinically significant increase in blood methemoglobin levels. These data support the concept that nitrite is a vasodilator acting through conversion to NO, a process coupled to hemoglobin deoxygenation and protonation, and evince a new, simple and inexpensive potential therapy for neonatal pulmonary hypertension. 相似文献
4.
Woldemeskel M Tegegne A Umunna NN Kaitho RJ Tamminga S 《Animal reproduction science》2001,67(3-4):253-265
Thirty Ethiopian highland rams with an average body weight of 23.7kg (S.D.=1.23) and age of 18 months and 25 East African bucks with an average body weight of 18.6kg (S.D.=2.06) and age of 14 months were used to study the long term effects of supplementation with the leaves of Leucaena pallida and Sesbania sesban on testicular histology. Within species, animals were blocked based on body weight and scrotal circumference and randomly assigned, within blocks, to five nutritional treatment groups in a complete randomised block design. All animals were provided with unchopped teff (Eragrostis tef) straw ad libitum and were supplemented with either 150g of wheat bran (control), leucaena (200 or 400g) or sesbania (200 or 400g) leaves for a period of 6 months. At the end of the experimental period, all animals were surgically castrated and testicular samples were collected and prepared for histopathological examination. In sheep 200g S. sesban induced relatively more necrosis of the seminiferous tubules than 200g L. pallida, but with similar degree of tubular degeneration. However, lesions in testis of goats fed on 200g S. sesban and 200g L. pallida did not differ. The effect of 400g S. sesban and 400g L. pallida in sheep indicated that the former hardly induced lesions except depressive effect on spermatogenesis. Similar results were observed in goats. About 400g S. sesban induced milder lesions in sheep and goats than were 200g S. sesban. The lesions were compared and discussed in relation to the phytochemical composition of the supplementary feeds. 相似文献
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Maroun Abi Moussa François Guillé Georges Kyriakou Jean François Griveau Dominique Le Lannou Bernard Lobel 《Andrologie》2003,13(2):122-127
Objective
To assess the efficacy and safety of percutaneous testicular biopsy to provide sperm cells for ICSI in male patients with azoospermia not amenable to surgical treatment.Materials and methods
From October 1995 to December 2001, 175 biopsies were performed in men with azoospermia to provide material for intracytoplasmic sperm injection. Azoospermia was obstructive (OA) in 41 cases and non-obstructive (NOA) in 134 cases. Open biopsy was performed in the first 15 patients in the series and percutaneous biopsy was performed on an outpatient basis, under local anesthesia, with a Biopty Gun® (14G needle), in the subsequent patients as the first step in management. Open surgical biopsies were performed in another 15 patients following a sperm cell-negative percutaneous biopsy.Results
All biopsies performed for OA were positive, but only 51/134 biopsies (38%) were positive in the NOA group. The material provided by percutaneous biopsy, when positive for sperm cells, was always sufficient to perform ICSI. When percutaneous biopsy was negative, open surgical biopsy failed to give better results. Five men developed minor complications (acute hematocele) following percutaneous biopsies requiring reoperation for hemostasis (3.12%). No major complications were observed. Results were comparable in terms of fertilization and pregnancy rates whether fresh or frozen-thawed sperm was used.Conclusion
Percutaneous testicular sperm extraction is a safe, well-tolerated and cost-effective procedure in the management of male-factor infertility related to azoospermia. 相似文献7.
Pedersen SK Harry JL Sebastian L Baker J Traini MD McCarthy JT Manoharan A Wilkins MR Gooley AA Righetti PG Packer NH Williams KL Herbert BR 《Journal of proteome research》2003,2(3):303-311
Abundant and hydrophilic nonmembrane proteins with isoelectric points below pH 8 are the predominant proteins identified in most proteomics projects. In yeast, however, low-abundance proteins make up 80% of the predicted proteome, approximately 50% have pl's above pH 8 and 30% of the yeast ORFs are predicted to encode membrane proteins with at least 1 trans-membrane span. By applying highly solubilizing reagents and isoelectric fractionation to a membrane fraction of yeast we have a purified and identified 780 protein isoforms, representing 323 gene products, including 28% low abundance proteins and 49% membrane or membrane associated proteins. More importantly, considering the frequency and importance of co- and post-translational modifications, the separation of protein isoforms is essential and two-dimensional electrophoresis remains the only technique which offers sufficient resolution to address this at a proteomic level. 相似文献
8.
Roles of hnRNP A1, SR proteins,and p68 helicase in c-H-ras alternative splicing regulation
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Guil S Gattoni R Carrascal M Abián J Stévenin J Bach-Elias M 《Molecular and cellular biology》2003,23(8):2927-2941
Human ras genes play central roles in coupling extracellular signals with complex intracellular networks controlling proliferation, differentiation, and apoptosis, among others processes. c-H-ras pre-mRNA can be alternatively processed into two mRNAs due to the inclusion or exclusion of the alternative exon IDX; this renders two proteins, p21H-Ras and p19H-RasIDX, which differ only at the carboxy terminus. Here, we have characterized some of the cis-acting sequences and trans-acting factors regulating IDX splicing. A downstream intronic silencer sequence (rasISS1), acting in concert with IDX, negatively regulates upstream intron splicing. This effect is mediated, at least in part, by the binding of hnRNP A1. Depletion and add-back experiments in nuclear extracts have confirmed hnRNP A1's inhibitory role in IDX splicing. Moreover, the addition of two SR proteins, SC35 and SRp40, can counteract this inhibition by strongly promoting the splicing of the upstream intron both in vivo and in vitro. Further, the RNA-dependent helicase p68 is also associated with both IDX and rasISS1 RNA, and suppression of p68 expression in HeLa cells by RNAi experiments results in a marked increase of IDX inclusion in the endogenous mRNA, suggesting a role for this protein in alternative splicing regulation. 相似文献
9.
Ippei Kanazawa Lucie Canaff Jad Abi Rafeh Aarti Angrula Jingjing Li Ryan C. Riddle Iris Boraschi-Diaz Svetlana V. Komarova Thomas L. Clemens Monzur Murshed Geoffrey N. Hendy 《The Journal of biological chemistry》2015,290(7):3910-3924
Menin, the product of the multiple endocrine neoplasia type 1 (Men1) tumor suppressor gene, mediates the cell proliferation and differentiation actions of transforming growth factor-β (TGF-β) ligand family members. In vitro, menin modulates osteoblastogenesis and osteoblast differentiation promoted and sustained by bone morphogenetic protein-2 (BMP-2) and TGF-β, respectively. To examine the in vivo function of menin in bone, we conditionally inactivated Men1 in mature osteoblasts by crossing osteocalcin (OC)-Cre mice with floxed Men1 (Men1f/f) mice to generate mice lacking menin in differentiating osteoblasts (OC-Cre;Men1f/f mice). These mice displayed significant reduction in bone mineral density, trabecular bone volume, and cortical bone thickness compared with control littermates. Osteoblast and osteoclast number as well as mineral apposition rate were significantly reduced, whereas osteocyte number was increased. Primary calvarial osteoblasts proliferated more quickly but had deficient mineral apposition and alkaline phosphatase activity. Although the mRNA expression of osteoblast marker and cyclin-dependent kinase inhibitor genes were all reduced, that of cyclin-dependent kinase, osteocyte marker, and pro-apoptotic genes were increased in isolated Men1 knock-out osteoblasts compared with controls. In contrast to the knock-out mice, transgenic mice overexpressing a human menin cDNA in osteoblasts driven by the 2.3-kb Col1a1 promoter, showed a gain of bone mass relative to control littermates. Osteoblast number and mineral apposition rate were significantly increased in the Col1a1-Menin-Tg mice. Therefore, osteoblast menin plays a key role in bone development, remodeling, and maintenance. 相似文献
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