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1.
Gutiérrez-Abad R Carbajo D Nolis P Acosta-Silva C Cobos JA Illa O Royo M Ortuño RM 《Amino acids》2011,41(3):673-686
Two diastereomeric series of hybrid γ,γ-peptides derived from conveniently protected derivatives of (1R,2S)- and (1S,2R)-3-amino-2,2-dimethylcyclobutane-1-carboxylic acid and cis-4-amino-l-proline joined in alternation have efficiently been prepared through convergent synthesis. High-resolution NMR experiments
show that these compounds present defined conformations in solution affording very compact structures as the result of intra
and inter residue hydrogen-bonded ring formation. (R,S)-cyclobutane containing peptides adopt more twisted conformations than (S,R) diastereomers. In addition, all these γ-peptides have high tendency to aggregation providing vesicles of nanometric size,
which were stable when allowed to stand for several days, as verified by transmission electron microscopy. 相似文献
2.
Tomàs Pinós Mario Marotta Eduard Gallardo Isabel Illa Jorge Díaz-Manera Emiliano Gonzalez-Vioque Elena García-Arumí Antoni L. Andreu Ramon Martí 《Mitochondrion》2011,11(1):228-233
We report a heteroplasmic novel mutation m.5636T>C in the mt-tRNAAla in a patient with bilateral ptosis and ophthalmoparesis in whom a muscle biopsy showed cytochrome c oxdidase (COX) negative and ragged red fibers. Using laser capture microdissection we have isolated COX negative fibers and COX positive fibers from the muscle of the patient and determined that the mutation load was clearly increased in COX negative muscle fibers. Additionally, the mutated m.5636T nucleotide is conserved in all the mammal and non-mammal species analyzed and might be structurally relevant as it is located in a position involved in the formation of tertiary structure of canonical mitochondrial tRNAs. 相似文献
3.
Epithelia and endothelia delineate tissue compartments and control their environments by regulating the passage of ions and solutes. This barrier function is essential for the development and maintenance of multicellular organisms, and its dysfunction is associated with numerous human diseases. Recent advances in biomaterials and microfabrication technologies have evolved in vitro approaches for modelling biological barriers. Current microphysiological systems have become more efficient and reliable in mimicking the cell microenvironment. Additionally, methods for the quantification of barrier permeability have long provided significant insight into their underlying mechanisms. In this review, we outline the current techniques to quantify the barrier function of engineered tissues, and we also give an overview of recent microphysiological systems of biological barriers that emulate the microenvironment and microarchitecture of native tissues. 相似文献
4.
Marilyne Labasque Bruno Hivert Gisela Nogales-Gadea Luis Querol Isabel Illa Catherine Faivre-Sarrailh 《The Journal of biological chemistry》2014,289(11):7907-7918
Cell adhesion molecules (CAMs) play a crucial role in the formation of the nodes of Ranvier and in the rapid propagation of the nerve impulses along myelinated axons. These CAMs are the targets of autoimmunity in inflammatory neuropathies. We recently showed that a subgroup of patients with aggressive chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) shows autoantibodies to contactin (1). The complex of contactin·Caspr·neurofascin-155 (NF155) enables the formation of paranodal junctions, suggesting that antibody attack against paranodes may participate in the severity of CIDP. In the present study, we mapped the molecular determinants of contactin targeted by the autoantibodies. In three patients, immunoreactivity was directed against the Ig domains of contactin and was dependent on N-glycans. The serum of one patient was selectively directed against contactin bearing mannose-rich N-glycans. Strikingly, the oligomannose type sugars of contactin are required for association with its glial partner NF155 (2). To investigate precisely the role of contactin N-glycans, we have mutated each of the nine consensus N-glycosylation sites independently. We found that the mutation of three sites (N467Q/N473Q/N494Q) in Ig domain 5 of contactin prevented soluble NF155-Fc binding. In contrast, these mutations did not abolish cis-association with Caspr. Next, we showed that the cluster of N-glycosylation sites (Asn-467, Asn-473, and Asn-494) was required for immunoreactivity in one patient. Using cell aggregation assays, we showed that the IgGs from the four CIDP patients prevented adhesive interaction between contactin·Caspr and NF155. Importantly, we showed that the anti-contactin autoantibodies induced alteration of paranodal junctions in myelinated neuronal culture. These results strongly suggest that antibodies to CAMs may be pathogenic and induce demyelination via functional blocking activity. 相似文献
5.
Cristin L. Bruce Illa L. Amerson Richard L. Johnson Paul C. Johnson 《Bioremediation Journal》2001,5(4):337-347
A diagnostic test designed to assess air distribution and oxygen delivery rate to the aquifer during in situ air sparging (IAS) is described. The conservative tracer gas, sulfur hexafluoride (SF6), is added upstream of the air injection manifold during steady IAS operation and groundwater samples are collected from the target treatment zone after some time period (usually 4 to 24 h). The appearance of SF6 in groundwater is used to characterize the air distribution in the target treatment zone, while the SF6 concentration increase with time is used to assess oxygen transfer rates to the target treatment zone. Conversion from SF6 concentration to oxygen mass transfer rate involves correcting the SF6 concentration increase over time for differences in the relevant chemical properties and injection air concentration. Data presented from a field demonstration site illustrate the utility of this test for identifying air distribution details not readily identified by deep vadose zone helium and groundwater pressure transducer response tests. Oxygen transfer rates at this site ranged from 0 to 20 mg-O2/L-H2O/d. Finally, a comparison of short-term SF6 test data with longer-term dissolved oxygen data illustrated this test's utility for anticipating long-term dissolved oxygen distributions. 相似文献
6.
Oikonomopoulou K Hansen KK Saifeddine M Vergnolle N Tea I Blaber M Blaber SI Scarisbrick I Diamandis EP Hollenberg MD 《Biological chemistry》2006,387(6):817-824
We tested the hypothesis that human tissue kallikreins (hKs) may regulate signal transduction by cleaving and activating proteinase-activated receptors (PARs). We found that hK5, 6 and 14 cleaved PAR N-terminal peptide sequences representing the cleavage/activation motifs of human PAR1 and PAR2 to yield receptor-activating peptides. hK5, 6 and 14 activated calcium signalling in rat PAR2-expressing (but not background) KNRK cells. Calcium signalling in HEK cells co-expressing human PAR1 and PAR2 was also triggered by hK14 (via PAR1 and PAR2) and hK6 (via PAR2). In isolated rat platelets that do not express PAR1, but signal via PAR4, hK14 also activated PAR-dependent calcium signalling responses and triggered aggregation. The aggregation response elicited by hK14 was in contrast to the lack of aggregation triggered by hK5 and 6. hK14 also caused vasorelaxation in a phenylephrine-preconstricted rat aorta ring assay and triggered oedema in an in vivo model of murine paw inflammation. We propose that, like thrombin and trypsin, the kallikreins must now be considered as important 'hormonal' regulators of tissue function, very likely acting in part via PARs. 相似文献
7.
Hernández Tienda Clara Beltrán Francés Víctor Majolo Bonaventura Romero Teresa Illa Maulany Risma Oka Ngakan Putu Amici Federica 《International journal of primatology》2021,42(4):528-532
International Journal of Primatology - Snake predation is considered an important evolutionary force for primates. Yet, very few studies have documented encounters between primates and snakes in... 相似文献
8.
Küster A Tea I Ferchaud-Roucher V Le Borgne S Plouzennec C Winer N Rozé JC Robins RJ Darmaun D 《PloS one》2011,6(11):e27626
Background
Depletion of blood glutathione (GSH), a key antioxidant, is known to occur in preterm infants.Objective
Our aim was to determine: 1) whether GSH depletion is present at the time of birth; and 2) whether it is associated with insufficient availability of cysteine (cys), the limiting GSH precursor, or a decreased capacity to synthesize GSH.Methodology
Sixteen mothers delivering very low birth weight infants (VLBW), and 16 mothers delivering healthy, full term neonates were enrolled. Immediately after birth, erythrocytes from umbilical vein, umbilical artery, and maternal blood were obtained to assess GSH [GSH] and cysteine [cys] concentrations, and the GSH synthesis rate was determined from the incorporation of labeled cysteine into GSH in isolated erythrocytes ex vivo, measured using gas chromatography mass spectrometry.Principal Findings
Compared with mothers delivering at full term, mothers delivering prematurely had markedly lower erythrocyte [GSH] and [cys] and these were significantly depressed in VLBW infants, compared with term neonates. A strong correlation was found between maternal and fetal GSH and cysteine levels. The capacity to synthesize GSH was as high in VLBW as in term infants.Conclusion
The current data demonstrate that: 1) GSH depletion is present at the time of birth in VLBW infants; 2) As VLBW neonates possess a fully active capacity to synthesize glutathione, the depletion may arise from inadequate cysteine availability, potentially due to maternal depletion. Further studies would be needed to determine whether maternal-fetal cysteine transfer is decreased in preterm infants, and, if so, whether cysteine supplementation of mothers at risk of delivering prematurely would strengthen antioxidant defense in preterm neonates. 相似文献9.
We describe a unique, versatile bioreactor consisting of two plates and a modified commercial porous membrane suitable for in vitro analysis of the liver sinusoid. The modular bioreactor allows i) excellent control of the cell seeding process; ii) cell culture under controlled shear stress stimulus, and; iii) individual analysis of each cell type upon completion of the experiment. The advantages of the bioreactor detailed here are derived from the modification of a commercial porous membrane with an elastomeric wall specifically moulded in order to define the cell culture area, to act as a gasket that will fit into the bioreactor, and to provide improved mechanical robustness. The device presented herein has been designed to simulate the in vivo organization of a liver sinusoid and tested by co-culturing endothelial cells (EC) and hepatic stellate cells (HSC). The results show both an optimal morphology of the endothelial cells as well as an improvement in the phenotype of stellate cells, most probably due to paracrine factors released from endothelial cells. This device is proposed as a versatile, easy-to-use co-culture system that can be applied to biomedical research of vascular systems, including the liver. 相似文献
10.
Tea I Le Gall G Küster A Guignard N Alexandre-Gouabau MC Darmaun D Robins RJ 《PloS one》2012,7(1):e29947