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31.
Clinical,genetic and neuropathological findings in a series of 138 fetuses with a corpus callosum malformation
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![点击此处可从《Birth defects research. Part A, Clinical and molecular teratology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Caroline Alby Valérie Malan Lucile Boutaud Maria Angela Marangoni Bettina Bessières Maryse Bonniere Amale Ichkou Nadia Elkhartoufi Nadia Bahi‐Buisson Pascale Sonigo Anne‐Elodie Millischer Sophie Thomas Yves Ville Michel Vekemans Férechté Encha‐Razavi Tania Attié‐Bitach 《Birth defects research. Part A, Clinical and molecular teratology》2016,106(1):36-46
32.
Alexis De Wever Karim Benzerara Margot Coutaud Graldine Caumes Mlanie Poinsot Friel Skouri‐Panet Thierry Laurent Elodie Duprat Muriel Gugger 《Geobiology》2019,17(6):676-690
Several species of cyanobacteria biomineralizing intracellular amorphous calcium carbonates (ACC) were recently discovered. However, the mechanisms involved in this biomineralization process and the determinants discriminating species forming intracellular ACC from those not forming intracellular ACC remain unknown. Recently, it was hypothesized that the intensity of Ca uptake (i.e., how much Ca was scavenged from the extracellular solution) might be a major parameter controlling the capability of a cyanobacterium to form intracellular ACC. Here, we tested this hypothesis by systematically measuring the Ca uptake by a set of 52 cyanobacterial strains cultured in the same growth medium. The results evidenced a dichotomy among cyanobacteria regarding Ca sequestration capabilities, with all strains forming intracellular ACC incorporating significantly more calcium than strains not forming ACC. Moreover, Ca provided at a concentration of 50 μM in BG‐11 was shown to be limiting for the growth of some of the strains forming intracellular ACC, suggesting an overlooked quantitative role of Ca for these strains. All cyanobacteria forming intracellular ACC contained at least one gene coding for a mechanosensitive channel, which might be involved in Ca influx, as well as at least one gene coding for a Ca2+/H+ exchanger and membrane proteins of the UPF0016 family, which might be involved in active Ca transport either from the cytosol to the extracellular solution or the cytosol toward an intracellular compartment. Overall, massive Ca sequestration may have an indirect role by allowing the formation of intracellular ACC. The latter may be beneficial to the growth of the cells as a storage of inorganic C and/or a buffer of intracellular pH. Moreover, high Ca scavenging by cyanobacteria biomineralizing intracellular ACC, a trait shared with endolithic cyanobacteria, suggests that these cyanobacteria should be considered as potentially significant geochemical reservoirs of Ca. 相似文献
33.
The distribution of residues in a polypeptide sequence is a determinant of aggregation optimized by evolution
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Monsellier E Ramazzotti M de Laureto PP Tartaglia GG Taddei N Fontana A Vendruscolo M Chiti F 《Biophysical journal》2007,93(12):4382-4391
It has been shown that the propensity of a protein to form amyloid-like fibrils can be predicted with high accuracy from the knowledge of its amino acid sequence. It has also been suggested, however, that some regions of the sequences are more important than others in determining the aggregation process. Here, we have addressed this issue by constructing a set of “sequence scrambled” variants of the first 29 residues of horse heart apomyoglobin (apoMb1-29), in which the sequence was modified while maintaining the same amino acid composition. The clustering of the most amyloidogenic residues in one region of the sequence was found to cause a marked increase of the elongation rate (kagg) and a remarkable shortening of the lag phase (tlag) of the fibril growth, as determined by far-UV circular dichroism and thioflavin T fluorescence. We also show that taking explicitly into consideration the presence of aggregation-promoting regions in the predictive methods results in a quantitative agreement between the theoretical and observed kagg and tlag values of the apoMb1-29 variants. These results, together with a comparison between homologous segments from the family of globins, indicate the existence of a negative selection against the clustering of highly amyloidogenic residues in one or few regions of polypeptide sequences. 相似文献
34.
Anne Mouré Elodie Bacou Steffi Bosch Dominique Jegou Apolline Salama David Riochet Olivier Gauthier Gilles Blancho Jean-Paul Soulillou Denis Poncelet Eric Olmos Jean-Marie Bach Mathilde Mosser 《Biotechnology and bioengineering》2019,116(5):1176-1189
The bioartificial pancreas encapsulating pancreatic islets in immunoprotective hydrogel is a promising therapy for Type 1 diabetes. As pancreatic islets are highly metabolically active and exquisitely sensitive to hypoxia, maintaining O2 supply after transplantation remains a major challenge. In this study, we address the O2 limitation by combining silicone-encapsulated CaO2 (silicone-CaO2) to generate O2 with an extracellular hemoglobin O2-carrier coencapsulated with islets. We showed that the hemoglobin improved by 37% the O2-diffusivity through an alginate hydrogel and displayed antioxidant properties neutralizing deleterious reactive O2 species produced by silicone-CaO2. While the hemoglobin alone failed to maintain alginate macroencapsulated neonate pig islets under hypoxia, silicone-CaO2 alone or combined to the hemoglobin restored islet viability and insulin secretion and prevented proinflammatory metabolism (PTGS2 expression). Interestingly, the combination took the advantages of the two individual strategies, improved neonate pig islet viability and insulin secretion in normoxia, and VEGF secretion and PDK1 normalization in hypoxia. Moreover, we confirmed the specific benefits of the combination compared to silicone-CaO2 alone on murine pseudo-islet viability in normoxia and hypoxia. For the first time, our results show the interest of combining an O2 provider with hemoglobin as an effective strategy to overcome O2 limitations in tissue engineering. 相似文献
35.
Bringaud F Biteau N Zuiderwijk E Berriman M El-Sayed NM Ghedin E Melville SE Hall N Baltz T 《Molecular biology and evolution》2004,21(3):520-528
The ingi (long and autonomous) and RIME (short and nonautonomous) non--long-terminal repeat retrotransposons are the most abundant mobile elements characterized to date in the genome of the African trypanosome Trypanosoma brucei. These retrotransposons were thought to be randomly distributed, but a detailed and comprehensive analysis of their genomic distribution had not been performed until now. To address this question, we analyzed the ingi/RIME sequences and flanking sequences from the ongoing T. brucei genome sequencing project (TREU927/4 strain). Among the 81 ingi/RIME elements analyzed, 60% are complete, and 7% of the ingi elements (approximately 15 copies per haploid genome) appear to encode for their own transposition. The size of the direct repeat flanking the ingi/RIME retrotransposons is conserved (i.e., 12-bp), and a strong 11-bp consensus pattern precedes the 5'-direct repeat. The presence of a consensus pattern upstream of the retroelements was confirmed by the analysis of the base occurrence in 294 GSS containing 5'-adjacent ingi/RIME sequences. The conserved sequence is present upstream of ingis and RIMEs, suggesting that ingi-encoded enzymatic activities are used for retrotransposition of RIMEs, which are short nonautonomous retroelements. In conclusion, the ingi and RIME retroelements are not randomly distributed in the genome of T. brucei and are preceded by a conserved sequence, which may be the recognition site of the ingi-encoded endonuclease. 相似文献
36.
El-Sayed NM Ghedin E Song J MacLeod A Bringaud F Larkin C Wanless D Peterson J Hou L Taylor S Tweedie A Biteau N Khalak HG Lin X Mason T Hannick L Caler E Blandin G Bartholomeu D Simpson AJ Kaul S Zhao H Pai G Van Aken S Utterback T Haas B Koo HL Umayam L Suh B Gerrard C Leech V Qi R Zhou S Schwartz D Feldblyum T Salzberg S Tait A Turner CM Ullu E White O Melville S Adams MD Fraser CM Donelson JE 《Nucleic acids research》2003,31(16):4856-4863
37.
Most of the approaches used to correct gene mutations in mammalian cells involve the targeting of short nucleotide molecules to homologous chromosomal sequences and the replacement of resident sequences via homologous recombination and mismatch repair. The limited efficiency and inconsistent reproducibility of these techniques are major constraints to their use in gene therapy. One of the main problems is that it is impossible to obtain reproducible results when the targeted gene loci differ. We investigated the effects of flanking sequences on homologous recombination by means of an in vitro assay of the efficiency of oligonucleotide targeting to its homologous sequence on a large duplex molecule in a reaction catalysed by the Escherichia coli RecA protein. We demonstrated that polypurine·polypyrimidine tracts (PPTs) in duplex DNA strongly stimulate the formation of D-loops with short oligodeoxynucleotides. This result was reproduced with various PPT sequences and oligonucleotides. The stimulatory effect was observed at loci as far as 4000 bp from the PPT. The formation of complexes between the oligonucleotide and the duplex molecule depended on the extent of sequence similarity between the two DNAs and the presence of the RecA protein. The stimulatory effect was inhibited by excess RecA and restored by adding heterologous DNA. We suggest that PPT sequences induce conformational changes in duplex DNA, leading to the aggregation of molecules, facilitating homology searches. We com pared, in vivo, the efficiency of the oligonucleotide-mediated correction of a URA3 chromosomal mutation for sequences with and without a PPT sequence in the vicinity. Consistent with our in vitro results, the efficiency of correction was eight times higher in the presence of the PPT sequence. 相似文献
38.
Duprat F Daw M Lim W Collingridge G Isaac J 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2003,358(1432):715-720
AMPA-type glutamate receptors mediate most fast excitatory synaptic transmissions in the mammalian brain. They are critically involved in the expression of long-term potentiation and long-term depression, forms of synaptic plasticity that are thought to underlie learning and memory. A number of synaptic proteins have been identified that interact with the intracellular C-termini of AMPA receptor subunits. Here, we review recent studies and present new experimental data on the roles of these interacting proteins in regulating the AMPA receptor function during basal synaptic transmission and plasticity. 相似文献
39.
40.
Artiguenave F Wincker P Brottier P Duprat S Jovelin F Scarpelli C Verdier J Vico V Weissenbach J Saurin W 《FEBS letters》2000,487(1):13-16
The generation of sequencing data for the hemiascomycetous yeast random sequence tag project was performed using the procedures established at GENOSCOPE. These procedures include a series of protocols for the sequencing reactions, using infra-red labelled primers, performed on both ends of the plasmid inserts in the same reaction tube, and their analysis on automated DNA sequencers. They also include a package of computer programs aimed at detecting potential assignation errors, selecting good quality sequences and estimating their useful length. 相似文献