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71.
Morales R Berna A Carpentier P Contreras-Martel C Renault F Nicodeme M Chesne-Seck ML Bernier F Dupuy J Schaeffer C Diemer H Van-Dorsselaer A Fontecilla-Camps JC Masson P Rochu D Chabriere E 《Structure (London, England : 1993)》2006,14(3):601-609
We report the serendipitous discovery of a human plasma phosphate binding protein (HPBP). This 38 kDa protein is copurified with the enzyme paraoxonase. Its X-ray structure is similar to the prokaryotic phosphate solute binding proteins (SBPs) associated with ATP binding cassette transmembrane transporters, though phosphate-SBPs have never been characterized or predicted from nucleic acid databases in eukaryotes. However, HPBP belongs to the family of ubiquitous eukaryotic proteins named DING, meaning that phosphate-SBPs are also widespread in eukaryotes. The systematic absence of complete genes for eukaryotic phosphate-SBP from databases is intriguing, but the astonishing 90% sequence conservation between genes belonging to evolutionary distant species suggests that the corresponding proteins play an important function. HPBP is the only known transporter capable of binding phosphate ions in human plasma and may become a new predictor of or a potential therapeutic agent for phosphate-related diseases such as atherosclerosis. 相似文献
72.
Mercier A Devillard S Ngoubangoye B Bonnabau H Bañuls AL Durand P Salle B Ajzenberg D Dardé ML 《PLoS neglected tropical diseases》2010,4(11):e876
Background
Toxoplasma gondii is found worldwide, but distribution of its genotypes as well as clinical expression of human toxoplasmosis varies across the continents. Several studies in Europe, North America and South America argued for a role of genotypes in the clinical expression of human toxoplasmosis. Genetic data concerning T. gondii isolates from Africa are scarce and not sufficient to investigate the population structure, a fundamental analysis for a better understanding of distribution, circulation, and transmission.Methodology/Principal Findings
Seropositive animals originating from urban and rural areas in Gabon were analyzed for T. gondii isolation and genotyping. Sixty-eight isolates, including one mixed infection (69 strains), were obtained by bioassay in mice. Genotyping was performed using length polymorphism of 13 microsatellite markers located on 10 different chromosomes. Results were analyzed in terms of population structure by Bayesian statistical modeling, Neighbor-joining trees reconstruction based on genetic distances, F ST and linkage disequilibrium. A moderate genetic diversity was detected. Three haplogroups and one single genotype clustered 27 genotypes. The majority of strains belonged to one haplogroup corresponding to the worldwide Type III. The remaining strains were distributed into two haplogroups (Africa 1 and 3) and one single genotype. Mouse virulence at isolation was significantly different between haplogroups. Africa 1 haplogroup was the most virulent.Conclusion
Africa 1 and 3 haplogroups were proposed as being new major haplogroups of T. gondii circulating in Africa. A possible link with strains circulating in South and Central America is discussed. Analysis of population structure demonstrated a local spread within a rural area and strain circulation between the main cities of the country. This circulation, favored by human activity could lead to genetic exchanges. For the first time, key epidemiological questions were addressed for the West African T. gondii population, using the high discriminatory power of microsatellite markers, thus creating a basis for further epidemiological and clinical investigations. 相似文献73.
Tan-Trung Nguyen Noelya Planchard Jennifer Dahan Nadge Arnal Sandrine Balzergue Abdelilah Benamar Pierre Bertin Vronique Brunaud Cline Dargel-Graffin David Macherel Marie-Laure Martin-Magniette Martine Quadrado Olivier Namy Hakim Mireau 《Molecular biology and evolution》2021,38(8):3445
The high mutational load of mitochondrial genomes combined with their uniparental inheritance and high polyploidy favors the maintenance of deleterious mutations within populations. How cells compose and adapt to the accumulation of disadvantageous mitochondrial alleles remains unclear. Most harmful changes are likely corrected by purifying selection, however, the intimate collaboration between mitochondria- and nuclear-encoded gene products offers theoretical potential for compensatory adaptive changes. In plants, cytoplasmic male sterilities are known examples of nucleo-mitochondrial coadaptation situations in which nuclear-encoded restorer of fertility (Rf) genes evolve to counteract the effect of mitochondria-encoded cytoplasmic male sterility (CMS) genes and restore fertility. Most cloned Rfs belong to a small monophyletic group, comprising 26 pentatricopeptide repeat genes in Arabidopsis, called Rf-like (RFL). In this analysis, we explored the functional diversity of RFL genes in Arabidopsis and found that the RFL8 gene is not related to CMS suppression but essential for plant embryo development. In vitro-rescued rfl8 plantlets are deficient in the production of the mitochondrial heme–lyase complex. A complete ensemble of molecular and genetic analyses allowed us to demonstrate that the RFL8 gene has been selected to permit the translation of the mitochondrial ccmFN2 gene encoding a heme–lyase complex subunit which derives from the split of the ccmFN gene, specifically in Brassicaceae plants. This study represents thus a clear case of nuclear compensation to a lineage-specific mitochondrial genomic rearrangement in plants and demonstrates that RFL genes can be selected in response to other mitochondrial deviancies than CMS suppression. 相似文献
74.
Jassey VE Chiapusio G Mitchell EA Binet P Toussaint ML Gilbert D 《Microbial ecology》2011,61(2):374-385
The ecology of peatland testate amoebae is well studied along broad gradient from very wet (pool) to dry (hummock) micro-sites
where testate amoebae are often found to respond primarily to the depth to water table (DWT). Much less is known on their
responses to finer-scale gradients, and nothing is known of their possible response to phenolic compounds, which play a key
role in carbon storage in peatlands. We studied the vertical (0–3, 3–6, and 6–9 cm sampling depths) micro-distribution patterns
of testate amoebae in the same microhabitat (Sphagnum fallax lawn) along a narrow ecological gradient between a poor fen with an almost flat and homogeneous Sphagnum carpet (fen) and a “young bog” (bog) with more marked micro-topography and mosaic of poor fen and bog vegetation. We analyzed
the relationships between the testate amoeba data and three sets of variables (1) “chemical” (pH, Eh potential, and conductivity),
(2) “physical” (water temperature, altitude, i.e., Sphagnum mat micro-topography, and DWT), and (3) phenolic compounds in/from Sphagnum (water-soluble and primarily bound phenolics) as well as the habitat (fen/bog) and the sampling depth. Testate amoeba Shannon
H′ diversity, equitability J of communities, and total density peaked in lower parts of Sphagnum, but the patterns differed between the fen and bog micro-sites. Redundancy analyses revealed that testate amoeba communities
differed significantly in relation to Eh, conductivity, water temperature, altitude, water-soluble phenolics, habitat, and
sampling depth, but not to DWT, pH, or primarily bound phenolics. The sensitivity of testate amoebae to weak environmental
gradients makes them particularly good integrators of micro-environmental variations and has implications for their use in
paleoecology and environmental monitoring. The correlation between testate amoeba communities and the concentration of water-soluble
phenolic suggests direct (e.g., physiological) and/or indirect (e.g., through impact on prey organisms) effects on testate
amoebae, which requires further research. 相似文献
75.
A new sporulated fermentative bacterium designated strain E1(T) (T=type strain), was isolated from an anaerobic mud of an olive mill wastewater basin contaminated by phosphogypse produced by a Tunisian factory. Strain E1(T) was a motile Gram-positive slightly curved rod with spherical terminal spore swelling the cell. It grew between 18 degrees C and 43 degrees C with an optimum at 37 degrees C and pH 7.8 (range 5.5-8.7), without NaCl (range 0-3%). Strain E1(T) was a chemoorganotrophic anaerobic bacterium fermenting only proteins and amino acids. Yeast extract was required for growth. Elemental sulfur was used as terminal electron acceptor. The G+C content of the DNA was 32.6 mol%. The closest phylogenetical relatives of strain E1(T) were Clostridium thiosulfatireducens and C. subterminale (97.3% similarity for partial rRNA gene sequences). DNA-DNA hybridization values between strain E1(T) and both species were 17% and 20.8%, respectively. On the basis of differences in genotypic and phenotypic characteristics, strain E1(T) (DSM 15206(T), CIP 107666(T)) is proposed as the type strain of a new species, C. tunisiense sp. nov. GenBank accession number for the 16S rRNA gene sequence of strain E1(T) is AY187622. 相似文献
76.
Hicham Benzekri Paula Armesto Xavier Cousin Mireia Rovira Diego Crespo Manuel Alejandro Merlo David Mazurais Rocío Bautista Darío Guerrero-Fernández Noe Fernandez-Pozo Marian Ponce Carlos Infante Jose Luis Zambonino Sabine Nidelet Marta Gut Laureana Rebordinos Josep V Planas Marie-Laure Bégout M Gonzalo Claros Manuel Manchado 《BMC genomics》2014,15(1)
77.
Aymeric Ravel-Chapuis Tara E. Crawford Marie-Laure Blais-Crépeau Guy Bélanger Chase T. Richer Bernard J. Jasmin 《Molecular biology of the cell》2014,25(23):3765-3778
Recent work has shown that Staufen1 plays key roles in skeletal muscle, yet little is known about its pattern of expression during embryonic and postnatal development. Here we first show that Staufen1 levels are abundant in mouse embryonic muscles and that its expression decreases thereafter, reaching low levels in mature muscles. A similar pattern of expression is seen as cultured myoblasts differentiate into myotubes. Muscle degeneration/regeneration experiments revealed that Staufen1 increases after cardiotoxin injection before returning to the low levels seen in mature muscles. We next prevented the decrease in Staufen1 during differentiation by generating stable C2C12 muscle cell lines overexpressing Staufen1. Cells overexpressing Staufen1 differentiated poorly, as evidenced by reductions in the differentiation and fusion indices and decreases in MyoD, myogenin, MEF2A, and MEF2C, independently of Staufen-mediated mRNA decay. However, levels of c-myc, a factor known to inhibit differentiation, were increased in C2C12 cells overexpressing Staufen1 through enhanced translation. By contrast, the knockdown of Staufen1 decreased c-myc levels in myoblasts. Collectively our results show that Staufen1 is highly expressed during early stages of differentiation/development and that it can impair differentiation by regulating c-myc, thereby highlighting the multifunctional role of Staufen1 in skeletal muscle cells. 相似文献
78.
Ikram Ghouili Seyma Bahdoudi Fabrice Morin Fatma Amri Yosra Hamdi Pierre Michael Coly Marie-Laure Walet-Balieu Jérôme Leprince Sami Zekri Hubert Vaudry David Vaudry Mohamed Amri Marie-Christine Tonon Olfa Masmoudi-Kouki 《Molecular neurobiology》2018,55(6):4596-4611
Astroglial cells are important actors in the defense of brain against oxidative stress injuries. Glial cells synthesize and release the octadecaneuropeptide ODN, a diazepam-binding inhibitor (DBI)-related peptide, which acts through its metabotropic receptor to protect neurons and astrocytes from oxidative stress-induced apoptosis. The purpose of the present study is to examine the contribution of the endogenous ODN in the protection of astrocytes and neurons from moderate oxidative stress. The administration of H2O2 (50 μM, 6 h) induced a moderate oxidative stress in cultured astrocytes, i.e., an increase in reactive oxygen species, malondialdehyde, and carbonyl group levels, but it had no effect on astrocyte death. Mass spectrometry and QPCR analysis revealed that 50 μM H2O2 increased ODN release and DBI mRNA levels. The inhibition of ODN release or pharmacological blockage of the effects of ODN revealed that in these conditions, 50 μM H2O2 induced the death of astrocytes. The transfection of astrocytes with DBI siRNA increased the vulnerability of cells to moderate stress. Finally, the addition of 1 nM ODN to culture media reversed cell death observed in DBI-deficient astrocytes. The treatment of neurons with media from 50 μM H2O2-stressed astrocytes significantly reduced the neuronal death induced by H2O2; this effect is greatly attenuated by the administration of an ODN metabotropic receptor antagonist. Overall, these results indicate that astrocytes produce authentic ODN, notably in a moderate oxidative stress situation, and this glio- and neuro-protective agent may form part of the brain defense mechanisms against oxidative stress injury. 相似文献
79.
80.
Summary A technique is described for the immobilization of active glutamate dehydrogenase (GDH) on behenic acid Langmuir-Blodgett (LB) films. The optimization of the immobilization conditions shows that the activities of GDH bound on hydrophobic and hydrophilic LB films were similar and decreased dramatically when the immobilized enzyme was dried. The GDH binding was followed by Fourier transform infrared (FTIR) spectroscopy. Modifications of GDH conformation and LB film structure were observed during the enzyme binding. After GDH activity test, a partial dissociation of behenic acid occurred and the -sheet band of the enzyme increased by comparison with the -helix band.Abbreviations LB
Langmuir-Blodgett
- FTIR spectroscopy
Fourier transform infrared spectroscopy
- GDH
glutamate dehydrogenase
- TEA
triethylamine 相似文献