295 research outputs found
Le cÎne kÀhlérien d'une surface
AbstractWe use Demailly's regularization theorem and cut-off theorems (Siu, Bassanelli) to prove a âZariski decompositionâ for positive d- or ddc-closed currents on a compact complex surface.For a compact KĂ€hler surface, we get a NakaiâMoishezon type characterization of the KĂ€hler cone
Synthesis of glutathione analogues and screening as substrates & inhibitors for human glutathione transferase p1â1
A major detoxification mechanism of the cell involves the glutathione transferase (GST)âcatalyzed formation of glutathione (GSH) conjugates with various xenobiotics Based on the same mechanism, GST overexpression may lead to multidrug resistant phenotypes Therefore, several compounds with inhibitory potency against GSTs have been developed as potential tools fortackling GST-Ââattributed MDR. Several individual compounds and prodrugs have been proposed as GSTâinhibiting substances. In addition, GSH analogues have been considered as specific GST inhibitors, with particular attention been directed towards the synthesis of GSH analogues stable against Îłâglutamyltranspeptidase (ÎłGT) and peptidases, as GST inhibitors
Taxonomy and chemical characterization of new antibiotics produced by Saccharothrix SA198 isolated from a Saharan soil
Actinomycete strain SA198, isolated from a Saharan soil sample of Algeria, exhibited antimicrobial activity
against Gram-positive and Gram-negative bacteria, and phytopathogenic and toxinogenic fungi. The
morphological and chemotaxonomic characteristics of the strain were consistent with those of the genus
Saccharothrix. Analysis of the 16S rRNA gene sequence of strain SA198 showed a similarity level ranging
between 97.2 and 98.8% within Saccharothrix species, S. australiensis being the most closely related. Two
new active products were isolated by reverse HPLC using a C18 column. The ultravioletâvisible (UVâVIS),
infrared (IR), mass, and 1Hand 14C nuclear magnetic resonance (NMR) spectra showed that these products
were new bioactive compounds. The minimum inhibitory concentrations of these antibiotics showed a
strong activity against fungi and moderate activities against Gram-positive and Gram-negative bacteria
LES UVEITES DE LâENFANT : A PROPOS DE 30 CAS
Uveitis is less frequent in children. The purpose of our study is to evaluate epidemiologic aspect, etiological profile and prognosis of children uveitis.We report 30 cases of uveitis in patients aged less than 16 years old followed in our department.Patients mean age is 9 years old (5 to 16 years) .We observed anterior uveitis in 46,7%, posterior uveitis in 26,7%, intermediate uveitis in 13,3% and panuveitis in 13,3%.Chronic juvenile arthritis is the main etiology followed by Behcet disease.Uveitis in children is rare but severe and can involve visual prognosis; it needs urgent diagnosis and adapted treatment. Principals etiologies are; idiopathic juvenile arthritis and spondiloarthropaties. Functional prognosis is variable and final visual acuity is less than 20/200 in 16 to 36% of cases.LâuvĂ©ite de lâenfant est rare. Le but de notre travail est dâĂ©valuer le profil Ă©pidĂ©miologique, Ă©tiologique et pronostic des uvĂ©ites de lâenfant.Nous rapportons 30 cas dâuvĂ©ites chez des patients dâĂąge infĂ©rieur Ă 16 ans et suivis dans notre unitĂ©.La moyenne dâĂąge des patients est de 9 ans (5 Ă 16 ans). Il sâagissait dâune uvĂ©ite antĂ©rieure dans 46,7% des cas, dâune uvĂ©ite postĂ©rieure dans 26,7%, dâune uvĂ©ite intermĂ©diaire dans 13,3% et dâune panuvĂ©ite dans 13,3%. Les principales causes retrouvĂ©es sont lâarthrite juvĂ©nile idiopathique suivie par la maladie de Behçet.LâuvĂ©ite de lâenfant est rare souvent grave engageant le pronostic visuel et imposant un diagnostic prĂ©coce et un traitement adaptĂ©. Les principales Ă©tiologies sont lâarthrite juvĂ©nile idiopathique et les spondyloarthropathies. Le pronostic visuel est variable et lâacuitĂ© visuelle est infĂ©rieure Ă 20/200 dans 16 Ă 36% des cas
Visualization of grapevine root colonization by the Saharan soil isolate Saccharothrix algeriensis NRRL B-24137 using DOPE-FISH microscopy
Background and aim There is currently a gap of
knowledge regarding whether some beneficial bacteria
isolated from desert soils can colonize epi- and
endophytically plants of temperate regions. In this
study, the early steps of the colonization process of
one of these bacteria, Saccharothrix algeriensis NRRL
B-24137, was studied on grapevine roots to determine
if this beneficial strain can colonize a non-natural host
plant. An improved method of fluorescence in situ
hybridization (FISH), the double labeling of oligonucleotide
probes (DOPE)-FISH technique was used to
visualize the colonization behavior of such bacteria as well as to determine if the method could be used to
track microbes on and inside plants.
Methods A probe specific to Saccharothrix spp. was
firstly designed. Visualization of the colonization behavior
of S. algeriensis NRRL B-24137 on and inside
roots of grapevine plants was then carried out with
DOPE-FISH microscopy.
Results The results showed that 10 days after inoculation,
the strain could colonize the root hair zone, root
elongation zone, as well as root emergence sites by
establishing different forms of bacterial structures as
revealed by the DOPE-FISH technique. Further observations
showed that the strain could be also endophytic
inside the endorhiza of grapevine plants.
Conclusions Taking into account the natural niches of
this beneficial strain, this study exemplifies that, in
spite of its isolation from desert soil, the strain can
establish populations as well as subpopulations on and
inside grapevine plants and that the DOPE-FISH tool
can allow to detect it
Contribution of Chondroitin Sulfate A to the Binding of Complement Proteins to Activated Platelets
Exposure of chondroitin sulfate A (CS-A) on the surface of activated platelets is well established. The aim of the present study was to investigate to what extent CS-A contributes to the binding of the complement recognition molecule C1q and the complement regulators C1 inhibitor (C1INH), C4b-binding protein (C4BP), and factor H to platelets.Human blood serum was passed over Sepharose conjugated with CS-A, and CS-A-specific binding proteins were identified by Western blotting and mass spectrometric analysis. C1q was shown to be the main protein that specifically bound to CS-A, but C4BP and factor H were also shown to interact. Binding of C1INH was dependent of the presence of C1q and then not bound to CS-A from C1q-depleted serum. The specific interactions observed of these proteins with CS-A were subsequently confirmed by surface plasmon resonance analysis using purified proteins. Importantly, C1q, C4BP, and factor H were also shown to bind to activated platelets and this interaction was inhibited by a CS-A-specific monoclonal antibody, thereby linking the binding of C1q, C4BP, and factor H to exposure of CS-A on activated platelets. CS-A-bound C1q was also shown to amplify the binding of model immune complexes to both microtiter plate-bound CS-A and to activated platelets.This study supports the concept that CS-A contributes to the binding of C1q, C4BP, and factor H to platelets, thereby adding CS-A to the previously reported binding sites for these proteins on the platelet surface. CS-A-bound C1q also seems to amplify the binding of immune complexes to activated platelets, suggesting a role for this molecule in immune complex diseases
Spintronics: Fundamentals and applications
Spintronics, or spin electronics, involves the study of active control and
manipulation of spin degrees of freedom in solid-state systems. This article
reviews the current status of this subject, including both recent advances and
well-established results. The primary focus is on the basic physical principles
underlying the generation of carrier spin polarization, spin dynamics, and
spin-polarized transport in semiconductors and metals. Spin transport differs
from charge transport in that spin is a nonconserved quantity in solids due to
spin-orbit and hyperfine coupling. The authors discuss in detail spin
decoherence mechanisms in metals and semiconductors. Various theories of spin
injection and spin-polarized transport are applied to hybrid structures
relevant to spin-based devices and fundamental studies of materials properties.
Experimental work is reviewed with the emphasis on projected applications, in
which external electric and magnetic fields and illumination by light will be
used to control spin and charge dynamics to create new functionalities not
feasible or ineffective with conventional electronics.Comment: invited review, 36 figures, 900+ references; minor stylistic changes
from the published versio
Recommended from our members
Association of Genetic Variants With Primary Open-Angle Glaucoma Among Individuals With African Ancestry.
Importance:Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders. Objectives:To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma. Design, Settings, and Participants:A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14âŻ917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma. Exposures:Genetic variants associated with primary open-angle glaucoma. Main Outcomes and Measures:Presence of primary open-angle glaucoma. Genome-wide significance was defined as Pâ<â5âĂâ10-8 in the discovery stage and in the meta-analysis of combined discovery and validation data. Results:A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-ÎČ A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; Pâ=â2âĂâ10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14âŻ917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; Pâ<â.001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; Pâ=â4âĂâ10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry. Conclusions and Relevance:In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies
Transcriptome sequencing of three Pseudo-nitzschia species reveals comparable gene sets and the presence of Nitric Oxide Synthase genes in diatoms
Diatoms are among the most diverse eukaryotic microorganisms on Earth, they are responsible for a large fraction of primary production in the oceans and can be found in different habitats. Pseudo-nitzschia are marine planktonic diatoms responsible for blooms in coastal and oceanic waters. We analyzed the transcriptome of three species, Pseudo-nitzschia arenysensis, Pseudo-nitzschia delicatissima and Pseudo-nitzschia multistriata, with different levels of genetic relatedness. These species have a worldwide distribution and the last one produces the neurotoxin domoic acid. We were able to annotate about 80% of the sequences in each transcriptome and the analysis of the relative functional annotations allowed comparison of the main metabolic pathways, pathways involved in the biosynthesis of isoprenoids (MAV and MEP pathways), and pathways putatively involved in domoic acid synthesis. The search for homologous transcripts among the target species and other congeneric species resulted in the discovery of a sequence annotated as Nitric Oxide Synthase (NOS), found uniquely in Pseudo-nitzschia multistriata. The predicted protein product contained all the domains of the canonical metazoan sequence. Putative NOS sequences were found in other available diatom datasets, supporting a role for nitric oxide as signaling molecule in this group of microalgae
Bioencapsulation and Colonization Characteristics of Lactococcus lactis subsp. lactis CF4MRS in Artemia franciscana: a Biological Approach for the Control of Edwardsiellosis in Larviculture
Predominance of beneficial bacteria helps to establish a healthy microbiota in fish gastrointestinal system and thus to reduce emerging pathogen. In this study, the colonization efficacy of Lactococcus lactis subsp. lactis CF4MRS in Artemia franciscana and its potential as a probiotic in suppressing Edwardsiella sp. infection were investigated in vivo. The colonization extent of the bioencapsulated L. lactis was established through visualization of gfp gene-transformed L. lactis in A. franciscana. Here, we demonstrate that when A. franciscana is administrated with L. lactis at 108 CFU mLâ1 for 8 h, the highest relative percentage of survival (RPS =â50.0) is observed after inoculation with Edwardsiella sp. The total counts of L. lactis entrapped in Artemia were the highest (ranged from 3.2 to 5.1âĂâ108 CFU mLâ1), when 108â109 CFU mLâ1 of L. lactis was used as starting inoculum, with the bioencapsulation performed within 8â24 h. Fluorescent microscopy showed gfp-transformed L. lactis colonized the external trunk surfaces, mid-gut and locomotion antennules of the A. franciscana nauplii. These illustrations elucidate the efficiency of colonization of L. lactis in the gastrointestinal tract and on the body surfaces of Artemia. In conclusion, L. lactis subsp. lactis CF4MRS shows a good efficacy of colonization in Artemia and has the potential for biocontrol/probiotic activity against Edwardsiella sp. infection
- âŠ