Use of CV and XTT to screen biofilm susceptibility to new QAC's compounds

This study evaluates the biocide ability of new quaternary ammonium compounds, against Pseudomonas fluorescens (a Gram- bacterium) and Staphylococcus sciuri (a Gram+ bacterium) biofilms. For comparison purposes the results were compared with the data obtained with a commercial QAC, cetyltrimethylammonium bromide (CTAB), often used in the sanitation of medical and industrial surfaces. The effect of the QAC´s preconditioning of the adhesion surfaces was also assessed. The new series of fluorinated ammonium compounds were achieved by the introduction of new molecular parameters in the chemical structure of the traditional surfactant, and catalogued as MF 6.8, AB 6.6 and A 6.8 according their chemical nature. The modified microtiter plate technique, using crystal violet (CV), together with the colorimetric assay using 2,3-bis (2-methoxy-4-nitro-5- sulfophenyl)-2H-tetrazolium-5-carboxanilide sodium (XTT) salt, was used to assess, respectively, the total attached biomass and respiratory activity of the biofilms. The results showed that the application of the new compounds, as well as CTAB, did not cause biomass removal, regardless the biofilm-formed bacterium. In fact, the contact of the biofilms with all the QAC´s results, in general, in an increase of the amount of the biofilm mass adhered to the wells of the microtiter plate, being the increase more evident for S. sciuri biofilms. Concerning respiratory activity, biofilms formed by the S. sciuri bacteria presents a different response to the QAC´s treatment when compared with the P.fluorescens biofilms. Conversely to P.fluorescens biofilms, the activity of the S. sciuri biofilms was significantly reduced after the application of the fluorinated ammonium compounds, even if total inactivation was not achieved. The treatment with CTAB resulted in the preservation or increase of the respiratory activity of both biofilms. The conditioning of the wells of the microtiter plate with the QAC´s, for 30 min, changed biofilms response to the antimicrobial products, specially noticed in terms of respiratory activity. The application of the QAC´s to the biofilms formed on the conditioning wells stills to increase the amount of the adhered biomass, independently of the kind of biofilmforming bacteria, but it reduces drastically the respiratory activity of the S. sciuri biofilms. In the latter, AB 6.6 caused total inactivation (MBC = 0.3 mM). Concerning P. fluorescens biofilms, the respiratory reduction is only observed for higher QAC´s concentrations and clearly in a less extent that the one observed with the S. sciuri biofilms. Regarding CTAB, the conditioning of the wells did not cause any significant alteration of biofilms susceptibility. The overall results showed that the new QAC´s compounds seems to have a promising better sanitation action than the traditional one, even though none of them presents both marked biofilm removal and biofilm inactivation at once. The results also highlighted that biofilms formed by a Gram- bacterium are more resistant than the ones formed by a Gram+ microrganism

The Syndrome of Arthrogryposis and Palatoschisis (SAP) in Charolais cattle; Abnormal motor innervation and defect in the focalization of 16 S acetylcholinesterase in the end-plates rich regions of the muscle

International audienc

Branched Hydrocarbon Low Surface Energy Materials for Superhydrophobic Nanoparticle Derived Surfaces

International audienceWe present a new class of superhydrophobic surfaces created from low-cost and easily synthesized aluminum oxide nanoparticles functionalized carboxylic acids having highly branched hydrocarbon (HC) chains. These branched chains are new low surface energy materials (LSEMs) which can replace environmentally hazardous and expensive fluorocarbons (FCs). Regardless of coating method and curing temperature, the resulting textured surfaces develop water contact angles (θ) of ~155° and root-mean-square roughnesses (Rq) ≈ 85 nm, being comparable with equivalent FC functionalized surfaces (θ = 157º and Rq = 100 nm). The functionalized nanoparticles may be coated onto a variety of substrates to generate different superhydrophobic materials

Synthesis and Properties New Derivatives of 3,4-Phenylenedioxythiophene

This work was supported by the Russian President PhD Scholarship for studying abroad and by an Act 211 Government of the Russian Federation for financial support (contract No 02.A03.21.0006)

A large-scale study of the random variability of a coding sequence: a study on the CFTR gene

Coding single nucleotide substitutions (cSNSs) have been studied on hundreds of genes using small samples (ngapproximate to100-150 genes). In the present investigation, a large random European population sample (average ngapproximate to1500) was studied for a single gene, the CFTR ( Cystic Fibrosis Transmembrane conductance Regulator). The nonsynonymous (NS) substitutions exhibited, in accordance with previous reports, a mean probability of being polymorphic (q>0.005), much lower than that of the synonymous ( S) substitutions, but they showed a similar rate of subpolymorphic (q<0.005) variability. This indicates that, in autosomal genes that may have harmful recessive alleles (nonduplicated genes with important functions), genetic drift overwhelms selection in the subpolymorphic range of variability, making disadvantageous alleles behave as neutral. These results imply that the majority of the subpolymorphic nonsynonymous alleles of these genes are selectively negative or even pathogenic

Are p.I148T, p.R74W and p.D1270N cystic fibrosis causing mutations ?

BACKGROUND: To contribute further to the classification of three CFTR amino acid changes (p.I148T, p.R74W and p.D1270N) either as CF or CBAVD-causing mutations or as neutral variations. METHODS: The CFTR genes from individuals who carried at least one of these changes were extensively scanned by a well established DGGE assay followed by direct sequencing and familial segregation analysis of mutations and polymorphisms. RESULTS: Four CF patients (out of 1238) originally identified as carrying the p.I148T mutation in trans with a CF mutation had a second mutation (c.3199del6 or a novel mutation c.3395insA) on the p.I148T allele. We demonstrate here that the deletion c.3199del6 can also be associated with CF without p.I148T. Three CBAVD patients originally identified with the complex allele p.R74W-p.D1270N were also carrying p.V201M on this allele, by contrast with non CF or asymptomatic individuals including the mother of a CF child, who were carrying p.R74W-p.D1270N alone. CONCLUSION: These findings question p.I148T or p.R74W-p.D1270N as causing by themselves CF or CBAVD and emphazises the necessity to perform a complete scanning of CFTR genes and to assign the parental alleles when novel missense mutations are identified

Large genomic rearrangements in the CFTR gene contribute to CBAVD

<p>Abstract</p> <p>Background</p> <p>By performing extensive scanning of whole coding and flanking sequences of the <it>CFTR (Cystic Fibrosis Transmembrane Conductance Regulator</it>) gene, we had previously identified point mutations in 167 out of 182 (91.7%) males with isolated congenital bilateral absence of the vas deferens (CBAVD). Conventional PCR-based methods of mutation analysis do not detect gross DNA lesions. In this study, we looked for large rearrangements within the whole <it>CFTR </it>locus in the 32 CBAVD patients with only one or no mutation.</p> <p>Methods</p> <p>We developed a semi-quantitative fluorescent PCR assay (SQF-PCR), which relies on the comparison of the fluorescent profiles of multiplex PCR fragments obtained from different DNA samples. We confirmed the gross alterations by junction fragment amplification and identified their breakpoints by direct sequencing.</p> <p>Results</p> <p>We detected two large genomic heterozygous deletions, one encompassing exon 2 (c.54-5811_c.164+2186del8108ins182) [or <it>CFTRdele2</it>], the other removing exons 22 to 24 (c.3964-3890_c.4443+3143del9454ins5) [or <it>CFTRdele 22_24</it>], in two males carrying a typical CBAVD mutation on the other parental <it>CFTR </it>allele. We present the first bioinformatic tool for exon phasing of the <it>CFTR </it>gene, which can help to rename the exons and the nomenclature of small mutations according to international recommendations and to predict the consequence of large rearrangements on the open reading frame.</p> <p>Conclusion</p> <p>Identification of large rearrangements further expands the <it>CFTR </it>mutational spectrum in CBAVD and should now be systematically investigated. We have designed a simple test to specifically detect the presence or absence of the two rearrangements identified in this study.</p