In Vitro and In Vivo evaluation of hydroxypropylmethyl cellulose phthalate capsules

The aim of this study was to develop a novel HPMCP capsule. The HPMCP capsule containing99mTc-DTPA and lactose was evaluated in in vitro and in vivo studies. First of all, the HPMCP capsules were prepared and characterized with lenght and diameter size, brittleness facility, moisture content and microbiological test. In vitro resistance and solubility studies of prepared capsules were tested at pH 1.2 and pH 7.4 buffers. The radiolabeled HPMCP capsules were administrated to fasted volunteers. The disintegration times and positions of capsules were recorded by using gamma scintigraphy. In vitro studies showed that HPMCP capsules were gastro resistant for 2 h at pH 1.2 and dissolved at pH 7.4 in 20-25 minutes. The radiolabeled capsules did not disintegrate in stomach whereas disintegrated in intestines. In conclusion, it was found that, the prepared HPMCP capsules can be an alternative to the hard gelatine capsules and used for intestinal targeting.Keywords: Capsule, hydroxypropylmethylcellulose phthalate (HPMCP), gamma scintigraphy, radiolabelling, technetium-99m

Prevalence of Type VI Secretion System in Spanish Campylobacter jejuni Isolates.

Infections from Campylobacter jejuni pose a serious public health problem and are now considered the leading cause of foodborne bacterial gastroenteritis throughout the world. Sequencing of C. jejuni genomes has previously allowed a number of loci to be identified, which encode virulence factors that aid survival and pathogenicity. Recently, a Type VI secretion system (T6SS) consisting of 13 conserved genes was described in C. jejuni strains and recognised to promote pathogenicity and adaptation to the environment. In this study, we determined the presence of this T6SS in 63 Spanish C. jejuni isolates from the food chain and urban effluents using whole-genome sequencing. Our findings demonstrated that nine (14%) strains harboured the 13 ORFs found in prototype strain C. jejuni 108. Further studies will be necessary to determine the prevalence and importance of T6SS-positive C. jejuni strains

Design of a Gd-DOTA-Phthalocyanine Conjugate Combining MRI Contrast Imaging and Photosensitization Properties as a Potential Molecular Theranostic

Cataloged from PDF version of article.The design and synthesis of a phthalocyanine - Gd-DOTA conjugate is presented to open the way to novel molecular theranostics, combining the properties of MRI contrast imaging with photodynamic therapy. The rational design of the conjugate integrates isomeric purity of the phthalocyanine core substitution, suitable biocompatibility with the use of polyoxo water-solubilizing substituents, and a convergent synthetic strategy ended by the use of click chemistry to graft the Gd-DOTA moiety to the phthalocyanine. Photophysical and photochemical properties, contrast imaging experiments and preliminary in vitro investigations proved that such a combination is relevant and lead to a new type of potential theranostic agent

Sodium taurocholate stimulates Campylobacter jejuni outer membrane vesicle production via down-regulation of the maintenance of lipid asymmetry pathway

Campylobacter jejuni outer membrane vesicles (OMVs) contain numerous virulence-associated proteins including the cytolethal distending toxin and three serine proteases. As C. jejuni lacks the classical virulence-associated secretion systems of other enteric pathogens that deliver effectors directly into target cells, OMVs may have a particularly important role in virulence. C. jejuni OMV production is stimulated by the presence of physiological concentrations of the bile salt sodium taurocholate (ST) through an unknown mechanism. The maintenance of lipid asymmetry (MLA) pathway has been implicated in a novel mechanism for OMV biogenesis, open to regulation by host signals. In this study we investigated the role of the MLA pathway in C. jejuni OMV biogenesis with ST as a potential regulator. OMV production was quantified by analyzing protein and lipid concentrations of OMV preparations and OMV particle counts produced by nanoparticle tracking analysis. Mutation of mlaA which encodes the outer membrane component of the MLA pathway significantly increased OMV production compared to the wild-type strain. Detergent sensitivity and membrane permeability assays confirmed the increased OMV production was not due to changes in membrane stability. The presence of 0.2% (w/v) ST increased wild-type OMV production and reduced OMV size, but did not further stimulate mlaA mutant OMV production or significantly alter mlaA mutant OMV size. qRT-PCR analysis demonstrated that the presence of ST decreased expression of both mlaA and mlaC in C. jejuni wild-type strains 11168 and 488. Collectively the data in this study suggests C. jejuni can regulate OMV production in response to host gut signals through changes in expression of the MLA pathway. As the gut bile composition is dependent on both diet and the microbiota, this study highlights the potential importance of diet and lifestyle factors on the varying disease presentations associated with gut pathogen infection

The bile salt sodium taurocholate induces Campylobacter jejuni outer membrane vesicle production and increases OMV-associated proteolytic activity

Campylobacter jejuni, the leading cause of bacterial acute gastroenteritis worldwide, secretes an arsenal of virulence‐associated proteins within outer membrane vesicles (OMVs). C. jejuni OMVs contain three serine proteases (HtrA, Cj0511, and Cj1365c) that cleave the intestinal epithelial cell (IEC) tight and adherens junction proteins occludin and E‐cadherin, promoting enhanced C. jejuni adhesion to and invasion of IECs. C. jejuni OMVs also induce IECs innate immune responses. The bile salt sodium taurocholate (ST) is sensed as a host signal to coordinate the activation of virulence‐associated genes in the enteric pathogen Vibrio cholerae. In this study, the effect of ST on C. jejuni OMVs was investigated. Physiological concentrations of ST do not have an inhibitory effect on C. jejuni growth until the early stationary phase. Coculture of C. jejuni with 0.1% or 0.2% (w/v) ST stimulates OMV production, increasing both lipid and protein concentrations. C. jejuni ST‐OMVs possess increased proteolytic activity and exhibit a different protein profile compared to OMVs isolated in the absence of ST. ST‐OMVs exhibit enhanced cytotoxicity and immunogenicity to T84 IECs and enhanced killing of Galleria mellonella larvae. ST increases the level of mRNA transcripts of the OMVs‐associated serine protease genes and the cdtABC operon that encodes the cytolethal distending toxin. Coculture with ST significantly enhances the OMVs‐induced cleavage of E‐cadherin and occludin. C. jejuni OMVs also cleave the major endoplasmic reticulum chaperone protein BiP/GRP78 and this activity is associated with the Cj1365c protease. These data suggest that C. jejuni responds to the presence of physiological concentrations of the bile salt ST that increases OMV production and the synthesis of virulence‐associated factors that are secreted within the OMVs. We propose that these events contribute to pathogenesis

Design of a modular Autonomous Underwater Vehicle for archaeological investigations

MARTA (MARine Tool for Archaeology) is a modular AUV (Autonomous Underwater Vehicle) designed and developed by the University of Florence in the framework of the ARROWS (ARchaeological RObot systems for the World's Seas) FP7 European project. The ARROWS project challenge is to provide the underwater archaeologists with technological tools for cost affordable campaigns: i.e. ARROWS adapts and develops low cost AUV technologies to significantly reduce the cost of archaeological operations, covering the full extent of an archaeological campaign (underwater mapping, diagnosis and cleaning tasks). The tools and methodologies developed within ARROWS comply with the "Annex" of the 2001 UNESCO Convention for the protection of Underwater Cultural Heritage (UCH). The system effectiveness and MARTA performance will be demonstrated in two scenarios, different as regards the environment and the historical context, the Mediterranean Sea (Egadi Islands) and the Baltic Sea

MdaB and NfrA, Two novel reductases important in the survival and persistence of the major enteropathogen Campylobacter jejuni

The paralogues RrpA and RrpB, which are members of the MarR family of DNA binding proteins, are important for the survival of the global bacterial foodborne pathogen Campylobacter jejuni under redox stress. We report that RrpA is a positive regulator of mdaB, encoding a flavin-dependent quinone reductase that contributes to the protection from redox stress mediated by structurally diverse quinones, while RrpB negatively regulates the expression of cj1555c (renamed nfrA for NADPH-flavin reductase A), encoding a flavin reductase. NfrA reduces riboflavin at a greater rate than its derivatives, suggesting that exogenous free flavins are the natural substrate. MdaB and NfrA both prefer NADPH as an electron donor. Cysteine substitution and posttranslational modification analyses indicated that RrpA and RrpB employ a cysteine-based redox switch. Complete genome sequence analyses revealed that mdaB is frequently found in Campylobacter and related Helicobacter spp., while nfrA is predominant in C. jejuni strains. Quinones and flavins are redox cycling agents secreted by a wide range of cell types that can form damaging superoxide by one-electron reactions. We propose a model for stress adaptation where MdaB and NfrA facilitate a two-electron reduction mechanism to the less toxic hydroquinones, thus aiding survival and persistence of this major pathogen. IMPORTANCE Changes in cellular redox potential result in alteration in the oxidation state of intracellular metabolites and enzymes; consequently, cells make adjustments that favor growth and survival. The work we present here answers some of the many questions that have remained elusive over the years of investigation into the enigmatic microaerophile bacterium Campylobacter jejuni. We employed molecular approaches to understand the regulation mechanisms and functional analyses to reveal the roles of two novel quinone and flavin reductases; both serve as major pools of cellular redox-active molecules. This work extends our knowledge on bacterial redox sensing mechanisms and the significance of hemostasis