Evaluation of single-use bioreactors for the production of a Hepatitis C vaccine candidate

During the last decade, the usage of single-use bioreactors has been increasing in the biopharmaceutical industry. This technology offers some appealing advantages over their conventional counterparts made of glass or stainless steel, such as operational flexibility, faster batch-to-batch turnaround times and the reduction of clean-up and validation characteristic of single-use materials. The present work examines a stirred single-use bioreactor for its suitability for the production of a Hepatitis C Virus-Like Particles (VLPs) vaccine candidate using the baculovirus expression system with Sf9 cells. In this sense a 2L glass stirred tank and a Mobius® 3L Bioreactor are compared in terms of viable cell concentration, viability percentage, growth kinetics, stability, and VLPs production, showing that comparable results can be obtained with a simple matching of hydrodynamic working parameters between the two systems. Moreover, we report on the successful scale-up of this disposable alternative from a 3L to a 50L scale, demonstrating the potential, and ease-of-use of this technology for the production of complex biopharmaceutical products

Evaluation and scale-up of single-use bioreactors for the production and harvesting of a hepatitis C vaccine candidate

The present work examines the suitability of single-use bioreactors for production of a Hepatitis C Virus-Like Particle (VLP) vaccine candidate using the baculovirus expression system with Sf9 cells. It can be shown that a Mobius® 3L bioreactor results in viable cell concentration, viability, growth kinetics, stability and VLP production that are comparable to standard glass bioreactors. A simple translation of hydrodynamic working parameters between the two systems is adequate to match performance. Furthermore, we report on the successful scale-up of this disposable alternative from a 3L to a 50L scale using minimal optimization. These results demonstrate the potential and ease of use of this technology for the production of complex biopharmaceutical products. Using the 50 liters harvested from the run, we evaluated depth filtration and compared the results to centrifugation. Multiple filter trains with different properties were tested and the results on recovery, turbidity and impurity reduction will be presented and discussed

Studying the Effect and Treatment of Misspelled Queries in Cross-Language Information Retrieval

[Abstract] The performance of Information Retrieval systems is limited by the linguistic variation present in natural language texts. Word-level Natural Language Processing techniques have been shown to be useful in reducing this variation. In this article, we summarize our work on the extension of these techniques for dealing with phrase-level variation in European languages, taking Spanish as a case in point. We propose the use of syntactic dependencies as complex index terms in an attempt to solve the problems deriving from both syntactic and morpho-syntactic variation and, in this way, to obtain more precise index terms. Such dependencies are obtained through a shallow parser based on cascades of finite-state transducers in order to reduce as far as possible the overhead due to this parsing process. The use of different sources of syntactic information, queries or documents, has been also studied, as has the restriction of the dependencies applied to those obtained from noun phrases. Our approaches have been tested using the CLEF corpus, obtaining consistent improvements with regard to classical word-level non-linguistic techniques. Results show, on the one hand, that syntactic information extracted from documents is more useful than that from queries. On the other hand, it has been demonstrated that by restricting dependencies to those corresponding to noun phrases, important reductions of storage and management costs can be achieved, albeit at the expense of a slight reduction in performance.Ministerio de Economía y Competitividad; FFI2014-51978-C2-1-RRede Galega de Procesamento da Linguaxe e Recuperación de Información; CN2014/034Ministerio de Economía y Competitividad; BES-2015-073768Ministerio de Economía y Competitividad; FFI2014-51978-C2-2-

Atmospheric plasma sources as potential tools for surface and hand disinfection

Good hand hygiene has proven to be essential in reducing the uncontrolled spread of human pathogens. Cold atmospheric plasma (CAP) may provide an alternative to disinfecting hands with ethanol-based handrubs when handwashing facilities are unavailable. CAP can be safely applied to the skin if the energy is well controlled. In this study, radio frequency (RF) and direct current (DC) plasma sources were built with a pin-to-mesh electrodes configuration inside a fused silica tube with a 5 mm inner diameter. Microbiological assays based on EN 13697:2015+A1:2019 using Escherichia coli DSM 682 or Staphylococcus epidermidis DSM 20044 were used to examine the antimicrobial effect of various plasma conditions. Metal and silicone disks that model skin were used as inoculation matrices. The prototype air RF CAP achieved significant disinfection in the MHz range on stainless steel and silicone substrates. This is equivalent to half the performance of direct current CAP, which is only effective on conductive substrates. Using only electricity and air CAP could, with further optimization to increase its efficacy, replace or complement current hand disinfection methods, and mitigate the economic burden of public health crises in the future

Genomic comparison of Francisella halioticida

International audienc

<i>Francisella halioticida</i>'s towards the mussel <i>Mytilus edulis</i> is strain-dependent

International audienc

Influence of strains in development of francisellosis in the blue mussel Mytilus edulis during experimental challenges

International audienceThe bacterium Francisella halioticida, known to induce francisellosis in abalone and Yesso scallop, is suspected of being involved in the blue mussel mortalities observed in France. Recently, several isolates of F. halioticida were obtained from moribund mussels and categorized into two type strains, FR21 and FR22. Two other strains, AG1 and AG3, determined to belong to the genus Francisella were isolated. To determine the virulence of these isolates, juvenile and adult blue mussels were injected with bacterial solutions at high dose and monitored for 11 days. FR22c and FR22d were found to induce 80% mortality in less than seven days. The isolates AG1 and AG3 led to over 50% mortality in adult mussels but only AG1 led to significant mortality in juveniles (41%). FR22c and FR22d, the most virulent isolates, were selected to determine their respective lethal dose at 50% (LD50) in juveniles and adults. This analysis was performed with bacterial solutions ranging from 10$^2$ to 10$^6$ CFU/mussel and monitored for 30 days. The isolate FR22c was found to be the most virulent. Observed LD50 for the isolate FR22c was 4.14 ×10$^3$ CFU/juvenile and 3.45 ×10$^3$ CFU/adult and for the isolate FR22d, 1.89 ×10$^4$ CFU/juvenile and 1.52 ×10$^4$ CFU/adult. To confirm Koch’s postulate, a selection of moribund, surviving and control animals were plated on specific media. The isolates were reisolated from moribund animals but not from surviving or controls. To confirm the proliferation, a specific real-time PCR was performed. All moribund individuals were positive by PCR. The main Ct values were lower for moribund compared to surviving animals and a dose effect was observed in DNA bacterial load. This study shows that some F. halioticida isolates are able to induce francisellosis in mussels and lead to high mortality, highlighting differences in virulence among the strains

First isolation of Francisella halioticida strains from blue mussel (Mytilus edulis) in Normandy, France

International audienceMass mortality events affecting the blue mussels Mytilus edulis have been observed in France since 2014. The DNA of the bacterium Francisella halioticida, reported as pathogen of giant abalone (Haliotis gigantea) and Yesso scallop (Mizuhopecten yessoensis) has been detected recently in mussels from areas suffering mortalities. Isolation of this bacterium was attempted from individuals collected during mortality events. Identification was performed by16S rRNA gene sequencing, real-time specific PCR and MALDI-ToF using spectra produced from the strain 8472-13A isolated from diseased Yesso scallop in Canada. Five isolates were identified as F. halioticida by real-time specific PCR and 16S rRNA sequencing. MALDI-ToF allowed the direct identification of four isolates(FR22a,b,c,d) which had 100% identity on the 16S rRNA gene with the known strains. On the other hand, one isolate (FR21) was not recognized by MALDI-ToF and had 99.9% identity on the 16S rRNA gene. The FR22 isolates showed difficult growth and required media optimization, which was not the case with the FR21 isolate. For these reasons, it was hypothesized that two type strains are present on French coasts, named FR21 and FR22. The FR21 isolate was selected for phenotypic analysis (growth curve, biochemical characteristics, electron microscopy), phylogenetic analysis and an experimental challenge.This isolate showed distinct differences compared to published F. halioticida strains, both at phenotypic and genotypic levels. Experimental infections of adult mussels led to 36% mortalities in 23 days following intramuscular injection with 3 x 107 CFU while a lower dose (3 x 103 CFU) did not lead to significant mortalities. In the context of this study, the strain FR21 was not virulent towards adult mussels