Publications by authors named "Stephane Thomas"

Although is a model yeast for the study of lipid metabolism, its diversity is poorly known, as studies generally consider only a few standard laboratory strains. To extend our knowledge of this biotechnological workhorse, we investigated the genomic and phenotypic diversity of 56 natural isolates. is classified into five clades with no correlation between clade membership and geographic or ecological origin.

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Background: Yarrowia lipolytica, a nonconventional oleaginous yeast species, has attracted attention due to its high lipid degradation and accumulation capacities. Y. lipolytica is used as a chassis for the production of usual and unusual lipids and lipid derivatives.

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Background: Concomitant administration of vaccines simplifies delivery. DTaP5-HB-IPV-Hib is a fully liquid, combination vaccine against 6 diseases. This study evaluated the compatibility of DTaP5-HB-IPV-Hib with 2 different meningococcus group C conjugate (MCC) vaccines in infants.

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Background: The oleaginous yeast Yarrowia lipolytica is increasingly used as an alternative cell factory for the production of recombinant proteins. Recently, regulated promoters from genes EYK1 and EYD1, encoding an erythrulose kinase and an erythritol dehydrogenase, respectively, have been identified and characterized in this yeast. Hybrid promoters up-regulated by polyols such as erythritol and erythrulose have been developed based on tandem copies of upstream activating sequences from EYK1 (UAS1) and XPR2 (encoding extracellular protease, UAS1) promoters.

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Background: In the context of sustainable development, yeast are one class of microorganisms foreseen for the production of oil from diverse renewable feedstocks, in particular those that do not compete with the food supply. However, their use in bulk production, such as for the production of biodiesel, is still not cost effective, partly due to the possible poor use of desired substrates or poor robustness in the practical bioconversion process. We investigated the natural capacity of , a yeast already used in biotechnology, to store lipids under different conditions.

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Invasive meningococcal disease caused by Neisseria meningitidis is a life-threatening disease. Several countries now include meningococcal serogroup C (MenC) conjugate and, more recently, a meningococcal serogroup ACWY conjugate (MenACWY) vaccination in their national immunization schedules. DTaP-IPV-HB-PRP-T is a hexavalent vaccine that provides protection against six diseases.

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Background: Monovalent varicella vaccines have been available in the Veneto Region of Italy since 2004. In 2006, a single vaccine dose was added to the immunisation calendar for children aged 14 months. ProQuad®, a quadrivalent measles-mumps-rubella-varicella vaccine, was introduced in May 2007 and used, among other varicella vaccines, until October 2008.

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Background: The oleaginous yeast Yarrowia lipolytica is increasingly used as alternative cell factory for the production of recombinant proteins. At present, several promoters with different strengths have been developed based either on the constitutive pTEF promoter or on oleic acid inducible promoters such as pPOX2 and pLIP2. Although these promoters are highly efficient, there is still a lack of versatile inducible promoters for gene expression in Y.

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Background And Aims: The strategy of vaccinating infants to prevent hepatitis B virus infection in adolescence or adulthood requires durable immunity. This study investigated responses to a challenge dose of monovalent hepatitis B vaccine in children primed with three doses of either Hexavac® or Infanrix hexa® 10years earlier during infancy.

Methods: This open-label, controlled, multicentre study conducted in Italy, enrolled 751 healthy pre-adolescents (aged 11-13years) who were given either Hexavac (n=409) or Infanrix hexa (n=342) at 3, 5 and 11months of life.

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DTaP5-IPV-HB-Hib vaccine is a fully-liquid, combination hexavalent vaccine. This phase III, open-label, multicentre study conducted in Spain, evaluated the immune response to all DTaP5-IPV-HB-Hib antigens when the vaccine was used in a mixed hexa/penta/hexa primary series. Infants (who had received one dose of hepatitis B vaccine at birth) received a mixed schedule including DTaP5-IPV-HB-Hib (PRP-OMP conjugate) at 2 and 6months of age, DTaP5-IPV-Hib at 4months, meningococcal serogroup C conjugate (MCC) vaccine at 2 and 4months, and routine rotavirus and pneumococcal vaccination.

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Erythritol (1,2,3,4-butanetetrol) is a four-carbon sugar alcohol with sweetening properties that is used by the agrofood industry as a food additive. In this study, we demonstrated that metabolic engineering can be used to improve the production of erythritol from glycerol in the yeast Yarrowia lipolytica. The best results were obtained using a mutant that overexpressed GUT1 and TKL1, which encode a glycerol kinase and a transketolase, respectively, and in which EYK1, which encodes erythrulose kinase, was disrupted; the latter enzyme is involved in an early step of erythritol catabolism.

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Article Synopsis
  • Triacylglycerol (TAG) and glycogen are key carbon storage metabolites in eukaryotes, and research on the oleaginous yeast Yarrowia lipolytica revealed it can store up to 16% glycogen in its biomass.
  • The deletion of the glycogen synthase gene (YlGSY1) led to a notable 60% increase in TAG accumulation when grown under conditions conducive to lipid production.
  • Further studies showed that eliminating glycogen synthesis is advantageous for neutral lipid storage, confirming that carbon storage through glycogen competes with TAG accumulation in oleaginous yeasts.
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Background: The yeast Yarrowia lipolytica is an increasingly common biofactory. To enhance protein expression, several promoters have been developed, including the constitutive TEF promoter, the inducible POX2 promotor, and the hybrid hp4d promoter. Recently, new hp4d-inspired promoters have been created that couple various numbers of UAS1 tandem elements with the minimal LEU2 promoter or the TEF promoter.

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Background: Droplet-based microfluidics is becoming an increasingly attractive alternative to microtiter plate techniques for enzymatic high-throughput screening (HTS), especially for exploring large diversities with lower time and cost footprint. In this case, the assayed enzyme has to be accessible to the substrate within the water-in-oil droplet by being ideally extracellular or displayed at the cell surface. However, most of the enzymes screened to date are expressed within the cytoplasm of Escherichia coli cells, which means that a lysis step must take place inside the droplets for enzyme activity to be assayed.

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Background: Combination vaccines simplify vaccination visits and improve coverage and timeliness. Diphtheria-tetanus toxoids-acellular pertussis 5, hepatitis B, inactivated poliovirus vaccine and Haemophilus influenzae type b (DTaP5-HB-IPV-Hib) is a new investigational, fully liquid, combination vaccine containing a 5-antigen pertussis component and is designed to protect against 6 infectious diseases.

Methods: In this multicenter, double-blind, comparator-controlled, phase III study (NCT01341639) conducted in Finland, Germany and Belgium, healthy infants were randomized 1:1 to receive 1 of 2 immunization regimens.

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Background: Long term follow-up of vaccine trials is essential to establish the duration of protection. In the context of worldwide concern about rising pertussis incidence, estimates of antibody persistence after vaccination, which do not account for the rise in antibody due to natural boosting or infection, may overestimate the degree of protection afforded by pertussis vaccines.

Methods: This was a 5year follow up study of a randomised controlled trial of diphtheria, tetanus, pertussis and polio booster vaccines in UK children aged 3.

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Background: A nine-valent human papilloma virus (9vHPV) vaccine has been developed to prevent infections and diseases related to HPV 6/11/16/18 (as per the licensed quadrivalent HPV (qHPV) vaccine) as well as to five additional oncogenic HPV types (HPV 31/33/45/52/58). The 9vHPV vaccine has the potential to prevent 90% of cervical cancers, HPV-related anal, vaginal and vulval cancers and anogenital warts. We compared the immunogenicity and safety of the 9vHPV vaccine versus the qHPV vaccine in 16-26-year-old men.

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Background: Combination vaccines simplify vaccination visits and improve coverage and timeliness. DTaP5-HB-IPV-Hib is a new investigational, fully-liquid, combination vaccine designed to protect against 6 infectious diseases, including 5 pertussis antigens and OMPC instead of PT as conjugated protein for Hib component.

Methods: In this multicenter, double-blind, comparator-controlled, Phase III study (NCT01480258) conducted in Sweden, Italy, and Finland, healthy infants were randomized 1:1 to receive one two immunization regimens.

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Background: A 9-valent human papillomavirus (9vHPV) vaccine has been developed to prevent infections and diseases related to HPV 6/11/16/18 [as per the licensed quadrivalent HPV (qHPV) vaccine], as well as 5 additional oncogenic HPV types (HPV 31/33/45/52/58). Compared with the qHPV vaccine, the 9vHPV vaccine potentially increases the coverage of protection from 70% to 90% of cervical cancers. We compared the immunogenicity and safety of the 9vHPV vaccine versus the qHPV vaccine in 9-15-year-old girls.

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Hepatitis B vaccines do not generate protective immune responses in older adults as effectively as they do in children and young adults. Improved formulations of existing vaccines may have the potential to improve this. This study investigated the persistence of serum antibodies against hepatitis B surface antigens (anti-HBs) 3.

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Background: Concomitant administration of vaccines can facilitate vaccination uptake, provided that no clinically significant effect on either vaccine is identified. We investigated the concomitant administration, during the second year of life, of one dose of the combined measles, mumps, rubella and varicella vaccine (ProQuad(®)) with a booster dose of a hexavalent vaccine.

Methods: In this multicentre, open-label study, participants were randomized to 3 groups: Group 1, concomitant administration of one dose of ProQuad(®) and a booster of hexavalent vaccine; Group 2, one dose of ProQuad(®) alone; Group 3, a booster dose of hexavalent vaccine alone.

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Zostavax(®) is a live, attenuated varicella zoster virus (VZV) vaccine developed specifically for the prevention of HZ and PHN in individuals aged ≥50 years. During the clinical development of Zostavax, which was mainly in the US, the vaccine was administrated by the subcutaneous (SC) route. In Europe, many healthcare professionals prefer administering vaccines by the intramuscular (IM) route.

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This study compared the levels of immunogenicity and safety of diphtheria-tetanus toxoid-five-component acellular pertussis (DTaP(5)), inactivated poliovirus (IPV), and Haemophilus influenzae type b (Hib) (DTaP(5)-IPV-Hib) and DTaP(3)-IPV/Hib vaccines for study participants 3, 5, and 12 months of age. Post-dose 3 noninferiority criteria comparing DTaP(5)-IPV-Hib to DTaP(3)-IPV/Hib using rates of seroprotection were demonstrated against diphtheria, tetanus, and polio types 1 to 3, but not for polyribosylribitol phosphate (PRP). While PRP did not meet noninferiority criteria, the seroprotection rate and geometric mean concentration (GMC) were high, indicating a clinically robust immune response.

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Disease protection provided by herpes zoster (HZ) vaccination tends to reduce as age increases. This study was designed to ascertain whether a second dose of the HZ vaccine, Zostavax(®), would increase varicella zoster virus (VZV)-specific immune response among individuals aged ≥ 70 y. Individuals aged ≥ 70 y were randomized to receive HZ vaccine in one of three schedules: a single dose (0.

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Background And Aims: The anamnestic response to a challenge dose of vaccine can assess immune memory and protection against hepatitis B infection. This study investigated responses to a challenge dose of monovalent hepatitis B vaccine in children immunised with three doses of either Hexavac or Infanrix-Hexa during infancy.

Methods: This open-label, randomised, controlled, four-arm study enrolled 410 healthy children aged 4-7 years who had received either Hexavac (n=201) or Infanrix-Hexa (n=209) at 3, 5 and 11 months of life.

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