4 research outputs found

    Molecular responses of Nile tilapia ( Oreochromis niloticus ) to different levels of dietary carbohydrates

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    The objective of the study was to test for the first time the molecular adaptation of the glucose metabolism to this fish species know to be a good user of carbohydrates. In this way, Nile tilapia were fed with 3 different levels of carbohydrates 0% (CHO-L) 30% (CHO-M) and 50% (CHO-H) dextrin. After 45 days and 90 days of feeding we analyzed the plasma parameters, zootechnical performance and the mRNA levels for genes involved in glycolysis, gluconeogenesis, lipogenesis and glucose transport in liver and muscle. The best growth performance was found for fish fed M-CHO diet, the fish fed with the H-CHO diets showing the worst growth performance. Increased of hepatic and muscle glycogen, hepatic somatic index and plasma metabolites (glucose, triglycerides and cholesterol) was linked to the increased of dietary carbohydrates. However, no hyperglycemia, no change of body compositions was found showing that dietary carbohydrates are efficiently used as an energy source in tilapia. Moreover, in contrats to the dietary protein-linked decreased of amino acid catabolic mRNA levels, no clear molecular adaptation for glycolysis, gluconeogenesis, lipogenesis in liver and glycolysis in muscle was detected except higher mRNA levels for glucose transporter in muscle. Our data suggest that these metabolic pathways at a molecular level are not the main actors explaining the efficient use of glucose in tilapia.Statement of relevance: Our study aimed at characterizing for the first time the molecular effects of increased dietary carbohydrates (dextrin) from 0% up to 50% in Nile tilapia during 45 and 90 days. Our study confirmed that Nile tilapia can use high level of carbohydrates without any deregulation of glucose homeostasis. However, no strong regulations of expression for genes involved in glucose metabolism in liver and muscle - which could explain the reasons for an efficient use of carbohydrate by this fish species - were detecte

    Immunogenicity of a Fractional Dose of mRNA BNT162b2 COVID-19 Vaccine for Primary Series and Booster Vaccination among Healthy Adolescents

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    Primary series vaccination with BNT162b2 followed by a booster 5 months later has been recommended for healthy adolescents. We aimed to describe the immunogenicity in a fractional dose of BNT162b2. Adolescents aged 12–18 years were randomized into six arms for primary series administration: 3wPZ30/30 (reference group), 3wPZ30/20, 3wPZ20/20, 6wPZ30/30, 6wPZ30/20, and 6wPZ20/20 μg. A booster was given at 5 months after the second dose using either 10 or 15 μg of BNT162b2. Immunogenicity following vaccination was determined by IgG against receptor-binding domain (anti-S-RBD IgG; BAU/mL), surrogate virus neutralization test (sVNT; %inhibition) and pseudovirus neutralization (pVNT;ID50) against Omicron. Non-inferiority criteria were defined as a lower boundary of the geometric mean ratio (GMR) being greater than 0.67. From September to October 2021, 118 adolescents with a median age (IQR) of 14.9 years (13.9–16.7) were enrolled. Fourteen days after the primary series, the geometric means (GMs) of anti-S-RBD IgG (BAU/mL) were 3090 (95% CI 2761–3460) in 3wPZ30/30. The GMRs of anti-S-RBD were: 0.80 (95% CI 0.67–0.97) in 3wPZ30/20; 1.00 (95% CI 0.83–1.20) in 3wPZ20/20; 1.37 (95% CI 1.13–1.65) in 6wPZ30/30; 1.24 (95% CI 1.02–1.50) in 6wPZ30/20; and 1.36 (1.13–1.64) in 6wPZ20/20. After a booster dose with 15 μg (n = 24) of BNT162b2, sVNT and pVNT against Omicron variant were 91.6 (95% CI 88.4–94.9) and 331 (95% CI 221–495), respectively. In the group that received 10 μg of BNT162b2 (n = 25), sVNT was 85.6 (95% CI 80.0–91.6) and pVNT was 397 (95% CI 267–590). Healthy adolescents had good immune responses to the fractional dose regimen of BNT162b2 and this may be considered as an alternative option

    Double antibody pairs sandwich-ELISA (DAPS-ELISA) detects Acidovorax citrulli serotypes with broad coverage.

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    Acidovorax citrulli, a seedborne bacterium and quarantine pest, causes the devastating bacterial fruit blotch disease in cucurbit plants. Immunological assays such as ELISA are widely used in routine field inspections for this bacterium. However, to the best of our knowledge, none of the currently available monoclonal antibodies (MAbs) can detect all common A. citrulli strains. We therefore aimed to produce a panel of MAbs and to develop an ELISA-based method capable of detecting all A. citrulli strains. We used a high-throughput bead array technique to screen and characterize A. citrulli-specific MAbs produced from hybridoma clones. The hybridoma library was simultaneously screened against five A. citrulli strains (PSA, KK9, SQA, SQB and P) and the closely related bacterium, Delftia acidovorans. Three MAbs exhibiting different binding patterns to A. citrulli were used to develop an ELISA-based method called "double antibody pairs sandwich ELISA" (DAPS-ELISA). DAPS-ELISA employing mixtures of MAbs was able to specifically detect all 16 A. citrulli strains tested without cross-reactivity with other bacteria. By contrast, our previously developed MAb capture-sandwich ELISA (MC-sELISA) and a commercial test kit detected only 15 and 14 of 16 strains, respectively. The sensitivity of the DAPS-ELISA ranged from 5Ă—105 to 1Ă—106 CFU/mL, while those of the MC-sELISA and the commercial test kit ranged from 5Ă—104 to 1Ă—107 CFU/mL and 5Ă—104 to 5Ă—105 CFU/mL, respectively. DAPS-ELISA thus represents an alternative method enabling rapid, accurate, and inexpensive detection of all A. citrulli strains. The method can be applied to seed testing prior to planting as well as to routine field inspections
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