D-allulose is a natural rare sugar with important physiological properties that is used in food, health care items, and even the pharmaceutical industry. In the current study, a novel D-allulose 3-epimerase gene (Bp-DAE) from the probiotic strain Blautia produca was discovered for the production and characterization of an enzyme known as Bp-DAE that can epimerize D-fructose into D-allulose. Bp-DAE was strictly dependent on metals (Mn2+ and Co2+), and the addition of 1 mM of Mn2+ could enhance the half-life of Bp-DAE at 55 °C from 60 to 180 min. It exhibited optimal activity in a pH of 8 and 55 °C, and the Km values of Bp-DAE for the different substrates D-fructose and D-allulose were 235.7 and 150.7 mM, respectively. Bp-DAE was used for the transformation from 500 g/L D-fructose to 150 g/L D-allulose and exhibited a 30% of conversion yield during biotransformation. Furthermore, it was possible to employ the food-grade microbial species Bacillus subtilis for the production of D-allulose using a technique of whole-cell catalysis to circumvent the laborious process of enzyme purification and to obtain a more stable biocatalyst. This method also yields a 30% conversion yield.
ObjectiveEarly screening contributes to the early detection of children with autism spectrum disorder (ASD). We conducted a longitudinal ASD screening study in a large community setting. The study was designed to investigate the diagnostic rate of ASD screening and determine the effectiveness of ASD screening model in a community-based sample.MethodsWe enrolled children who attended 18- and 24-month well-child care visits in Shanghai Xuhui District. Modified Checklist for Autism in Toddlers, Revised with Follow-up (M-CHAT-R/F) and Binomial Observation Test (BOT) were selected as screening instruments. Screen-positive children were referred to a tertiary diagnostic center for comprehensive ASD diagnostic evaluation. Screen-negative children received well-child checkups and follow-up every 3–6 months until age three and were referred if they were suspected of having ASD.ResultsA total of 11,190 toddlers were screened, and 36 screen-positive toddlers were diagnosed with ASD. The mean age at diagnosis for these children was 23.1 ± 4.55 months, diagnosed 20 months earlier than ASD children not screened. The diagnostic rate of ASD was 0.32% (95% CI: 0.23–0.45%) in this community-based sample. In addition, 12 screen-negative children were diagnosed with ASD during subsequent well-child visit and follow-up. The average diagnostic rate of ASD rose to 0.43% (95% CI: 0.32–0.57%) when toddlers were followed up to 3 years old. The positive predictive values (PPVs) of M-CHAT-R/F, M-CHAT-R high risk, and BOT for ASD were 0.31, 0.43, and 0.38 respectively.ConclusionOur findings provide reliable data for estimating the rate of ASD detection and identifying the validity of community-based screening model. M-CHAT-R/F combined with BOT can be an effective tool for early detection of ASD. This community-based screening model is worth replicating.
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