No effect of 6-month supplementation with 300 mg/d docosahexaenoic acid on executive functions among healthy school-aged children: a randomized, double-blind, placebo-controlled trial.

PURPOSE: Docosahexaenoic acid (DHA) plays an essential role in brain, and its status is dependent on dietary intakes. School-aged children in rural China, who consume diets low in omega-3 polyunsaturated fatty acids, may benefit from DHA supplementation. Therefore, this trial was performed to examine the effect of 6-month DHA supplementation on executive functions (EFs) among healthy school-aged children in rural China. METHODS: A randomized, double-blind, placebo-controlled trial was conducted among 106 primary school children aged 7-12 years in rural China. Participants were randomized to receive either 300 mg/d DHA or placebo for 6 months. EFs including working memory and cognitive flexibility were evaluated at baseline, at 3 months and at 6 months, using Digit Span Backwards and Wisconsin card sorting test, respectively. Socio-demographic data were collected at baseline, and erythrocyte membrane fatty acids and serum neurotransmitters were measured at baseline and after 6-month intervention. RESULTS: Ninety-four children (88.7%) completed the study according to the protocol. Changes in erythrocyte membrane fatty acids indicated good compliance of the participants. There was no significant intervention effect on serum neurotransmitters. In two-factor ANCOVA, both groups showed a significant improvement in the Digit Span Backwards and the Wisconsin card sorting test from baseline to endpoint. However, no significant intervention effect was found on any EF scores. Linear regression analysis suggested no significant association between changes in erythrocyte DHA level with changes in any EF scores. CONCLUSIONS: Supplementation with 300 mg/d DHA for 6 months had no benefit on EFs including working memory and cognitive flexibility among healthy school-aged children. This trial was registered at clinicaltrials.gov as NCT02308930 on December 5, 2014.

Comparative transcriptome study of hairy and hairless tea plant (Camellia sinensis) shoots.

Trichome (also referred to as 'háo' in tea) is a key feature in both tea products and tea plant (Camellia sinensis) selection breeding. Although trichomes are used as a model for studying cell differentiation and have been well studied in many plant species, the regulation of trichome formation at the molecular level is poorly understood in tea plants. In the present study, the hairy and hairless tea plant cultivars Fudingdabaicha (FDDB) and Rongchunzao (RCZ), respectively, were used to study this mechanism. We characterised tea plant trichomes as unicellular and unbranched structures. High-throughput Illumina sequencing yielded approximately 277.0 million high-quality clean reads from the FDDB and RCZ cultivars. After de novo assembly, 161,444 unigenes were generated, with an average length of 937 bp. Among these unigenes, 81,425 were annotated using public databases, and 55,201 coding sequences and 4004 transcription factors (TFs) were identified. In total, 21,599 differentially expressed genes (DEGs) were identified between RCZ and FDDB, of which 10,785 DEGs were up-regulated and 10,814 DEGs were down-regulated. Genes involved in the DNA replication pathway were significantly enriched. Furthermore, between FDDB and RCZ, DEGs related to TFs, phytohormone signals, and cellulose synthesis were identified, suggesting that certain genes involved in these pathways are crucial for trichome initiation in tea plants. Together, the results of this study provide novel data to improve our understanding of the potential molecular mechanisms of trichome formation and lay a foundation for additional trichome studies in tea plants.