Caffeoyl-coenzyme A O-methyltransferase mediates regulation of carbon flux fluctuations during phenylpropenes and lignin biosynthesis in the vegetative organ roots of Asarum sieboldii Miq.

Asarum sieboldii Miq. possesses remarkable medicinal value due to its essential oil enriched with phenylpropenes (e.g., methyleugenol and safrole). Although the biosynthesis of phenylpropenes shares a common pathway with lignin, the regulation mechanisms in carbon flux allocation between them are unclear. This study is the first to genetically verify the carbon flux regulation mechanism in A. sieboldii roots. We regulated the expression of Caffeoyl-coenzyme A O-methyltransferase (CCoAOMT), an essential enzyme in the common pathway, to investigate carbon flux allocation in vegetative organs. Here, the lignin and phenylpropene content fluctuation was analyzed by wet chemistry and GC-MS methods. A bona fide CCoAOMT gene from A. sieboldii was firstly cloned and verified. Preliminary heterologous expression validation in transgenic Arabidopsis thaliana showed that RNAi-induced CCoAOMT down-regulation significantly decreased lignin content by 24% and increased the S/G ratio by 30%; however, AsCCoAOMT over-expression in A. thaliana resulted in a 40% increase in lignin content and a 20% decrease in the S/G ratio when compared to the wild type. Similar trends were noted in homologous transformation in A. sieboldii, although the variations were not conspicuous. Nevertheless, the transgenic A. sieboldii plants displayed substantial differences in the level of phenylpropene compounds methyleugenol and safrole leading to a 168% increase in the methyleugenol/safrole ratio in the over-expression line and a 73% reduction in RNAi-suppression line. These findings suggest that the biosynthesis of phenylpropene constituents methyleugenol and safrole seems to be prioritized over lignin. Furthermore, this study indicated that suppression of AsCCoAOMT resulted in marked root susceptibility to pathogenic fungal disease, implying a significant additional role of CCoAOMT in protecting plant vegetative parts from diseases. Overall, the present study provides important references and suggests that future research should be aimed at elucidating the detailed mechanisms of the carbon flux allocation between phenylpropenes and lignin biosynthesis, as well as the disease resistance competency.

Cognitive Defusion and Psychological Flexibility Predict Negative Body Image in the Chinese College Students: Evidence from Acceptance and Commitment Therapy.

Body dissatisfaction is a global phenomenon. Despite the significant cultural difference, most research on negative body image was conducted in Western countries. How do cognitive fusion and psychological flexibility relate to negative body image in the Chinese population? In the present study, this question was investigated through the intervention technique, Acceptance and Commitment Therapy (ACT). Here, 86 young Chinese university students with high negative physical self were invited, in which 42 students received 10 sessions of group-based ACT intervention in a clinical setting while the remained acted as the control group with no intervention. Pretests showed no statistical differences in negative body image between these two groups, while both cognitive fusion and psychological flexibility predicted negative body image. Post-pre tests showed no change in the control group, while enhanced cognitive defusion and psychological flexibility in the ACT group. Individual differences in psychological flexibility and cognitive defusion enhancement predicted improved body image. A strong association of implicit body image with Fatness and Shortness changes suggested that although with individual differences, those components could be internalized during the intervention in the College students.

[Effect of children's oral health cognition and behavior on oral health status].

PURPOSE: To investigate the current status of oral health cognition behavior and oral health status of children, and to provide countermeasures for the prevention and treatment of oral diseases in children. METHODS: A total of 387 primary school students in the urban area of Shanghai from December 2018 to February 2019 were surveyed using Children's Oral Health Questionnaire and child oral health impact profile（COHIP）. SPSS 24.0 software package was used to conduct statistical analysis of the results through descriptive, univariate and multivariate analysis. RESULTS: The cognition of oral health of children aged 6-9 years old in Shanghai urban area was generally good, but their oral health behavior was average. The caries rate of 387 children reached 57.4%, and the oral health status was not good. Correlation analysis and regression analysis showed that children's oral health behavior was positively correlated with oral health cognition（r=0.260，P<0.05）, and negatively correlated with positive and negative effects of oral health status（r=-0.333，-0.181，P<0.05）, while children's oral health cognition had no significant effect on their oral health status（P>0.05）. CONCLUSIONS: The better the oral health behavior habits of children, the greater the positive impact on oral health status; the development of oral health education for children requires more attention to the cultivation of oral health behavior patterns.

Self-paired dumbbell DNA -assisted simple preparation of stable circular DNAzyme and its application in Pb2+ sensor.

During its development in recent decades, DNAzyme has become a promising candidate for application in biosensor field. However, it still suffers from the problem of thermodynamic and biological instability such as nuclease digestion, which limits its applications in complex samples. Here we have presented a simple and common strategy to resolve this problem by engineering the linear DNAzyme into a circular shape DNAzyme based on the integration of substrate and enzyme parts into one single-stranded sequence. This circular DNAzyme system is indeed endowed with excellent stability due to the stable intramolecular double-stranded formation and extraordinary resistance to nuclease digestion due to the closed structure. We demonstrated that this circular DNAzyme system gained excellent stability and could active under conditions across a broader range of temperature, salt concentrations, and pH. Depending on this circular DNAzyme, combing with Terminal deoxynucleotidyl transferase (TdT)-generated G-quadruplexes, a label free colorimetric sensing platform for Pb2+ quantitation was developed, and a detection limit of 0.085 nM was achieved. Then the enzyme digestion cycle amplification was introduced to further improve the sensitivity of the sensing system, an ultralow detection limit of 0.0015 nM for this fluorescence method was achieved. Based on the two sensing platforms, ultrasensitive analysis of Pb2+ in environmental water and food samples was successfully realized. It is anticipated that this stable circular DNAzyme design will be helpful for trace detection in complex samples.

Ultrasensitive ratiometric detection of Pb2+ using DNA tetrahedron-mediated hyperbranched hybridization chain reaction.

A fluorescent sensing strategy was developed for rapid, highly sensitive and specific detection of lead (II) ion (Pb2+) on the basis of Pb2+ DNAzyme-controlled tetrahedral DNA nanostructure (TDN)-mediated hyper-branched hybridization chain reaction (hHCR). In this strategy, DNA hairpins used for HCR amplification are modified on the four vertexes of TDN, which are then used to perform rapid TDN-hHCR in the presence of an initiator strand, producing large-sized cross-linked reaction products and thus giving greatly improved fluorescence resonance energy transfer (FRET) signal output. Pb2+ DNAzyme catalyzes the cleavage of the initiator strand, inhibiting the initiation of TDN-hHCR and giving decreased FRET signal. Synergetic signal amplification of Pb2+ DNAzyme-catalyzed cleavage reaction and subsequent TDN-hHCR confers the sensing platform with ultrahigh sensitivity. As low as 0.25 pM Pb2+ can be detected by using either signal "turn-on" or "turn-off" mode. The whole detection process can be finished within 20 min. Strong anti-interference capacity of FRET-based ratiometric detection and high specificity of Pb2+ DNAzyme endow the sensing platform with great practical application potential, which was demonstrated by the accurate detection of Pb2+ in real river water, fruit, vegetable and grain samples.