Search

MYB transcription factors are crucial in regulating stress tolerance and expression of major genes involved in flavonoid biosynthesis. The functions of MYBs is well explored in a number of plants, yet no study is reported in Apocynum venetum. We identified a total of 163 MYB candidates, that comprised of 101 (61.96%) R2R3, 6 3R, 1 4R and 55 1R. Syntenic analysis of A. venetum R2R3 (AvMYBs) showed highest orthologous pairs with Vitis vinifera MYBs followed by Arabidopsis thaliana among the four species evaluated. Thirty segmental duplications and 6 tandem duplications were obtained among AvMYB gene pairs signifying their role in the MYB gene family expansion. Nucleotide substitution analysis (Ka/Ks) showed the AvMYBs to be under the influence of strong purifying selection. Expression analysis of selected AvMYBs under low temperature and cadmium stresses resulted in the identification of AvMYB48 , AvMYB97 , AvMYB8 , AvMYB4 as potential stress responsive genes and AvMYB10 and AvMYB11 in addition, proanthocyanidin biosynthesis regulatory genes which is consistent with their annotated homologues in Arabidopsis. Tissue specific expression profile analysis of the AvMYBs further supported the qPCR analysis result. MYBs with higher transcript levels in root, stem and leaf like AvMYB4 for example, was downregulated under the stresses and such with low transcript level such as AvMYB48 which had low transcript in the leaf was upregulated under both stresses. Transcriptome and phylogenetic analyses suggested AvMYB42 as a potential regulator of anthocyanin biosynthesis. Thus, this study provided valuable information on AvR2R3-MYB gene family with respect to stress tolerance and flavonoid biosynthesis. • Apocynum venetum is an important medicinal and bast fiber plant. • A. venetum R2R3 MYB showed highest orthologous pairs with Vitis vinifera and Arabidopsis thaliana. • Expression analysis of selected AvMYB pointed AvMYB48 , AvMYB97 , AvMYB8 , AvMYB4 as potential stress responsive genes. • AvMYB10 and AvMYB11 in addition to to regulating stress function in proanthocyanidin biosynthesis. • AvMYB42 is according to transcriptome and phylogenetic analysis a potential regulator of anthocyanin biosynthesis. [ABSTRACT FROM AUTHOR]

• Novel CRB vibration model considering contact stiffness and natural frequency characteristics. • The outer raceway spalling fault with varying sizes is simulated in this paper, considering spalling defect extents and load distribution. • This paper showed that the effects of contact stiffness variation on natural frequency characteristics by the statistical distribution of fault feature signals. The modeling of early spalling defects in cylindrical roller bearings (CRB) is a challenging problem in fault diagnosis. Due to the absence of prominent "drop-in" excitation, accurately describing the signal characteristics of the early failure mechanism model for CRBs becomes difficult. In this paper, the failure of cylindrical roller bearings due to spalling caused by fatigue is a frequent occurrence. The previous defect models have been centered on sharp-edge impact between the roller and spalling defects. However, they have not provided an adequate depiction of the variation in contact stiffness caused by roller-fault interaction. In this paper, a novel CRB vibration model that takes into account contact stiffness and natural frequency characteristics is proposed. The model considers both the load redistribution and contact stiffness variation caused by spalling defects. This new model provides a spring-damper system based on contact stiffness between the roller and raceway, enabling an estimation of the CRB system's natural frequency characteristics. The outer raceway spalling fault with varying sizes is simulated in this paper, taking into account spalling defect extents and load distribution. The vibration response of the fault signal model is investigated. The simulation results show that the load and contact stiffness will change as the roller passes through the defect zone. Furthermore, the statistical distribution of fault feature signals demonstrates the effects of contact stiffness variation on natural frequency characteristics. The experiments given in this paper have verified the simulation results of the proposed signal model. [ABSTRACT FROM AUTHOR]

Ramie (Boehmeria nivea L.) is an ideal crop for cadmium (Cd) pollution remediation due to its advantages of both remediating and utilizing, however, it is mainly carried out in dry land, whose restoration effect is relatively slow. Previously, we found that the ramie plants cultivated by hydroponics has several tens of times higher Cd absorption capacity than that planted in soil. However, the issue of how to use hydroponic ramie to remediate Cd contaminated paddy fields needs to be addressed. In this study, we innovatively developed the ramie floating island technology and studied its remediation model on simulated Cd contaminated paddy fields. Different ramie varieties were used to compare the remediation effects, and the results showed that there were differences in adaptability among different varieties on floating islands and the remediation ability of the tested ramie varieties was Z2 > Z1 > Z3. Different harvested times were set to analyze the effects of harvested model on remediation, and it was suggested that multiple harvests can be carried out according to the plant growth status of ramie floating island after 30 days of remediation to achieve better remediation effects. Low water level height (5 cm) of paddy field was beneficial for the accumulation of Cd in the roots, but considering the adaptability of various ramie varieties and the effect of long-term restoration, it was recommended that the water level height of 20 cm for the cultivation of ramie floating island was more suitable. Moreover, we found that low concentration of citric acid (≤2 g L−1) or polyaspartic acid (≤3 g L−1) can improve the remediation effects for ramie floating island. Our study opens up a novel approach for ramie to remediate heavy metal pollution and provides a technical reference for water body Cd remediation by plants. [Display omitted] • Ramie varieties showed different adaptability on Cd contaminated paddy field. • A novel repair model of ramie floating island has been successfully established. • Multiple harvests can be carried out to achieve better remediation effects. • 20 cm of water height for the cultivation of floating island ramie was suitable. • Heavy metal activators can improve the repair effects for ramie floating island. [ABSTRACT FROM AUTHOR]

Abstract: Cecropins are linear cationic antibacterial peptides that have potent activities against microorganisms. In the present study, a 480bp full-length cDNA encoding diamondback moth (Plutella xylostella) cecropin 1 (designated as Px-cec1) was obtained using RT-PCR. A Northern blot analysis showed that the Px-cec1 transcript was predominantly expressed in fat bodies, hemocytes, midgut and epidermis with the highest expression level in fat bodies. The expression of Px-cec1 mRNA in fat bodies was significantly increased 24h after microbial challenge, with the highest induced expression by Staphylococcus aureus. A circular dichroism (CD) analysis revealed that the recombinant Px-cec1 mainly contained α-helixes. Antimicrobial assays demonstrated that recombinant Px-cec1 exhibited a broad spectrum of anti-microbial properties against fungi, Gram-positive and Gram-negative bacteria, but it did not exhibit hemolytic activity against human erythrocytes. Furthermore, Px-cec1 caused significant morphological alterations of S. aureus, as shown by scanning electron microscopy and transmission electron microscopy. These results demonstrated that Px-cec1 exerts its antibacterial activity by acting on the cell membrane to disrupt bacterial cell structures. [Copyright &y& Elsevier]

In this study, the polyphenol oxidase (PPO) activity of whole potatoes was inhibited by ultrasound. A 17-run Box-Behnken Design was used to optimize the ultrasound conditions for inhibiting the PPO activity. Three factors of ultrasound treatment including power, time, and temperature were investigated. Moreover, the effects of ultrasound treatment on the PPO activity of ultrasound-treated bruising damaged whole potatoes as well as on the micro-structure of the ultrasound-treated whole potatoes were evaluated. The adjusted coefficients of determination for models of Y 1 and Y 2 were 0.9980 and 0.9991, respectively. The p-values of two models for the responses were below 0.05, implying that the models can well represent PPO activities. The optimal ultrasound conditions were determined to be: ultrasound power 540 W, ultrasound time 15 min, and temperature 20 °C. Under these conditions, the mean PPO activities of the whole potatoes were 44.948 U/g, in accordance with the values predicted by the model. Besides, the PPO activity increases in the damaged whole potatoes. Nevertheless, the PPO activity of the ultrasound-treated whole potatoes was lower than that of untreated whole potatoes. Moreover, the power and time of ultrasound have a large impact on the micro-structures of the whole potatoes. • Polyphenol oxidase activity of whole potato was affected by ultrasound condition. • Response surface methodology was a useful tool for optimize the ultrasound condition. • The polyphenol oxidase activity of ultrasound-whole potato was increased by damage. • Ultrasound power and time have a large impact on micro-structures of whole potato. • The ultrasound has the potential for inhibiting the polyphenol oxidase activity. [ABSTRACT FROM AUTHOR]