Genome-wide identification and expression analysis of calmodulin-like proteins in cucumber.

Background: The calmodulin-like (CML) protein is a crucial Ca2+-binding protein that can sense and conduct the Ca2+ signal in response to extracellular stimuli. The CML protein families have been identified and characterized in many species. Nevertheless, scarce information on cucumber CML is retrievable. Methods: In this study, bioinformatic analyses, including gene structure, conserved domain, phylogenetic relationship, chromosome distribution, and gene synteny, were comprehensively performed to identify and characterize CsCML gene members. Spatiotemporal expression analysis in different organs and environment conditions were assayed with real-time quantitative polymerase chain reaction (qRT-PCR). Results: Forty-four CsCMLs family members were well characterized, and the results showed that the 44 CsCML proteins contained one to four EF-hand domains without other functional domains. Most of the CsCML proteins were intron-less and unevenly distributed on seven chromosomes; two tandemly duplicated gene pairs and three segmentally duplicated gene pairs were identified in the cucumber genome. Cis-acting element analysis showed that the hormone, stress, and plant growth and development-related elements were in the promotor regions. In addition, spatiotemporal expression analysis revealed distinctive expression patterns for CsCML genes in different tissues and environmental conditions, and a putative protein interaction network also confirmed their potential role in responding to various stimuli. These results provide a foundation for understanding CsCMLs and provide a theoretical basis for further study of the physiological functions of CsCMLs.

Variety-Specific Flowering of Sugarcane Induced by the Smut Fungus Sporisorium scitamineum.

Sugarcane smut is the most severe sugarcane disease in China. The typical symptom is the emerging of a long, black whip from the top of the plant cane. However, in 2018, for the first time we observed the floral structures of sugarcane infected by smut fungus in the planting fields of China. Such smut-associated inflorescence in sugarcane was generally curved and short, with small black whips emerging from glumes of a single floret on the cane stalk. Compatible haploid strains, named Ssf1-7 (MAT-1) and Ssf1-8 (MAT-2), isolated from teliospores that formed black whips in inflorescence of sugarcane were selected for sexual mating assay, ITS DNA sequencing analysis and pathogenicity assessment. The isolates Ssf1-7 and Ssf1-8 showed stronger sexual mating capability than the reported Sporisorium scitamineum strains Ss17 and Ss18. The ITS DNA sequence of the isolates Ssf1-7 and Ssf1-8 reached 100% similarity to the isolates of S. scitamineum strains available in GenBank. Inoculating Ssf1-7 + Ssf1-8 to six sugarcane varieties, i.e., GT42, GT44, GT49, GT55, LC05-136 and ROC22, resulted in different smut morphological modifications. The symptoms of floral structure only occurred in LC05-136, indicating that the flowering induction by S. scitamineum is variety-specific. Furthermore, six selected flowering-related genes were found to be differentially expressed in infected Ssf1-7 + Ssf1-8 LC05-13 plantlets compared to uninfected ones. It is concluded that the flowering induction by S. scitamineum depends on specific fungal race and sugarcane variety, suggesting a specific pathogen-host interaction and expression of some flowering-related genes.

Postharvest melatonin treatment inhibited longan (Dimocarpus longan Lour.) pericarp browning by increasing ROS scavenging ability and protecting cytomembrane integrity.

Postharvest melatonin treatments have been reported to improve the quality and storability, especially to inhibit browning in many fruits, but the effect had not been systematically investigated on longan fruit. In this study, the effect of 0.4 mM melatonin (MLT) dipping on the quality and pericarp browning of longan fruits stored at low temperature was investigated. The MLT treatment did not influence the TSS content of longan fruits but lead to increased lightness and h° value while decreased a* value of pericarp. More importantly, the treatment significantly delayed the increase in electrolyte leakage and malonaldehyde accumulation, inhibited the activities of polyphenol oxidase and peroxidase, and thus retarded pericarp browning. In addition, the treatment significantly inhibited the production of O2 •- and H2O2 while promoted the accumulation of glutathione, flavonoids, and phenolics at earlier storage stages in longan pericarp. Interestingly, the activities of ascorbate peroxidase (APX) and superoxide dismutase (SOD) were significantly upregulated but activities of catalase were downregulated in the MLT-treated longan pericarp. MLT treatment effectively enhanced APX and SOD activities, increased flavonoid, phenolics, and glutathione content, protected cytomembrane integrity, inhibited the production of O2 •- and H2O2 and browning-related enzymes, and thus delayed the longan pericarp browning.

Widely targeted metabolic analysis revealed the changed pigmentation and bioactive compounds in the ripening Berchemia floribunda (Wall.) Brongn. fruit.

Berchemia plants were important materials for Chinese traditional medicines due to their special secondary metabolites. Unlike the root, stem and leaf tissues, Berchemia floribunda (Wall.) Brongn. fruit was lacked of systematic metabolic investigation. Biochemical analysis found that the total flavonoid and total phenolic content of Berchemia fruit pulp showed a peak value at red ripe stage, and then decreased, but the total anthocyanin content sharply increased along with the coloration. By widely targeted metabolomic analysis, 644 metabolites were identified and categorized into 23 groups mainly including flavonoid, organic acids, amino acids, lipids, phenylpropanoid, nucleotides, alkaloids, carbohydrates, alcohols, anthocyanins & proanthocyanidins, vitamins, terpenes, polyphenols, phenolamides, quinones, indole derivatives, and sterides. Among them, 111 metabolites and 123 metabolites respectively showed up- and down-regulation from break stage to full mature. KEGG enrichment analysis indicated that active secondary metabolism such as biosynthesis of phenylpropanoids, flavonoid, and alkaloids happened during Berchemia fruit ripening. More importantly, Cyanidin-3-O-galactoside and other 3 cyanidins were found to be the predominant pigments in mature Berchemia fruit and increased cyanidins and pelargonidins but decreased anthocyanins might be contributed to the purple pigmentation of Berchemia fruit. Interestingly, 29 pharmaceutical compounds previously reported in other Berchemia tissues were also detected in ripening Berchemia fruit pulp: 8 flavonoid, 2 quinones & sucrose showed up-regulated accumulation while 6 polyphenols, 5 flavonoid, 3 phenylpropanoid, 2 organic acids, 1 quinones and ß-sitosterol showed down-regulated accumulation In conclusion, our first comprehensive metabolic fingerprint will promote the further study of B. floribunda fruit and its medical and food application.

Cyclodextrin-Modified CeO2 Nanoparticles as a Multifunctional Nanozyme for Combinational Therapy of Psoriasis.

PURPOSE: Reactive oxygen species (ROS)-induced oxidative stress plays a key role in the pathogenesis and progression of psoriasis by causing inflammation. Antioxidative strategies eradicating ROS may serve as effective and easy treatment options for psoriasis, while nanozymes with intrinsic antioxidant enzyme-like activity have not been explored for psoriasis treatment. The aim of this study is to fabricate ß-cyclodextrins (ß-CDs)-modified ceria nanoparticles (ß-CDs/CeO2 NPs) with drug-loaded and multimimic-enzyme activities for combinational psoriasis therapy. METHODS: The ß-CDs/CeO2 NPs were synthesized by a hydrothermal method using unmodified ß-CDs as a protecting agent. The structure, size and morphology were analyzed by dynamic light scattering, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. Considering the superoxide dismutase (SOD)- and catalase-mimetic activities, the in vitro antioxidant activity of the ß-CDs/CeO2 NPs was investigated. After dithranol (DIT) was loaded, the drug-loading capacity and release profile were determined by UV-visible light spectrophotometer and high-performance liquid chromatography. The anti-psoriatic efficacy was studied in the imiquimod (IMQ)-induced mouse model on the basis of morphological evaluation, psoriasis area and severity index calculation (PASI), and inflammatory cytokine expression. RESULTS: The average particle size of the blank ß-CDs/CeO2 NPs was 60.89±0.32 nm with a polydispersity index (PDI) of 0.12, whereas that of the DIT-loaded NPs was 79.38±1.06 nm with a PDI of 0.27. TEM results showed the as-prepared NPs formed a uniform quasi-spherical shape with low polydispersity. XPS indicates synthesized NPs have a mixed Ce3+/Ce4+ valence state. FTIR spectroscopy confirmed the presence of ß-CDs and DIT in the NPs. Inhibition of superoxide anion rate by NPs could be reached to 79.4% in the presence of 200 µg/mL, and elimination of H2O2 efficiency reached about 50% in the presence of 40 µg/mL, demonstrating excellent superoxide dismutase- and catalase-mimicking activities, thereby providing remarkable cryoprotection against ROS-mediated damage. Furthermore, ß-CDs on the surface endowed the NPs with drug-loading function via host-guest interactions. The entrapment efficiency and drug loading of DIT are 94.7% and 3.48%, respectively. The in vitro drug release curves revealed a suitable release capability of DIT@ß-CDs/CeO2 NPs under physiological conditions. In IMQ-induced psoriatic model, the DIT@ß-CDs/CeO2 NPs exhibited excellent therapeutic effect. CONCLUSION: This study may pave the way for the application of nanozyme ß-CDs/CeO2 NPs as a powerful tool for psoriasis therapy.

Role of phospholipase C in banana in response to anthracnose infection.

Phospholipase C (PLC) plays an important role in plant immunity, and anthracnose caused by the Colletotrichum species is a common postharvest disease of the banana fruit. This study aims to evaluate the role of PLC in anthrax resistance in banana. The experimental group of banana samples was treated with a banana anthracnose conidia suspension, and the control group was treated with distilled water. After inoculation, the groups were sprayed with ethephon, and indicators, such as hardness and conductivity changes; PLC activity, 1,2-diacylglycerol (DAG) and phosphatidic acid (PA)content; and MaPLC-1and MaPLC-2 expression levels, were assessed at 0, 3, 6, 9, 12, and 15 days. Moreover, the expression levels of MaPLC-1 and MaPLC-2 were detected in various tissues. The hardness of banana fruits in the experimental group decreased faster than that in the control group. Furthermore, the conductivity was higher in the experimental group than in the control group. Regarding PLC activity, DAG, and PA content, bananas in the experimental group showed higher activities than those in the control group. Moreover, relatively higher expression of PLC mRNA was detected in anthracnose-inoculated tissues. The evaluation of MaPLC-1 and MaPLC-2 expression levels showed that the mature peel had the highest MaPLC-1 expression level. However, the MaPLC-2 gene was expressed at relatively low levels in the fruit and at relatively high levels in the flower organs. PLC might play a role in fruit ripening in response to anthracnose resistance.

Soluble Acid Invertases Act as Key Factors Influencing the Sucrose/Hexose Ratio and Sugar Receding in Longan ( Dimocarpus longan Lour.) Pulp.

Soluble acid invertases (SAIs) cleave sucrose into hexose in vacuoles and play important roles in influencing fruit quality. However, their potential roles in regulating sugar composition and the "sugar receding" process of longan fruits lacked systematic investigations. Our results showed that sucrose/hexose ratios and sugar receding rates of longan pulp varied among cultivars. Analysis of enzymes for sucrose synthesis and cleavage indicated that DlSAI showed the highest negative correlation with sucrose/hexose ratio at both of activity and expression level. Moreover, high SAI activity and DlSAI expression resulted in extremely low sucrose/hexose ratio in 'Luosanmu' longan from development to mature stages and a remarkable loss of sugar in 'Shixia' longan fruits during on-tree preservation. In conclusion, DlSAIs act as key factors influencing sucrose/hexose ratio and sugar receding through transcriptional and enzymatic regulations. These results might help improve the quality of on-tree preserved longan.

Highly efficient photodimerization of olefins in a nanotemplate on HOPG by scanning tunneling microscopy.

Efficient photochemical reactions on a surface are of great importance for their potential applications in optoelectronic devices. In this work, a highly efficient photodimerization reaction of an olefin cocrystal built from two trans-1,2-bis(4-pyridyl)ethylenes (4,4'-bpe) and two isophthalic acid molecules via N···H-O hydrogen bonds in between was achieved in a nanotemplate on a highly oriented pyrolytic graphite (HOPG) surface. 4,4'-Bpe molecules first undergo the trans-cis isomerization followed by [2+2] photodimerization in the nanotemplate on HOPG upon UV irradiation. The efficiency of the isomerization as well as the photodimerization in the presence of the nanotemplate is much higher than that in its absence. These results provide a facile way to achieve highly efficient photodimerization of olefins on a large scale on surfaces.

Polymerization or cyclic dimerization: solvent dependent homo-coupling of terminal alkynes at HOPG surface.

Surface reactivity has become one of the most important issues in surface chemistry over the past few years. In this work, we, for the first time, have investigated the homo-coupling of a special terminal alkyne derivative on the highly oriented pyrolitic graphite (HOPG) surface. Using scanning tunneling microscopy (STM) technique, we have found that such coupling reaction seriously depends on the supramolecular assembly of the monomer on the studied substrate, whereas the latter appears an obvious solvent effect. As a result, the reaction in our system undergoes polymerization and cyclic dimerization process in 1-phenyloctane and 1,2,4-trichlorobenzene, respectively. That is to say, the solvent effect can be extended from the two-dimensional (2D) supramolecular self-assembly to surface chemical reactions, and the selective homo-coupling has been successfully achieved at the solid/liquid interface.