Microbulbifer litoralis sp. nov., Isolated from Seashore of Weizhou Island.

A bacterium designated GXH0434T was isolated from sea shore samples collected from Weizhou Island, Beihai, Guangxi, China. The organism is motile, strictly aerobic, and possesses a rod-coccus cell cycle in association with the growth phase. It can grow at 15-45 °C (optimum 37 °C), at pH 6.0-11.0 (optimum 6.0), and at 0-20% (w/v) NaCl (optimum 5.0-8.0%). The strain is positive for peroxidase and oxidase activity, negative for Voges-Proskauer test, can hydrolyze Tween 20, Tween 60, Tween 80, casein, and is able to produce siderophore and has the function of nitrogen fixation. Molecular phylogenetic analysis based on 16S rRNA gene sequences indicated that GXH0434T was most closely related to Microbulbifer halophilus KCTC 12848T with the similarity of 97.2%, followed by Microbulbifer chitinilyticus JCM 16148T (97.1%) and Microbulbifer taiwanensis LMG 26125T (96.5%). The digital DNA-DNA hybridization and the average nucleotide identity values between GXH0434T and Microbulbifer halophilus KCTC 12848T were 28.90% and 83.38%, respectively, which were below thresholds of species delineation. The genomic DNA G+C content of the strain was 61.9%. The major fatty acids were iso-C15:0, C16:0, iso-C11:0 3-OH, iso-C11:0 and Summed features 8 (C18:0 ω7c and/or C18:0 ω6c). The major polar lipids detected in GXH0434T were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylcholine (PC). The major respiratory quinone was ubiquinone Q-8. Based on the above polyphasic classification indicated strain GXH0434T represents a novel species of the genus Microbulbifer, for which the name Microbulbifer litoralis sp. nov. is proposed. The type strain is GXH0434T (= MCCC 1K07158T = KCTC 92169T).

Transcriptome analysis of the growth-promoting effect of volatile organic compounds produced by Microbacterium aurantiacum GX14001 on tobacco (Nicotiana benthamiana).

BACKGROUND: Plant growth-promoting rhizobacteria (PGPR) release volatile organic compounds (VOCs), which promote plant growth. RESULTS: A potential PGPR strain GX14001 was isolated from marine samples, and the VOCs produced by GX14001 significantly promoted tobacco (Nicotiana benthamiana) growth in a plate experiment. Based on 16S rRNA sequence alignment and physiological and biochemical characterization, GX14001 was identified as Microbacterium aurantiacum. Comparative transcriptome analysis was conducted between GX14001 VOCs-treated tobacco and the control; it was found that 1286 genes were upregulated and 1088 genes were downregulated. Gene ontology (GO) analysis showed that upregulated genes were involved in three biological processes: polysaccharide metabolic, polysaccharide catabolic and carbohydrate metabolic. The downregulated genes were involved in six biological processes, namely cell redox homeostasis, cellular homeostasis, carbohydrate metabolic process, homeostatic process, obsolete electron transport, and regulation of biological quality. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis showed that 190 upregulated differentially expressed genes were mainly involved in plant hormone signal transduction, phenylpropyl biosynthesis, plant-pathogen interaction, and flavonoid biosynthesis. The 148 downregulated differentially expressed genes were mainly involved in plant hormone signal transduction and the metabolism of ascorbic, aldehyde, and pyruvate acids. Further analysis revealed that many genes were differentially expressed in the metabolic pathways of plant hormone signals, which were speculated to be the main reason why GX14001 VOCs promoted tobacco growth. To further study its regulatory mechanism, we found that GX14001 promoted plant growth through auxin, salicylic acid, and gibberellin in Arabidopsis mutant experiments. CONCLUSION: The VOCs produced by Microbacterium aurantiacum GX14001 may promote the growth of tobacco through the auxin, salicylic acid and gibberellin pathways.

Isolation and characterization of a new bioactive isoflavone from Derris eriocarpa.

Derris eriocarpa How is an important medicinal plant, which is used as Zhuang ethnomedicine and Dai ethnomedicine to treat various diseases. One new compound, 3',4'-di-O-methylene-5-hydroxy-7-methoxy-6-isopentenyl isoflavone (1) and a known synthetic but new naturally occurring compound trans-3,4,5-trimethoxy-4'-isopentenyloxyl-stilbene (2), together with five known compounds, 5,7-dimethoxy-6-(3-methyl-2-butenyl)-4'-hydroxyl isoflavones (3), robustone (4), trans-3,4,5,4'-tetramethoxy-stilbene (5), robustic acid (6), and robustin (7) were isolated from the stem of D. eriocarpa. Spectroscopic analysis revealed the chemical structures of compounds 1-7.. Compounds 1 and 3 exhibited significant scavenging activities against 1,1-diphenyl-2-picrylhydrazyl radical and superoxide anions. Compounds 1-3 exhibited potent antiproliferative activity on Hela cells.

Preparation, characterization, and application of gallic acid-mediated photodynamic chitosan-nanocellulose-based films.

In this study, an active film composed of gallic acid (GA), chitosan (CS), and cellulose nanocrystals (CNC) was prepared using a solution casting method and synergistic photodynamic inactivation (PDI) technology. Characterization of the film showed that the CS-CNC-GA composite film had high transparency and UV-blocking ability. The addition of GA (0.2 %-1.0 %) significantly enhanced the mechanical properties, water resistance, and thermal stability of the film. The tensile strength increased up to 46.30 MPa, and the lowest water vapor permeability was 1.16 × e-12 g/(cm·s·Pa). The PDI-treated CS-CNC-GA1.0 composite film exhibited significantly enhanced antibacterial activity, with inhibition zone diameters of 31.83 mm against Staphylococcus aureus and 21.82 mm against Escherichia coli. The CS-CNC-GA composite film also showed good antioxidant activity. Additionally, the CS-CNC-GA1.0 composite film generated a large amount of singlet oxygen under UV-C light irradiation. It was found that using the CS-CNC-GA1.0 composite film for packaging and storage of oysters at 4 °C effectively delayed the increase in pH, total colony count, and lipid oxidation in oysters. In conclusion, the CS-CNC-GA composite film based on PDI technology has great potential for applications in the preservation of aquatic products.

Discovery of a triphenylamine-benzofuran derivative as fluorescent probe for hydrogen polysulfide in tea samples.

In this work, a novel triphenylamine-benzofuran derived fluorescent probe, TBF-SS, was developed for detecting hydrogen polysulfide in tea samples and intracellular imaging. TBF-SS showed the practical advantages including high sensitivity (LOD = 0.01 µM), high selectivity, rapid response (within 15 min), and steadiness in various environmental conditions. The detecting system was steady within pH range of 6.0-11.0 and temperature range of 20-55 °C. The probe TBF-SS could guarantee the stable detection of H2Sn for 7 d in storage of either solid or solution. In particular, in the application of various tea samples with different brewing times and testing temperatures, the recovery percentages varied in the range of 95.22 % to 105.0 %. Therefore accurate monitoring of H2Sn could be achieved by using the probe TBF-SS. In addition, TBF-SS could monitor the exogenous level, the ß-lapachone-induced generation and the tea-sample-treated introduction of H2Sn in living MCF-7 cells. This work might inspire the improvement of the serviceability of fluorescent implements.

A new isoflavone from the stems of Derris eriocarpa How.

A preliminary screening test was performed to discover new antihyperlipidaemic active compounds from the leguminous plant Derris eriocarpa How. A new compound, derris-isoflavone F (1), and derrubone dimethyl ether (6), a known synthetic compound of natural origin, were isolated from the stems of D. eriocarpa alongside eight recognised compounds. To our knowledge, this is the first instance of documenting the identification of compounds 1-10 from this plant. The new compound were evaluated for their antihyperlipidemic and antiproliferative properties. Compound 1 evidently reduced the triglyceride (TG) content in oleic acid-treated HepG2 cells, which validated its efficacy as a potential TG-lowering agent.

Design, synthesis and biological evaluation of a series of new resveratrol analogues as potential anti-cancer agents.

A series of novel resveratrol derivatives were designed, synthesized and evaluated as anti-cancer agents. Most of the compounds showed significant anti-proliferative activities against three human cancer cell lines (HepG2, A549 and Hela). Among these compounds, compound r displayed the most potent inhibitory activity and showed low cytotoxic activity. Cell apoptosis and cell cycle assays demonstrated that compound r significantly induced apoptosis (p < 0.001) and arrested cell cycle at S phase. Immunofluorescence microscopy analysis showed compound r disrupted the tubulin network. Docking simulations supported the pharmacological results of compound r. It is believed that this work would be very useful for designing a new series of tubulin inhibitors.