Cell viability in the cadmium-stressed cell suspension cultures of tobacco is regulated by extracellular ATP,possibly by a reactive oxygen species-associated mechanism

Cadmium(Cd)is one of the most widespread and toxic heavy metals to plants.Extracellular ATP(exATP)is thought to be an extracellular effector in regulating the physiological responses of plant cells to environmental stresses.However,the function of exATP in Cd-stressed plant cells is much unknown.The present work showed that treating tobacco(Nicotiana tabacum L.cv.Bright Yellow-2)cell-suspension cultures with exogenous CdCl2 reduced the cell viability,exATP level,and Mg content.However,the production of reactive oxygen species(ROS),Cd content,and electrolyte leakage of the cells were enhanced by exogenous CdCl2.When the Cd-induced accumulation of ROS was decreased by the supplement with DMTU(dimethylthiourea,a scavenger of ROS),the Cd-induced increases of the electrolyte leakage and Cd content were alleviated,and the Cd-induced reductions of cell viability were partly rescued,suggesting that Cd-induced reduction of cell viability could be related to the ROS accumulation.Under the condition of Cd stress,when the reduction of exATP level was partly rescued by exogenous ATP(20μM),the increases of ROS production,electrolyte leakage,and Cd content were attenuated,and the reduction of cell viability was also alleviated.These observations indicate that exATP can regulate the cell viability in the Cd–stressed plant cells possibly by an ROS-associated mechanism.

Antimicrobial activities and analysis of the crude extract,fractions and compounds from the Lomatogonium rotatum

This study was evaluated the antimicrobial activities of the crude extract,different fractions,and compounds from the plant of Lomatogonium carinthiacum.The fractions of chloroform and compounds 5,2 and 6 exhibited stronger antimicrobial activities.Compound 5 was the most active while Staphylococcus aureus and Candida albicans were sensitive to all the tested compounds.The existence of a relationship between the xanthone structures and inhibition of microorganism activity.The antimicrobial activity of this plant was reported here firstly.The results provided evidence that the studied plant extract,fractions as well as some of the isolated compounds might be potential sources of new antimicrobial drug.

Activity of xanthones isolated from Lomatogonium rotatum

Thirteen xanthones were isolated from L.rotatum,which were established as l,8-dihydroxy-3,4,5-trimethoxyxanthone(1);l-hydroxy-3异,8-trimethoxyxanthone(2);8-hydroxy-l,3?5-trimethoxyxaiithone(3);l-hydroxy-3,4,5-trimethoxyxanthone(4);l-hydroxy-3,5,8-trimethoxyxanthone(5);l,4,8-trihydroxy-5,6-dimethoxyxanthone(6);l,3,8-trihydroxy-4,7-dimethoxyxanthone(;7)l,8-dihydroxy-3,7-dimethoxyxanthone(8);l-hydroxy-3,5-dimethoxyxanthone(9);l-hydroxy-2,3,4,5-tetramethoxyxanthone(;10)l-hydroxy-2,3,4,7-tetramethoxyxanthone(11);l,7-dihydroxy-3,8-dimethoxyxanthone(12);rel-l,3,5,8-tetrahydroxy-2,4,6,7-tetrahydroxanthen-9-one(13).Compounds 4,6,7,9,10,11,12 and 13 are reported for the first time from Lomatogonium.Furthermore,the activity of xanthones was assessed.

Degradation of polycyclic aromatic hydrocarbons by Pseudomonas sp.JM2 isolated from active sewage sludge of chemical plant

It is important to screen strains that can decompose polycyclic aromatic hydrocarbons （PAHs） completely and rapidly with good adaptability for bioremedlation in a local area. A bacterial strain JM2, which uses pbenanthrene as its sole carbon source, was isolated from the active sewage sludge from a chemical plant in Jilin, China and identified as Pseudomonas based on 16S rDNA gene sequence analysis. Although the optimal growth conditions were determined to be pH 6.0 and 37~C, JM2 showed a broad pH and temperature profile. At pH 4.5 and 9.3, JM2 could degrade more than 40% of fluorene and phenanthrene （50 mg/L each） within 4 days. In addition, when the temperature was as low as 4~C, JM2 could degrade up to 24% fluorene and 12% phenanthrene. This showed the potential for JM2 to be applied in bioremediation over winter or in cold regions. Moreover, a nutrient augmentation study showed that adding formate into media could promote PAH degradation, while the supplement of salicylate had an inhibitive effect. Furthermore, in a metabolic pathway study, salicylate, phthalic acid, and 9-fluorenone were detected during the degradation of fluorene or phenanthrene. In conclusion, Pseudomonas sp. JM2 is a high performance strain in the degradation of fluorene and phenanthrene under extreme pH and temperature conditions. It might be useful in the bioremediation of PAHs.

Analysis of the chemical composition of Angelicae Pubescentis Radix by ultra-performance liquid chromatography and quadrupole time-of-flight tandem mass spectrometry

Angelicae Pubescentis Radix (APR, Duhuo) is a commonly used traditional Chinese medicine and usually used for the treatments of rheumatic diseases. To assess the chemical composition of APR extract, a sensitive and reliable UPLC-Q?TOF-MS method was used for qualitative analysis. The separation was achieved on an Agilent SB-Ci8 column (1.8 pm, 2.1 mm><50 mm) with a gradient elution system consisting of acetonitrile and water containing 0.1% formic acid. An electrospray ionization (ESI) was used for mass spectrometer, and the data were collected in the positive ion mode, which was operated in a full-scan mode at m/z 100-800. A total of 49 compounds including 46 coumarins were identified according to the MS and MS/MS data. Among them, two were new compounds, and isoangenomalin, scoparone, 4-methyl-umbelliferyl acetate, suberenol,/raw5-dehydroosthol, and oroselone were first reported in APR.