ABSTRACT
Three phenolic endocrine-disrupting compounds, 4-nonylphenol, 4-tert-octylphenol and bisphenol A, were determined in water, sediment and biota (fish, shrimp and mollusk) collected from sites along the Pearl River Estuary, China. The 4-nonylphenol, 4-tert-octylphenol and bisphenol A concentrations ranged from 1.20-3352.86ng/L in the water, <0.17-20.80ng/g dw in the sediment and <1.49-237.12ng/g dw in the biota. The concentrations of 4-nonylphenol were higher than those of 4-tert-octylphenol and bisphenol A in the water, sediment and organisms. Moreover, the bioconcentration factors (BCFs) and biota-sediment accumulation factors (BSAFs) of 4-nonylphenol and bisphenol A were calculated, and were found to be higher for 4-nonylphenol and in demersal organisms. To assess co-exposure to phenolic endocrine-disrupting compounds, the 4-nonylphenol equivalent was employed to evaluate the potential risks to aquatic organisms and human health, and the results indicated a low risk.
Subject(s)
Endocrine Disruptors/analysis , Environmental Monitoring , Estuaries , Water Pollutants, Chemical/analysis , Animals , Benzhydryl Compounds , China , Humans , Phenols , Risk Assessment , RiversABSTRACT
Fifty-eight terrestrial and salt-tolerant myxobacteria were isolated from the saline-alkaline soils collected from Xinjiang, China. Based on the morphologies and the 16S rRNA gene sequences, these isolates were assigned into 6 genera, Myxococcus, Cystobacter, Corallococcus, Sorangium, Nannocystis and Polyangium. All the strains grew better with 1% NaCl than without NaCl. Some Myxococcus strains were able to grow at 2% NaCl concentration, suggesting that these strains may be particular type of terrestrial myxobacteria.
Subject(s)
Myxococcales/classification , Myxococcales/isolation & purification , Soil Microbiology , Soil/chemistry , China , DNA, Bacterial/genetics , Hydrogen-Ion Concentration , Myxococcales/drug effects , Myxococcales/growth & development , Phylogeny , Sequence Analysis, DNA , Sodium Chloride/pharmacologyABSTRACT
OBJECTIVE: We isolated myxobacteria in saline-alkaline soils of Xinjiang using a prey-predator strategy where the prey bacteria can induce the predator myxobacteria to form visible fruiting body, and evaluated intrinsic relationships between prey and predator myxobacteria. METHODS: Sixteen bacteria with inductive effects of fruiting body formation were obtained, and then used as preys to isolate the myxobacteria. RESULTS: A total of 55 myxobacteria strains were isolated from 25 soil samples, which were identified to the genera of Myxococcus, Corallococcus, Pyxidicoccus, Cystobacter, and Nannocystis. Besides, 6 unpurified isolates were believed to be myxobacteria. All the 16 prey bacteria had preferable inductive effects on Myxococcus spp., whereas Pyxidicoccus spp. and Cystobacter spp. were only induced by Gram-positive strains. CONCLUSION: The prey-predator strategy provided a new and more effective way to isolate myxobacteria.
