[Objective] The aim was to study on the effects of heavy metal stress on the growth curves of Escherichia coli and Bacillus subtili. [Method] Using traditional culture method,Escherichia coli and Bacillus subtili were...[Objective] The aim was to study on the effects of heavy metal stress on the growth curves of Escherichia coli and Bacillus subtili. [Method] Using traditional culture method,Escherichia coli and Bacillus subtili were cultured under heavy metal stress including Cu2＋,Hg2＋,Pb2＋,Cd2＋ and Cr6＋ in different concentrations. Then the growth curves of the bacteria were determined to investigate the effects of exogenous heavy metals on the growth of the two kinds of bacteria. [Result] The proliferation of the two bacteria was inhibited at high concentrations of Hg2＋ and Cd2＋ respectively,and G＋ is more sensitive to them than G-; when the heavy metal concentration was 50 mg/L,the toxicity of the five kinds of heavy metals on the two bacteria was Hg2＋Cd2＋Cu2＋Cr6＋≈Pb2＋. [Conclusion] The research will provide a basis to explore the effects of heavy metal on environment and ecological system.展开更多
The responses of the growth and metabolism activity of Phanerochaete chrysosporium （P. chrysosporium） to cadmium （Cd）, lead （Pb） and their combined pollution stress, were investigated in plate and liquid culture...The responses of the growth and metabolism activity of Phanerochaete chrysosporium （P. chrysosporium） to cadmium （Cd）, lead （Pb） and their combined pollution stress, were investigated in plate and liquid culture conditions. The diameter of colony, biomass ofP. chrysosporium, ligninolytic enzyme activities and bioaccumulation quantity of heavy metals were detected. The results indicated that Cd was more toxic than Pb to P. chrysosporium and the toxicity of Cd and Pb to P. chrysosporium was further strengthened under Cd＋Pb combined pollution in different culture conditions. Heavy metals Cd and Pb had indirect influence on the production of ligninolytic enzymes by directly affecting the fungal growth and metabolic activity, and by another way in liquid culture. In addition, the results provided an evidence of the accumulation of Cd and Pb on the mycelia ofP. chrysosporium.展开更多
OBJECTIVE： The increasing popularity and widespread use of traditional Chinese herbs as alterna- tive medicine have sparked an interest in understanding their biosafety, especially in decoctions that are consumed. Th...OBJECTIVE： The increasing popularity and widespread use of traditional Chinese herbs as alterna- tive medicine have sparked an interest in understanding their biosafety, especially in decoctions that are consumed. This study aimed to assess the level of microbial and heavy metal contamination in commonly consumed herbal medicine in Malay- sia and the effects of boiling on these contamination levels. METHODS： Four commonly consumed Chinese herbal medicine in Malaysia-＂Eight Treasure Herbal Tea＂, ＂Herbal Tea＂, Xiyangshen （Radix Panacis Quin- quefolii） and Dangshen （Radix Codonopsis） were evaluated in this study. Herbal medicines were pre- pared as boiled and non-boiled decoctions, and their microbial enumeration and heavy metal detection were conducted with plate assay and atom- ic absorption spectroscopy, respectively. RESULTS： Findings revealed that herbal medicines generally had 6 Iogl0cfu/mL microbial cells and that boiling had significantly reduced microbial contaminants, where no Bacillus spp., Staphylococcus spp. and Clostridium spp. were recovered. Heavy metals such as Mn, Cu, Cd, Pb, Fe and Zn were also detect- ed from all the samples, generally in low concentra- tions （〈1 mg/L） except for Mn （18.545 mg/L）. All de- coctions （after boiling） have reduced concentra- tions of Cu, while others were not significantly dif- ferent. Comparisons between samples with single and multi-herbs suggest level of microbial and metal contamination is not influenced by number of herbs in sample. CONCLUSION： Herbal medicines generally have microbial and heavy metal contaminants. However, the boiling process to generate decoctions was able to successfully reduce the number of microbes and Cu, ensuring safety of herbal medicines for consumption.展开更多
基金Supported by Science Research Fund Project of Yunnan Provincial Education Department "Physiological Toxicity of Heavy Metal Stress on Several Microorganisms" (09Y0382)Yunnan Natural Science Foundation Project "Toxicity Mechanism of Three Aquatic Plants under Heavy Metal Pollution" (2008ZC161M)~~
文摘[Objective] The aim was to study on the effects of heavy metal stress on the growth curves of Escherichia coli and Bacillus subtili. [Method] Using traditional culture method,Escherichia coli and Bacillus subtili were cultured under heavy metal stress including Cu2＋,Hg2＋,Pb2＋,Cd2＋ and Cr6＋ in different concentrations. Then the growth curves of the bacteria were determined to investigate the effects of exogenous heavy metals on the growth of the two kinds of bacteria. [Result] The proliferation of the two bacteria was inhibited at high concentrations of Hg2＋ and Cd2＋ respectively,and G＋ is more sensitive to them than G-; when the heavy metal concentration was 50 mg/L,the toxicity of the five kinds of heavy metals on the two bacteria was Hg2＋Cd2＋Cu2＋Cr6＋≈Pb2＋. [Conclusion] The research will provide a basis to explore the effects of heavy metal on environment and ecological system.
基金Projects(21477027,51278176)supported by the National Natural Science Foundation of ChinaProject(2014A020216048)supported by the Science and Technology Planning Project of Guangdong Province,ChinaProject(2015M582363)supported by the China Postdoctoral Science Foundation
文摘The responses of the growth and metabolism activity of Phanerochaete chrysosporium （P. chrysosporium） to cadmium （Cd）, lead （Pb） and their combined pollution stress, were investigated in plate and liquid culture conditions. The diameter of colony, biomass ofP. chrysosporium, ligninolytic enzyme activities and bioaccumulation quantity of heavy metals were detected. The results indicated that Cd was more toxic than Pb to P. chrysosporium and the toxicity of Cd and Pb to P. chrysosporium was further strengthened under Cd＋Pb combined pollution in different culture conditions. Heavy metals Cd and Pb had indirect influence on the production of ligninolytic enzymes by directly affecting the fungal growth and metabolic activity, and by another way in liquid culture. In addition, the results provided an evidence of the accumulation of Cd and Pb on the mycelia ofP. chrysosporium.
文摘OBJECTIVE： The increasing popularity and widespread use of traditional Chinese herbs as alterna- tive medicine have sparked an interest in understanding their biosafety, especially in decoctions that are consumed. This study aimed to assess the level of microbial and heavy metal contamination in commonly consumed herbal medicine in Malay- sia and the effects of boiling on these contamination levels. METHODS： Four commonly consumed Chinese herbal medicine in Malaysia-＂Eight Treasure Herbal Tea＂, ＂Herbal Tea＂, Xiyangshen （Radix Panacis Quin- quefolii） and Dangshen （Radix Codonopsis） were evaluated in this study. Herbal medicines were pre- pared as boiled and non-boiled decoctions, and their microbial enumeration and heavy metal detection were conducted with plate assay and atom- ic absorption spectroscopy, respectively. RESULTS： Findings revealed that herbal medicines generally had 6 Iogl0cfu/mL microbial cells and that boiling had significantly reduced microbial contaminants, where no Bacillus spp., Staphylococcus spp. and Clostridium spp. were recovered. Heavy metals such as Mn, Cu, Cd, Pb, Fe and Zn were also detect- ed from all the samples, generally in low concentra- tions （〈1 mg/L） except for Mn （18.545 mg/L）. All de- coctions （after boiling） have reduced concentra- tions of Cu, while others were not significantly dif- ferent. Comparisons between samples with single and multi-herbs suggest level of microbial and metal contamination is not influenced by number of herbs in sample. CONCLUSION： Herbal medicines generally have microbial and heavy metal contaminants. However, the boiling process to generate decoctions was able to successfully reduce the number of microbes and Cu, ensuring safety of herbal medicines for consumption.
