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Are we biologically safe with snow precipitation? A case study in beijing.

Shen F, Yao M - PLoS ONE (2013)

Bottom Line: The results revealed that snow samples had bacterial concentrations as much as 16000 CFU/ml for those cultured at 26°C, and the conductance levels ranged from 5.6×10(-6) to 2.4×10(-5) S.Absent from the outdoor air, certain human, plant, and insect fungal pathogens were found in the snow samples.The results here suggest that snow precipitations are important sources of fungal pathogens and ice nucleators, thus could affect local climate, human health and agriculture security.

View Article: PubMed Central - PubMed

Affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China.

ABSTRACT
In this study, the bacterial and fungal abundances, diversities, conductance levels as well as total organic carbon (TOC) were investigated in the snow samples collected from five different snow occurrences in Beijing between January and March, 2010. The collected snow samples were melted and cultured at three different temperatures (4, 26 and 37°C). The culturable bacterial concentrations were manually counted and the resulting colony forming units (CFUs) at 26°C were further studied using V3 region of 16 S rRNA gene-targeted polymerase chain reaction -denaturing gradient gel electrophoresis (PCR-DGGE). The clone library was constructed after the liquid culturing of snow samples at 26°C. And microscopic method was employed to investigate the fungal diversity in the samples. In addition, outdoor air samples were also collected using mixed cellulose ester (MCE) filters and compared with snow samples with respect to described characteristics. The results revealed that snow samples had bacterial concentrations as much as 16000 CFU/ml for those cultured at 26°C, and the conductance levels ranged from 5.6×10(-6) to 2.4×10(-5) S. PCR-DGGE, sequencing and microscopic analysis revealed remarkable bacterial and fungal diversity differences between the snow samples and the outdoor air samples. In addition, DGGE banding profiles for the snow samples collected were also shown distinctly different from one another. Absent from the outdoor air, certain human, plant, and insect fungal pathogens were found in the snow samples. By calculation, culturable bacteria accounted for an average of 3.38% (±1.96%) of TOC for the snow samples, and 0.01% for that of outdoor air samples. The results here suggest that snow precipitations are important sources of fungal pathogens and ice nucleators, thus could affect local climate, human health and agriculture security.

Show MeSH
The total organic carbon (TOC) concentrations (mg/L) in snow samples and an outdoor air sample collected in January-March, 2010 in Beijing.Data points represent averages of the mixture of snow samples collected from five different locations; outdoor air samples were collected using a MCE filter.
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pone-0065249-g008: The total organic carbon (TOC) concentrations (mg/L) in snow samples and an outdoor air sample collected in January-March, 2010 in Beijing.Data points represent averages of the mixture of snow samples collected from five different locations; outdoor air samples were collected using a MCE filter.

Mentions: It was shown that bacterial and fungal species contribute to the total carbon in the atmosphere [16], [55]. Here, the total oragnic carbon (TOC) in the snow samples and the outdoor air sample were also measured and presented in Fig. 8. In this work, TOC levels with similar magnitudes were found among different snow samples, however for the outdoor air samples (540 L of air extracted into 4 ml DI water) the TOC levels were shown to be substantially higher, ranging from 6 to 16 times of those of the snow samples. However, it is difficult to quantitatively assess the comparison because of different collection methods for the snow samples and the outdoor air. According to the conversion factor of 17 fg carbon per bacterium [42], culturable bacteria in the snow samples collected in this work were calculated to account for an average of 3.38%(±1.96%) of TOC, while those in the outdoor air samples accounted for about 0.01%. Therefore, outdoor air sample might have had larger TOC contribution from other sources rather than the bacteria than the snow samples. In a previous study, it was found that the most abundant group of organic compounds in the aerosol samples were phthalic acid esters with diisobutylphthalate as the main substance, which was considered to originate from local emisisons [58]. In their study, they also found that diisobutylphthalate was the dominant substance in snow samples. It was shown in a previous study that total bacteria in cloud water accounted for about 1.5% of TOC [16]. In this work, only culturable bacteria were used, thus the actual contributions could be higher if those non-living ones are also included.


Are we biologically safe with snow precipitation? A case study in beijing.

Shen F, Yao M - PLoS ONE (2013)

The total organic carbon (TOC) concentrations (mg/L) in snow samples and an outdoor air sample collected in January-March, 2010 in Beijing.Data points represent averages of the mixture of snow samples collected from five different locations; outdoor air samples were collected using a MCE filter.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3675146&req=5

pone-0065249-g008: The total organic carbon (TOC) concentrations (mg/L) in snow samples and an outdoor air sample collected in January-March, 2010 in Beijing.Data points represent averages of the mixture of snow samples collected from five different locations; outdoor air samples were collected using a MCE filter.
Mentions: It was shown that bacterial and fungal species contribute to the total carbon in the atmosphere [16], [55]. Here, the total oragnic carbon (TOC) in the snow samples and the outdoor air sample were also measured and presented in Fig. 8. In this work, TOC levels with similar magnitudes were found among different snow samples, however for the outdoor air samples (540 L of air extracted into 4 ml DI water) the TOC levels were shown to be substantially higher, ranging from 6 to 16 times of those of the snow samples. However, it is difficult to quantitatively assess the comparison because of different collection methods for the snow samples and the outdoor air. According to the conversion factor of 17 fg carbon per bacterium [42], culturable bacteria in the snow samples collected in this work were calculated to account for an average of 3.38%(±1.96%) of TOC, while those in the outdoor air samples accounted for about 0.01%. Therefore, outdoor air sample might have had larger TOC contribution from other sources rather than the bacteria than the snow samples. In a previous study, it was found that the most abundant group of organic compounds in the aerosol samples were phthalic acid esters with diisobutylphthalate as the main substance, which was considered to originate from local emisisons [58]. In their study, they also found that diisobutylphthalate was the dominant substance in snow samples. It was shown in a previous study that total bacteria in cloud water accounted for about 1.5% of TOC [16]. In this work, only culturable bacteria were used, thus the actual contributions could be higher if those non-living ones are also included.

Bottom Line: The results revealed that snow samples had bacterial concentrations as much as 16000 CFU/ml for those cultured at 26°C, and the conductance levels ranged from 5.6×10(-6) to 2.4×10(-5) S.Absent from the outdoor air, certain human, plant, and insect fungal pathogens were found in the snow samples.The results here suggest that snow precipitations are important sources of fungal pathogens and ice nucleators, thus could affect local climate, human health and agriculture security.

View Article: PubMed Central - PubMed

Affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China.

ABSTRACT
In this study, the bacterial and fungal abundances, diversities, conductance levels as well as total organic carbon (TOC) were investigated in the snow samples collected from five different snow occurrences in Beijing between January and March, 2010. The collected snow samples were melted and cultured at three different temperatures (4, 26 and 37°C). The culturable bacterial concentrations were manually counted and the resulting colony forming units (CFUs) at 26°C were further studied using V3 region of 16 S rRNA gene-targeted polymerase chain reaction -denaturing gradient gel electrophoresis (PCR-DGGE). The clone library was constructed after the liquid culturing of snow samples at 26°C. And microscopic method was employed to investigate the fungal diversity in the samples. In addition, outdoor air samples were also collected using mixed cellulose ester (MCE) filters and compared with snow samples with respect to described characteristics. The results revealed that snow samples had bacterial concentrations as much as 16000 CFU/ml for those cultured at 26°C, and the conductance levels ranged from 5.6×10(-6) to 2.4×10(-5) S. PCR-DGGE, sequencing and microscopic analysis revealed remarkable bacterial and fungal diversity differences between the snow samples and the outdoor air samples. In addition, DGGE banding profiles for the snow samples collected were also shown distinctly different from one another. Absent from the outdoor air, certain human, plant, and insect fungal pathogens were found in the snow samples. By calculation, culturable bacteria accounted for an average of 3.38% (±1.96%) of TOC for the snow samples, and 0.01% for that of outdoor air samples. The results here suggest that snow precipitations are important sources of fungal pathogens and ice nucleators, thus could affect local climate, human health and agriculture security.

Show MeSH