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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.

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Dendrograms obtained from the DGGE profiles of different snow samples processed as described in Fig.3. Direct PCR-DGGE, liquid culturing followed by PCR-DGGE, and liquid-plate culturing followed by PCR-DGGE; 2–6: snow samples collected in Beijing from five different snow occurrences that happened on March 14, 8, 1, Feb 7 and January 1 of 2010.
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pone-0065249-g004: Dendrograms obtained from the DGGE profiles of different snow samples processed as described in Fig.3. Direct PCR-DGGE, liquid culturing followed by PCR-DGGE, and liquid-plate culturing followed by PCR-DGGE; 2–6: snow samples collected in Beijing from five different snow occurrences that happened on March 14, 8, 1, Feb 7 and January 1 of 2010.

Mentions: In our work, different culturing methods for the bacterial diversity analysis were also investigated in addition to the agar plate culturing followed by PCR-DGGE. Fig. 3 shows the results obtained using three additional methods: direct PCR-DGGE, liquid culturing followed by PCR-DGGE, and liquid-plate culturing followed by PCR-DGGE. As observed in Fig. 3, the direct PCR-DGGE method resulted in poorest quality of DGGE banding profiles for all snow samples as a result of PCR inhibitions, which was likely due to the complex environmental matrix in the snow samples, while the liquid culturing followed by PCR-DGGE performed best among these three methods. Similar to the results obtained using agar plate culturing shown in Fig. 2, there were distinct differences observed in the bacterial diversities of the snow samples collected. Dendrograms tree analysis shown in Fig. 4 indicated that the diversity similarity was as low as 30% between some snow samples collected and the outdoor air samples. As observed in Fig. 2 and Fig. 3, different methods produced different banding profiles for the snow samples. Among the culturing methods investigated, the plate culturing followed by PCR-DGGE method produced the best banding profiles. For liquid culturing type methods, there might be fast bacteria growers in the snow samples, which could overgrow and suppress others.


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

Shen F, Yao M - PLoS ONE (2013)

Dendrograms obtained from the DGGE profiles of different snow samples processed as described in Fig.3. Direct PCR-DGGE, liquid culturing followed by PCR-DGGE, and liquid-plate culturing followed by PCR-DGGE; 2–6: snow samples collected in Beijing from five different snow occurrences that happened on March 14, 8, 1, Feb 7 and January 1 of 2010.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0065249-g004: Dendrograms obtained from the DGGE profiles of different snow samples processed as described in Fig.3. Direct PCR-DGGE, liquid culturing followed by PCR-DGGE, and liquid-plate culturing followed by PCR-DGGE; 2–6: snow samples collected in Beijing from five different snow occurrences that happened on March 14, 8, 1, Feb 7 and January 1 of 2010.
Mentions: In our work, different culturing methods for the bacterial diversity analysis were also investigated in addition to the agar plate culturing followed by PCR-DGGE. Fig. 3 shows the results obtained using three additional methods: direct PCR-DGGE, liquid culturing followed by PCR-DGGE, and liquid-plate culturing followed by PCR-DGGE. As observed in Fig. 3, the direct PCR-DGGE method resulted in poorest quality of DGGE banding profiles for all snow samples as a result of PCR inhibitions, which was likely due to the complex environmental matrix in the snow samples, while the liquid culturing followed by PCR-DGGE performed best among these three methods. Similar to the results obtained using agar plate culturing shown in Fig. 2, there were distinct differences observed in the bacterial diversities of the snow samples collected. Dendrograms tree analysis shown in Fig. 4 indicated that the diversity similarity was as low as 30% between some snow samples collected and the outdoor air samples. As observed in Fig. 2 and Fig. 3, different methods produced different banding profiles for the snow samples. Among the culturing methods investigated, the plate culturing followed by PCR-DGGE method produced the best banding profiles. For liquid culturing type methods, there might be fast bacteria growers in the snow samples, which could overgrow and suppress others.

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