Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not mee...Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not meet the requirements of analysis for time-sensitive samples and/or complicated environmental samples. Since energy-dispersive X-ray spectrometry(EDS) can be used to simultaneously detect multiple elements in a sample, including sulfur, with minimal sample treatment, this technology was applied to detect sulfur-oxidizing bacteria using their high sulfur content within the cell. This article describes the application of scanning electron microscopy imaging coupled with EDS mapping for quick detection of sulfur oxidizers in contaminated environmental water samples, with minimal sample handling. Scanning electron microscopy imaging revealed the existence of dense granules within the bacterial cells, while EDS identified large amounts of sulfur within them. EDS mapping localized the sulfur to these granules. Subsequent 16S rRNA gene sequencing showed that the bacteria detected in our samples belonged to the genus Chromatium, which are sulfur oxidizers. Thus, EDS mapping made it possible to identify sulfur oxidizers in environmental samples based on localized sulfur within their cells, within a short time(within 24 h of sampling). This technique has wide ranging applications for detection of sulfur bacteria in environmental water samples.展开更多
Stable isotope values of oxygen （180） and hydrogen （2H） of surface waters were used to study the origin and environmental significanees in the Issyk-Kul basin of Kyrgyzstan in Central Asia, which is the most impor...Stable isotope values of oxygen （180） and hydrogen （2H） of surface waters were used to study the origin and environmental significanees in the Issyk-Kul basin of Kyrgyzstan in Central Asia, which is the most important intermountain basin in the modern Tien Shan orogen. This study is the first analysis of hydrochemical spatial differentiation in the stable isotopes of surface waters in this watershed. 75 samples were collected from rivers, springs, lakes, rain and snow during the rainy season in July and August of 2o16. Stable isotopes of 180 and 2H were studied for all samples, and cation ratios （Sr/Ca and Mg/Ca） were also determined for lake water samples. Stable isotope values from precipitation scattered around the Local Meteoric Water Line （determined from Urumqi Station of the global network of isotopes in precipitation （GNIP））, together with values of the Deuterium excess parameter （d） from 15.3‰ to 30.5‰, with an average of 19.8‰, indicating that the moisture sources are primarily from regions with low relative humidity. The 8180 and 52H values were significantly different between the river and lake samples, indicating that regional evaporation caused the isotopic enrichment of lake water. Geospatial autocorrelation, measured by Moran＇s I coefficient, indicated weak spatial autocorrelation within stable isotopes of oxygen and hydrogen in the surface waters of the studied area, which is primarily an effect of climate during the water chemistry evolution. The cation ratios Sr/Ca and Mg/Ca in lake water samples were not correlated with the concentration of total dissolved solids, but did show correlation with stable isotopic values, which is significant for paleoenvironmental reconstruction.展开更多
Legionellae are found in freshwater environments or wet soil, but the major reservoirs are man-made aquatic environments, particularly warm water systems. Our aim was to study the occurrence of Legionella contaminatio...Legionellae are found in freshwater environments or wet soil, but the major reservoirs are man-made aquatic environments, particularly warm water systems. Our aim was to study the occurrence of Legionella contamination in hot potable water supply systems in apartment and public buildings. Correlations between Legionella spp. positive cases and water source, sampling point and temperature of hot water at the point of consumption were studied. A total of 149 hot water samples were collected in 16 cities and districts of Latvia. Only Legionella pneumophila was isolated. L. pneumophila was found in 63 out of 149 （42%） hot water samples. From all Legionella spp. positive samples, 17% represented L. pneumophila serogroup 1 and 78% L. pneumophila serogroups 2-14 （15）. In 5% of Legionella spp. positive samples, both serogroups 1 and 2-14（15） were isolated. Statistically significant differences were observed in the distribution of L. pneumophila serogroup 1 in samples from various water sources. L. pneumophila was found in 45% of samples from private apartments and in 27% of samples from public buildings. Data analysis confirmed that the temperature of hot water significantly affects the frequency of L. pneumophila positive cases （p 〈 0.05）. Data showed that 85% of consumers received hot water at a temperature below 50°C.展开更多
Moulds have been reported to destroy volumes of timbers in buildings annually. As a result, timber components within the built environment decline and fail to fulfill their basic requirements. This research focused on...Moulds have been reported to destroy volumes of timbers in buildings annually. As a result, timber components within the built environment decline and fail to fulfill their basic requirements. This research focused on the isolation and evaluation of the prevalence and effects of deteriorating moulds in the rain forest and swampy rain forest regions of Nigeria where the water activity is as high as 0.7. To accomplish this, decayed timber samples were aseptically collected on buildings from six strategic locations. The samples were serially diluted and inoculated onto Sabouraud Dextrose Agar medium in Petal dishes. The Petri dishes were incubated for 72 h at 30 ~C. Thereafter, moulds were isolated through visual and microscopic observations. The commonly encountered moulds were evaluated and analyzed. It was observed that, prevalence of moulds on buildings used for non residential purpose were higher. There was no significant difference between the prevalence on the components located inside the building and those outside the building. Ceiba pentandra exhibited highest degradation while Masonia altissima resisted most. The most deteriorating moulds were Aspergillus, Mucor, Rhizopus and Gliocladium. The deteriorations of Ceiba pentandra, Afzelia africana, Lophira alata, Anogessus leocarpus and Gossweilerodendron balsamiferum timbers under Aspergillus attack were projected.展开更多
基金Supported by the Basic Scientific Fund for National Public Research Institutes of China(Nos.GY02-2011T10,2015P07)the Qingdao Talent Program(No.13-CX-20)+1 种基金the National Natural Science Foundation of China(Nos.31100567,41176061)the National Natural Science Foundation for Creative Groups(No.41521064)
文摘Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not meet the requirements of analysis for time-sensitive samples and/or complicated environmental samples. Since energy-dispersive X-ray spectrometry(EDS) can be used to simultaneously detect multiple elements in a sample, including sulfur, with minimal sample treatment, this technology was applied to detect sulfur-oxidizing bacteria using their high sulfur content within the cell. This article describes the application of scanning electron microscopy imaging coupled with EDS mapping for quick detection of sulfur oxidizers in contaminated environmental water samples, with minimal sample handling. Scanning electron microscopy imaging revealed the existence of dense granules within the bacterial cells, while EDS identified large amounts of sulfur within them. EDS mapping localized the sulfur to these granules. Subsequent 16S rRNA gene sequencing showed that the bacteria detected in our samples belonged to the genus Chromatium, which are sulfur oxidizers. Thus, EDS mapping made it possible to identify sulfur oxidizers in environmental samples based on localized sulfur within their cells, within a short time(within 24 h of sampling). This technique has wide ranging applications for detection of sulfur bacteria in environmental water samples.
基金supported by the Science and Technology Service Network Fund Project in the Chinese Academy of Sciences (TSS-2015-014-FW1-2)National Natural Science Foundation of China (U1603242+2 种基金 41471173)West Light Foundation of the Chinese Academy of Sciences (2016-QNXZ-A4)Youth Innovation Promotion Association, Chinese Academy of Sciences (2014390)
文摘Stable isotope values of oxygen （180） and hydrogen （2H） of surface waters were used to study the origin and environmental significanees in the Issyk-Kul basin of Kyrgyzstan in Central Asia, which is the most important intermountain basin in the modern Tien Shan orogen. This study is the first analysis of hydrochemical spatial differentiation in the stable isotopes of surface waters in this watershed. 75 samples were collected from rivers, springs, lakes, rain and snow during the rainy season in July and August of 2o16. Stable isotopes of 180 and 2H were studied for all samples, and cation ratios （Sr/Ca and Mg/Ca） were also determined for lake water samples. Stable isotope values from precipitation scattered around the Local Meteoric Water Line （determined from Urumqi Station of the global network of isotopes in precipitation （GNIP））, together with values of the Deuterium excess parameter （d） from 15.3‰ to 30.5‰, with an average of 19.8‰, indicating that the moisture sources are primarily from regions with low relative humidity. The 8180 and 52H values were significantly different between the river and lake samples, indicating that regional evaporation caused the isotopic enrichment of lake water. Geospatial autocorrelation, measured by Moran＇s I coefficient, indicated weak spatial autocorrelation within stable isotopes of oxygen and hydrogen in the surface waters of the studied area, which is primarily an effect of climate during the water chemistry evolution. The cation ratios Sr/Ca and Mg/Ca in lake water samples were not correlated with the concentration of total dissolved solids, but did show correlation with stable isotopic values, which is significant for paleoenvironmental reconstruction.
文摘Legionellae are found in freshwater environments or wet soil, but the major reservoirs are man-made aquatic environments, particularly warm water systems. Our aim was to study the occurrence of Legionella contamination in hot potable water supply systems in apartment and public buildings. Correlations between Legionella spp. positive cases and water source, sampling point and temperature of hot water at the point of consumption were studied. A total of 149 hot water samples were collected in 16 cities and districts of Latvia. Only Legionella pneumophila was isolated. L. pneumophila was found in 63 out of 149 （42%） hot water samples. From all Legionella spp. positive samples, 17% represented L. pneumophila serogroup 1 and 78% L. pneumophila serogroups 2-14 （15）. In 5% of Legionella spp. positive samples, both serogroups 1 and 2-14（15） were isolated. Statistically significant differences were observed in the distribution of L. pneumophila serogroup 1 in samples from various water sources. L. pneumophila was found in 45% of samples from private apartments and in 27% of samples from public buildings. Data analysis confirmed that the temperature of hot water significantly affects the frequency of L. pneumophila positive cases （p 〈 0.05）. Data showed that 85% of consumers received hot water at a temperature below 50°C.
文摘Moulds have been reported to destroy volumes of timbers in buildings annually. As a result, timber components within the built environment decline and fail to fulfill their basic requirements. This research focused on the isolation and evaluation of the prevalence and effects of deteriorating moulds in the rain forest and swampy rain forest regions of Nigeria where the water activity is as high as 0.7. To accomplish this, decayed timber samples were aseptically collected on buildings from six strategic locations. The samples were serially diluted and inoculated onto Sabouraud Dextrose Agar medium in Petal dishes. The Petri dishes were incubated for 72 h at 30 ~C. Thereafter, moulds were isolated through visual and microscopic observations. The commonly encountered moulds were evaluated and analyzed. It was observed that, prevalence of moulds on buildings used for non residential purpose were higher. There was no significant difference between the prevalence on the components located inside the building and those outside the building. Ceiba pentandra exhibited highest degradation while Masonia altissima resisted most. The most deteriorating moulds were Aspergillus, Mucor, Rhizopus and Gliocladium. The deteriorations of Ceiba pentandra, Afzelia africana, Lophira alata, Anogessus leocarpus and Gossweilerodendron balsamiferum timbers under Aspergillus attack were projected.
