AIMS: To provide information on the time-dependent behaviour of microbe staining by fluorescent dyes in the order of seconds, which is important in terms of the recent rapid and online techniques for microbe measurements and/or environmental microbe analysis. METHODS AND RESULTS: For combinations of yeast (Saccharomyces cerevisiae) and typical dyes, including DAPI (4',6-diamidino-2-phenylindole) and Auramine-O, a suspension of yeast cells in ultrapure water was injected into a dye solution in a micro cuvette placed inside a spectrofluorometer and the fluorescence intensity of the resulting solution was measured at 1 s intervals, starting immediately after the mixing and continued until the time for the maximum intensity using various concentrations of yeast and dyes. The relaxation time tau, which corresponds to ~63.2% of the maximum fluorescence intensity, was shown to decrease to below 1 s with increasing DAPI concentration, whereas it remained constant for 2-3 s with increasing Auramine-O concentration, for example at a yeast concentration of 100 microg ml(-1) . CONCLUSIONS: For the conditions of yeast >10 microg ml(-1) , DAPI >1 microg ml(-1) and Auramine-O >0.1 microg ml(-1) , tau could be adjusted to below 5 s to achieve a rapid and stable staining. SIGNIFICANCE AND IMPACT OF THE STUDY: Design and operating conditions for rapid and online measurements of microbes can be optimized.
The ever-increasing need for high-quality drinking and process waters, and growing public awareness about possible contamination, drive efforts for the further development of automated control of water treatment plants. For example, membrane filtration processes and reverse osmosis in particular are generally regarded as a safe barrier for inorganic, organic, and microbial contamination. Yet, to ensure the final water quality and to increase the confidence of the end-user, intensive and preferab...
Abstract We assessed the utility of online fluorescence spectroscopy for the real-time evaluation of the microbial quality of untreated drinking water. Online fluorimeters were installed on the raw water intake at four groundwater-derived UK public water supplies alongside existing turbidity sensors that are used to forewarn of the presence of microbial contamination in the water industry. The fluorimeters targeted fluorescent dissolved organic matter (DOM) peaks at excitation/emission wavelengt...
Last. Giorgio Gilli(UNITO: University of Turin)H-Index: 28
view all 12 authors...
Abstract Anaerobic digestion is a consolidated biotechnology able to produce renewable energy from biomasses. In the European countries, quick growth of biogas production from different organic matrices including wastes has been observed. In relation to the characteristics and quantity of the anaerobic digestion of feedstock, there are different technologies, advantages and criticisms. An accurate occupational risk assessment and development of management tools for green jobs involved in the ana...
The issue of healthy educational buildings is a global concern because children are particularly at risk of lung damage and infection caused by poor indoor air quality (IAQ). This article presents the results of a preliminary study of the concentration and size distribution of bacterial aerosol in three educational buildings: a preschool, primary school, and high school. Sampling was undertaken in the classrooms with an Andersen six-stage impactor (with aerodynamic cut-off diameters of 7.0, 4.7,...
Laser-induced fluorescence (LIF) techniques to analyze atmospheric aerosols are commonly applied for research and human exposure monitoring, but are very expensive or offer poor spectral resolution. Here, we discuss how a recently proposed instrument can acquire resolved fluorescence spectra from many individual particles in a single camera image using four excitation wavelengths matched with common biological fluorophores for particle discrimination at lower cost. We discuss emission intensity ...
#1Jianjian Wei(HKU: University of Hong Kong)H-Index: 15
#2Jie Zhou(Li Ka Shing Faculty of Medicine, University of Hong Kong)H-Index: 6
Last. Yuguo Li(HKU: University of Hong Kong)H-Index: 74
view all 9 authors...
Abstract Interspecies transmissions of avian influenza viruses (AIV) occur at the human-poultry interface, among which the live poultry markets (LPMs) are easily assessed by urban residents. Thousands of live poultry from different farms arrive daily at wholesale markets before being sold to retail markets. We assessed the risk of AIV downwind spread via airborne particles from a representative wholesale market in Guangzhou. Air samples were collected using the cyclone-based NIOSH bioaerosol sam...
#2Yonglong Lu(CAS: Chinese Academy of Sciences)H-Index: 57
Last. Ruoyu Liang(CAS: Chinese Academy of Sciences)H-Index: 9
view all 16 authors...
Abstract Fecal bacteria contaminate water resources and result in associated waterborne diseases. This study assessed drinking water quality and evaluated their potential health risks in Swat, Pakistan. Ground and surface drinking water were randomly collected from upstream to downstream in the River Swat watershed and analyzed for fecal contamination using fecal indicator bacteria ( Escherichia coli ) and physiochemical parameters (potential of hydrogen, turbidity, temperature, electrical condu...
Last. Xiaoguang Li(PKU: Peking University)H-Index: 5
view all 4 authors...
Abstract It is generally believed that influenza outbreak is associated with breath-borne transmission of viruses, however relevant evidence is little for that of respiratory bacterial infections. On another front, point-of-care infection diagnostic methods at the bedside are significantly lacking. Here, we used a newly developed protocol of integrating an exhaled breath condensate (EBC) collection device (PKU BioScreen) and Loop Mediated Isothermal Amplification (LAMP) to investigate what bacte...
