Simultaneous detection of trace Hg2+ and Ag+ by SERS aptasensor based on a novel cascade amplification in environmental water

2021 ◽  
pp. 133879
Author(s):  
Cheng Tian ◽  
Lei Zhao ◽  
Jin Zhu ◽  
Shusheng Zhang
Keyword(s):  
Simultaneous Detection ◽  
Environmental Water ◽  
Cascade Amplification

scholarly journals Detection of Bioavailable Cadmium by Double-Color Fluorescence Based on a Dual-Sensing Bioreporter System

2021 ◽  
Vol 12 ◽  
Author(s):  
Chang-ye Hui ◽  
Yan Guo ◽  
Jian Wu ◽  
Lisa Liu ◽  
Xue-qin Yang ◽  
...  
Keyword(s):  
Anthropogenic Activities ◽  
Simultaneous Detection ◽  
Environmental Water ◽  
High Concentration ◽  
Whole Cell ◽  
Specificity And Sensitivity ◽  
Improved Performance ◽  
Whole Cell Biosensor ◽  
Cell Biosensor ◽  
Dual Sensing

Cadmium (Cd) is carcinogenic to humans and can accumulate in the liver, kidneys, and bones. There is widespread presence of cadmium in the environment as a consequence of anthropogenic activities. It is important to detect cadmium in the environment to prevent further exposure to humans. Previous whole-cell biosensor designs were focused on single-sensing constructs but have had difficulty in distinguishing cadmium from other metal ions such as lead (Pb) and mercury (Hg). We developed a dual-sensing bacterial bioreporter system to detect bioavailable cadmium by employing CadC and CadR as separate metal sensory elements and eGFP and mCherry as fluorescent reporters in one genetic construct. The capability of this dual-sensing biosensor was proved to simultaneously detect bioavailable cadmium and its toxic effects using two sets of sensing systems while still maintaining similar specificity and sensitivity of respective signal-sensing biosensors. The productions of double-color fluorescence were directly proportional to the exposure concentration of cadmium, thereby serving as an effective quantitative biosensor to detect bioavailable cadmium. This novel dual-sensing biosensor was then validated to respond to Cd(II) spiked in environmental water samples. This is the first report of the development of a novel dual-sensing, whole-cell biosensor for simultaneous detection of bioavailable cadmium. The application of two biosensing modules provides versatile biosensing signals and improved performance that can make a significant impact on monitoring high concentration of bioavailable Cd(II) in environmental water to reduce human exposure to the harmful effects of cadmium.

scholarly journals Simultaneous Quantification of Multiple Food- and Waterborne Pathogens by Use of Microfluidic Quantitative PCR

2013 ◽  
Vol 79 (9) ◽  
pp. 2891-2898 ◽  
Author(s):  
Satoshi Ishii ◽  
Takahiro Segawa ◽  
Satoshi Okabe
Keyword(s):  
Quantitative Pcr ◽  
Water Samples ◽  
Simultaneous Detection ◽  
Environmental Water ◽  
Waterborne Pathogens ◽  
Fecal Indicator ◽  
Content Type ◽  
Template Dna ◽  
Multiple Pathogens ◽  
Taqman Qpcr

ABSTRACTThe direct quantification of multiple pathogens has been desired for diagnostic and public health purposes for a long time. In this study, we applied microfluidic quantitative PCR (qPCR) technology to the simultaneous detection and quantification of multiple food- and waterborne pathogens. In this system, multiple singleplex qPCR assays were run under identical detection conditions in nanoliter-volume chambers that are present in high densities on a chip. First, we developed 18 TaqMan qPCR assays that could be run in the same PCR conditions by using prevalidated TaqMan probes. Specific and sensitive quantification was achieved by using these qPCR assays. With the addition of two previously validated TaqMan qPCR assays, we used 20 qPCR assays targeting 10 enteric pathogens, a fecal indicator bacterium (generalEscherichia coli), and a process control strain in the microfluidic qPCR system. We preamplified the template DNA to increase the sensitivity of the qPCR assays. Our results suggested that preamplification was effective for quantifying small amounts of the template DNA without any major impact on the sensitivity, efficiency, and quantitative performance of qPCR. This microfluidic qPCR system allowed us to detect and quantify multiple pathogens from fecal samples and environmental water samples spiked with pathogens at levels as low as 100 cells/liter. These results suggest that the routine monitoring of multiple pathogens in food and water samples is now technically feasible. This method may provide more reliable information for risk assessment than the current fecal contamination indicator approach.

Detection and rapid differentiation of human enteroviruses in water sources by restriction enzyme analysis

2001 ◽  
Vol 43 (12) ◽  
pp. 209-212 ◽  
Author(s):  
J.C. Vivier ◽  
C.G. Clay ◽  
W.O.K. Grabow
Keyword(s):  
Restriction Enzyme ◽  
Informal Settlement ◽  
Simultaneous Detection ◽  
Cost Effective ◽  
Environmental Water ◽  
Molecular Techniques ◽  
Enzyme Analysis ◽  
Restriction Enzyme Analysis ◽  
High Incidence ◽  
Coxsackie B Viruses

The objective of this study was to assess the application and efficiency of molecular techniques for the detection and serotyping of enteroviruses from environmental water samples. Samples of water were collected at regular intervals upstream and downstream of an informal settlement. Techniques for the detection of enteroviruses included a reverse transcription polymerase chain reaction (RT-PCR), nested PCR (n-PCR) and Sabin-specific triplex PCR. A specific 297 bp fragment was amplified by the n-PCR and subjected to restriction enzyme (RE) analysis to differentiate between various serotypes of prototypical enteroviruses. Enteroviruses that gave inconclusive restriction patterns were typed by partial sequencing of the VP1 region. Results indicated a high incidence of enteroviruses, predominantly coxsackie B viruses. The results on polioviruses, as well as other enteroviruses, contributed valuable information on enteroviruses circulating in the community. The molecular approach described here proved suitable for the rapid, sensitive, specific and cost effective, simultaneous detection and typing of enteroviruses in water.

scholarly journals Real-Time PCR for Quantification of Giardia and Cryptosporidium in Environmental Water Samples and Sewage

2003 ◽  
Vol 69 (9) ◽  
pp. 5178-5185 ◽  
Author(s):  
Rebecca A. Guy ◽  
Pierre Payment ◽  
Ulrich J. Krull ◽  
Paul A. Horgen
Keyword(s):  
Real Time ◽  
Water Samples ◽  
Real Time Pcr ◽  
Simultaneous Detection ◽  
Environmental Water ◽  
Qpcr Assay ◽  
Detection Methods ◽  
Environmental Water Samples ◽  
Dna Yield ◽  
Chelex 100

ABSTRACT The protozoan pathogens Giardia lamblia and Cryptosporidium parvum are major causes of waterborne enteric disease throughout the world. Improved detection methods that are very sensitive and rapid are urgently needed. This is especially the case for analysis of environmental water samples in which the densities of Giardia and Cryptosporidium are very low. Primers and TaqMan probes based on the β-giardin gene of G. lamblia and the COWP gene of C. parvum were developed and used to detect DNA concentrations over a range of 7 orders of magnitude. It was possible to detect DNA to the equivalent of a single cyst of G. lamblia and one oocyst of C. parvum. A multiplex real-time PCR (qPCR) assay for simultaneous detection of G. lamblia and C. parvum resulted in comparable levels of detection. Comparison of DNA extraction methodologies to maximize DNA yield from cysts and oocysts determined that a combination of freeze-thaw, sonication, and purification using the DNeasy kit (Qiagen) provided a highly efficient method. Sampling of four environmental water bodies revealed variation in qPCR inhibitors in 2-liter concentrates. A methodology for dealing with qPCR inhibitors that involved the use of Chelex 100 and PVP 360 was developed. It was possible to detect and quantify G. lamblia in sewage using qPCR when applying the procedure for extraction of DNA from 1-liter sewage samples. Numbers obtained from the qPCR assay were comparable to those obtained with immunofluorescence microscopy. The qPCR analysis revealed both assemblage A and assemblage B genotypes of G. lamblia in the sewage. No Cryptosporidium was detected in these samples by either method.

A strategy of electrochemical simultaneous detection of acetaminophen and levofloxacin in water based on g-C3N4 nanosheet-doped graphene oxide

2021 ◽  
Author(s):  
Wenwen Yi ◽  
Chunxiao Han ◽  
Zhongping Li ◽  
Yujing Guo ◽  
Meng Liu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Simultaneous Determination ◽  
Carbon Nitride ◽  
Simultaneous Detection ◽  
Environmental Water ◽  
Graphitic Carbon Nitride ◽  
Water Based ◽  
Doped Graphene ◽  
Electroanalytical Method

A novel electroanalytical method for the simultaneous determination of acetaminophen (AC) and levofloxacin (LEV) in environmental water was proposed based on graphitic carbon nitride nanosheet-doped graphene oxide (CNNS/GO).

scholarly journals Simultaneous direct detection of toxigenic and non-toxigenic Vibrio cholerae from rectal swabs and environmental samples by sandwich ELISA

2007 ◽  
Vol 56 (10) ◽  
pp. 1340-1345 ◽  
Author(s):  
Urmil Tuteja ◽  
Sanjay Kumar ◽  
Jyoti Shukla ◽  
Joseph Kingston ◽  
Harsh V. Batra
Keyword(s):  
Vibrio Cholerae ◽  
Water Samples ◽  
Direct Detection ◽  
Polyclonal Antibodies ◽  
Sandwich Elisa ◽  
Simultaneous Detection ◽  
Environmental Water ◽  
Environmental Water Samples ◽  
Bacterial Strains ◽  
Rectal Swabs

A mAb-based simple, specific and rapid two-tip dipstick ELISA was developed for simultaneous detection of toxin- and non-toxin-producing strains of Vibrio cholerae, and for direct detection of V. cholerae from rectal swabs of patients and from environmental water samples. Rabbit polyclonal antibodies and murine mAbs were raised against recombinant protein (r-protein) antigens of cholera toxin B (CtxB) and outer membrane protein W (OmpW). Rabbit polyclonal antibodies to both r-proteins were coated individually onto the tips of nitrocellulose (NC) membranes of a two-tipped NC dipstick as capture antibodies and a mixture of two mAbs was used for the detecting antibodies. The test was found to be specific for V. cholerae strains O1, O139, non-O1 and non-O139, and did not show any cross-reaction to closely related bacterial strains. The test was evaluated on rectal swabs collected at the bedside of 75 hospitalized diarrhoeal patients and on 50 environmental water samples after enrichment for 4 h in alkaline peptone water. The mAb two-tip dipstick ELISA detected V. cholerae in 52/75 rectal swabs and 2/50 environmental water samples for CtxB antigen, and in 1/50 environmental water samples for the non-toxin OmpW antigen of V. cholerae within 1.5 h. These findings were identical to those observed using PCR and conventional culture methods. Thus, this mAb-based two-tip dipstick ELISA could be used for early and reliable simultaneous detection of toxigenic and non-toxigenic strains of V. cholerae from clinical and environmental water samples.

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