An improved method for determining microbially available phosphorus in drinking water

2016 ◽  
Vol 16 (4) ◽  
pp. 1149-1158 ◽  
Author(s):  
Gang Wen ◽  
Qin Deng ◽  
Ting-Lin Huang ◽  
Jun Ma
Keyword(s):  
Drinking Water ◽  
Microbial Consortium ◽  
Incubation Temperature ◽  
Organic Phosphorus ◽  
High Sensitivity ◽  
Cell Number ◽  
Growth Potential ◽  
Utilization Efficiency ◽  
Available Phosphorus ◽  
Time Saving

Microbially available phosphorus (MAP) is the labile phosphorus that is readily assimilated by microorganisms, which is linearly correlated to bacterial re-growth in drinking water in some regions. The conventional MAP bioassay for drinking water was originally developed by Markku based on the growth potential of Pseudomonas fluorescens P17 (P17). However, the bioassay bears some demerits, such as time-consuming and labor-intensive enumeration. For convenience, an alternative method based on a similar principle was developed to assess the content of MAP in drinking water, in which natural microbial consortium was used as inoculum instead of pure culture P17, cell number was counted using flow cytometry (FCM), and cultivation at 30 °C was adopted. Natural microbial consortium is able to efficiently utilize organic phosphorus and exhibit high sensitivity since more cells are produced per μg P utilized. FCM is a rapid method to count all bacteria growing in drinking water. With incubation temperature increasing up to 30 °C, there is a shorter test period (64 h), excellent sensitivity and better utilization efficiency for organic phosphorus. The results show that the developed bioassay is sensitive, time-saving and easily operated.

H2S papers as presumptive tests for Salmonella contamination in tropical drinking water

1996 ◽  
Vol 34 (7-8) ◽  
pp. 187-194 ◽  
Author(s):  
Tanya Gawthorne ◽  
Robyn A. Gibbs ◽  
Kuruvilla Mathew ◽  
Goen E. Ho
Keyword(s):  
Drinking Water ◽  
Hydrogen Sulphide ◽  
Incubation Temperature ◽  
Indicator Bacteria ◽  
Coliform Bacteria ◽  
Salmonella Spp ◽  
Faecal Contamination ◽  
Tropical Waters ◽  
Remote Areas ◽  
Traditional Indicator

Coliform bacteria may not be adequate as sole indicators of recent faecal contamination in tropical waters. Salmonella spp. in particular have been found in tropical waters in the absence of traditional indicator bacteria. Remote areas without access to a laboratory have no opportunity for salmonellae analysis as portable tests are currently not available. H2S papers indicate the presence of hydrogen sulphide producing bacteria, a characteristic shared by the majority of Salmonella spp.. The potential of H2S papers to act as a presumptive test for salmonellae in the absence of coliform bacteria was assessed. Salmonella spp. grew in the H2S medium, with an optimum incubation temperature of 37°C and a recommended length of incubation for a negative result of 48 hours. The presence of high numbers of the type of noncoliform bacteria commonly found in drinking water did not affect the performance of the H2S strips. H2S papers are recommended for use in conjunction with a coliform test as a presumptive test for the presence of Salmonella spp. in drinking water.

Rapid detection and enumeration of total bacteria in drinking water and tea beverages using a laboratory-built high-sensitivity flow cytometer

2015 ◽  
Vol 7 (7) ◽  
pp. 3072-3079 ◽  
Author(s):  
Muxin Yu ◽  
Lina Wu ◽  
Tianxun Huang ◽  
Shuo Wang ◽  
Xiaomei Yan
Keyword(s):  
Drinking Water ◽  
Rapid Detection ◽  
High Sensitivity ◽  
Flow Cytometer ◽  
Total Bacteria

This paper describes a method for the rapid detection and enumeration of total bacteria in drinking water and tea beverages.

The Study on Organic Acid Detection Using Lon Chromatography

2012 ◽  
Vol 424-425 ◽  
pp. 923-926
Author(s):  
Xiao Jian Hu ◽  
Wen Chen ◽  
Li Li ◽  
Jin Ping Zhou ◽  
Bao Shou Guo ◽  
...  
Keyword(s):  
Drinking Water ◽  
Convenient Method ◽  
High Sensitivity ◽  
Microwave Oven ◽  
Good Recovery ◽  
Microwave Technology ◽  
Trace Level ◽  
Recovery Treatment ◽  
Technology Foundation

A simple and convenient method for the determination of μ g/l level in the real drinking water bromate overcome traditional methods of defects. Argentina by electrolyzing the smallest electrode interference and then focus on extra chlorine use microwave technology foundation evaporation and concentration, the proposed method is very sensitive to the determination of trace level of the sales of the drinking water. And a microwave oven, drinking water ten times the sample can be concentrated in 10 minutes can get and good recovery. Treatment of the silver electrode, the method of interference, and can effectively eliminate the Cl- This method is successfully applied to the detection in water sample level in the trace. It is the advantage of the operation is simple, fast, high sensitivity, accurate results. This method can be applied widely, suitable for trace analysis of water samples.

scholarly journals Comparison of Triangular Silver Nanoprisms with Different Capping Agents and Structural Size for H2O2 Etching-Based Biosensors

NANO ◽  
2018 ◽  
Vol 13 (02) ◽  
pp. 1850022 ◽  
Author(s):  
Lishi Huang ◽  
Caihong Yuan ◽  
Wenli Chen ◽  
Fanshu Zeng ◽  
Hui Xu ◽  
...  
Keyword(s):  
Point Of Care ◽  
High Sensitivity ◽  
Wavelength Shift ◽  
Time Saving ◽  
Capping Agents ◽  
Silver Nanoprisms ◽  
Structural Size ◽  
Point Of Care Diagnostics ◽  
Citrate Capping ◽  
Capping Ligands

This study compared the susceptibility of different triangular silver nanoprisms (TSNPRs) towards the etching of hydrogen peroxide (H2O2), a catalytical product of glucose oxidase (GOx). The influence of capping agents and structural size have been explored towards the oxidation of silver nanoprisms. Results indicated that the etching of the TSNPRs was extremely effected by surface capping agents, in which citrate contributed a highest H2O2-sensitive effect in the absence of secondary capping ligands (e.g., glycerol and ethanol). Meanwhile, compared to bigger TSNPRs, smaller nanoprisms exhibited a different signal output of plasma resonance peak through intensity decrease rather than wavelength shift, making them more H2O2-etching susceptibile. In virtue of GOx etching-based system, TSNPRs with a small size and citrate capping were served as a substitute for big nanoprisms to sense glucose, offering a number of advantages such as high sensitivity, improved calibration, time-saving and extended detection ranges. Moreover, the small sized TSNPRs capping with citrate alone have been expected to be of great interest in the trace of GOx, providing an ultrahigh sensitive GOx etching-based analytical platform for point-of-care diagnostics towards other analytes (e.g., DNA, protein).

158 IMPACT OF MATURED CATTLE OOCYTES AT HIGHER INCUBATION TEMPERATURE ON IN VITRO EMBRYO PRODUCTION

2016 ◽  
Vol 28 (2) ◽  
pp. 209
Author(s):  
M. Nkadimeng ◽  
E. van Marle-Koster ◽  
K. P. M. Lekola ◽  
M. L. Mphaphathi ◽  
M. M. Seshoka ◽  
...  
Keyword(s):  
Incubation Temperature ◽  
Cell Types ◽  
Cell Number ◽  
Cleavage Rate ◽  
Embryo Production ◽  
Developmental Potential ◽  
Cell Numbers ◽  
Significant Difference ◽  
In Vitro Embryo Production

Heat stress during IVF is associated with reduced fertility in cattle oocytes. It may, however, enhance thermo-tolerance or cause detrimental effects on a variety of cell types or organisms, depending on the duration and intensity of the thermal challenge. The aim of this study was to evaluate the developmental potential of cumulus-oocyte complexes (COC) matured for 18 or 24 h and incubated at 39°C or 41°C. A total of 1000 immature oocytes were collected at slaughter from indigenous South African cow ovaries. The COC were randomly allocated (100/treatment) into 2 maturation times (18 or 24 h) and cultured in M199 + FSH-LH-estradiol medium under oil at 100% humidity and 5% CO2 at 39°C or 41°C. Post maturation, oocytes were subjected to normal subsequent embryo conditions. The Bracket and Oliphant medium was used for IVF. All matured oocytes were fertilised for 6 h with frozen-thawed Nguni bull semen at a concentration of 265 × 106. The presumptive zygotes from each treatment were cultured into SOF-BSA medium under oil and incubated at 39°C for assessment of cleavage rate 48 h post IVF. After Day 7 of culture, blastocyst were stained (Hoechst 33323) for nuclei cell count. Statistical analyses was performed using Genstat® software of SAS (SAS Institute, Cary, NC, USA; P < 0.05). Oocytes that were matured for 18 h in 41°C resulted in more 8-cell embryos (41%) compared with those incubated at 39°C (21.6%). However, no difference was observed for cleavage rate at both maturation times and incubation temperatures (41 or 39°C). There was more morula formation from oocytes matured for 18 h (19.6%) and 24 h (19.0%) at 41°C compared to 39°C (8.4%) group. The results further showed more blastocyst formation during 18 h at 41°C (15.2%) than at 39°C (7.4%) and during 24 h at 41°C (11.2%), 39°C (11.4%). However there was no difference in the nuclei cell number during 18 h at 41°C (45.2), 24 h (45.8), and 18 h at 39°C (43.4) of maturation. Thus, there was a significant difference in the nuclei cell numbers at 24 h on 39°C (n = 133.2) and 41°C (n = 45.8). In conclusion, oocytes that were matured for 18 and 24 h at 41°C or for 18 h at 39°C developed further to blastocyst stage on in vitro embryo production, however, with low nuclei cell numbers due to accelerated maturation temperature or shortened maturation period.

scholarly journals Marine Toxins Detection by Biosensors Based on Aptamers

Toxins ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 1 ◽  
Author(s):  
Wei Ye ◽  
Taomei Liu ◽  
Weimin Zhang ◽  
Muzi Zhu ◽  
Zhaoming Liu ◽  
...  
Keyword(s):  
Detection Limit ◽  
Sensitivity And Specificity ◽  
High Efficiency ◽  
Rapid Development ◽  
High Sensitivity ◽  
Detection Methods ◽  
Marine Toxins ◽  
Time Saving ◽  
Low Detection Limit ◽  
The Future

Marine toxins cause great harm to human health through seafood, therefore, it is urgent to exploit new marine toxins detection methods with the merits of high sensitivity and specificity, low detection limit, convenience, and high efficiency. Aptasensors have emerged to replace classical detection methods for marine toxins detection. The rapid development of molecular biological approaches, sequencing technology, material science, electronics and chemical science boost the preparation and application of aptasensors. Taken together, the aptamer-based biosensors would be the best candidate for detection of the marine toxins with the merits of high sensitivity and specificity, convenience, time-saving, relatively low cost, extremely low detection limit, and high throughput, which have reduced the detection limit of marine toxins from nM to fM. This article reviews the detection of marine toxins by aptamer-based biosensors, as well as the selection approach for the systematic evolution of ligands by exponential enrichment (SELEX), the aptamer sequences. Moreover, the newest aptasensors and the future prospective are also discussed, which would provide thereotical basis for the future development of marine toxins detection by aptasensors.

QM/MM simulations of organic phosphorus adsorption at the diaspore–water interface

2019 ◽  
Vol 21 (44) ◽  
pp. 24316-24325 ◽  
Author(s):  
Prasanth B. Ganta ◽  
Oliver Kühn ◽  
Ashour A. Ahmed
Keyword(s):  
Surface Water ◽  
Molecular Mechanisms ◽  
Organic Phosphorus ◽  
Md Simulations ◽  
Available Phosphorus ◽  
Water Interface ◽  
Mineral Surfaces ◽  
Soil Mineral ◽  
Phosphorus Adsorption ◽  
Binding Process

The available phosphorus for plants is mainly affected by the strong binding of phosphates to soil mineral surfaces. Here, we have investigated the molecular mechanisms for this binding process at the surface–water interface by QM/MM MD simulations.

Novel on-tap passive sampling for odorous compounds in drinking water

2008 ◽  
Vol 8 (2) ◽  
pp. 197-205
Author(s):  
Christophe Tondelier ◽  
David Benanou ◽  
Thomas Thouvenot ◽  
Arnaud Genin
Keyword(s):  
Drinking Water ◽  
Passive Sampling ◽  
Water Flow Rate ◽  
Internal Standard ◽  
High Sensitivity ◽  
Qualitative Aspect ◽  
Mixing Chamber ◽  
In Series ◽  
Loading And Unloading ◽  
Private Network

Because taste and odour events in drinking water are often fleeting and unpredictable phenomena, an innovating passive sampler has been developed to trap off-flavour compounds, directly at the tap of the consumer: ARISTOT (Advanced Relevant Investigation Sampler for Taste & Odour at Tap). Each tool is equipped with seven SBSE stir bars, magnetic stirring roads coated with a polydimethylsiloxane (PDMS) phase, allowing the sorption of water organic compounds into PDMS at each tap opening. To study the efficiency of these passives samplers, a private network pilot unit has been created in our laboratory, equipped with four faucets in series, solenoids valves for automation of the system and a mixing chamber, developed to spike drinking water with odourous compounds in order to have homogenous smelling water at each tap. After enrichment, the bars are taken out and are then in-line thermo-desorbed and analysed by gas chromatography coupled with a mass spectrometer. Results showed a high sensitivity of the system, which was able to quickly analyse odourous compounds at the sub ng/L level. A “multishot” method was developed to analyse every molecule trapped on the seven stir bars in only one chromatographic run increasing sensitivity. To follow enrichment of stir bars, loading and unloading were studied and showed a very slight unloading of the stir bar under a clean water flow rate which allowed us to previously spike every stir bar with an internal standard to see analytical variations. The influence of heated water was also investigated and seems to lead to a higher unloading of the stir bar, but according to a qualitative aspect this loss is balanced by the high sensitivity.

Sign in / Sign up

Export Citation Format

Share Document