A new application of microplate reader in oceanography: Colorimetric assays to determine some nitrogen forms

Baudinet, Dominique; Galgani, François

doi:10.1016/0272-7714(91)90084-o

Cited by 8 publications

(5 citation statements)

References 7 publications

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“…There was no addition of detergent. The absorbance was measured on an ELA microplate reader (EL-307, Bio-Tec Instruments, Inc., Vermont) as described by Baudinet and Galgani [34].' The samples were heated before adding them to the microplate.…”

Section: Sediment Characteristicsmentioning

confidence: 99%

Evidence for bacterial urea production in marine sediments

Pedersen¹,

Lomstein²,

Henry³

1993

FEMS Microbiology Ecology

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The quantitative importance of bacteria in urea production and turnover in a defaunated sediment from a Danish estuary was studied. After collecting the sediment, benthic infauna was removed by sieving, followed by anoxic pre-incubation for a week. Yeast extract was added to half of the samples. The urea concentration, urea production/turnover rates and the net ammonium production rate, were followed during a 338 h incubation. The urea concentration was highest in the enriched sediment, although urea production and turnover rates were the same in the enriched and control sediment, indicating that the urea concentration was controlled by the urea turnover rate constant, kttre a. Net ammonium production, urea concentrations and the urea turnover declined towards the end of the experiment. Comparison of the net ammonium production rate and the urea turnover rate in the enriched and control treatments, showed that urea hydrolysis accounted for up to 100% of the ammonium produced, from all sources. More than 98% of the urea which was hydrolyzed, originated from production during incubation. This suggests that urea was a major nitrogen excretion product from bacteria in this sediment, and that bacteria could also be an important source of urea in other marine sediments.

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Section: Sediment Characteristicsmentioning

confidence: 99%

Evidence for bacterial urea production in marine sediments

Pedersen¹,

Lomstein²,

Henry³

1993

FEMS Microbiology Ecology

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“…The method was scaled down and used manually in 600 tzl samples; there was no addition of detergent. The absorbance was measured on a ELA microplate reader (EL-307, Bio-Tec Instruments, Inc., Vermont), as described by Baudinet and Galgani [21], however, heating the samples before adding them to the microplate. Internal urea pools were measured in 600 /zl of culture which had been directly subjected to the reagents of the diacetylmonoxime method.…”

Section: Methodsmentioning

confidence: 99%

Urea production by Thiosphaera pantotropha and by anaerobic enrichment cultures from marine sediments

Pedersen

Lomstein

Isaksen

et al. 1993

FEMS Microbiology Ecology

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The production of urea by Thiosphaera pantotropha was studied. Batch cultures were grown on acetate as energy source and with NO3− or O2 as terminal electron acceptor. Urea accumulated in the media during exponential growth in aerobic and anaerobic cultures of T. pantotropha. Urea production continued after the cells had entered the stationary growth phase. Bacterial ability to produce urea was supported by studies of cultures enriched for denitrifying, sulphate‐reducing and fermenting bacteria. The results implied that urea production was common among bacteria normally considered to be important in marine sediments.

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“…Multi-channel pipettes can be used to dispense reagents to increase the efficiency of the manual sample preparation. Microplate methods have also been developed for the determination of urea in human blood serum (Lin et al 2000) and seawater (Baudinet and Galgani 1991). The method proposed by Lin et al (2000) incorporates the use of urease-positive Helicobacter pylori in place of purified urease and a pH indicator dye, BromoCresol Purple, to provide a colour change.…”

Section: Low-cost High-throughput Analysesmentioning

confidence: 99%

“…The method proposed by Lin et al (2000) incorporates the use of urease-positive Helicobacter pylori in place of purified urease and a pH indicator dye, BromoCresol Purple, to provide a colour change. Baudinet and Galgani (1991) examined microplate procedures for ammonia, nitrate, and urea in estuarine and coastal waters. For the determination of urea they used the diacetyl monoxime/thiosemicarbazide method presented by Rahmatullah and Boyde (1980), which provided a detection limit of around 1 µM.…”

Section: Low-cost High-throughput Analysesmentioning

confidence: 99%

The determination of urea in soil extracts and related samples—a review

2004

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Although the dominant methods for the determination of urea in clinical applications incorporate selective enzymatic hydrolysis of urea, the determination of urea in soil extracts is complicated by the presence of urease inhibitors. The spectrophotometric determination of urea with an acidic solution diacetyl monoxime and semicarbazide is a viable option but traditional manual procedures are time-consuming. New variations on these procedures, based on microplates or flow-injection analysis methodologies, allow a far greater number of samples to be analysed with high precision and sensitivity.

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A new application of microplate reader in oceanography: Colorimetric assays to determine some nitrogen forms

Cited by 8 publications

References 7 publications

Evidence for bacterial urea production in marine sediments

Evidence for bacterial urea production in marine sediments

Urea production by Thiosphaera pantotropha and by anaerobic enrichment cultures from marine sediments

The determination of urea in soil extracts and related samples—a review

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