Rapid assessment of metabolic activity in marine microalgae: application in ecotoxicological tests and evaluation of water quality

Gilbert, Franck; Galgani, François; Cadiou, Yvon

doi:10.1007/bf00702462

Cited by 74 publications

(41 citation statements)

References 25 publications

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“…For FDAconcentrations of 1, 2, 3 and 4me/ml, the rate of hvdrolvsis was linear for both E. coli and S. aureus. These results are in agreement with previous findings on the hydrolysis of FDAby other microorganisms (Swisher and Caroll, 1980;Gilbert et aL, 1992). However, 6, 8 and lOmg/ml concentrations of FDAgave non linear results over time (Figs.…”

Section: Resultssupporting

confidence: 93%

“…FDAhydrolysis/staining has found application in the determination of microbial populations NOV. 1994 growing on plant tissues (Swisher and Carroll, 1980), microbial cultures (Sugar et al, 1983), textiles (McCarthy, 1987), soil profiles (Federle et al, 1990) and sea water (Gilbert et al, 1992). Swisher and Carroll (1980) demonstrated, by spectrophotometric means, that the amount of fiuorescein produced by hydrolysis of FDAprovided a good approximation of the cumulative biomass of fungi, bacteria and algae growing on Douglas fir (Pseudotsuga minziesii) foliage.…”

mentioning

confidence: 99%

“…Similarly, Federle et al (1990) while investigating the vertical distribution of microbial biomass in soil profiles, found that the FDA hydrolysis was as accurate as the incorporation of radio-labeled thymidine into microbial DNA in estimating total microbial biomass. Gilbert et al (1992) have recently shown that fluorescein is released quantitatively as a function of the numberof cells of the marine micro-alga, Tetraselmis suecica. Arapid ecotoxicological test method was developed to measure the effect of various environmental toxins {e.g.…”

mentioning

confidence: 99%

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Rapid screening of the antimicrobial activity of extracts and natural products.

et al. 1994

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A spectrophotometric method has been developed for the rapid measurement of the antimicrobial activity of natural products, including crude extracts or pure materials. The assay depends on the measurement of non-specific esterase activity using fluorescein diacetate (FDA) hydrolysis in broth cultures of microbes after they have been treated with test compounds. The assay is accurate, reproducible and economical in both time and materials. The speed and economyof the method make it suitable for the rapid screening of manysamples and the bioassay directed purification of antimicrobial substances. The assay can also be used with a wide variety of micro-organisms since most micro-organisms are FDApositive. Applications are described in the fields of marine natural products chemistry and essential oils research. 1295 The objective of this study was to develop a simple, rapid, inexpensive, accurate and reproducible method for the determination of the minimuminhibitory concentration (MIC) of large numbers of test samples ranging from crude extracts or fractions of natural products to essential oils or pure substances.Methods used for the determination of the MICare varied although they can be grouped into either a single disc diffusion assay (Bauer et ai, 1966) or the dilution plate/broth methods (Haltalin et ai, 1973). The former relates the zone of inhibition produced to the varying concentration of a test compound applied on to a paper disc for the determination of the MIC. There are several problems associated with the disc diffusion method for comparing the relative antimicrobial activity of different compounds. The assay does not always give a sharp demarkation between bacterial growth and inhibition. The time taken for incubation (18~24 hours) may render it unsuitable for volatile or unstable antimicrobial agents. The zones of inhibition may only be compared among antimicrobial agents with similar physical properties such as diffusion rates in agar, volatility or solubilities in aqueous solutions.The dilution plate/broth group of methods measure the bacteriocidal/bacteriostatic effect of a potential antibiotic at a series of concentrations on a given microbial population. While being accurate, these methods are laborious due to the inclusion of viability counts in the assay and are liable to contamination of either the broth or the viable count agar plates or from test samples that often cannot easily be sterilised. Again, the time period involved (1~2 days) can be a major drawback.The method described here is ideal for implementation in a chemistry laboratory by non-microbiologists, can be run under non-aseptic conditions, requires only small amounts of materials and gives results in two hours.Non-specific esterases occur widely amongst microbes (Lundgren, 1981) and have been shown to hydrolyse colourless fluorescein diacetate (FDA) to fluorescein, a yellowish green compound, which absorbs strongly in the visible (/lmax 498 nm; £ l x 105, methanol -potassium hydroxide; Grasselli and Ritchey, 1975). FDAhydr...

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Section: Resultssupporting

confidence: 93%

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confidence: 99%

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confidence: 99%

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Rapid screening of the antimicrobial activity of extracts and natural products.

et al. 1994

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“…As the esterase activity is the rate-limiting step for FDA fluorescence, brief episodes of 'low viability' without a concomitant decrease in cell numbers must be the result of a transient decrease in esterase concentration or activity. Gilbert et al (1992) also observed that the intensity of the FDA fluorescence per cell varied, and found that fluorescence of Tetraselmis suecica was high before the exponential phase, dropping appreciably during the growth phase. It was assumed that cells were undergoing different metabolic pathways during the rapid growth phase, thereby impacting the fluorescence signal.…”

Section: Changes In the Viability Of Thalassiosira Weissflogii Kept Umentioning

confidence: 90%

“…The retained fluorescein fluoresces green under blue-light excitation. The percentage of viable (fluorescing) cells may be determined microscopically, using flow cytometry (Jochem 1999) or a spectrofluorometric reader (Gilbert et al 1992).…”

Section: Methodsmentioning

confidence: 99%

Applicability of the FDA assay to determine the viability of marine phytoplankton under different environmental conditions

Garvey¹,

Moriceau²,

Passow³

2007

Mar. Ecol. Prog. Ser.

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Knowing which fraction of a phytoplankton population is viable would often be helpful in answering ecological or physiological questions. However, viability stains (1) often do not function properly, especially with diatoms, (2) are rarely used, and (3) frequently appear to give ambiguous results. Here, we investigate the performance of the FDA viability assay in detail and test its applicability for investigating 2 ecologically important questions. The functioning of the assay was tested for several diatom species, as well as for Emiliania huxleyi (coccolithophorid) and Phaeocycstis globosa (Prymnesiophyceae). Additionally, changes in the viability of Thalassiosira weissflogii (diatom) -(1) due to aggregation and (2) during a prolonged stationary phase induced by nutrient limitation -were explored. Whereas the method generated solid results with some species, including T. weissflogii, it was less trustworthy or even totally ineffective with others. Ambiguous definitions of viability and cell death, as well as temporary changes in the strength of the fluorescence signal, complicate the interpretation of viability measurements. However, exiting ecological results can be attained with this method. Experiments with T. weissflogii suggested that the vast majority of cells, rather than individual survivors remained viable for over a month in an illuminated, nutrient-devoid environment. Aggregation significantly prolonged the viability of T. weissflogii cells compared to non-aggregated cells kept under otherwise identical conditions. KEY WORDS: Viability of phytoplankton · FDA assay · Nutrient limitation · AggregationResale or republication not permitted without written consent of the publisher

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Fungal biodegradation of a phenylurea herbicide, diuron?:?structure and toxicity of metabolites

Tixier¹,

Bogaerts

Sancelme³

et al. 2000

Pest Manag. Sci.

140

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Microbial degradation, organic synthesis and ecotoxicology were used to investigate the fate of diuron after spreading on soils. Quantitative biodegradation assays were performed with fungal strains, showing that diuron was degraded but not entirely mineralized. The modifications observed consisted in demethylation of the terminal nitrogen atom. The identified metabolites were synthesized in sufficient amounts to confirm their structures and determine their non‐target toxicity using four biotests. The two metabolites exhibited higher effects than parent diuron. This limited biodegradability and potential aquatic toxicity suggest that diuron is of higher environmental concern than previously recognized. © 2000 Society of Chemical Industry

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Rapid assessment of metabolic activity in marine microalgae: application in ecotoxicological tests and evaluation of water quality

Cited by 74 publications

References 25 publications

Rapid screening of the antimicrobial activity of extracts and natural products.

Rapid screening of the antimicrobial activity of extracts and natural products.

Applicability of the FDA assay to determine the viability of marine phytoplankton under different environmental conditions

Fungal biodegradation of a phenylurea herbicide, diuron?:?structure and toxicity of metabolites

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