Organic solute accumulation in osmotically-stressed Enteromorpha intestinalis

Edwards, D. M.; Reed, Robert H.; Chudek, J. A.; Foster, R.; Stewart, W. D. P.

doi:10.1007/bf00393102

Cited by 72 publications

(53 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, DMSP does not seem to be synthesized rapidly following changes in water potential. In the present study, most observations indicated that under such conditions DMSP is produced only slowly, if at all (Reed, 1983;Dickson & Kirst, 1986;Edwards et al, 1987;Stefels et al, 1996). On the other hand, it is quite possible that lower concentrations of this compound were not detected due to the method used.…”

Section: Importance Of Polyols Quaternary Ammonium and Tertiary Sulfmentioning

confidence: 49%

Compatible solutes in three marine intertidal microphytobenthic Wadden Sea diatoms exposed to different salinities

Scholz

Liebezeit

2012

European Journal of Phycology

View full text Add to dashboard Cite

Diatoms inhabiting intertidal flats are subject to strongly changing salinities due to exposure to rain and desiccation at low tide. In order to determine the physiological responses of marine benthic diatoms to salinity changes, cultures of Navicula phyllepta, Achnanthes delicatula subsp. hauckiana and Nitzschia constricta, isolated from the Soltho¨rn tidal flat (lower Saxony, southern North Sea), were used to study the effect on growth rates of different salinities (0.5, 10, 20, 30, 40, 50). During short (1, 3, 10, 60 min) and long exposures (30 days), the composition of free amino acids and the accumulation of polyols, saccharides, quaternary ammonium compounds and -dimethylsulphoniopropionate (DMSP) were determined. The growth rates of N. phyllepta were not affected by salinity in the tested range, synthesizing and accumulating proline as the only response to salinity increases in the growth medium. The growth responses of A. delicatula subsp. hauckiana were significantly weaker at the lowest and highest salinities in comparison to the control treatment (at a salinity of 30), producing proline, glycine betaine, glycerol and the quaternary ammonium compound homarine. In contrast, N. constricta showed the highest growth rate in the low-salinity treatment and the lowest proline concentrations in the high-salinity assay in comparison to the other species. In addition, N. constricta was the only species that synthesized the tertiary sulphonium compound DMSP. Furthermore, results from the salinity treatments showed particular similarities in compound accumulation. While quaternary ammonium compounds as well as DMSP were synthesized during high-salinity treatments, polyols and carbohydrates were found predominantly in the low-salinity experiments. Enzyme activities specific to proline metabolism in A. delicatula and N. constricta indicated that the high salinity-induced free proline accumulation may be due to a stimulation of synthesis via the ornithine pathway, whereas in N. phyllepta the glutamate pathway may contribute significantly to the free proline accumulation. In conclusion, significant differences in osmolyte compositions were found in the three diatom species during exposure to different salinities, suggesting specific intracellular acclimation processes that provide possible explanations of the species' insensitivity towards environmental short-time salinity variations.

show abstract

Section: Importance Of Polyols Quaternary Ammonium and Tertiary Sulfmentioning

confidence: 49%

Compatible solutes in three marine intertidal microphytobenthic Wadden Sea diatoms exposed to different salinities

Scholz

Liebezeit

2012

European Journal of Phycology

View full text Add to dashboard Cite

show abstract

“…Indeed, the compatibility of this solute with 'E-mail: stefelsj@b~ol rug nl algal metabolism was confirmed in studies on the impact of DMSP on enzyme activities in extracts of the marine phytoplankter Tetraselmis subcordiformis (Grone & Kirst 1991). Several authors have reported an increased cellular DMSP concentration at higher salinity levels (Vairavamurthy et al 1985, Dickson & Kirst 1986, 1987a, but rapid changes in the intracellular concentrations of DMSP upon salinity changes were not always o'bserved (van Diggelen et al 1986, Edwards et al 1987. Others suggested a function as cryoprotectant (Kirst et al 1991, Nishiguchi & Somero 1992, methyl donor (Ishida 1968) or sulfur storage (van Diggelen et al 1986).…”

Section: Phytoplanktonmentioning

confidence: 99%

Characteristics of DMSP-lyase in Phaeocystis sp. (Prymnesiophyceae)

Stefels¹,

Dijkhuizen²

1996

Mar. Ecol. Prog. Ser.

110

View full text Add to dashboard Cite

The marine phytoplankton species Phaeocystis sp. is one of the few microalgae known to be able to convert dimethylsulfoniopropionate (DMSP) enzymatically into dimethyl sulfide (DMS) and acrylic acid. The function of this enzymatic process for the organism is not known. From experiments with crude extracts and whole cells of axenic cultures of Phaeocystis it was concluded that DMSP-lyase is membrane-bound and located extracellularly because: (1) the enzyme activity in extracts and in whole cells varied in a simllar manner with pH; (2) between 50 and 80% of the DhdSPlyase activity was associated w~t h the membrane fraction, (3) lyase activity in whole cells was inhibited by the nonpermeable thiol-reagent p-chloromercuribenzenesulfonic acid @CMBS). The pH optimum was 10.5 or higher, which is in contrast with available data for the enzyme from other organisms. The pH profile, the requirement for reduced thiol groups in extracts and the inhibition by pCMBS suggest the involvement of cysteine residues a t the active site. Production of DMSP as well as its cleavage by DMSP-lyase are apparently not involved in the short term regulation of the osmot~c potential of cells upon changes in salinity.

show abstract

“…Also, the efficiency of extraction of osmoprotectants and others would have varied from one alga to the other, depending on thalli structures and compositions. It is well established that -/-BB is present consistently in A. nodosum and E serratus, and DMSP occurs in very large amounts in Ulva, Enteromorpha, and Polysiphonia [3,4,15,16,33]. Because they remain chemically unmodified within the cells [24,32], osmoprotectants extracted from the bacterial cells reflect those naturally present in algal thalli.…”

Section: Discussionmentioning

confidence: 99%

“…They likely contribute to alleviating salt or water stress. The possible role of DMSP in the maintenance of osmotic balance has been pointed out in Ulva lactuca, Enteromorpha intestinalis, and Polysiphonia lanosa [14][15][16]33]. Osmoregulatory activities could be intense within macroalgae occupying the intertidal zones and estuaries and thus affected by rapid changes in salinity that are due to the interactions of tides, rainfall, and evaporation.…”

Section: Introductionmentioning

confidence: 99%

Marine macroalgae as a source for osmoprotection for Escherichia coli

Ghoul

Minet

Bernard³

et al. 1995

Microb Ecol

View full text Add to dashboard Cite

At elevated osmolarity of the mineral medium M63, marine macroalgae constitute important osmoprotectants and nutrients sources for Escherichia coli. Growth of bacterial population (16 strains) was improved by supplementing M63 salts medium with either aqueous or ethanolic algal extracts obtained from Ascophyllum nodosum, Fucus serratus, Enteromorpha ramulosa, Ulva lactuca, and Palmaria palmata. In their presence, growth was still observed even at 1.02 M NaCl. Furthermore, the E. coli ZB400 growth in presence of whole macroalgae thalli in M63/0.85 M NaCI reached its maximum within 24 h (5 × 10(7) - 5 × 10(8) colony-forming units [CFU] per milliliter). In the presence of A. nodosum, bacterial growth was inhibited. In the same experimental conditions, ethanolic extracts improved E. coli growth significantly, because the yield reached 10(11) CFU per milliliter. Ulva lactuca and P. palmata allowed the better growth. The Dragendorff-positive compounds extracted from bacterial cells growing on each ethanolic extract exhibited an osmoprotective effect as proved by a disk-diffusion assay. On the other hand, the -onium compounds (quaternary ammonium [betaines] and tertiary sulphonium) and total free amino acid contents of U. lactuca ethanolic extracts were higher than in others. Fucaceae extracts demonstrated especially high protein content. Algal extracts constitute not only an appreciable osmoprotection source for E. coli but also nutrient sources.

show abstract

Organic solute accumulation in osmotically-stressed Enteromorpha intestinalis

Cited by 72 publications

References 43 publications

Compatible solutes in three marine intertidal microphytobenthic Wadden Sea diatoms exposed to different salinities

Compatible solutes in three marine intertidal microphytobenthic Wadden Sea diatoms exposed to different salinities

Characteristics of DMSP-lyase in Phaeocystis sp. (Prymnesiophyceae)

Marine macroalgae as a source for osmoprotection for Escherichia coli

Contact Info

Product

Resources

About