Loss of Intracellular Glycerol from Dunaliella tertiolecta after Decreasing the External Salinity

Zidan, M. A.; Hipkins, M.F.; Boney, A. D.

doi:10.1016/s0176-1617(87)80254-7

Cited by 23 publications

(20 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ben-Amotz & Avron, 1973;Gimmler & Hartung, 1988). It is also evident that, when Dunaliella cells are exposed to a severe hypotonic stress, glycerol is excreted from the cell, in a process which requires energy (Zidan et al, 1987). However, the mutant of D. parva described in this paper leaks glycerol under isotonic conditions (Table 1).…”

Section: Discussionmentioning

confidence: 76%

“…The plasma membrane of Dunaliella is unusual in that it is largely impermeable to glycerol (Ben-Amotz & Avron, 1973). However, after a hypotonic shock to a lower salt concentration, excess glycerol is either converted to the storage product starch (Degani et al, 1985) or in more extreme cases excreted by an energy dependent transport process into the medium (Zidan et al, 1987). Cells can also be induced to leak glycerol by increasing the temperature to more than 40 C (Wegmann et al, 1980).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A mutant ofDunaliella parva CCAP 19/9 leaking large amounts of glycerol into the medium

Hard

Gilmour

1991

J Appl Phycol

View full text Add to dashboard Cite

A mutant of the halotolerant green alga Dunaliella parva, which leaks large amounts of intracellular glycerol into the surrounding medium, was isolated. The mutant has potential applications in the commercial production of glycerol on a large scale since there is no need to extract glycerol from the cells. The mutant was compared with the wild type and it was found that, despite the leakage of glycerol, the mutant showed the same growth rate as the wild type. However, when the rates of oxygen evolution and uptake and intracellular starch content between mutant and wild type were compared at high salinity, considerable differences were found.

show abstract

Section: Discussionmentioning

confidence: 76%

Section: Introductionmentioning

confidence: 99%

A mutant ofDunaliella parva CCAP 19/9 leaking large amounts of glycerol into the medium

Hard

Gilmour

1991

J Appl Phycol

View full text Add to dashboard Cite

show abstract

“…Gilmour et al (13) reported that most of the glycerol in D. tertiolecta cells that was lost following a downshock from 0.43 M to 0.09 M NaCl was due to release into the medium and not to metabolism. According to Zidan et al (32), two-thirds of the intracellular glycerol lost from the cells when D. tertiolecta cells were transferred from 1.3 M to 0.1 M NaCl was detected in the medium. On the other hand, Ben-Amotz and Avron (1) reported that the intracellular glycerol lost from Dunaliella parva cells by decreasing the salinity from 1.5 M to 0.6 M NaCl was due to dissimilation because no leakage of the intracellular glycerol was observed.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, the decrease of intracellular glycerol in Dunaliella in response to hypotonic shock has been interpreted to be mainly due to leakage into the medium (13,32) or to dissimilation via intracellular metabolism (1,16). Goyal (16) proposed that leakage of intracellular glycerol into the medium is mainly due to cell damage caused by resuspension of cells directly in hypotonic media.…”

Section: Introductionmentioning

confidence: 99%

Release of intracellular glycerol and pore formation in Dunaliella tertiolecta exposed to hypotonic stress

Fujii¹,

Hellebust²

1992

Can. J. Bot.

View full text Add to dashboard Cite

FUJII, S., and HELLEBUST, J. A. 1992. Release of intracellular glycerol and pore formation in Dunaliella tertiolecta exposed to hypotonic stress. Can. J. Bot. 70: 1313-1318. When Dunaliella tertiolecta cells, previously cultured in a 0.5 M NaCl medium, were resuspended in a 0.25 NaCl medium, about 50% of the intracellular glycerol was lost within 2 min. A corresponding amount of glycerol appeared inthe medium, while other organic solutes, such as amino acids and sugars, were not detected. These results indicate that intracellular glycerol is rapidly released without significant concomitant cell damage. Rubidum, in the case of rubidium-loaded cells, was also rapidly teleased to the medium in response to hypotonic shock. Gramicidin, dimers of which form stable membrane pores, caused rapid release of intracellular glycerol, while the ionophore, valinomycin, had no effect. When 0.5 M NaC1-grown cells were resuspended in 0.25 M NaCl medium, intracellular trapping of 14C-glycerol occurred but not of I4C-glucose, 14C-sucrose, or I4C-glycine. However, when 0.5 M NaC1-grown cells were resuspended in 0.05 M NaCl medium, intracellular trapping of small amounts of '4C-glucose, 14C-sucrose, or I4C-glycine, in addition to considerable amounts of 14C-glycerol, occurred. These results indicate that abrupt hypotonic shocks cause transient formation of small nonspecific pores in the plasma membrane of D. tertiolecta cells and that intracellular glycerol is released to the medium through such nonspecific transient pores.Key words: Dunaliella, hypotonic shock, glycerol release, rubidum, pore formation.FUJII, S., et HELLEBUST, J. A. 1992. Release of intracellular glycerol and pore formation in Dunaliella tertiolecta exposed to hypotonic stress. Can. J. Bot. 70 : 1313-1318. Lorsqu'on transfert des cellules de Dunaliella tertiolecta prkalablement cultivCes dans une solution 0,5 M en NaC1, dans un milieu contenant du NaCl 0,25 M, elles perdent environ 50% du glycCrol intracelulaire en moins de 2 min. On retrouve dans le milieu une quantitC correspondante de glycCrol, alors que les autres solutCs organiques, tels que les acides aminks et les sucres, en sont absents. Ces rCsultats indiquent que le glycCrol intracellulaire est rapidement reliche sans que les cellules soient au mCme moment blessCes. Dans le cas de cellules chargCes de rubidium, celui-~i est Cgalement rapidement reliche dans le milieu en rCaction au choc hypotonique. La gramicidine, dont les dimkres forment des pores membranaires stables, dCclenche un rellchement rapide du glycCrol intracellulaire, alors que l'ionophore valinomycine reste sans effet. Lorsqu'on resuspend des cellules prkalablement cultivCes en presence de NaCl0,5 M dans un milieu de NaCl0,25 M, on observe une skquestration intracellulaire du I4C-glycCro1, mais non du 14C-glucose, du 14C-sucrose ou de la I4C-glycine. Cependant, lorsqu'on resuspend des cellules prkalablement cultivies en prCsence de NaCl 0,5 M dans un milieu de NaCl 0,05 M, on observe une ~Cquestration intracellulaire de petites quantitCs de 14...

show abstract

“…1 The leakage of glycerol to the external medium under decreasing salinity is in confirinity with the results obtained for D . salina (DEGANI et al 1985 and D. tertiolecta (ZIDAN et al 1987). This decrease in intracellular glycerol of D. bioculata could be due to leakage of glycerol to the external medium andlor to glycerol conversion t o an osmotically inactive storage carbohydrate (DEGANI et al 1985).…”

Section: Discussionmentioning

confidence: 99%

Glycerol production by Dunaliella bioculata

Ahmed¹,

Zidan²

1987

J. Basic Microbiol.

View full text Add to dashboard Cite

Dunaliellu bioculatu, a marine unicellular euryhaline green alga, accumulated intracellular glycerol as a response to increaed osmolality due to increased concentrations of NaCl, KCl or sucrose, but not ethylene glycol. A decrease in salinity, below the normal, of the outel medium resulted in a decrease in the intracellular glycerol. Glycerol was retained (NaCl salinization) or released (KCl salinization) by the alga. Glycerol production slightly depended on photosynthesis since it took place in the light and in the dark.Dunaliella is a genus of biflagellate unicellular green algae, the cells of which are wallless (ROUND 1973). The ability of Dunaliella cells to survive and flourish in marine environments under the influence of osmotic stresses has received considerable attention. These euryhaline organisms, because of their remarkable capacity to adjust to salinity stress, have been studied t o determine mechanisms used t o maintain osmotic equilibrium between cells and environment. Some species of Dunaliella were recorded to grow in salinities ranging from 0.3 to 12% (MCHLACHLAN 1960). The high degree of correlation between the internal concentration of glycerol and osmolarity of the clear whether the glycerol production is induced by ionic and/or osmotic stress. Thus the aim of the present work was t o study the effect of some ions and osmotica on glycerol production by D. bioculata. NaCl of KCl (osmotic and ionic components) and sucrose or ethylene glycol (osmotic components) were applied to D. bioculata cdture to elucidate the roles played by the two types of stresses on glycerol formation. Materials and methodsDunuliella bioculutu was cultivated axenically in an artifical sea water medium containing 0.5 M NaCl (BRUQOMANN et ul., 1978). The cells were illuminated with irradiation from high-pressure mercury lamps (radiant flux density 11 Wm-2, 12 h photoperiod) a t a temperature of 25 "C. Algae were used a t the late log phase of growth.Cells were harvested by centrifugation at 3500 x g for 5 min, and weie suspended, with minimal agitation, a t ten times the original cell density, in 16 mM phosphate buffer, pH 7.5, containing 2 m~. MgCl, and the same concentration of NaCl as in the growth medium. Chlorophyll was determined from methanolic extmcts of the cells (HOLDEN 1976). I n the stress experiments the osmotica were added to a medium which contained 0.5 M NaCl was taken into account in determining the final osmolality (WOLF et ul. 1977). 30

show abstract

Loss of Intracellular Glycerol from Dunaliella tertiolecta after Decreasing the External Salinity

Cited by 23 publications

References 16 publications

A mutant ofDunaliella parva CCAP 19/9 leaking large amounts of glycerol into the medium

A mutant ofDunaliella parva CCAP 19/9 leaking large amounts of glycerol into the medium

Release of intracellular glycerol and pore formation in Dunaliella tertiolecta exposed to hypotonic stress

Glycerol production by Dunaliella bioculata

Contact Info

Product

Resources

About