Interaction de la salinité et de la température sur la morphologie, la croissance et la composition cellulaire d’une Cyanobactérie halotolérante (Aphanothece sp.)

Abstract

ResumeUn clone de cyanobacterie chroococcale (Aphanothece sp.) isole des salines de Santa Pola (Espagne) a ete etudie d'un point de vue morphologique et ultrastructural. De plus, outre la chlorophylle a, la phycocyanine et Pallophycocyanine, une analyse par HPLC a permis de separer 10 caroteno'ides: myxoxanthophylles, nostoxanthine, caloxanthine, zeaxanthine, cryptoxanthine, echinenone, epoxydes de ß-carotene et ß-carotene. Ce dernier pigment forme ä lui seul 70-80% de la masse totale des caroteno'ides.Uimpact de la salinite (de 0,6 M ä 3 M de NaCl), de la temperature (de 25 °C ä 40 °C) et leur interaction sur la croissance de cette chroococcale ont ete etudies. C'est une algue eurytherme et halotolerante, s'adaptant rapidement aux stress causes par ces 2 facteurs. La croissance est relativement lente, le temps minimum de generation observe est de 29,7 h et a ete obtenu pour une salinite de 2 M et une temperature de 40 °C; on a observe une etroite interdependance entre ces deux facteurs. Salinite et temporature n'ont pas engendre de variations importantes ni dans la composition pigmentaire (chl a et caroteno'ides varient de fa?on identique), ni dans la taille des cellules (correlation hautement significative entre longueur et largeur). On observe des variations importantes dans la concentration protoinique et glucidique des cellules, mais sans relation previsible avec la temperature et la salinite.Cette souche pourrait presenter un interet en aquiculture intensive de par sa richesse en proteines et polysaccharides. Abstract Interaction of Salinity and Temperature on Morphology, Growth and Cell Composition of a Halotolerant Cyanobacterium (Aphanothece sp.)A strain of Aphanothece sp., a chroococcalian cyanobacterium, was isolated from Santa Pola Salt Marsh (Spain) and studies were carried out concerning its morphological and ultrastructural aspects. In addition to the following light-harvesting pigments, chlorophyll a, phycocyanin and allophycocyanin, ten algal carotenoids were identified by HPLC: mixoxanthophylls, nostoxanthin, caloxanthin, zeaxanthin, cryptoxanthin, echinenone, several derivatives of ß-earotene containing epoxidic functions and ß-carotene. The latter pigment accounted for 70 to 80% of total carotenoids. 318 Berland et al: Interaction salinite-temperature sur Aphanothece sp.The effect of salinity (0,6 to 3 M NaCl) on the growth of this alga was investigated at different temperatures (25 °C to 40 °C). The results indicate that this cyanobacteria is an eurythermal and halotolerant organism exhibiting rapid adaptation to salinity and temperature changes. Aphanothece sp. showed a low relative growth rate with a minimum doubling time of 29.7 h at 2 M NaCl and 40 °C. No significant influence of the different salt concentations and temperatures on pigmentation (similar changes in chla and carotenoid contents) and cell size (highly significant correlation between length and breadth) was found in Aphanothece sp. Variations in carbohydrate and protein cell contents showed no evident relationship to salinity...

Influence of salinity on the growth and biochemical composition of the cyanobacterium Synechococcus sp.

“…In Cyanothece 16Som2, an increase in salinity from 29‰ to 117‰ also reduced protein and carbohydrate production (De Philippis et al, 1993). In Aphanothece sp., however, increased salinity resulted in an increase in protein production, both cellular and by culture volume (Berland et al, 1989).…”

“…En Aphanothece sp. se ha descrito una rápida adaptación a la salinidad entre 34‰ y 174‰ debido a su capacidad halotolerante (Berland et al, 1989).…”

“…A rapid adaptation to salinity between 34‰ and 174‰ has been described for Aphanothece sp. due to its halotolerant capability (Berland et al, 1989).…”

“…Sin embargo, en Aphanothece sp. el aumento de la salinidad produce un aumento de la producción proteica, tanto celular como por volumen de cultivo (Berland et al, 1989).…”

Structure, function and management of the biological system for seasonal solar saltworks

“…These euryhaline, slime-producing algae grow best in intermediate salinities (Oren, 2000;Margheri et al, 1987), but the organisms survive and continue to release mucilage well into high salinities (Berland et al, 1989;personal experience). Techniques that minimize growth of Aphanothece halophytica include establishment of sufficient numbers of ponds to keep the salinity gradient in each pond narrow, adjustment of depths in low and intermediate salinity ponds to allow light to reach the pond floors and permit nutrient-sequestering benthic communities to develop and function (De Medeiros Rocha and Camara, 1993), use of an «artificial wetland» 6 to strip nutrients from the intake water (see below), and establishment of functioning Artemia populations.…”