Determinations of the salt sensitivity of enzymes extracted from the halophilic alga Dunaliella viridis revealed that pentose phosphate isomerase, ribulose diphosphate carboxylase, glucose-6-phosphate dehydrogenase, and phosphohexose isomerase were inhibited by NaCl concentrations far lower than that in the growth medium (3.75 m). The inhibition was reversible and was not prevented by preparing...

A simple, rapid ultrafiltration technique has been used to separate free vitamin B12 from that attached to the binding factor present in the media of cultures of the marine microalgae Mantoniella squamata and Pavlova lutheri (auxotrophic spec~es) , and Dunaliella primolecta and Phaeodactylum tricomuturn (species with no B12 requirement). The dissociation constant (K,) for the B12-binder complex...

microalgal growth curve, after the exponential phase, shows a stationary phase where algalbiomass production is inhibited and remains constant by some factors such as nutrientdepletion and intrinsic behavior. the present study is concerned with evaluating effects ofthe culture medium condition and intrinsic behavior on biomass production by dunaliellatertiolecta. to this end, effect of ph, nutr...

A new hypothesis is presented for the mechanism of metabolic response during osmoregulation in the alga Dunaliella salina. We propose that the osmotic response is initiated by differential volume changes of the cytoplasm and the chloroplast (observed using the electron microscope) which alter the cytoplasmic orthophosphate concentration. This triggers a flow through the Pi/triose-phosphate shut...

A new HPLC/DAD (Diode Array Detector) method is proposed for the identification of some carotene isomers. The operating conditions adopted permit the resolution of α-carotene, all-trans-β-carotene, 9-cis-β-carotene, 13-cis-β-carotene and 15-cis-β-carotene. Moreover, the chromatographic conditions reported are simplified in respect of those reported up to now. The method is applied to the determ...

A quantitative capillary assay is described for measuring chemoreception in the neritic and littoral unicellular alga Dunaliella tertiolecta. Lucite chemotaxis plates were used in the assay with 3-microliter capillaries. A Coulter Counter was employed to determine algal cell numbers. D. tertiolecta is attracted to ammonium ion with a maximum positive response at 10(-3) M. Inclusion of calcium a...