the microalgae, dunaliella salina was isolated from maharlu salt lake, south east of shiraz, iran. the isolated strain was identified by both morphological and physiological markers. the complete its region (its1 + its2) including the 5.8s rdna gene used as molecular marker confirmed our identification. growth and cell proliferation, total chlorophyll and carotenoid contents were determined in ...

We examined the role of bacteriochlorophyll synthesis on the regulation of carotenoid synthesis in Rhodopseudomonas capsulata. Strains capable of making bacteriochlorophyll accumulated greater amounts of carotenoids under low oxygen than they did under high oxygen. However, strains unable to produce bacteriochlorophyll did not regulate their carotenoid production in response to changes in oxyge...

1. We have obtained an action spectrum for chlorophyll formation in Euglena gracilis. This action spectrum is similar to the absorption spectrum of protochlorophyll. However, efforts to isolate and identify this pigment have been unsuccessful. 2. Porphyrins have been extracted from both the normal and dark-adapted Euglena and a chlorophyll-free mutant. 3. The "action" spectra for chlorophyll an...

The temperature dependence of carotenoid synthesis in Neurospora crassa was investigated. The primary light reaction is independent of temperature, but the amount of carotenoid pigment which subsequently accumulates in the dark is strongly dependent on the temperature during the dark incubation. Carotenoid synthesis shows a sensitivity to both high and low temperatures, and of the temperatures ...

Solanum lycopersicum (tomato) and its wild relatives harbor genetic diversity that yields heritable variation in fruit chemistry that could be exploited to identify genes regulating their synthesis and accumulation. Carotenoids, for example, are essential in plant and animal nutrition, and are the visual indicators of ripening for many fruits, including tomato. Whereas carotenoid synthesis is w...

The biosynthesis pathway of carotenoids in cyanobacteria is partly described. However, the subcellular localization of individual steps is so far unknown. Carotenoid analysis of different membrane subfractions in Synechocystis sp. PCC6803 shows that "light" plasma membranes have a high carotenoid/protein ratio, when compared to "heavier" plasma membranes or thylakoids. The localization of CrtQ ...

Carotenoids constitute an important component of the defense system against photooxidative stress in bacteria. In Azospirillum brasilense Sp7, a nonphotosynthetic rhizobacterium, carotenoid synthesis is controlled by a pair of extracytoplasmic function sigma factors (RpoEs) and their cognate zinc-binding anti-sigma factors (ChrRs). Its genome harbors two copies of the gene encoding geranylgeran...

Enzymes that are able to oxidatively cleave carotenoids at specific positions have been identified in animals and plants. The first such enzyme to be identified was a nine-cis-epoxy carotenoid dioxygenase from maize, which catalyzes the rate-limiting step of abscisic acid biosynthesis. Similar enzymes are necessary for the synthesis of vitamin A in animals and other carotenoid-derived molecules...

In plants, continuous formation of lateral roots (LRs) facilitates efficient exploration of the soil environment. Roots can maximize developmental capacity in variable environmental conditions through establishment of sites competent to form LRs. This LR prepattern is established by a periodic oscillation in gene expression near the root tip. The spatial distribution of competent (prebranch) si...