Functional Organization of Chlorophyll a and Carotenoids in the Alga, Nannochloropsis salina

Abstract

Chlorophyll-protein complexes were isolated from a yellow-reen alg, Nannochloropsis salina after mild detergent treatment and gel electrophoresis. Three different complexes were obtained which correspond to the three major kinds of chlorophyll-proteins isolated from spinach chloroplasts by the same procedure and previously identified as reaction center complexes for photosystems I and II and a light-harvesting complex. The analogy between the algal complexes and those from spinach was drawn from their absorption and fluorescence spectra and relative pigment content. The identities and amounts of the major carotenoids associated with each isolated complex were determined by HPLC. Although the reaction center complexes accounted for only 14% of the total chlorophyll, they were highly enriched in a-carotene, whereas the lightharvesting complex contained a high proportion of xanthophylls (mainly violaxanthin and vaucheriaxanthin-ester). Fluorescence excitation spectra of the alpl membranes showed that one or both of the major xanthophylls may act as antenna pigment for photosynthesis.In higher plant chloroplasts, photosynthetic pigments are noncovalently bound to at least three different intrinsic membrane protein complexes (26

The Response of Nannochloropsis gaditana to Nitrogen Starvation Includes De Novo Biosynthesis of Triacylglycerols, a Decrease of Chloroplast Galactolipids, and Reorganization of the Photosynthetic Apparatus

“…However, the spectrum was significantly red shifted compared to a typical ECS spectrum measured in chlorophytes. This could reflect either the different nature of the carotenoids present in the light-harvesting complexes (20,21) (Table 2) or a different protein environment experienced by these chromophores, as previously suggested (21). The ECS signal in Nannochloropsis cells was unchanged under nitrogen-replete and -starved conditions (Fig.…”

“…They have cells of reduced size (ϳ3 m) and present a single chloroplast that is encircled by four membranes and that occupies most of the cell volume. They also have a peculiar pigment content, presenting only chlorophyll a and lacking other accessory chlorophylls, such as Chl b or c. Violaxanthin and vaucheraxanthin are the most represented carotenoids (Car) in the cells (20,21). Although it has been documented that exposure of Nannochloropsis to N deprivation results in a large accumulation of oil (6), no clear picture of the changes occurring in their chloroplasts during this starvation has been provided so far.…”

Anoxic and oxic degradation of 14C‐labeled chloropigments and a 14C‐labeled diatom in Long Island Sound sediments

“…For example, most chlorophyll in living cells is noncovalently bound to various proteins (Larkum and Barrett 1983). The relative proportions of these pigment-protein complexes vary with the type of plants and species (Brown 1987). Larkum and Barrett (1983) found that different pigment-protein complexes have different reactivities to degradation agents such as enzymes and acids due to variations in size, solubility, and molecular association.…”

A comparative study of acid and alkaline phosphatase activities in several strains ofNannochloris(Chlorophyceae) andNannochloropsis(Eustigmatophyceae)

“…Of the species studied by Kuenzler & Perras (1965) one strain (GSB Sticho) was incorrectly referred to in many works as Stichococcus cylindricus. This strain has actually been reclassified as N. salina (Brown, 1987;Boussiba et al, 1987) and posesses only acid phosphatase with a maximum of activity at pH 4-8. In conclusion, we consider that the lack of phosphatases in N. oculata may represent a new feature differentiating it from the other two species studied.…”