Comparative analysis of photosynthetic and respiratory parameters in the psychrophilic unicellular green alga , cultured in indoor and outdoor photo-bioreactors.

Effect of temperatures and illumination of temperate winter on photosynthesis and respiration was studied in the psychrophilic microalgae, (Trebouxiophyceae). Outdoor and indoor algal cultures were compared. Photosynthetic as well as respiration rates increased as light and temperature increased, until 35 °C, more in outdoor than in indoor cells, in agreement with the calculated values.

Impact of Sulfur Starvation in Autotrophic and Heterotrophic Cultures of the Extremophilic Microalga Galdieria phlegrea (Cyanidiophyceae).

In plants and algae, sulfate assimilation and cysteine synthesis are regulated by sulfur (S) accessibility from the environment. This study reports the effects of S deprivation in autotrophic and heterotrophic cultures of Galdieria phlegrea (Cyanidiophyceae), a unicellular red alga isolated in the Solfatara crater located in Campi Flegrei (Naples, Italy), where H2S is the prevalent form of gaseous S in the fumarolic fluids and S is widespread in the soils near the fumaroles. This is the first report on the effects of S deprivation on a sulfurous microalga that is also able to grow heterotrophically in the dark.

Sulfur Deprivation Results in Oxidative Perturbation in Chlorella sorokiniana (211/8k).

Sulfur deficiency in plant cells has not been considered as a potential abiotic factor that can induce oxidative stress. We studied the antioxidant defense system of Chlorella sorokiniana cultured under sulfur (S) deficiency, imposed for a maximum period of 24 h, to evaluate the effect of an S shortage on oxidative stress. S deprivation induced an immediate (30 min) but transient increase in the intracellular H2O2 content, which suggests that S limitation can lead to a temporary redox disturbance.

Physiological and morphological responses of Lead or Cadmium exposed Chlorella sorokiniana 211-8K (Chlorophyceae).

The heavy metal pollution in soils and aquatic environments is a serious ecological problem. In the green-microalga Chlorella sorokiniana 211-8K (Chlorophyceae) exposed to ions of lead (Pb) and cadmium (Cd) we studied the metabolic responses to the toxicity of these two heavy metals. Our data indicate that both the pollutants alter the alga cell ultrastructure and its physiological characteristics (growth, photosynthesis, respiration, enzyme activities).

Changes in cysteine and O-acetyl-L-serine levels in the microalga Chlorella sorokiniana in response to the S-nutritional status.

We analyzed the effects of deprivation and subsequent restoration of sulphate (S) in the nutrient solution on cysteine (Cys) and O-acetyl-L-serine (OAS) levels in Chlorella sorokiniana (211/8k). The removal of S from the culture medium caused a time-dependent increase in O-acetyl-L-serine(thiol)lyase (OASTL) activity and a decrease in soluble proteins content. The protein gel blot analysis was used to show that OASTL isoforms are located in the chloroplast and in the cytoplasm of S-starved cells.

Temperature dependence of nitrate reductase in the psychrophilic unicellular alga Koliella antarctica and the mesophilic alga Chlorella sorokiniana.

Temperature responses of nitrate reductase (NR) were studied in the psychrophilic unicellular alga, Koliella antarctica, and in the mesophilic species, Chlorella sorokiniana. Enzymes from both species were purified to near homogeneity by Blue Sepharose (Pharmacia, Uppsala, Sweden) affinity chromatography and high-resolution anion-exchange chromatography (MonoQ; Pharmacia; Uppsala, Sweden). Both enzymes have a subunit molecular mass of 100 kDa, and K.

Glucose-6P dehydrogenase in Chlorella sorokiniana (211/8k): an enzyme with unusual characteristics.

In Chlorella sorokiniana (211/8k), glucose-6 phosphate dehydrogenase (G6PDH-EC 1.1.1.

Glutamate synthase activities and protein changes in relation to nitrogen nutrition in barley: the dependence on different plastidic glucose-6P dehydrogenase isoforms.

In barley (Hordeum vulgare L. var. Nure), glutamate synthesis and the production of reducing power by the oxidative pentose phosphate pathway (OPPP) are strictly correlated biochemical processes.

Temperature responses of growth, photosynthesis, respiration and NADH: nitrate reductase in cryophilic and mesophilic algae.

•  Temperature effects on growth, photosynthesis, respiration and nitrate reductase (NR) were studied in the cryophilic algae Koliella antarctica and 'Chlorella'saccharophila, and in the mesophilic Chlorella sorokiniana. •  Growth rate was measured as increase in optical density. Photosynthesis at saturating light and respiration in darkness were measured as O exchange.

Glutamate synthesis in barley roots: the role of the plastidic glucose-6-phosphate dehydrogenase.

Evidence is provided for a close link between glutamate (Glu) synthesis and the production of reducing power by the oxidative pentose phosphate pathway (OPPP) in barley ( Hordeum vulgare L. var. Alfeo) root plastids.