Application of algal assay for defining nutrient limitation in two streams at Shillong

A biological monitoring program (1992-93) was undertaken with the aim of testing the toxic effect of the Lambro, one of the most polluted rivers in Northern Italy. The filtered river samples were tested with S. capricornutum in a 96h exposure growth inhibition assay and with a photobacterial inhibition assay with the LUMISTox System. The unfiltered samples were also tested with LUMISTox, in order to evaluate the role played by the suspended and colloidal material in the water toxicity. The river samples were passed through a series of columns filled with Carbopack B, XAD-2 and C-18 respectively to concentrate organic compound for chemical analysis and enriched with EDTA to complex metals. The Carbopack B procedure proved to be the most efficient among the tested extraction techniques. The de-toxificant effect of the sample treatments was evaluated in terms of percentage increase of the cell density by the algal assay, while the toxicity of the extracted organic compounds was evaluated by LUMISTox System. The comparison of algal assay with chemical analysis results pointed out that the toxicity of the Lambro waters was mainly related to pesticide contamination.

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Estimation of Limiting Nutrient by Algal Assay Procedure with Indigenous Phytoplankton Assemblage.

Journal of Japan Society on Water Environment ◽

10.2965/jswe.19.373 ◽

1996 ◽

Vol 19 (5) ◽

pp. 373-380 ◽

Cited By ~ 3

Author(s):

Young Sik LEE ◽

Tetsuo MUKAI ◽

Kazuto TAKIMOTO ◽

Mitsumasa OKADA

Keyword(s):

Phytoplankton Assemblage ◽

Assay Procedure ◽

Limiting Nutrient ◽

Algal Assay

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Metabolic response of Botryococcus braunii to high bicarbonate dosages and other conditions: analysis of photosynthetic performance, productivity, and lipidomic profile

Journal of Applied Phycology ◽

10.1007/s10811-021-02544-7 ◽

2021 ◽

Author(s):

Néstor David Giraldo ◽

Sandra Marcela Correa ◽

Andrés Arbeláez ◽

Felix L. Figueroa ◽

Rigoberto Ríos-Estepa ◽

...

Keyword(s):

Nutrient Limitation ◽

Metabolic Response ◽

Neutral Lipids ◽

Biomass Productivity ◽

Botryococcus Braunii ◽

Photosynthetic Performance ◽

Lipid Productivity ◽

Cellular Growth ◽

Adaptive Responses ◽

Nitrogen And Phosphorus

AbstractIn this study the metabolic responses of Botryococcus braunii were analyzed upon different inorganic carbon dosages and nutrient limitation conditions in terms of lipid and biomass productivity, as well as photosynthetic performance. The nutritional schemes evaluated included different levels of sodium bicarbonate and nitrogen and phosphorus starvation, which were contrasted against standard cultures fed with CO2. Bicarbonate was found to be an advantageous carbon source since high dosages caused a significant increase in biomass and lipid productivity, in addition to an enhanced photosynthetic quantum yield and neutral lipids abundance. This contrasts to the commonly used approach of microalgae nutrient limitation, which leads to high lipid accumulation at the expense of impaired cellular growth, causing a decline in overall lipid productivity. The lipidome analysis served to hypothesize about the influence of the nutritional context on B. braunii structural and storage lipid metabolism, besides the adaptive responses exhibited by cells that underwent nutrient stress.

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Kog1/Raptor mediates metabolic rewiring during nutrient limitation by controlling SNF1/AMPK activity

Science Advances ◽

10.1126/sciadv.abe5544 ◽

2021 ◽

Vol 7 (16) ◽

pp. eabe5544

Author(s):

Zeenat Rashida ◽

Rajalakshmi Srinivasan ◽

Meghana Cyanam ◽

Sunil Laxman

Keyword(s):

Amino Acid ◽

Nutrient Limitation ◽

Carbon Flux ◽

Metabolic Flux ◽

Carbon Allocation ◽

Carbon Utilization ◽

Acid Biosynthesis ◽

Control Growth ◽

Ampk Activity ◽

Delayed Growth

In changing environments, cells modulate resource budgeting through distinct metabolic routes to control growth. Accordingly, the TORC1 and SNF1/AMPK pathways operate contrastingly in nutrient replete or limited environments to maintain homeostasis. The functions of TORC1 under glucose and amino acid limitation are relatively unknown. We identified a modified form of the yeast TORC1 component Kog1/Raptor, which exhibits delayed growth exclusively during glucose and amino acid limitations. Using this, we found a necessary function for Kog1 in these conditions where TORC1 kinase activity is undetectable. Metabolic flux and transcriptome analysis revealed that Kog1 controls SNF1-dependent carbon flux apportioning between glutamate/amino acid biosynthesis and gluconeogenesis. Kog1 regulates SNF1/AMPK activity and outputs and mediates a rapamycin-independent activation of the SNF1 targets Mig1 and Cat8. This enables effective glucose derepression, gluconeogenesis activation, and carbon allocation through different pathways. Therefore, Kog1 centrally regulates metabolic homeostasis and carbon utilization during nutrient limitation by managing SNF1 activity.

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