Summary: Chloroplast development requires coordinated expression of both nuclear‐ and chloroplast‐encoded genes. To better understand the roles played by nuclear‐encoded chloroplast proteins in chloroplast biogenesis, we isolated an Arabidopsis mutant, egy1‐1, which has a dual phenotype, reduced chlorophyll accumulation and abnormal hypocotyl gravicurvature. Subsequent map‐based cloning and DNA sequencing of the mutant gene revealed a 10‐bp deletion in an EGY1 gene, which encodes a 59‐kDa metalloprotease that contains eight trans‐membrane domains at its C‐terminus, and carries out β‐casein degradation in an ATP‐independent manner. EGY1 protein accumulation varies between tissue types, being most prominent in leaf and stem tissues, and is responsive to light and ethylene. EGY1‐GFP hybrid proteins are localized in the chloroplast. egy1 mutant chloroplasts had reduced granal thylakoids and poorly developed lamellae networks. Furthermore, the accumulation of chlorophyll a/b binding proteins of the light‐harvesting complexes I and II (Lhca and Lhcb) are significantly decreased in three separate loss‐of‐function egy1 mutants. Taken together, these results suggest that EGY1 metalloprotease is required for chloroplast development and, hence, a defective EGY1 gene has pleiotropic effects both on chloroplast development and on ethylene‐dependent gravitropism of light‐grown hypocotyls.

Hyperlipidemia is one of the major risk factor for the development of cardiovascular disease. Hypolipidemic nutraceuticals and functional foods help improve serum lipid profiles as reducing total cholesterol, triglyceride, and low-density lipoprotein cholesterol, while elevating high-density lipoprotein cholesterol. The effectiveness of omega-3 polyunsaturated fatty acid, phytosterols, dietary fiber, and tea catechin in management of hyperlipidemia has been clearly demonstrated in epidemiological and interventional trials. Studies on mechanism reveal that they act as inhibitor or activator of critical enzyme, agonist or inhibitor of transcription factor, competitor of transporter, and sequestrant of bile acid to modulate lipid homeostasis. Hypolipidemic effects are also claimed in dietary proteins, many polyphenols, other phytochemicals, raw extract, or even whole food. This review attempts to give an overview of lipid homeostasis and summarize recent findings of hypolipidemic nutraceuticals and functional foods according to their active ingredients, focusing on the efficacy and underlying mechanisms.

Heterotrophic fermentation of microalgae has been shown to accumulate high amounts of microalgal lipids, which are regarded as one of the most promising feedstocks for sustainable biodiesel production. To increase the biomass and reduce the cost of microalgal culture, the purpose of this study was to evaluate the possibility of using cassava starch hydrolysate (CSH) instead of glucose as carbon source for heterotrophic culture of Chlorella protothecoides in flasks. First, the two-step enzymatic process of hydrolysis of cassava starch by α-amylase and glucoamylase was optimized; the conversion efficiency for cassava starch was up to 97.7%, and over 80% of CSH was glucose. Subsequently, we compared heterotrophic cultures of C. protothecoiedes using glucose or CSH as carbon source. The results demonstrated that when using CSH as the organic carbon source, the highest biomass and the maximum total lipid yield obtained were 15.8 and 4.19 g/L, representing increases of 42.3 and 27.7%, respectively, compared to using glucose as the organic carbon source. This suggests that CSH is a better carbon source than glucose for heterotrophic Chlorella protothecoides.