Consequences of Mixotrophy on Cell Energetic Metabolism in Revealed by Genetic Engineering and Metabolic Approaches.

Algae belonging to the genus are promising organisms for biotech purposes, being able to accumulate large amounts of lipid reserves. These organisms adapt to different trophic conditions, thriving in strict photoautotrophic conditions, as well as in the concomitant presence of light plus reduced external carbon as energy sources (mixotrophy). In this work, we investigated the mixotrophic responses of (formerly ).

Screening for Biologically Annotated Drugs That Trigger Triacylglycerol Accumulation in the Diatom .

Microalgae are a promising feedstock for the production of triacylglycerol (TAG) for a variety of potential applications, ranging from food and human health to biofuels and green chemistry. However, obtaining high TAG yields is challenging. A phenotypic assay for the accumulation of oil droplets was developed to screen a library of 1,200 drugs, annotated with pharmacology information, to select compounds that trigger TAG accumulation in the diatom Using this screen, we identified 34 molecules acting in a dose-dependent manner.

Nitric Oxide Mediates Nitrite-Sensing and Acclimation and Triggers a Remodeling of Lipids.

Nitric oxide (NO) is an intermediate of the nitrogen cycle, an industrial pollutant, and a marker of climate change. NO also acts as a gaseous transmitter in a variety of biological processes. The impact of environmental NO needs to be addressed.

Investigating mixotrophic metabolism in the model diatom .

Diatoms are prominent marine microalgae, interesting not only from an ecological point of view, but also for their possible use in biotechnology applications. They can be cultivated in phototrophic conditions, using sunlight as the sole energy source. Some diatoms, however, can also grow in a mixotrophic mode, wherein both light and external reduced carbon contribute to biomass accumulation.

Membrane glycerolipid remodeling triggered by nitrogen and phosphorus starvation in Phaeodactylum tricornutum.

Diatoms constitute a major phylum of phytoplankton biodiversity in ocean water and freshwater ecosystems. They are known to respond to some chemical variations of the environment by the accumulation of triacylglycerol, but the relative changes occurring in membrane glycerolipids have not yet been studied. Our goal was first to define a reference for the glycerolipidome of the marine model diatom Phaeodactylum tricornutum, a necessary prerequisite to characterize and dissect the lipid metabolic routes that are orchestrated and regulated to build up each subcellular membrane compartment.

Spiralisones A-D: acylphloroglucinol hemiketals from an Australian marine brown alga, Zonaria spiralis.

An intertidal sample of the Australian marine brown alga, Zonaria spiralis, exhibited promising kinase inhibitory and antibacterial activity. Chemical analysis returned six phloroglucinol-derived lipids, the new hemiketal spiralisones A-D (1-4) and the known chromones 5-6, and the known norsesquiterpenoid apo-9'-fucoxanthinone (7). Structures 1-7 were assigned on the basis of detailed spectroscopic analysis, biosynthetic considerations and total synthesis.

Kinase inhibitor scaffolds against neurodegenerative diseases from a Southern Australian ascidian, Didemnum sp.

Screening a library of Southern Australian and Antarctic marine invertebrates and algae for inhibitors of neurodegenerative disease kinase targets casein kinase 1 (CK1δ), cyclin-dependent kinase 5 (CDK5) and glycogen synthase kinase 3β (GSK3β) identified a Western Australian Didemnum species (CMB-02127) as a high-priority specimen. Chemical fractionation returned the known aromatic alkaloids ningalins B-D as the major metabolites, together with six minor metabolites, the new ningalins E-G and the known hexacyclic pyrrole alkaloids lamellarins Z, G and A6. All structures were assigned by detailed spectroscopic analysis and literature comparisons, and the structural assignments were supported by biosynthetic considerations.

A search for BACE inhibitors reveals new biosynthetically related pyrrolidones, furanones and pyrroles from a southern Australian marine sponge, Ianthella sp.

Fractionation of a southern Australian marine sponge, Ianthella sp., yielded sixteen metabolites including a new class of pyrrolidone, ianthellidones A-F (1-6), a new class of furanone, ianthellidones G-H (7-8), new and known lamellarins, lamellarins O1 (9), O2 (10), O (11) and Q (12), plus the known 4-hydroxybenzaldehyde (13), 4-hydroxybenzoic acid (14), 4-methoxybenzoic acid (15) and ethyl 4-hydroxybenzoate (16). Structures for all Ianthella metabolites were determined by detailed spectroscopic analysis, supported by a plausible biosynthetic relationship.

Heronamides A-C, new polyketide macrolactams from an Australian marine-derived Streptomyces sp. A biosynthetic case for synchronized tandem electrocyclization.

A Streptomyces sp. isolated from a shallow water sediment sample collected off Heron Island, Australia, afforded three new polyketide macrolactams, heronamides A-C (1-3). Structures were assigned to the heronamides on the basis of detailed spectroscopic analysis, chemical derivatization and biosynthetic considerations.

Heterofibrins: inhibitors of lipid droplet formation from a deep-water southern Australian marine sponge, Spongia (Heterofibria) sp.

A bioassay-guided search for inhibitors of lipid droplet formation in a deep-water southern Australian marine sponge, Spongia (Heterofibria) sp., yielded six new compounds, fatty acids heterofibrins A1 (1) and B1 (4), along with related monolactyl and dilactyl esters, heterofibrins A2 (2), B2 (5), A3 (3) and B3 (6). Heterofibrin structures were assigned on the basis of detailed spectroscopic analysis, with comparison to chiral synthetic model compounds.

Nocardiopsins: new FKBP12-binding macrolide polyketides from an Australian marine-derived actinomycete, Nocardiopsis sp.

A marine-derived actinomycete, Nocardiopsis sp. (CMB-M0232), obtained from a sediment sample collected at a depth of 55 m off the coast of Brisbane, Australia, yielded two new macrolide polyketides. Structures for nocardiopsins A and B were assigned by detailed spectroscopic analysis, degradation and chemical derivatization.

Mirabilins revisited: polyketide alkaloids from a southern Australian marine sponge, Clathria sp.

Chemical investigation of a southern Australian marine sponge, Clathria sp., yielded the known mirabilins C, F and G, together with three new analogues, mirabilins H-J. For the first time mirabilins C and F are documented as the underivatized natural products, and a complete absolute stereochemistry is assigned to mirabilin F.

Naseseazines A and B: a new dimeric diketopiperazine framework from a marine-derived actinomycete, Streptomyces sp.

Chemical analysis of a Streptomyces sp. (CMB-MQ030) isolated from a Fijian marine sediment yielded two new diketopiperazines, naseseazines A and B (1, 2), featuring a new dimeric framework. Structures were determined by detailed spectroscopic analysis and C(3) Marfey's analysis.

The role of PKCdelta and PKCepsilon in the neonatal rat colon in response to hypoxia challenge.

Previous studies have determined that, in response to bacterial endotoxin, the colonic mucosa of the 10-d-old neonatal rat was more susceptible to injury than was the colon of the 25-d-old mature animal. Furthermore, it is known that certain isoforms of protein kinase C (PKC), specifically PKCdelta and PKCepsilon, mediate intestinal inflammatory responses to specific challenges. Therefore, in the present study, we have examined the association between the activation of these PKC isoforms and the enhanced susceptibility to hypoxia-induced challenge.