Bioprospecting marine plankton

Bioprospection of the Antarctic Diatoms Craspedostauros ineffabilis IMA082A and Craspedostauros zucchelli IMA088A

In extreme environments such as Antarctica, a diverse range of organisms, including diatoms, serve as essential reservoirs of distinctive bioactive compounds with significant implications in pharmaceutical, cosmeceutical, nutraceutical, and biotechnological fields. This is the case of the new species Craspedostauros ineffabilis IMA082A and Craspedostauros zucchellii IMA088A Trentin, Moschin, Lopes, Custódio and Moro (Bacillariophyta) that are here explored for the first time for possible biotechnological applications. For this purpose, a bioprospection approach was applied by preparing organic extracts (acetone and methanol) from freeze-dried biomass followed by the evaluation of their in vitro antioxidant properties and inhibitory activities on enzymes related with Alzheimer's disease (acetylcholinesterase: AChE, butyrylcholinesterase: BChE), Type 2 diabetes mellitus (T2DM, α-glucosidase, α-amylase), obesity (lipase) and hyperpigmentation (tyrosinase). Extracts were then profiled by ultra-high-performance liquid chromatography-mass spectrometry (UPLC-HR-MS/MS), while the fatty acid methyl ester (FAME) profiles were established by gas chromatography-mass spectrometry (GC-MS). Our results highlighted strong copper chelating activity of the acetone extract from C. ineffabilis and moderate to high inhibitory activities on AChE, BChE, α-amylase and lipase for extracts from both species. The results of the chemical analysis indicated polyunsaturated fatty acids (PUFA) and their derivatives as the possible compounds responsible for the observed activities. The FAME profile showed saturated fatty acids (SFA) as the main group and methyl palmitoleate (C16:1) as the predominant FAME in both species. Overall, our results suggest both Antarctic strains as potential sources of interesting molecules with industrial applications. Further studies aiming to investigate unidentified metabolites and to maximize growth yield and natural compound production are required.

Phytochemicals: A Promising Alternative for the Prevention of Alzheimer's Disease

Alzheimer's disease (AD) is a neurological condition that worsens with ageing and affects memory and cognitive function. Presently more than 55 million individuals are affected by AD all over the world, and it is a leading cause of death in old age. The main purpose of this paper is to review the phytochemical constituents of different plants that are used for the treatment of AD. A thorough and organized review of the existing literature was conducted, and the data under the different sections were found using a computerized bibliographic search through the use of databases such as PubMed, Web of Science, Google Scholar, Scopus, CAB Abstracts, MEDLINE, EMBASE, INMEDPLAN, NATTS, and numerous other websites. Around 360 papers were screened, and, out of that, 258 papers were selected on the basis of keywords and relevant information that needed to be included in this review. A total of 55 plants belonging to different families have been reported to possess different bioactive compounds (galantamine, curcumin, silymarin, and many more) that play a significant role in the treatment of AD. These plants possess anti-inflammatory, antioxidant, anticholinesterase, and anti-amyloid properties and are safe for consumption. This paper focuses on the taxonomic details of the plants, the mode of action of their phytochemicals, their safety, future prospects, limitations, and sustainability criteria for the effective treatment of AD.

Microalgal bioactive metabolites as promising implements in nutraceuticals and pharmaceuticals: inspiring therapy for health benefits

The rapid increase in global population and shrinkage of agricultural land necessitates the use of cost-effective renewable sources as alternative to excessive resource-demanding agricultural crops. Microalgae seem to be a potential substitute as it rapidly produces large biomass that can serve as a good source of various functional ingredients that are not produced/synthesized inside the human body and high-value nonessential bioactive compounds. Microalgae-derived bioactive metabolites possess various bioactivities including antioxidant, anti-inflammatory, antimicrobial, anti-carcinogenic, anti-hypertensive, anti-lipidemic, and anti-diabetic activities, thereof rapidly elevating their demand as interesting option in pharmaceuticals, nutraceuticals and functional foods industries for developing new products. However, their utilization in these sectors has been limited. This demands more research to explore the functionality of microalgae derived functional ingredients. Therefore, in this review, we intended to furnish up-to-date knowledge on prospects of bioactive metabolites from microalgae, their bioactivities related to health, the process of microalgae cultivation and harvesting, extraction and purification of bioactive metabolites, role as dietary supplements or functional food, their commercial applications in nutritional and pharmaceutical industries and the challenges in this area of research.

Graphical abstract

Prebiotic Chemistry: The Role of Trimetaphosphate in Prebiotic Chemical Evolution

Life’s origins have always been a scientific puzzle. Understanding the production of biomolecules is crucial for understanding the evolution of life on Earth. Numerous studies on trimetaphosphate have been conducted in the field of prebiotic chemistry. However, its role in prebiotic chemistry has been documented infrequently in the review literature. The goal of this thesis is to review the role of trimetaphosphate in the early Earth’s biomolecule synthesis and phosphorylation. Additionally, various trimetaphosphate-mediated reaction pathways are discussed, as well as the role of trimetaphosphate in prebiotic chemistry. Finally, in our opinion, interactions between biomolecules should be considered in prebiotic synthesis scenarios since this may result in some advances in subsequent research on this subject. The research establishes an essential and opportune foundation for an in-depth examination of the “mystery of life".

Marine microbial bioprospecting: Exploitation of marine biodiversity towards biotechnological applications-a review

The increase in the human population causes an increase in the demand for nutritional supplies and energy resources. Thus, the novel, natural, and renewable resources became of great interest. Here comes the optimistic role of bioprospecting as a promising tool to isolate novel and interesting molecules and microorganisms from the marine environment as alternatives to the existing resources. Bioprospecting of marine metabolites and microorganisms with high biotechnological potentials has gained wide interest due to the variability and richness of the marine environment. Indeed, the existence of extreme conditions that increases the adaptability of marine organisms, especially planktons, allow the presence of interesting biological species that are able to produce novel compounds with multiple health benefits and high economical value. This review aims to provide a comprehensive overview of marine microbial bioprospecting as a growing field of interest. It emphasizes functional bioprospecting that facilitates the discovery of interesting metabolites. Marine bioprospecting was also discussed from a legal aspect for the first time, focusing on the shortcomings of international law. We also summarized the challenges facing bioprospecting in the marine environment including economic feasibility issues.

Phytoplankton Toxins and Their Potential Therapeutic Applications: A Journey toward the Quest for Potent Pharmaceuticals

Phytoplankton are prominent organisms that contain numerous bioactive substances and secondary metabolites, including toxins, which can be valuable to pharmaceutical, nutraceutical, and biotechnological industries. Studies on toxins produced by phytoplankton such as cyanobacteria, diatoms, and dinoflagellates have become more prevalent in recent years and have sparked much interest in this field of research. Because of their richness and complexity, they have great potential as medicinal remedies and biological exploratory probes. Unfortunately, such toxins are still at the preclinical and clinical stages of development. Phytoplankton toxins are harmful to other organisms and are hazardous to animals and human health. However, they may be effective as therapeutic pharmacological agents for numerous disorders, including dyslipidemia, obesity, cancer, diabetes, and hypertension. In this review, we have focused on the properties of different toxins produced by phytoplankton, as well as their beneficial effects and potential biomedical applications. The anticancer properties exhibited by phytoplankton toxins are mainly attributed to their apoptotic effects. As a result, phytoplankton toxins are a promising strategy for avoiding postponement or cancer treatment. Moreover, they also displayed promising applications in other ailments and diseases such as Alzheimer’s disease, diabetes, AIDS, fungal, bacterial, schizophrenia, inflammation, allergy, osteoporosis, asthma, and pain. Preclinical and clinical applications of phytoplankton toxins, as well as future directions of their enhanced nano-formulations for improved clinical efficacy, have also been reviewed.

Up-to-Date Overview of the Use of Natural Ingredients in Sunscreens

The photoprotective skincare segment is in high demand to meet consumer concerns on UV-induced skin damage, with a recent trend towards sunscreen alternatives with a natural origin. In this study, the use of natural ingredients, either from terrestrial or marine origin, in a panel of 444 sunscreen commercial formulations (2021) was analyzed. Ingredients from terrestrial organisms represent the large majority found in the analyzed sunscreen formulations (48%), whereas marine ingredients are present only in 13% of the analyzed products. A deeper analysis regarding the most prevalent families of ingredients from terrestrial and marine organisms used as top ingredients is also presented, as well as their mechanisms of action. This study provides an up-to-date overview of the sunscreen market regarding the use of natural ingredients, which is of relevance for scientists involved in the development of new sunscreens to identify opportunities for innovation.

Comparative Response of Marine Microalgae to H2O2-Induced Oxidative Stress

There have been growing interests in the biorefining of bioactive compounds from marine microalgae, including pigments, omega-3 fatty acids or antioxidants for use in the nutraceutical and cosmetic sectors. This study focused on the comparative responses of five marine microalgal species from different lineages, including the dinoflagellate Amphidinium carterae, chlorophyte Brachiomonas submarina, diatom Stauroneis sp., haptophyte Diacronema sp. and rhodophyte Rhodella violacea, to exposure during their batch growth to hydrogen peroxide (H₂O₂). A. carterae returned an enhanced signal with the DPPH assay (8.8 µmol Trolox eq/g DW) when exposed to H₂O₂, which was associated with reduced pigment yields and increased proportions in saturated C16 and C18 fatty acids. B. submarina showed enhanced antioxidant response upon exposure to H₂O₂ with the DPPH assay (10 µmol Trolox eq/g DW), a threefold decrease in lutein (from 2.3 to 0.8 mg/g) but a twofold increase in chlorophyll b (up to 30.0 mg/g). Stauroneis sp. showed a downward response for the antioxidant assays, but its pigment yields did not vary significantly from the control. Diacronema sp. showed reduced antioxidant response and fucoxanthin content (from 4.0 to 0.2 mg/g) when exposed to 0.5 mM H₂O₂. R. violacea exposed to H₂O₂ returned enhanced antioxidant activity and proportions of EPA but was not significantly impacted in terms of pigment content. Results indicate that H₂O₂ can be used to induce stress and initiate metabolic changes in microalgae. The responses were however species-specific, which would require further dosage optimisation to modulate the yields of specific metabolites in individual species.

Exploitation of Marine Molecules to Manage Alzheimer's Disease

Neurodegenerative diseases are sociosanitary challenges of today, as a result of increased average life expectancy, with Alzheimer’s disease being one of the most prevalent. This pathology is characterized by brain impairment linked to a neurodegenerative process culminating in cognitive decline and behavioral disorders. Though the etiology of this pathology is still unknown, it is usually associated with the appearance of senile plaques and neurofibrillary tangles. The most used prophylaxis relies on anticholinesterase drugs and NMDA receptor antagonists, whose main action is to relieve symptoms and not to treat or prevent the disease. Currently, the scientific community is gathering efforts to disclose new natural compounds effective against Alzheimer’s disease and other neurodegenerative pathologies. Marine natural products have been shown to be promising candidates, and some have been proven to exert a high neuroprotection effect, constituting a large reservoir of potential drugs and nutraceutical agents. The present article attempts to describe the processes of extraction and isolation of bioactive compounds derived from sponges, algae, marine bacteria, invertebrates, crustaceans, and tunicates as drug candidates against AD, with a focus on the success of pharmacological activity in the process of finding new and effective drug compounds.

Characterization of the Bubblegum acyl-CoA synthetase of Microchloropsis gaditana

The metabolic pathways of glycerolipids are well described in cells containing chloroplasts limited by a two-membrane envelope but not in cells containing plastids limited by four membranes, including heterokonts. Fatty acids (FAs) produced in the plastid, palmitic and palmitoleic acids (16:0 and 16:1), are used in the cytosol for the synthesis of glycerolipids via various routes, requiring multiple acyl-Coenzyme A (CoA) synthetases (ACS). Here, we characterized an ACS of the Bubblegum subfamily in the photosynthetic eukaryote Microchloropsis gaditana, an oleaginous heterokont used for the production of lipids for multiple applications. Genome engineering with TALE-N allowed the generation of MgACSBG point mutations, but no knockout was obtained. Point mutations triggered an overall decrease of 16:1 in lipids, a specific increase of unsaturated 18-carbon acyls in phosphatidylcholine and decrease of 20-carbon acyls in the betaine lipid diacylglyceryl-trimethyl-homoserine. The profile of acyl-CoAs highlighted a decrease in 16:1-CoA and 18:3-CoA. Structural modeling supported that mutations affect accessibility of FA to the MgACSBG reaction site. Expression in yeast defective in acyl-CoA biosynthesis further confirmed that point mutations affect ACSBG activity. Altogether, this study supports a critical role of heterokont MgACSBG in the production of 16:1-CoA and 18:3-CoA. In M. gaditana mutants, the excess saturated and monounsaturated FAs were diverted to triacylglycerol, thus suggesting strategies to improve the oil content in this microalga.

Marine microorganisms as an untapped source of bioactive compounds

The search for novel biologically active molecules has extended to the screening of organisms associated with less explored environments. In this sense, Oceans, which cover nearly the 67% of the globe, are interesting ecosystems characterized by a high biodiversity that is worth being explored. As such, marine microorganisms are highly interesting as promising sources of new bioactive compounds of potential value to humans. Some of these microorganisms are able to survive in extreme marine environments and, as a result, they produce complex molecules with unique biological interesting properties for a wide variety of industrial and biotechnological applications. Thus, different marine microorganisms (fungi, myxomycetes, bacteria, and microalgae) producing compounds with antioxidant, antibacterial, apoptotic, antitumoral and antiviral activities have been already isolated. This review compiles and discusses the discovery of bioactive molecules from marine microorganisms reported from 2018 onwards. Moreover, it highlights the huge potential of marine microorganisms for obtaining highly valuable bioactive compounds.

Proteomic Profiling of Emiliania huxleyi Using a Three-Dimensional Separation Method Combined with Tandem Mass Spectrometry

Emiliania huxleyi is one of the most abundant marine planktons, and it has a crucial feature in the carbon cycle. However, proteomic analyses of Emiliania huxleyi have not been done extensively. In this study, a three-dimensional liquid chromatography (3D-LC) system consisting of strong cation exchange, high- and low-pH reversed-phase liquid chromatography was established for in-depth proteomic profiling of Emiliania huxleyi. From tryptic proteome digest, 70 fractions were generated and analyzed using liquid chromatography-tandem mass spectrometry. In total, more than 84,000 unique peptides and 10,000 proteins groups were identified with a false discovery rate of ≤0.01. The physicochemical properties of the identified peptides were evaluated. Using ClueGO, approximately 700 gene ontology terms and 15 pathways were defined from the identified protein groups with p-value ≤0.05, covering a wide range of biological processes, cellular components, and molecular functions. Many biological processes associated with CO₂ fixation, photosynthesis, biosynthesis, and metabolic process were identified. Various molecular functions relating to protein binding and enzyme activities were also found. The 3D-LC strategy is a powerful approach for comparative proteomic studies on Emiliania huxleyi to reveal changes in its protein level and related mechanism.

Marine-Derived Compounds with Potential Use as Cosmeceuticals and Nutricosmetics

The cosmetic industry is among the fastest growing industries in the last decade. As the beauty concepts have been revolutionized, many terms have been coined to accompany the innovation of this industry, since the beauty products are not just confined to those that are applied to protect and enhance the appearance of the human body. Consequently, the terms such as cosmeceuticals and nutricosmetics have emerged to give a notion of the health benefits of the products that create the beauty from inside to outside. In the past years, natural products-based cosmeceuticals have gained a huge amount of attention not only from researchers but also from the public due to the general belief that they are harmless. Notably, in recent years, the demand for cosmeceuticals from the marine resources has been exponentially on the rise due to their unique chemical and biological properties that are not found in terrestrial resources. Therefore, the present review addresses the importance of marine-derived compounds, stressing new chemical entities with cosmeceutical potential from the marine natural resources and their mechanisms of action by which these compounds exert on the body functions as well as their related health benefits. Marine environments are the most important reservoir of biodiversity that provide biologically active substances whose potential is still to be discovered for application as pharmaceuticals, nutraceuticals, and cosmeceuticals. Marine organisms are not only an important renewable source of valuable bulk compounds used in cosmetic industry such as agar and carrageenan, which are used as gelling and thickening agents to increase the viscosity of cosmetic formulations, but also of small molecules such as ectoine (to promote skin hydration), trichodin A (to prevent product alteration caused by microbial contamination), and mytiloxanthin (as a coloring agent). Marine-derived molecules can also function as active ingredients, being the main compounds that determine the function of cosmeceuticals such as anti-tyrosinase (kojic acid), antiacne (sargafuran), whitening (chrysophanol), UV protection (scytonemin, mycosporine-like amino acids (MAAs)), antioxidants, and anti-wrinkle (astaxanthin and PUFAs).

Potential utilization of bioproducts from microalgae for the quality enhancement of natural products

Microalgae are autotroph organisms that utilise light energy to synthesize various high-value bioactive compounds such as polysaccharides, proteins and lipids. Due to its fast growth rate and capability to survive in harsh environment, microalgae nowadays are applied in various industrial areas. The process of obtaining microalgae-based biomolecules starts with the selection of suitable microalgae strain, cultivation, followed by downstream processing of the biomass (i.e., pre-treatment, harvesting, extraction and purification). The end products of the processes are biofuels and other valuable bioproducts. Nevertheless, low production yield and high-cost downstream processes are the emerging bottlenecks which need to be addressed in the upscaling of extracted compounds from microalgae biomass. To conclude, tremendous efforts are required to overcome these challenges to revolutionize microalgae into a novel and green factory of different bioactive compounds for industrial necessities to satisfy and fulfil global demands.

The origin and evolution of cell-intrinsic antibacterial defenses in eukaryotes

To survive in a world dominated by bacteria, eukaryotes have evolved numerous self-defense strategies. While some defenses are recent evolutionary innovations, others are ancient, with roots early in eukaryotic history. With a focus on antibacterial immunity, we highlight the evolution of pattern recognition receptors that detect bacteria, where diverse functional classes have been formed from the repeated use and reuse of a small set of protein domains. Next, we discuss core microbicidal strategies shared across eukaryotes, and how these systems may have been co-opted from ancient cellular mechanisms. We propose that studying antibacterial responses across diverse eukaryotes can reveal novel modes of defense, while highlighting the critical innovations that occurred early in the evolution of our own immune systems.

Metabolic Innovations Underpinning the Origin and Diversification of the Diatom Chloroplast

Of all the eukaryotic algal groups, diatoms make the most substantial contributions to photosynthesis in the contemporary ocean. Understanding the biological innovations that have occurred in the diatom chloroplast may provide us with explanations to the ecological success of this lineage and clues as to how best to exploit the biology of these organisms for biotechnology. In this paper, we use multi-species transcriptome datasets to compare chloroplast metabolism pathways in diatoms to other algal lineages. We identify possible diatom-specific innovations in chloroplast metabolism, including the completion of tocopherol synthesis via a chloroplast-targeted tocopherol cyclase, a complete chloroplast ornithine cycle, and chloroplast-targeted proteins involved in iron acquisition and CO₂ concentration not shared between diatoms and their closest relatives in the stramenopiles. We additionally present a detailed investigation of the chloroplast metabolism of the oil-producing diatom Fistulifera solaris, which is of industrial interest for biofuel production. These include modified amino acid and pyruvate hub metabolism that might enhance acetyl-coA production for chloroplast lipid biosynthesis and the presence of a chloroplast-localised squalene synthesis pathway unknown in other diatoms. Our data provides valuable insights into the biological adaptations underpinning an ecologically critical lineage, and how chloroplast metabolism can change even at a species level in extant algae.

Marine Microalgae: Promising Source for New Bioactive Compounds

The study of marine natural products for their bioactive potential has gained strength in recent years. Oceans harbor a vast variety of organisms that offer a biological and chemical diversity with metabolic abilities unrivalled in terrestrial systems, which makes them an attractive target for bioprospecting as an almost untapped resource of biotechnological applications. Among them, there is no doubt that microalgae could become genuine “cell factories” for the biological synthesis of bioactive substances. Thus, in the course of inter-laboratory collaboration sponsored by the European Union (7th FP) into the MAREX Project focused on the discovery of novel bioactive compounds of marine origin for the European industry, a bioprospecting study on 33 microalgae strains was carried out. The strains were cultured at laboratory scale. Two extracts were prepared for each one (biomass and cell free culture medium) and, thus, screened to provide information on the antimicrobial, the anti-proliferative, and the apoptotic potential of the studied extracts. The outcome of this study provides additional scientific data for the selection of Alexandrium tamarensis WE, Gambierdiscus australes, Prorocentrum arenarium, Prorocentrum hoffmannianum, and Prorocentrum reticulatum (Pr-3) for further investigation and offers support for the continued research of new potential drugs for human therapeutics from cultured microalgae.

Metagenomics Sheds Light on the Ecology of Marine Microbes and Their Viruses

Advances brought about by omics-based approaches have revolutionized our understanding of the diversity and ecological processes involving marine archaea, bacteria, and their viruses. This broad review discusses recent examples of how genomics, metagenomics, and ecogenomics have been applied to reveal the ecology of these biological entities. Three major topics are covered in this revision: (i) the novel roles of microorganisms in ecosystem processes; (ii) virus-host associations; and (iii) ecological associations of microeukaryotes and other microbes. We also briefly comment on the discovery of novel taxa from marine ecosystems; development of a robust taxonomic framework for prokaryotes; breakthroughs on the diversity and ecology of cyanobacteria; and advances on ecological modelling. We conclude by discussing limitations of the field and suggesting directions for future research.

Minireview: algal natural compounds and extracts as antifoulants

Marine biofouling is a paramount phenomenon in the marine environment and causes serious problems to maritime industries worldwide. Marine algae are known to produce a wide variety of chemical compounds with antibacterial, antifungal, antialgal, and anti-macrofouling properties, inhibiting the settlement and growth of other marine fouling organisms. Significant investigations and progress have been made in this field in the last two decades and several antifouling extracts and compounds have been isolated from micro- and macroalgae. In this minireview, we have summarized and evaluated antifouling compounds isolated and identified from macroalgae and microalgae between January 2010 and June 2016. Future directions for their commercialization through metabolic engineering and industrial scale up have been discussed. Upon comparing biogeographical regions, investigations from Southeast Asian waters were found to be rather scarce. Thus, we have also discussed the need to conduct more chemical ecology based research in relatively less explored areas with high algal biodiversity like Southeast Asia.

The transcription factor bZIP14 regulates the TCA cycle in the diatom Phaeodactylum tricornutum

Diatoms are amongst the most important marine microalgae in terms of biomass, but little is known concerning the molecular mechanisms that regulate their versatile metabolism. Here, the pennate diatom Phaeodactylum tricornutum was studied at the metabolite and transcriptome level during nitrogen starvation and following imposition of three other stresses that impede growth. The coordinated upregulation of the tricarboxylic acid (TCA) cycle during the nitrogen stress response was the most striking observation. Through co-expression analysis and DNA binding assays, the transcription factor bZIP14 was identified as a regulator of the TCA cycle, also beyond the nitrogen starvation response, namely in diurnal regulation. Accordingly, metabolic and transcriptional shifts were observed upon overexpression of bZIP14 in transformed P. tricornutum cells. Our data indicate that the TCA cycle is a tightly regulated and important hub for carbon reallocation in the diatom cell during nutrient starvation and that bZIP14 is a conserved regulator of this cycle.

Marine Natural Products from New Caledonia--A Review

Marine micro- and macroorganisms are well known to produce metabolites with high biotechnological potential. Nearly 40 years of systematic prospecting all around the New Caledonia archipelago and several successive research programs have uncovered new chemical leads from benthic and planktonic organisms. After species identification, biological and/or pharmaceutical analyses are performed on marine organisms to assess their bioactivities. A total of 3582 genera, 1107 families and 9372 species have been surveyed and more than 350 novel molecular structures have been identified. Along with their bioactivities that hold promise for therapeutic applications, most of these molecules are also potentially useful for cosmetics and food biotechnology. This review highlights the tremendous marine diversity in New Caledonia, and offers an outline of the vast possibilities for natural products, especially in the interest of pursuing collaborative fundamental research programs and developing local biotechnology programs.

Marine natural products

This review covers the literature published in 2013 for marine natural products (MNPs), with 982 citations (644 for the period January to December 2013) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1163 for 2013), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

Diatom-Specific Oligosaccharide and Polysaccharide Structures Help to Unravel Biosynthetic Capabilities in Diatoms

Diatoms are marine organisms that represent one of the most important sources of biomass in the ocean, accounting for about 40% of marine primary production, and in the biosphere, contributing up to 20% of global CO₂ fixation. There has been a recent surge in developing the use of diatoms as a source of bioactive compounds in the food and cosmetic industries. In addition, the potential of diatoms such as Phaeodactylum tricornutum as cell factories for the production of biopharmaceuticals is currently under evaluation. These biotechnological applications require a comprehensive understanding of the sugar biosynthesis pathways that operate in diatoms. Here, we review diatom glycan and polysaccharide structures, thus revealing their sugar biosynthesis capabilities.

[Screening marine resources to find novel chemical inhibitors of disease-relevant protein kinases]

Since the early 1970's, investigators at Station Biologique de Roscoff (SBR), France, have been using marine organisms as models to describe molecular pathways conserved through evolution in mammalian cells (e.g. the cyclin-dependent kinases involved in the control of the cell division cycle). Some kinases are misregulated in various human pathologies, including cancers. Using a specialized screening approach, chemical libraries were analysed, using on-site facilities at Roscoff, in order to identify small chemical inhibitors of protein kinases. Eight chemical scaffolds produced by marine organisms were characterized as candidate drugs by our screening facility, some of which are being considered as chemical tools to pinpoint specific cellular functions of the targeted kinases. In this review, we describe our existing screening facilities and we discuss new perspectives related to marine bioprospecting.