Characterization of Amphidinium(Amphidiniales,Dinophyceae)species from the China Sea based on morphological,molecular,and pigment data

Amphidinium species are amongst the most abundant benthic dinoflagellates in marine intertidal sandy ecosystems.Some of them are able to produce a variety of bioactive compounds that can have both harmful effects and pharmaceutical potentials.The diversity of Amphidinium in shallow waters along the Chinese coast was investigated by isolating single cells from sand,coral,and macroalgal samples collected from 2012 to 2020.Their morphologies were subjected to examination using light microscopy(LM)and scanning electron microscopy(SEM).A total of 74 Amphidinium strains were morphologically identified,belonging to 11 species:A.carterae,A.gibbosum,A.operculatum,A.massartii,A.cf.massartii,A.fijiensis,A.pseudomassartii,A.steinii,A.thermaeum,A.theodori,A.tomasii,as well as an undefined species.The last seven species have not been previously reported in Chinese waters.Amphidinium carterae subcladesⅠ,Ⅱ,andⅣwere found in the South China Sea,while subcladeⅢwas only found in the Yellow Sea.Threadlike body scales were observed on the surface of subcladesⅢ and Ⅳ,supporting the idea that A.carterae might contain several different species.Large subunit ribosomal RNA(LSU rRNA)sequencesbased phylogeny revealed two groups(GroupsⅠandⅡ)within Amphidinium,which is consistent with the relative position of sulcus(in touch with cingulum or not).In addition,large differences in morphology and molecular phylogeny between A.operculatum(the type species of Amphidinium)and other species,suggest that a subdivision of Amphidinium might be needed.The pigment profiles of all available strains were analyzed by high performance liquid chromatography(HPLC).Eleven pigments,including peridinin,diadinoxanthin,diatoxanthin,pheophorbide(and pheophorbide a),antheraxanthin,β-carotene,and four different chlorophylls were detected.The high pheophorbide/pheophorbide a ratio in Amphidinium implies that it may be a good candidate as a natural source of photosensitizers,a well-known anticancer drug.

The recent progress on the bioactive compounds from algal biomass for human health applications

The secondary metabolites produced by algae(including macroalgae and microalgae)possess several human health benefits.The bioactive compounds in algae have potential to be used in the medical and pharmaceutical industries for drug discovery.The rapid development of genetic tools and omics approaches has extended the understanding of algal metabolism along with enhanced productivity and improving the properties of bioactive compounds.Thus,the focus of this review is to discuss the molecular progress on algae for bioactive compound production which includes genomics,transcriptomics,proteomics,and metabolomics.The comprehensive discussion on multi-omics approaches provides the potential knowledge for future research.The structural and functional genomics,application of genetic tools,molecular mechanisms of bioactive compound synthesis,protein modification,and the omics performance of algae at various levels under abiotic stress are discussed.Gene annotation and identification of key functions are the basis of genomics which provides the comprehensive overview of genetic modification.The recent development of molecular modifications and their application in algae to produce high-yield bioactive compounds that meet human needs through the optimization of algal target strains are also emphasized.The exploration of the molecular mechanisms of bioactive compounds under abiotic stress is of great practical significance to guide the optimization of culture conditions.