Tetraselmis Species Research Articles

Tetraselmis species for environmental sustainability: biology, water bioremediation, and biofuel production.

With increasing demand of fossil fuels and water pollution and their environmental impacts, marine green microalgae have gained special attention in both scientific and industrial fields.This is due to their fast growth in non-arable lands with high photosynthetic activity, theirmetabolic plasticity, as well as theirhigh CO2 capture capacity. Tetraselmis species, green and eukaryotic microalgae, are not onlyconsidered as a valuable source of biomolecules including pigments, lipids, and starch but also widely used in biotechnological applications. Tetraselmis cultivation for high-value biomolecules and industrial use was demonstrated to be a non-cost-effective strategy because of its low demand in nutrients, such as phosphorus and nitrogen. Recently, phycoremediation of wastewater rich in nutrients, chemicals, and heavy metals has become an efficient and economic-alternative that allows the detoxification of waters and inducesmechanisms in algal cells for biomolecules rich-energy synthesis to regulate their metabolic pathways. This review aims to shed light on Tetraselmis species for their different culture conditions and metabolites bioaccumulation, as well as their human health and environmental applications. Additionally, phycoremediation of contaminants associated to biofuel production in Tetraselmis cells and their different intracellular and extracellular mechanismshave also been investigated.

Biodiversity of symbiotic microalgae associated with meiofaunal marine acoels in Southern Japan.

Acoels in the family Convolutidae are commonly found with microalgal symbionts. Convolutids can host green algal Tetraselmis and dinoflagellates within the family Symbiodiniaceae and the genus Amphidinium. The diversity of these microalgae has not been well surveyed. In this study, we used PCR and culture techniques to demonstrate the biodiversity of Tetraselmis and dinoflagellates in symbiosis with meiofaunal acoels. Here, 66 acoels were collected from seven localities around Okinawa, Ishigaki, and Kochi, Japan. While convolutids were heavily represented in this sampling, some acoels formed a clade outside Convolutidae and are potentially a new family of acoels harboring symbiotic microalgae. From the acoels collected, a total of 32 Tetraselmis and 26 Symbiodiniaceae cultures were established. Molecular phylogenies were constructed from cultured material (and from total host DNA) using the 18S rRNA gene (Tetraselmis) and 28S rRNA gene (dinoflagellates). The majority of Tetraselmis sequences grouped within the T. astigmatica clade but strains closely related to T. convolutae, T. marina, and T. gracilis were also observed. This is the first report of Tetraselmis species, other than T. convolutae, naturally associating with acoels. For dinoflagellates, members of Cladocopium and Miliolidium were observed, but most Symbiodiniaceae sequences formed clusters within Symbiodinium, grouping with S. natans, or sister to S. tridacnidorum. Several new Symbiodinium sequences from this study may represent novel species. This is the first molecular record of Miliolidium and Symbiodinium from acoels. Microalgal strains from this study will provide a necessary framework for future taxonomic studies and research on symbiotic relationships between acoels and microalgae.

Antioxidant, Antiviral, and Anti-Inflammatory Activities of Lutein-Enriched Extract of Tetraselmis Species.

Microalgae are proposed to have powerful applications for human health in the pharmaceutical and food industries. Tetraselmis species (sp.), which are green microalgae, were identified as a source of broad-spectrum health-promoting biological activities. However, the bioactivity of these species has not been elucidated. We aimed to confirm the antioxidant, antiviral, and anti-inflammatory effects of Tetraselmis sp. extract (TEE). TEE showed 2,2-diphenyl-1-picryl-hydrazyl-hydrate radical and hydrogen peroxide scavenging activities and reduced plaque formation in Vero E6 cells infected with vaccinia virus. TEE treatment also significantly inhibited nitric oxide (NO) production and improved cell viability in lipopolysaccharide (LPS)-induced RAW264.7 cells. These anti-inflammatory effects were further analyzed in LPS-induced RAW 264.7 cells and the zebrafish model. Further, TEE reduced induced NO synthase expression and proinflammatory cytokine release, including tumor necrosis factor-α, interleukin-6, and interleukin-1β, through MAPKs and NF-κB-dependent mechanisms. Further analysis revealed that TEE increased the survival rate and reduced cell death and NO production in an LPS-stimulated zebrafish model. Further, high-performance liquid chromatography revealed a strong presence of the carotenoid lutein in TEE. Overall, the results suggest that lutein-enriched TEE may be a potent antioxidant, antiviral, and anti-inflammatory agent that could be sustainably utilized in industrial applications.

Changes in volatile and fatty acid compositions of selected microalgal suspensions with high pressure homogenization

This is the first report on the fatty acid and volatile analysis of high pressure homogenization (HPH)-treated microalgal suspensions using chemometrics methods to increase insight into the complex (bio)chemical changes. Four microalgal suspensions, namely Arthrospira , Isochrysis , Nannochloropsis , and Tetraselmis species, were processed by HPH at 300, 600, and 900 bar. While cell disruption due to HPH seemed to have a minimal impact on the fatty acid profile, the high number of discriminating volatiles suggest several (bio)chemical reactions that the treatment may have triggered. Alterations in terpene and ketones indicate the induction of carotenoid degradation. Lipid oxidation could also have occurred during HPH, as noted in the changes in furans in Arthrospira sp. and aldehydes in Nannochloropsis sp. and Tetraselmis sp. Maillard reaction may have likewise been triggered by HPH as shown by the pyrazines in Arthrospira sp. and Tetraselmis sp. Sulphur compounds were only significantly changing in Isochrysis sp. and are typically associated with the degradation of sulphur-containing amino acids. The abundance of hydrocarbons as discriminant volatiles suggests that HPH can induce the synthesis of long-chain fatty acids. This study provides insight into how the volatile profile of microalgae can potentially be manipulated by applying specific pressure levels of HPH. • The effect of HPH on the volatile and fatty acid profile was investigated. • HPH (especially at 900 bar) modified the volatile fraction of microalgal suspensions. • Changes in furans and pyrazines show a possible effect on the Maillard reactions. • HPH triggered the degradation of sulphur-containing amino acids and carotenoids. • A microalgal volatile profile can be modified by applying specific pressure-levels.

Kinematic analysis and visualization of Tetraselmis microalgae 3D motility by digital holography.

A study on locomotion in a 3D environment of Tetraselmis microalgae by digital holographic microscopy is reported. In particular, a fast and semiautomatic criterion is revealed for tracking and analyzing the swimming path of a microalga (i.e., Tetraselmis species) in a 3D volume. Digital holography (DH) in a microscope off-axis configuration is exploited as a useful method to enable fast autofocusing and recognition of objects in the field of view, thus coupling DH with appropriate numerical algorithms. Through the proposed method we measure, simultaneously, the tri-dimensional paths followed by the flagellate microorganism and the full set of the kinematic parameters that describe the swimming behavior of the analyzed microorganisms by means of a polynomial fitting and segmentation. Furthermore, the method is capable to furnish the accurate morphology of the microorganisms at any instant of time along its 3D trajectory. This work launches a promising trend having as the main objective the combined use of DH and motility microorganism analysis as a label-free and non-invasive environmental monitoring tool, employable also for in situ measurements. Finally, we show that the locomotion can be visualized intriguingly by different modalities to furnish marine biologists with a clear 3D representation of all the parameters of the kinematic set in order to better understand the behavior of the microorganism under investigation.

Tetraselmis jejuensis sp. nov. (Chlorodendrophyceae), a Euryhaline Microalga Found in Supralittoral Tide Pools at Jeju Island, Korea.

We found the euryhaline microalga, Tetraselmis jejuensis sp. nov., which was adapted to supralittoral tide pools with salinities varying from 0.3–3.1%. Fifteen strains of T. jejuensis were isolated from Daejeong (DJ) and Yongduam (YO), and clonal cultures were established in the laboratory. Morphological characterization revealed that the cells have a compressed shape, four flagella emerging from a depression near the apex in two opposite pairs, a cup-shaped chloroplast containing one pyrenoid surrounded by starch, and eyespot regions not located near the flagellar base. T. jejuensis cells showed distinct characteristics compared to other Tetraselmis species. First, a regular subunit pattern with honeycomb-like structures was predominantly displayed on the surface in the middle of the cell body. Second, the pyrenoid was invaded by both cytoplasmic channels comprising electron-dense material separated from the cytoplasm, and two branches of small cytoplasmic channels (canaliculi) in various directions, which characterize the subgenus Tetrathele. Eyespot regions containing a large number of osmiophilic globules, packed closely together and arranged in subcircular close packing of diverse sizes, were dispersed throughout the chloroplast. In the phylogenetic analysis of small subunit (SSU) rDNA sequences, the 15 strains isolated from DJ and YO separated a newly branched clade in the Chlorodendrophyceae at the base of a clade comprising the T. carteriiformi/subcordiformis clade, T. chuii/suecica clade, and T. striata/convolutae clade. The strains in the diverging clade were considered to belong to the same species. The SSU rDNA sequences of the DJ and YO strains showed a maximum difference of 1.53% and 1.19% compared to Tetraselmis suecica (MK541745), the closest species of the family based on the phylogenetic analysis, respectively. Based on morphological, molecular, and physiological features, we suggest a new species in the genus Tetraselmis named Tetraselmis jejuensis, with the species name “jejuensis” referring to the collection site, Jeju Island, Korea.

Biomineralization Capacities of Chlorodendrophyceae: Correlation Between Chloroplast Morphology and the Distribution of Micropearls in the Cell

Several species of the genus Tetraselmis (Chlorodendrophyceae, Chlorophyta) were recently discovered to possess unsuspected biomineralization capacities: they produce multiple intracellular inclusions of amorphous calcium carbonate (ACC), called micropearls. Early light-microscopists had spotted rows of refractive granules in some species, although without identifying their mineral nature. Scanning electron microscope (SEM) observations showed that the distribution of the micropearls in the cell forms a pattern, which appears to be characteristic for a given species. The present study shows that this pattern correlates with the shape of the chloroplast, which differs between Tetraselmis species, because micropearls align themselves along the incisions between chloroplast lobes. This was observed both by SEM and in live cells by light microscopy (LM) using Nomarski differential interference contrast. Additionally, molecular phylogenetic analyses, of rbcL and ITS2 gene sequences from diverse strains of Chlorodendrophyceae, corroborated the morphological observations by identifying two groups among nominal Tetraselmis spp. that differ in chloroplast morphology, micropearl arrangement, and ITS2 RNA secondary structure.

Influence of different diets on the growth, survival, fecundity and proximate composition of brine shrimpArtemia franciscana(Kellog, 1906)

Artemia franciscana was studied under in vitro conditions, and fed with five different microalgae species, two organic diets and one mixed diet to evaluate the nutritional profile and growth performance. The A. franciscana instar-I nauplii were stocked at a density of 100 per litre of ground borewell water with a salinity of 70 ppt in a plastic container and the culture continued for 12 days. The A. franciscana was fed with five microalgal species, such as Tetraselmis sp., Chaetoceros sp., Isochrysis sp., Thalassiosira sp. and Nannochloropsis sp., and organic diets of rice bran, soybean meal, and a mixture of Tetraselmis sp. and Chaetoceros sp. with rice bran, giving a total of eight experiments. The growth of A. franciscana was measured by length, and was observed to be the greatest (10,850 μm) in the group that was fed the mixed algae combination, and the lowest (7,290 μm) in the group that was fed Nannochloropsis sp. Among the different treatments, the highest survival value of 76% was seen in the group that was fed Chaetoceros sp. The fecundity was higher in A. franciscana that were fed with algae Chaetoceros sp., while the lower rate was observed with the group that was fed Nannochloropsis sp. Analysis of proximate composition showed increased levels in the animals fed with Chaetoceros sp. (lipid, 19.40%; eicosapentaenoic acid, 6.70 mg; docosahexaenoic acid, 10.20 mg; amino acids: proline, 2.06 μg; histidine, 0.77 μg, arginine, 0.65 μg, glycine, 0.80 μg, glutamic acid, 1.75 μg; threonine, 1.42 μg) and the mixed diet (protein, 58.59%; carbohydrate, 21.30%; amino acids: asparagine, 0.90 μg; serine, 1.65 μg; tryptophan, 1.66 μg; leucine, 1.50 μg; phenylalanine, 1.14 μg; valine, 0.66 μg). All components showed the lowest level in the diet fed with Tetraselmis species. These A. franciscana populations showed better survival, higher fecundity and biochemical profiles when cultured with microalgae Chaetoceros sp. These data are useful to improve A. franciscana culture in aquaculture to produce quality cysts and biomass, especially in feeding larvae of marine species.

Marine and freshwater micropearls: biomineralization producing strontium-rich amorphous calcium carbonate inclusions is widespread in the genus <i>Tetraselmis</i> (Chlorophyta)

Abstract. Unicellular algae play important roles in the biogeochemical cycles of numerous elements, particularly through the biomineralization capacity of certain species (e.g., coccolithophores greatly contributing to the “organic carbon pump” of the oceans), and unidentified actors of these cycles are still being discovered. This is the case of the unicellular alga Tetraselmis cordiformis (Chlorophyta) that was recently discovered to form intracellular mineral inclusions, called micropearls, which had been previously overlooked. These intracellular inclusions of hydrated amorphous calcium carbonates (ACCs) were first described in Lake Geneva (Switzerland) and are the result of a novel biomineralization process. The genus Tetraselmis includes more than 30 species that have been widely studied since the description of the type species in 1878. The present study shows that many other Tetraselmis species share this biomineralization capacity: 10 species out of the 12 tested contained micropearls, including T. chui, T. convolutae, T. levis, T. subcordiformis, T. suecica and T. tetrathele. Our results indicate that micropearls are not randomly distributed inside the Tetraselmis cells but are located preferentially under the plasma membrane and seem to form a definite pattern, which differs among species. In Tetraselmis cells, the biomineralization process seems to systematically start with a rod-shaped nucleus and results in an enrichment of the micropearls in Sr over Ca (the Sr∕Ca ratio is more than 200 times higher in the micropearls than in the surrounding water or growth medium). This concentrating capacity varies among species and may be of interest for possible bioremediation techniques regarding radioactive 90Sr water pollution. The Tetraselmis species forming micropearls live in various habitats, indicating that this novel biomineralization process takes place in different environments (marine, brackish and freshwater) and is therefore a widespread phenomenon.

Microencapsulation of algal biomass (Tetraselmis chuii) by spray-drying using different encapsulation materials for better preservation of beta-carotene and antioxidant compounds

The awareness of harmful effects of synthetic compounds and an inclination towards the usage of natural products have led to the exploitation of microalgae as a source of natural colors. Because of their health benefits, algal pigments have massive commercial value as natural colorants in the nutraceutical, cosmetics, and pharmaceutical industries. One of the important natural sources of microalgae are antioxidants, bioactive components: such as polyunsaturated fatty acids, β-carotene, sulfated polysaccharides and sterols. However, these antioxidant-rich fractions and carotenoids possess low storage stability and exhibit high sensitivity to light, heat, and oxygen. During the extraction process, there is some loss of required materials, and also, chances of the contamination from toxic solvents. There are few reports on algal-extract encapsulation and algal biomass encapsulation, and only a few types of wall materials that can show better stability, shelf life, and controlled release have been investigated.In this work, we investigated micro-encapsulation of the fresh algal biomass of Tetraselmis chuii and studied the effect of the wall material and the processing conditions of the spray dryer on the preservation of β-carotene and antioxidant compounds. Our studies revealed that a native species of Tetraselmis from Mexico, which is an important aquaculture feed, produce a considerable amount of β-carotene as much as 1.3% of its biomass. We found preservation of 80–92% of beta-carotene and 46–81% phenolic-compounds in freshly microencapsulated microalgae even after three months of storage in dark condition at 25 °C, maltodextrin at 130 °C was found the best wall material. This alga is suitable for use in aquaculture and food industry because fresh microalgae can be microencapsulated without loss of its nutritional values, and it is easier to handle and transport. This can serve as a functional food with better preservation of its antioxidant value and can be processed without any toxic solvent component.

Potent biomedical applications of isolated polysaccharides from marine microalgae Tetraselmis species.

Microalgae Tetraselmis species were used to evaluate the biological characteristics of water-soluble polysaccharides (WSPs) as one of the significant bioactive substances (BAS) from these photosynthetic microalgae species. Compositional analysis of these BAS shows that they are mainly composed of WSPs along with negligible amount of proteins and lipids. WSPs were partially purified and characterized for their compositional, structural and biological properties such as antioxidant, tyrosinase inhibitory activity and antifungal activies. These WSPs showed the significant antioxidant, antifungal and tyrosinase inhibitory activities, respectively. The outcomes of this study demonstrated that WSPs can be the potent source of biological moieties for further investigations along with specific potent biological activities.

Influence of darkness on pigments of Tetraselmis indica (Chlorodendrophyceae, Chlorophyta)

In the photic zone, phytoplankton experience diurnal variation in light intensity. However, prolonged exposure to aphotic condition influences their physiological state. Pigment composition is a useful biomarker to decipher cells physiological state and adaptive response to changing environmental conditions. Chlorophyll, a natural pigment, is biosynthesised even in darkness and studies have shown this ability is determined by genetic characteristics of an organism. The purpose of this study was to examine the influence of darkness on pigments and chlorophyll autofluorescence of Tetraselmis indica. Dark exposure (up to 6 months) had no significant impact on chlorophyll a and b concentration, whereas carotenoids were enhanced. Upon re-illumination pigments gradually recovered to pre-dark phase condition. These adaptive survival strategies of T. indica by altering pigment concentration in response to prolonged darkness are interesting. The absence of loroxanthin and loroxanthin esters in T. indica is reported in a first Tetraselmis species so far. In addition, the evaluation of autofluorescence and cellular chlorophyll concentration pointed out that they are not interdependent in this species. Hence, careful consideration of these two factors is needed when either of them is used as a proxy for other. The results obtained encourage a thorough study of pigment analysis, especially when subjected to darkness, to elucidate potential role in the evolution, chemotaxonomy, and survivability of species.

Isolation and Characterization of Water Soluble Bioactive Substances from Marine Photosynthetic Microalga Tetraselmis Species

Isolation, quantification and characterization of bioactive compounds from microalgae Tetraselmis species have been performed to elucidate the potential use as a bioactive material. Microalga are a promising source of lipids for biofuel production and represent a diverse group of microscopic photosynthetic organisms and are able to convert solar energy into biomasses. The imposition of oxidative stresses by various environmental factors leads to the production of reactive oxygen species (ROS) in plant cells, including algal cell. Antioxidant activity of water soluble bioactive substances (WSBS) was determined by DPPH, ABTS, FRAP and similar SOD radical-scavenging assay. The content analysis of lipid, sugar, polyphenol and protein was performed to evaluate the potent usefulness of WSBS from the whole cells cultivated under the optimum conditions for the production of biodiesel. The yield of WSBS was determined to be 17% based on the total carbohydrate assay. The relative activity of WSBS toward FRAP and DPPH reagent was observed ranging from 13 to 55%, showing the significant anti-oxidative properties with wide range of temperatures from room temperature to 80℃. The outcomes of this study support utilization of WSBS from microalgae Tetraselmis species as a potential source of naturally occurring antioxidants.

Biochemical properties of water soluble polysaccharides from photosynthetic marine microalgae Tetraselmis species

Water soluble polysaccharides (WSPs) were isolated from defatted microalgae Tetraselmis sp. KCTC 12432 BP (T.S1) and KCTC 12236 BP (T.S2), and purified by a combination of ethanol precipitation, immobilized metal affinity chromatography and size-exclusion column chromatography. Biochemical properties of WSPs obtained from the supernatant (S 1 and S 2) and purification steps (EP 1 and EP 2) have been elucidated for their potential use as a biologically active material. Oxidative effect on efficiency from the hydrolytic fenton reaction (FS 1 and FS 2) was also employed to assess the WSPs production and biological activity from T.S1 and T.S2, respectively. Antioxidant activity of the purified WSPs from EP 2 toward 1,1-diphenyl-2-picryl-hy-drazyl (DPPH), 2,2’-Azinobis (3-ethylbenzothiazoline-6-sulfonic acid) di-ammonium salt (ABTS), and ferric reducing antioxidant power (FRAP) of radical-scavenging showed significant differences depending on the monosaccharide compositions of WSPs. On the other hand, a significant specific tyrosinase inhibitory activity was observed from the WSPs purified from EP 1 (10 ¼mol/g/min) indicating the potential use as a whitening source. The outcomes of our study support the utilization of WSPs from these microalgal species as a potential source of naturally occurring whitening and antioxidants to ease oxidative stresses. According to our knowledge related to microalgal studies, until now this is the first study which demonstrates the significance between primary structure and potential biological activities of WSPs purified from the defatted microalgae Tetraselmis species.

Evaluation of the Volatile Composition and Sensory Properties of Five Species of Microalgae

Due to their high content of polyunsaturated fatty acids, antioxidants, and proteins, microalgae hold a lot of potential for nutritional applications. When microalgae are integrated into foodstuffs, the aroma is an important aspect to consider. In this study the aroma properties of microalgae were studied by correlating data on the volatile composition with sensory evaluations. Four species of marine microalgae ( Botryococcus braunii, , Rhodomonas , Tetraselmis species, and Nannochloropsis oculata ) and one fresh water microalga ( Chlorella vulgaris ) were investigated. Multivariate data processing revealed that microalgal samples having a seafood-like odor character contain high levels of sulfuric compounds (dimethyl disulfide, dimethyl trisulfide, and methional), diketones, α-ionone, and β-ionone. Fresh green, fruity flavors were linked with typical aldehydes such as 2,4-alkadienals and 2,4,6-alkatrienals. The presence of these compounds in fresh microalga pastes is explained by aroma formation mechanisms such as enzymatic lipid oxidation, enzymatic and chemical degradation of dimethylsulfoniopropionate (generating dimethyl sulfide), phenylalanine (generating benzaldehyde), and carotenoids (generating ionones).

Tetraselmis indica (Chlorodendrophyceae, Chlorophyta), a new species isolated from salt pans in Goa, India

A new species of Tetraselmis, T. indica Arora & Anil, was isolated from nanoplankton collected from salt pans in Goa (India) and is described based on morphological, ultrastructural, 18S rRNA gene sequence and genome size data. The species is characterized by a distinct eyespot, rectangular nucleus, a large number of Golgi bodies, two types of flagellar pit hairs and a characteristic type of cell division. In nature, the species was found in a wide range of temperatures (48°C down to 28°C) and salinities, from hypersaline (up to 350 psu) down to marine (c. 35 psu) conditions. Phylogenetic analysis based on 18S rDNA sequence data showed that T. indica is most closely related to unidentified Tetraselmis strains from a salt lake in North America.

Cryopreserved Marine Microalgae Grown Using Different Freezing Methods

Marine microalgae are a key diet component in finfish and shellfish aquaculture. Cryopreservation of the microalgae is suggested by many other studies as the best method for long-term storage. To test cryopreservation efficacy, 19 taxas of marine microalgal species were examined. In the first experiment we compared dimethylsulfoxide (Me2SO) and glycerol, which are most widely used as cryoprotectant agents (CPAs). The cryopreservation comprised two freezing procedures. Firstly, the samples containing the CPAs were kept at 4℃ for 10 min before being plunged into liquid nitrogen (-196℃). Secondly, samples containing CPAs were pre-cooled (-1℃ min-1) to -80℃ before being plunged into liquid nitrogen. Most of the species were successfully cryopreserved using Me2SO, whereas the Prasinophyceae (T. striata and T. suecica) were successfully cryopreserved using glycerol. In general, the cooling method had no influence on the survival of the microalgae except in the case of the Tetraselmis species. In the second experiment, the cultured solution was divided before cryopreservation into concentrated and non-concentrated groups to identify the effect of cell density during cryopreservation. After 12 months of storage, the samples were again divided into centrifugation and non-centrifugation groups to learn the effect of Me2SO on the culture. Viability and growth of the microalgae were not influenced by cell density or the centrifugal removal of the Me2SO after thawing.

OCCURRENCE OF LOROXANTHIN, LOROXANTHIN DECENOATE, AND LOROXANTHIN DODECENOATE IN TETRASELMIS SPECIES (PRASINOPHYCEAE, CHLOROPHYTA)(1).

The pigment composition of six species of Tetraselmis (Prasinophyceae) was analyzed using improved HPLC methods. All pigment extracts showed three peaks corresponding to unknown carotenoids. The isolated pigments were analyzed using UV-Vis spectroscopy, electrospray ionization-mass spectrometry (ESI-MS), and when carotenoid esters were suspected, gas chromatography-mass spectrometry (GC-MS) of the methyl ester and dimethyloxazoline derivative of the corresponding fatty acid. The new pigments were determined to be loroxanthin, loroxanthin 19-(2-decenoate), and loroxanthin 19-(2-dodecenoate); this is the first time these pigments have been described in the genus Tetraselmis. Moreover, this is the first report of esterification of 2-decenoic acid to loroxanthin. The relative contents of these pigments depended on the light regime, with the lowest proportions measured at the highest photon flux density assayed. The implications of the identification of these pigments in the genus Tetraselmis for the pigment types previously described in the class Prasinophyceae are discussed.

Life history and fatty acid composition of the marine rotifer Synchaeta cecilia valentina fed different algae

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 193:125-133 (2000) - doi:10.3354/meps193125 fed different algae Rafael Oltra1,*, Rafael Todolí1, Teresa Bosque1, Luis M. Lubián2, Juan C. Navarro3 1Departamento de Microbiología y Ecología, Facultad de Ciencias Biológicas, Universitat de València, Dr. Moliner 50, 46100 Burjassot (Valencia), Spain 2Instituto de Ciencias Marinas de Andalucía (CSIC), Campus Río San Pedro s/n, 11510 Puerto Real (Cadiz), Spain 3Instituto de Acuicultura Torre de la Sal (CSIC), Ribera de Cabanes, 12595 Torre la Sal (Castellón), Spain *E-mail: rafael.oltra@uv.es ABSTRACT: A strain of the marine rotifer Synchaeta cecilia valentina, isolated from 'El Hondo de Elche', a Spanish Mediterranean coastal lagoon, was cultured in the laboratory in 20 ml test tubes, at 20°C and 25 ppt salinity and fed with the algae Tetraselmis sp., T. chuii, Cryptomonas sp., Rhodomonas salina and R. baltica. The effects of these 5 algal diets and 3 food levels (2.1, 3.2 and 4.2 µg ml-1 dry wt) on life history traits of this rotifer were studied in life tables performed with replicated individual cultures of 1 ml, at the temperature and salinity mentioned above. Algal diet had a significant effect on both average lifespan (LS) and net reproductive rate (R0), but food concentration only had an effect on R0. Tetraselmis sp. provided the best results: LS ranging from 4.4 to 6 d, R0 from 10.9 to 12.8 offsping female-1, and intrinsic growth rate (r) from 0.84 to 1.12 d-1. S. cecilia valentina also grew with the remainder of the algae, except with R. baltica. With this alga the rotifer grew only in 500 ml cultures performed at a higher food concentration (5.55 µg ml-1 dry wt). The effect of the algal diet on the fatty acid composition of the rotifers was analysed to infer its nutritional value according to the changes induced by diet. Saturated fatty acids made up 34 to 40% of total fatty acids, whereas monoenes accounted for 15 to 23%, and polyunsaturated fatty acids constituted 20 to 29%. Main fatty acids were: 16:0 (which ranged from 17 to 22%), 18:0 (10 to 12%), and 18:1 (8.5 to 12%). In certain algal treatments (both Tetraselmis species), the linolenic acid 18:3n-3 was moderately abundant (5 to 9%). Eicosapentaenoic acid, 20:5n-3, was markedly lower in rotifers fed with R. baltica (less than 3%), whereas docosahexaenoic acid, 22:6n-3, was found in a higher proportion in Cryptomonas sp. (4.9%) and R. salina (3.4%) treatments. The nutritional value deduced from the lipid composition was similar to that reported in the literature for other rotifers such as Brachionus plicatilis. KEY WORDS: Life table · Growth rate · Tetraselmis · Cryptomonas · Rhodomonas · Fatty acids Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 193. Publication date: February 28, 2000 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 2000 Inter-Research.

Prasinococcus capsulatus gen. et sp. nov., a new marine coccoid prasinophyte.

A new genus, Prasinococcus, and a new species, P. capsulatus, are described on the basis of specimen that appeared in enriched cultures inoculated from water samples in the western Pacific Ocean. Cells of this unicellular alga are spherical and surrounded with a large amount of gelatinous matrix. The pigment composition, which includes chlorophylls a and b, prasinoxanthin, Mg 2, 4-diviriylphaeoporphyrin a5 monomethyl ester (Mg 2, 4-D) and 5, 6-epoxy-3, 3′-dihydroxy-5, 6, 7′, 8′-tetrahydro-β-ε-caroten-11′, 19-olide (uriolide), is close to that observed in the Mamiellales (Prasinophyceae). The cell is non-flagellate and has a firm cell wall, but no scales on the cell body. The pyrenoid has a characteristic structure in which a mitochondrial lobe and chloroplast outer membranes protrude into the pyrenoid matrix. The cell wall has a projecting appendage like a circle collar surrounded by distinctive holes penetrating the cell wall. Since the cell contains no 3-deoxy-manno-octulosonic acid (KDO), the wall is considered to have a different origin from the cell coverings which consist of fused scales in Tetraselmis species. It has a characteristic way of asexual reproduction in which, after cell division, one cell remains within the parent cell wall while the other is extruded. This suggests that this alga be placed tentatively in the Pycnococcaceae (Order Mamiellales) on the basis of the pigment composition and morphological characteristics, but the taxonomic position of coccoid prasinophytes may need to be reconsidered.