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Laurencia catarinensis (Ceramiales, Rhodomelaceae) has a high diversity of secondary metabolites such as acetogenin and halogenated terpenoids, with biological activities. We tested different combinations of auxins and cytokinins to evaluate their effects on the growth, total soluble proteins, pigments, and carbohydrates of L. catarinensis with the aim of improving the culture techniques of this species. To accomplish this, algae were cultivated in seawater enriched with quarter strength of von Stosch solution (VSES/4) with the addition of plant growth regulators (PGRs), and the treatment control without PGRs addition. The auxins tested were indole-3-acetic acid (IAA) and 2,4-dichlorophenoxyacetic acid (2,4-D), and cytokinins were benzylaminopurine (BA) and 2-isopentenyladenine (2iP), in the following combinations: IAA:BA, IAA:2iP, 2,4-D:BA, and 2,4-D:2iP, in the concentrations of 5:5, 5:50, 50:5, and 50:50 μM for each auxin:cytokinin combination. Addition of PGRs had significant effects on the growth rates of L. catarinensis, which varied from 7.62 ± 0.12% to 9.30 ± 0.55% day−1. The highest growth rates were observed in treatments with 5:5 μM of IAA:BA and 2,4-D:BA, and 50:5 μM of 2,4-D:2iP. Higher contents of total soluble proteins were observed in treatments with 50:50 μM of IAA:BA and 2,4-D:BA. The auxin:cytokinin combinations inhibited allophycocyanin contents, but did not affect chlorophyll a and carbohydrate concentrations. Therefore, supplementation of auxins and cytokinins, especially the IAA:BA and 2,4-D:BA combinations, is useful approach to stimulate growth rates or soluble protein contents of L. catarinensis, improving the cultivation of this species with high biotechnological potential.

The genus Hypnea (Rhodophyta, Gigartinales) has currently 61 accepted species distributed in tropical, subtropical, and temperate regions, growing in different habitats with a wide range of environmental factors and interactions with abiotic and biotic factors. Some Hypnea species are consumed by humans mostly in Asian and Indo-Pacific countries and are also exploited as raw material for kappa-carrageenan production, consequently, have been harvested and/or cultivated in several countries for decades. Hypnea musciformis has the widest geographical distribution around the world and it is the most studied species. However, more molecular studies on H. musciformis from different countries are necessary to understand the phenotypic plasticity and to reveal cryptic species. The present review is a compilation of information on taxonomy, morphology, anatomy, life history, distribution, ecology, physiology, cultivation and harvesting, chemical composition, and biotechnological applications. Although Hypnea species are well known as sources of carrageenans, reports on chemical diversity and biological activities highlight their remarkable potential for biotechnological applications.

Made available in DSpace on 2019-10-06T16:40:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Benthic marine algae, especially Rhodophyta, are within a well-known marine group able to produce secondary metabolites with bioactive properties. Among them are halogenated terpenes, synthesized by vanadium-dependent haloperoxidase (V-BPO). The red alga Ochtodes secundiramea (Montagne) M. Howe produces high amounts of halogenated monoterpenes (HMT) which have the potential to control phytopathogenic fungi. Culture closed a system is a tool used to manipulate conditions to increase the synthesis of HMT and other metabolites. The apical segments of O. secundiramea were cultivated in a bioreactor, either in seawater enriched with half strength von Stosch’s solution (VSES/2) without (control) and with the addition of 250 mg L−1 bromine (treatment). In response to these conditions, specific growth rate, HMT profile, soluble protein, phycobiliproteins, soluble carbohydrate, and chlorophyll as well as the V-BPO activity, uptake, and accumulated bromine within the biomass were evaluated. The treatment did not promote significant alterations in the growth but increased the V-BPO activity and bromine uptake and incorporation (2.5 fold). No changes in the HMT profiles of the extracts from both cultures conditions were observed by gas chromatography–mass spectrometry analyses, whereas the values of total soluble protein and phycobiliproteins were 2-fold higher in samples from the bromine-enriched medium when compared to samples from control. These results support the evidences of protective effects promoted by V-BPO activity. Furthermore, carbohydrate and chlorophyll contents were not affected by experimental conditions. These results provided new low-cost strategies that can be applied to increase of certain biomass components, which here are algal proteins, especially in Rhodophyta-based biotechnological industries for food and agriculture. Coordenadoria de Engenharia de Pesca Universidade Estadual Paulista—UNESP, Campus Experimental de Registro, Vila Tupi: Av. Nelson Brihi Badur, 430 Departamento de Bioquímica Instituto de Química da Universidade de São Paulo, Av. Prof. Lineu Prestes, 748—Cidade Universitária Núcleo de Pesquisa em Ficologia Instituto de Botânica da Secretaria de Estado do Meio Ambiente, Av. Miguel Estefano, 3687, Água Funda Coordenadoria de Engenharia de Pesca Universidade Estadual Paulista—UNESP, Campus Experimental de Registro, Vila Tupi: Av. Nelson Brihi Badur, 430

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Extracts of brown algae are used commercially for agricultural crops due to their plant growth-promoting effects and they can also be applied to help improve seaweed cultivation. Gracilaria caudata is commercially exploited as a raw material for agar production in Brazil, and Laurencia catarinensis is a source of halogenated terpenoids with several biological activities. Investigations to understand the development of seaweeds of biotechnological interest are required in order to improve their cultivation and the sustainability for biomass production on an industrial scale. The aim of the present study was to evaluate the effects of Ascophyllum/Acadian marine plant extract powder (AMPEP), a commercial, water-soluble extract of the brown alga Ascophyllum nodosum, on the growth, branching development, and pigment content of G. caudata and L. catarinensis. Four concentrations of AMPEP (0, 0.1, 1.0, and 5.0 mg L−1) were added to sterilized seawater (seawater+AMPEP), and to a medium comprised of half-strength von Stosch solution (VSES/2+AMPEP). Experiments were performed under conditions of 23 ± 2 °C, a light:dark cycle of 14:10 h, salinity at 32 psu, and photon flux densities of 60 ± 10 μmol photons m−2 s−1. Data were analyzed by one-way ANOVA, followed by a posteriori multiple comparison, Student-Newman-Keuls’ test. Treatments of seawater+AMPEP at concentrations of 0.1 and 1.0 mg L−1 stimulated the growth rates of G. caudata when compared to the control. However, the effects of seawater+AMPEP and VSES/2+AMPEP on the branching architecture of the thalli were not significant for either species. Concentrations of phycoerythrin, phycocyanin, allophycocyanin, and chlorophyll-a in L. catarinensis were stimulated by the highest concentration of VSES/2+AMPEP (i.e., 5.0 mg L−1). This is the first study to report the stimulatory effect of AMPEP on the phycobiliprotein contents of selected red algae. Furthermore, seawater+AMPEP in concentrations of 0.1 and 1.0 mg L−1 stimulated growth rates of G. caudata, which could be applied in its large-scale cultivation. The results obtained for G. caudata and L. catarinensis, an agar-producing and a terpenoid-producing species, respectively, contributed to extending the knowledge of the beneficial uses of a brown seaweed-derived extract with biostimulatory properties for use with cultivated, economically important red algae.

Gracilaria domingensis (Kutzing) Sonder ex Dickie is widely distributed in the Brazilian coast and is one of a few Gracilaria species with occurrence in the southern region of the country. Its commercial importance is in the use in human food (in natura) and knowledge of the physiology is fundamental to make its cultivation successful. The objectives of the present work were to determine the limits of tolerance to temperature and irradiance variations and to evaluate comparatively their effects on growth rates and contents of total soluble proteins and pigments in female gametophytes of G. domingensis from Brazilian tropical region (ES strain) and from subtropical region (SC strain). Variations in temperature (from 15 to 35 °C) and irradiance (from 20 to 250 μmol photons m−2 s−1) were tested. Both strains tolerated temperature variation from 15 to 30 °C, but died at 35 °C. The ES strain had higher growth rates (from 3.1 to 6.1% day−1) in relation to the SC strain (from 1.3 to 4.1% day−1), but the two strains had the highest growth rate at 25 °C. The ES strain had higher concentrations of total soluble proteins at low temperature (15 °C), while the SC strain showed higher protein concentrations at high temperatures (25 and 30 °C). In addition, the chlorophyll a concentration of the ES strain was higher at 20 °C and lower at 30 °C. The irradiance variation influenced the growth rates of the two strains (from 2.7 to 6.0% day−1) and the lowest growth rates were observed at irradiance of 20 μmol photons m−2 s−1 and the highest growth rates were observed at a wide range of irradiance variation (from 40 to 250, and from 60 to 250 μmol photons m−2 s−1 for SC and ES strains, respectively). The studied strains of G. domingensis showed higher concentrations of total soluble protein at low irradiances (20, 40, and 80 μmol photons m−2 s−1). The highest concentrations of phycoerythrin (423.0 μg g−1 FW) and phycocyanin (215.3 μg g−1 FW) were observed in the ES strain grown at low irradiance (40 μmol photons m−2 s−1). The chlorophyll a concentration of the two strains decreased with increased irradiance, indicating a photoacclimation. Our results showed that the tropical strain of G. domingensis has higher growth rates over a broader temperature range than the subtropical strain, which could be an advantageous feature for maricultural purposes.

The present study characterizes the spatial distribution of seaweed diversity on eight islands from the South Shetlands based on an updated taxonomic survey, discussing the higher number of species compared with previous studies and the possible relationships with environmental parameters. Seaweeds were sampled in Deception, Livingston, Halfmoon, Robert, Nelson, King George, Penguin, and Elephant Islands during the austral summer between 2010 and 2013 in intertidal and shallow subtidal zones. The taxonomic analyses evaluated morphological characteristics, reproductive structures, and molecular features. Physicochemical parameters of seawater were also monitored using standard analytical methods. A total of 104 species of benthic marine algae were identified (28 Phaeophyceae, 24 Chlorophyta, and 52 Rhodophyta), ~82% of all seaweeds taxa described to Antarctica, including six new records previously recorded only at lower latitudes, four confirmed taxa, and two putative new species. Spatial variation in species diversity was observed among the collecting sites, and Livingston and King George Islands showed the highest diversity among the islands. Deception, an area with geothermal activity and intense tourism, was dominated by opportunistic and broadly distributed filamentous green algae. Antarctic macroalgae diversity was higher than in previous studies, most likely due to more efficient techniques of sampling, and combined taxonomical methods. However, changes in the biogeographical distribution or introduction of some taxa, resulting from anthropogenic activities and/or climate changes, should be considered. Therefore, the higher number of taxa and the new records reported in this study suggest the need for long-term monitoring in the area for conservation purposes.

The activities of bioactive compounds can be influenced by countless factors, including post-collection sample treatment. In this study, the activities of Ochtodes secundiramea extracts obtained using different processes are compared; the biomass was macerated immediately, lyophilized in liquid nitrogen, or dried in an oven at 50 °C after collection. The chemical profiles of the extracts were evaluated using gas chromatography-mass spectrometry (GC-MS), and their biological activities were assessed using qualitative and quantitative bioautography thin-layer chromatography (TLC) assays against phytopathogenic fungi. Preparative high-performance liquid chromatography (HPLC) was employed to isolate the major compound observed in semi-quantitative (CG-MS). The biomass processing methods were shown to influence the chemical profiles of the extracts that promote the oxidation of halogenated monoterpenes; however, C10H15Br2Cl was the major compound identified in all of the extracts regardless of the preparation method used. Similarly, changes in qualitative antifungal activity were observed depending on the preparation method, even though the minimum amount of material required for the inhibition of fungal growth (the activity detection limit) was 5 μg in all cases. The activity detection limits for the HPLC-purified majority compound were 5 and 10 μg against Cladosporium sphaerospermum and Colletotrichum lagenarium, respectively; these values are similar to those obtained for the crude extracts. These results point towards the possibility of using these crude extracts for the control of anthracnose in cucumbers post-harvest.

Bioinvasion events causing serious environmental damage have been a concern with the mariculture of Kappaphycus alvarezii (Doty) Doty ex P.C. Silva, suggesting the importance of studying the biological aspects of drifting specimens of K. alvarezii for monitoring programs. The present study aims to evaluate the tolerance and growth of drifting color variants of K. alvarezii under different temperatures and salinities to determine their physiological capacity for growing outside cultivation rafts. Drifting color variants were collected in Paraiba State, Brazil, in November 2011(dry month) and August 2012 (rainy month), and cultivated in the laboratory under different temperatures (20, 24, 28, and 32 °C) and salinities (15, 25, 35, 45, and 55 psu). Growth rates as well as pigment and protein contents were determined. Results showed that drifting specimens collected in the dry month showed higher tolerance to variation in temperature (20 to 28 °C) and salinity (25 to 35 psu) than drifting specimens collected in the rainy month. Higher growth rates occurred in samples cultured at 20 and 24 °C (2.8–3 % day−1) and 25 to 35 psu (3.4–3.5 % day−1), suggesting temperature and salinity optima. Higher phycobiliprotein levels were observed in the red and brown variants under hypersaline conditions (45 and 55 psu). Higher chlorophyll a contents were associated with samples cultivated at 20–24 °C and 24–35 psu. Based on the results of the present study, drifting specimens collected in dry month are more tolerant to temperature and salinity variations, suggesting that the drifting K. alvarezii should be monitored especially during this period to prevent its establishment outside the cultivation rafts and dispersion along the northeastern coast of Brazil.

Chondracanthus chamissoi (C. Agardh) Kutzing (Gigartinales, Rhodophyta) is an edible species and commercialised for carrageenan production in Chile. Investigations on growth and development are needed to improve its cultivation; therefore, this study aims to evaluate the effects of plant growth regulators (PGRs) on its growth and morphogenesis. PGRs tested were two auxins [indole-3-acetic acid (IAA) and 2,4-dichlorophenoxyacetic acid (2,4-D)] and one cytokinin (benzylaminopurine (BA)) in concentrations of 0.5, 5.0 and 50.0 μM. These PGRs were added to seawater enriched with half strength of von Stosch solution and were gelled with 0.6 % agar, and treatment control (without PGR addition) was conducted simultaneously. Apical and intercalary segments were used as initial explants. Each treatment was tested with six replicates of five axenic explants, and statistical analyses were performed. After culturing in a solid medium for 10 weeks to induce growth and callus formation, explants were cultured in liquid medium with the same experimental conditions for 10 weeks. Effects of auxins (IAA and 2,4-D) and the cytokinin BA on growth rates of apical segments of C. chamissoi were not significant, while low concentration of IAA stimulated the growth of intercalary segments. On the other hand, high concentrations of BA and IAA stimulated the callus formation in apical and intercalary segments, respectively. In liquid medium, PGR did not have a significant effect on growth rates of apical segments, while 2,4-D in concentrations from 0.5 to 50.0 μM stimulated growth of intercalary segments, and formation of lateral branches was stimulated by low 2,4-D in apical segments. These results suggest that PGRs have a regulatory role on callus formation and growth of specific explants of C. chamissoi. Furthermore, the formation of lateral branches stimulated by auxin could be used for seedling production under controlled conditions and could improve the micropropagation and cultivation of C. chamissoi in the Chilean coast.

The selection of seaweed species for their use as biofilters should be based on the knowledge of their nutrient requirements and tolerance to wide variations of nutrient concentrations. Therefore, tolerance and the physiological capabilities of Hypnea cervicornis J. Agardh (Gigartinales, Rhodophyta) to growth under nitrate, ammonium, and phosphate variations and to assimilate them into soluble proteins and photosynthetic pigments were evaluated in laboratory conditions. Treatments were composed of sterilized seawater enriched with 25 % von Stosch solution (without nitrogen and phosphorus), and nitrate or ammonium and phosphate were added in combination of 100:1 and 10:1 nitrogen/phosphorus (N/P). Nitrate concentrations varied from 0 to 500 μM, and ammonium concentrations varied from 0 to 50 μM. Growth rates of H. cervicornis increased linearly with addition of ammonium, but with nitrate addition, growth varied following a saturation kinetic, and the highest growth rate (14.45 % d−1) was observed in 200 μM of N/P ratio of 10:1. An excess of nutrients was accumulated as proteins and phycobiliproteins (mainly as allophycocyanin and phycoerythrin) at higher phosphate availability (N/P ratio of 10:1), and H. cervicornis tolerated the highest ammonium and nitrate concentrations (50 and 500 μM, respectively). These physiological responses suggest that this species could be used as biofilter for nutrient removal in eutrophicated seawater and could be cultivated in integrated multitrophic aquaculture systems.

In the present study, the daily relative growth rates (DRGR, in percent per day) of the red macroalga Gracilaria domingensis in synthetic seawater was investigated for the combined influence of five factors, i.e., light (L), temperature (T), nitrate (N), phosphate (P), and molybdate (M), using a statistical design method. The ranges of the experimental cultivation conditions were T, 18–26°C; L, 74–162 μmol photons m−2 s−1; N, 40–80 μmol L−1; P, 8–16 μmol L−1; and M, 1–5 nmol L−1. The optimal conditions, which resulted in a maximum growth rate of ≥6.4% d−1 from 7 to 10 days of cultivation, were determined by analysis of variance (ANOVA) multivariate factorial analysis (with a 25 full factorial design) to be L, 74 μmol photons m−2 s−1; T, 26°C; N, 80 μmol L−1; P, 8 μmol L−1; and M, 1 nmol L−1. In additional, these growth rate values are close to the growth rate values in natural medium (von Stosch medium), i.e., 6.5–7.0% d−1. The results analyzed by the ANOVA indicate that the factors N and T are highly significant linear terms, X L, (α = 0.05). On the other hand, the only significant quadratic term (X Q) was that for L. Statistically significant interactions between two different factors were found between T vs. L and N vs. T. Finally, a two-way (linear/quadratic interaction) model provided a quite reasonable correlation between the experimental and predicted DRGR values (R adjusted 2 = 0.9540).

MicroRNAs (miRNAs) are single-stranded, noncoding RNAs that are important in many biological processes1,2. Although the oncogenic and tumour-suppressive functions of several miRNAs have been characterized, the role of miRNAs in mediating tumour metastasis was addressed only recently3 and still remains largely unexplored4,5. To identify potential metastasis-promoting miRNAs, we set up a genetic screen using a non-metastatic, human breast tumour cell line that was transduced with a miRNA-expression library and subjected to a trans-well migration assay. We found that human miR-373 and miR-520c stimulated cancer cell migration and invasion in vitro and in vivo, and that certain cancer cell lines depend on endogenous miR-373 activity to migrate efficiently. Mechanistically, the migration phenotype of miR-373 and miR-520c can be explained by suppression of CD44. We found significant upregulation of miR-373 in clinical breast cancer metastasis samples that correlated inversely with CD44 expression. Taken together, our findings indicate that miRNAs are involved in tumour migration and invasion, and implicate miR-373 and miR-520c as metastasis-promoting miRNAs.