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Open AccessArticle Isolation and Selection of Microalgal Strains from Natural Water Sources in Viet Nam with Potential for Edible Oil Production

by Tran Yen Thao, Dinh Thi Nhat Linh, Vo Chi Si, Taylor W. Carter and Russell T. Hill

Mar. Drugs 2017, 15(7), 194; doi:10.3390/md15070194

Received: 11 April 2017 / Revised: 11 June 2017 / Accepted: 14 June 2017 / Published: 23 June 2017

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Abstract

Industrial vegetable oil production in Viet Nam depends on oil seeds and crude plant oils that are currently more than 90% imported. As the first step in investigating the feasibility of using microalgae to provide Viet Nam with a domestic source of oil

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Industrial vegetable oil production in Viet Nam depends on oil seeds and crude plant oils that are currently more than 90% imported. As the first step in investigating the feasibility of using microalgae to provide Viet Nam with a domestic source of oil for food and edible oil industries, fifty lipid-producing microalgae were isolated and characterized. The microalgae were isolated from water sources ranging from freshwater to brackish and marine waters from a wide geographic distribution in Viet Nam. Initial analyses showed that 20 of the 50 strains had good growth rates, produced high biomass and had high lipid content, ranging up to 50% of dry weight biomass. 18S rRNA gene sequence analyses of the 50 strains showed a great diversity in this assemblage of microalgae, comprising at least 38 species and representatives of 25 genera: Chlamydomonas, Poterioochromonas, Scenedesmus, Desmodesmus, Chlorella, Bracteacoccus, Monoraphidium, Selenastrum, Acutodesmus, Mychonastes, Ankistrodesmus, Kirchneriella, Raphidocelis, Dictyosphaerium, Coelastrella, Schizochlamydella, Oocystidium, Nannochloris, Auxenochlorella, Chlorosarcinopsis, Stichococcus, Picochlorum, Prasinoderma, Chlorococcum, and Marvania. Some of the species are closely related to well-known lipid producers such as Chlorella sorokiniana, but some other strains are not closely related to the strains found in public sequence databases and likely represent new species. Analysis of oil quality showed that fatty acid profiles of the microalgal strains were very diverse and strain-dependent. Fatty acids in the microalgal oils comprised saturated fatty acids (SFAs), poly-unsaturated fatty acids (PUFAs), and mono-unsaturated fatty acids (MUFAs). The main SFA was palmitic acid. MUFAs and PUFAs were dominated by oleic acid, and linoleic and linolenic acids, respectively. Some strains were especially rich in the essential fatty acid α-linolenic acid (ALA), which comprised more than 20% of the fatty acids in these strains. Other strains had fatty acid compositions similar to that of palm oil. Several strains have been selected on the basis of their suitable fatty acid profiles and high lipid content for further chemical and physical characterization, toxicity and organoleptic tests of their oils, and for scale-up. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessArticle Biotechnological Potential of Cold Adapted Pseudoalteromonas spp. Isolated from ‘Deep Sea’ Sponges

by Erik Borchert, Stephen Knobloch, Emilie Dwyer, Sinéad Flynn, Stephen A. Jackson, Ragnar Jóhannsson, Viggó T. Marteinsson, Fergal O’Gara and Alan D. W. Dobson

Mar. Drugs 2017, 15(6), 184; doi:10.3390/md15060184

Received: 22 February 2017 / Revised: 9 June 2017 / Accepted: 14 June 2017 / Published: 19 June 2017

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Abstract

The marine genus Pseudoalteromonas is known for its versatile biotechnological potential with respect to the production of antimicrobials and enzymes of industrial interest. We have sequenced the genomes of three Pseudoalteromonas sp. strains isolated from different deep sea sponges on the Illumina MiSeq

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The marine genus Pseudoalteromonas is known for its versatile biotechnological potential with respect to the production of antimicrobials and enzymes of industrial interest. We have sequenced the genomes of three Pseudoalteromonas sp. strains isolated from different deep sea sponges on the Illumina MiSeq platform. The isolates have been screened for various industrially important enzymes and comparative genomics has been applied to investigate potential relationships between the isolates and their host organisms, while comparing them to free-living Pseudoalteromonas spp. from shallow and deep sea environments. The genomes of the sponge associated Pseudoalteromonas strains contained much lower levels of potential eukaryotic-like proteins which are known to be enriched in symbiotic sponge associated microorganisms, than might be expected for true sponge symbionts. While all the Pseudoalteromonas shared a large distinct subset of genes, nonetheless the number of unique and accessory genes is quite large and defines the pan-genome as open. Enzymatic screens indicate that a vast array of enzyme activities is expressed by the isolates, including β-galactosidase, β-glucosidase, and protease activities. A β-glucosidase gene from one of the Pseudoalteromonas isolates, strain EB27 was heterologously expressed in Escherichia coli and, following biochemical characterization, the recombinant enzyme was found to be cold-adapted, thermolabile, halotolerant, and alkaline active. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessArticle Running the Stop Sign: Readthrough of a Premature UAG Termination Signal in the Translation of a Zebrafish (Danio rerio) Taurine Biosynthetic Enzyme

by Mary E.M. Larkin and Allen R. Place

Mar. Drugs 2017, 15(6), 162; doi:10.3390/md15060162

Received: 17 March 2017 / Revised: 22 May 2017 / Accepted: 30 May 2017 / Published: 3 June 2017

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Abstract

The UAG termination codon is generally recognized as the least efficient and least frequently used of the three universal stop codons. This is substantiated by numerous studies in an array of organisms. We present here evidence of a translational readthrough of a mutant

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The UAG termination codon is generally recognized as the least efficient and least frequently used of the three universal stop codons. This is substantiated by numerous studies in an array of organisms. We present here evidence of a translational readthrough of a mutant nonsense UAG codon in the transcript from the cysteine sulfinic acid decarboxylase (csad) gene (ENSDARG00000026348) in zebrafish. The csad gene encodes the terminal enzyme in the taurine biosynthetic pathway. Taurine is a critical amino acid for all animals, playing several essential roles throughout the body, including modulation of the immune system. The sa9430 zebrafish strain (ZDB-ALT-130411-5055) has a point mutation leading to a premature stop codon (UAG) 20 amino acids 5’ of the normal stop codon, UGA. Data from immunoblotting, enzyme activity assays, and mass spectrometry provide evidence that the mutant is making a CSAD protein identical to that of the wild-type (XP_009295318.1) in terms of size, activity, and amino acid sequence. UAG readthrough has been described in several species, but this is the first presentation of a case in fish. Also presented are the first data substantiating the ability of a fish CSAD to utilize cysteic acid, an alternative to the standard substrate cysteine sulfinic acid, to produce taurine. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessArticle Salt Sensitive Tet-Off-Like Systems to Knockdown Primordial Germ Cell Genes for Repressible Transgenic Sterilization in Channel Catfish, Ictalurus punctatus

by Hanbo Li, Baofeng Su, Guyu Qin, Zhi Ye, Ahmed Alsaqufi, Dayan A. Perera, Mei Shang, Ramjie Odin, Khoi Vo, David Drescher, Dalton Robinson, Dan Zhang, Nermeen Abass and Rex A. Dunham

Mar. Drugs 2017, 15(6), 155; doi:10.3390/md15060155

Received: 1 April 2017 / Revised: 22 May 2017 / Accepted: 25 May 2017 / Published: 31 May 2017

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Abstract

Repressible knockdown approaches were investigated for transgenic sterilization in channel catfish, Ictalurus punctatus. Two primordial germ cell (PGC) marker genes, nanos and dead end, were targeted for knockdown, and an off-target gene, vasa, was monitored. Two potentially salt sensitive repressible

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Repressible knockdown approaches were investigated for transgenic sterilization in channel catfish, Ictalurus punctatus. Two primordial germ cell (PGC) marker genes, nanos and dead end, were targeted for knockdown, and an off-target gene, vasa, was monitored. Two potentially salt sensitive repressible promoters, zebrafish adenylosuccinate synthase 2 (ADSS) and zebrafish racemase (Rm), were each coupled with four knockdown strategies: ds-sh RNA targeting the 5′ end (N1) or 3′ end (N2) of channel catfish nanos, full-length cDNA sequence of channel catfish nanos for overexpression (cDNA) and ds-sh RNA targeting channel catfish dead end (DND). Each construct had an untreated group and treated group with sodium chloride as the repressor compound. Spawning rates of full-sibling P₁ fish exposed or not exposed to the constructs as treated and untreated embryos were 93% and 59%, respectively, indicating potential sterilization of fish and repression of the constructs. Although the mRNA expression data of PGC marker genes were inconsistent in P₁ fish, most F₁ individuals were able to downregulate the target genes in untreated groups and repress the knockdown process in treated groups. The results indicate that repressible transgenic sterilization is feasible for reproductive control of fish, but more data from F₂ or F₃ are needed for evaluation. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessArticle Enhancement of Biomass and Lipid Productivities of Water Surface-Floating Microalgae by Chemical Mutagenesis

by Daisuke Nojima, Yuki Ishizuka, Masaki Muto, Asuka Ujiro, Fumito Kodama, Tomoko Yoshino, Yoshiaki Maeda, Tadashi Matsunaga and Tsuyoshi Tanaka

Mar. Drugs 2017, 15(6), 151; doi:10.3390/md15060151

Received: 31 January 2017 / Revised: 19 May 2017 / Accepted: 24 May 2017 / Published: 27 May 2017

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Abstract

Water surface-floating microalgae have great potential for biofuel applications due to the ease of the harvesting process, which is one of the most problematic steps in conventional microalgal biofuel production. We have collected promising water surface-floating microalgae and characterized their capacity for biomass

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Water surface-floating microalgae have great potential for biofuel applications due to the ease of the harvesting process, which is one of the most problematic steps in conventional microalgal biofuel production. We have collected promising water surface-floating microalgae and characterized their capacity for biomass and lipid production. In this study, we performed chemical mutagenesis of two water surface-floating microalgae to elevate productivity. Floating microalgal strains AVFF007 and FFG039 (tentatively identified as Botryosphaerella sp. and Chlorococcum sp., respectively) were exposed to ethyl methane sulfonate (EMS) or 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), and pale green mutants (PMs) were obtained. The most promising FFG039 PM formed robust biofilms on the surface of the culture medium, similar to those formed by wild type strains, and it exhibited 1.7-fold and 1.9-fold higher biomass and lipid productivities than those of the wild type. This study indicates that the chemical mutation strategy improves the lipid productivity of water surface-floating microalgae without inhibiting biofilm formation and floating ability. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessArticle Characterization of Acetyl-CoA Carboxylases in the Basal Dinoflagellate Amphidinium carterae

by Saddef Haq, Tsvetan R. Bachvaroff and Allen R. Place

Mar. Drugs 2017, 15(6), 149; doi:10.3390/md15060149

Received: 29 March 2017 / Revised: 20 May 2017 / Accepted: 23 May 2017 / Published: 26 May 2017

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Abstract

Dinoflagellates make up a diverse array of fatty acids and polyketides. A necessary precursor for their synthesis is malonyl-CoA formed by carboxylating acetyl CoA using the enzyme acetyl-CoA carboxylase (ACC). To date, information on dinoflagellate ACC is limited. Through transcriptome analysis in Amphidinium

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Dinoflagellates make up a diverse array of fatty acids and polyketides. A necessary precursor for their synthesis is malonyl-CoA formed by carboxylating acetyl CoA using the enzyme acetyl-CoA carboxylase (ACC). To date, information on dinoflagellate ACC is limited. Through transcriptome analysis in Amphidinium carterae, we found three full-length homomeric type ACC sequences; no heteromeric type ACC sequences were found. We assigned the putative cellular location for these ACCs based on transit peptide predictions. Using streptavidin Western blotting along with mass spectrometry proteomics, we validated the presence of ACC proteins. Additional bands showing other biotinylated proteins were also observed. Transcript abundance for these ACCs follow the global pattern of expression for dinoflagellate mRNA messages over a diel cycle. This is one of the few descriptions at the transcriptomic and protein level of ACCs in dinoflagellates. This work provides insight into the enzymes which make the CoA precursors needed for fatty acid and toxin synthesis in dinoflagellates. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessArticle Taurine Biosynthesis in a Fish Liver Cell Line (ZFL) Adapted to a Serum-Free Medium

by Chieh-Lun Liu, Aaron M. Watson, Allen R. Place and Rosemary Jagus

Mar. Drugs 2017, 15(6), 147; doi:10.3390/md15060147

Received: 1 April 2017 / Revised: 18 May 2017 / Accepted: 22 May 2017 / Published: 25 May 2017

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Abstract

Although taurine has been shown to play multiple important physiological roles in teleosts, little is known about the molecular mechanisms underlying dietary requirements. Cell lines can provide useful tools for deciphering biosynthetic pathways and their regulation. However, culture media and sera contain variable

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Although taurine has been shown to play multiple important physiological roles in teleosts, little is known about the molecular mechanisms underlying dietary requirements. Cell lines can provide useful tools for deciphering biosynthetic pathways and their regulation. However, culture media and sera contain variable taurine levels. To provide a useful cell line for the investigation of taurine homeostasis, an adult zebrafish liver cell line (ZFL) has been adapted to a taurine-free medium by gradual accommodation to a commercially available synthetic medium, UltraMEM™-ITES. Here we show that ZFL cells are able to synthesize taurine and be maintained in medium without taurine. This has allowed for the investigation of the effects of taurine supplementation on cell growth, cellular amino acid pools, as well as the expression of the taurine biosynthetic pathway and taurine transporter genes in a defined fish cell type. After taurine supplementation, cellular taurine levels increase but hypotaurine levels stay constant, suggesting little suppression of taurine biosynthesis. Cellular methionine levels do not change after taurine addition, consistent with maintenance of taurine biosynthesis. The addition of taurine to cells grown in taurine-free medium has little effect on transcript levels of the biosynthetic pathway genes for cysteine dioxygenase (CDO), cysteine sulfinate decarboxylase (CSAD), or cysteamine dioxygenase (ADO). In contrast, supplementation with taurine causes a 30% reduction in transcript levels of the taurine transporter, TauT. This experimental approach can be tailored for the development of cell lines from aquaculture species for the elucidation of their taurine biosynthetic capacity. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessArticle Morphogenetically-Active Barrier Membrane for Guided Bone Regeneration, Based on Amorphous Polyphosphate

by Xiaohong Wang, Maximilian Ackermann, Meik Neufurth, Shunfeng Wang, Heinz C. Schröder and Werner E. G. Müller

Mar. Drugs 2017, 15(5), 142; doi:10.3390/md15050142

Received: 10 April 2017 / Revised: 4 May 2017 / Accepted: 8 May 2017 / Published: 17 May 2017

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Abstract

We describe a novel regeneratively-active barrier membrane which consists of a durable electrospun poly(ε-caprolactone) (PCL) net covered with a morphogenetically-active biohybrid material composed of collagen and inorganic polyphosphate (polyP). The patch-like fibrous collagen structures are decorated with small amorphous polyP nanoparticles (50 nm)

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We describe a novel regeneratively-active barrier membrane which consists of a durable electrospun poly(ε-caprolactone) (PCL) net covered with a morphogenetically-active biohybrid material composed of collagen and inorganic polyphosphate (polyP). The patch-like fibrous collagen structures are decorated with small amorphous polyP nanoparticles (50 nm) formed by precipitation of this energy-rich and enzyme-degradable (alkaline phosphatase) polymer in the presence of calcium ions. The fabricated PCL-polyP/collagen hybrid mats are characterized by advantageous biomechanical properties, such as enhanced flexibility and stretchability with almost unaltered tensile strength of the PCL net. The polyP/collagen material promotes the attachment and increases the viability/metabolic activity of human mesenchymal stem cells compared to cells grown on non-coated mats. The gene expression studies revealed that cells, growing onto polyP/collagen coated mats show a significantly (two-fold) higher upregulation of the steady-state-expression of the angiopoietin-2 gene used as an early marker for wound healing than cells cultivated onto non-coated mats. Based on our results we propose that amorphous polyP, stabilized onto a collagen matrix, might be a promising component of functionally-active barrier membranes for guided tissue regeneration in medicine and dentistry. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessFeature PaperArticle Transcriptomic Profiling of the Allorecognition Response to Grafting in the Demosponge Amphimedon queenslandica

by Laura F. Grice and Bernard M. Degnan

Mar. Drugs 2017, 15(5), 136; doi:10.3390/md15050136

Received: 30 March 2017 / Revised: 3 May 2017 / Accepted: 5 May 2017 / Published: 11 May 2017

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Abstract

Sponges, despite their simple body plan, discriminate between self and nonself with remarkable specificity. Sponge grafting experiments simulate the effects of natural self or nonself contact under laboratory conditions. Here we take a transcriptomic approach to investigate the temporal response to self and

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Sponges, despite their simple body plan, discriminate between self and nonself with remarkable specificity. Sponge grafting experiments simulate the effects of natural self or nonself contact under laboratory conditions. Here we take a transcriptomic approach to investigate the temporal response to self and nonself grafts in the marine demosponge Amphimedon queenslandica. Auto- and allografts were established, observed and sampled over a period of three days, over which time the grafts either rejected or accepted, depending on the identity of the paired individuals, in a replicable and predictable manner. Fourteen transcriptomes were generated that spanned the auto- and allograft responses. Self grafts fuse completely in under three days, and the process appears to be controlled by relatively few genes. In contrast, nonself grafting results in a complete lack of fusion after three days, and appears to involve a broad downregulation of normal biological processes, rather than the mounting of an intense defensive response. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessFeature PaperArticle Transcriptome Analysis of Core Dinoflagellates Reveals a Universal Bias towards “GC” Rich Codons

by Ernest Williams, Allen Place and Tsvetan Bachvaroff

Mar. Drugs 2017, 15(5), 125; doi:10.3390/md15050125

Received: 7 March 2017 / Revised: 11 April 2017 / Accepted: 20 April 2017 / Published: 27 April 2017

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Abstract

Although dinoflagellates are a potential source of pharmaceuticals and natural products, the mechanisms for regulating and producing these compounds are largely unknown because of extensive post-transcriptional control of gene expression. One well-documented mechanism for controlling gene expression during translation is codon bias, whereby

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Although dinoflagellates are a potential source of pharmaceuticals and natural products, the mechanisms for regulating and producing these compounds are largely unknown because of extensive post-transcriptional control of gene expression. One well-documented mechanism for controlling gene expression during translation is codon bias, whereby specific codons slow or even terminate protein synthesis. Approximately 10,000 annotatable genes from fifteen “core” dinoflagellate transcriptomes along a range of overall guanine and cytosine (GC) content were used for codonW analysis to determine the relative synonymous codon usage (RSCU) and the GC content at each codon position. GC bias in the analyzed dataset and at the third codon position varied from 51% and 54% to 66% and 88%, respectively. Codons poor in GC were observed to be universally absent, but bias was most pronounced for codons ending in uracil followed by adenine (UA). GC bias at the third codon position was able to explain low abundance codons as well as the low effective number of codons. Thus, we propose that a bias towards codons rich in GC bases is a universal feature of core dinoflagellates, possibly relating to their unique chromosome structure, and not likely a major mechanism for controlling gene expression. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessArticle Indole Derivatives Isolated from Brown Alga Sargassum thunbergii Inhibit Adipogenesis through AMPK Activation in 3T3-L1 Preadipocytes

by Min-Cheol Kang, Yuling Ding, Eun-A Kim, Youn Kyung Choi, Thiago de Araujo, Soo-Jin Heo and Seung-Hong Lee

Mar. Drugs 2017, 15(4), 119; doi:10.3390/md15040119

Received: 9 March 2017 / Revised: 31 March 2017 / Accepted: 7 April 2017 / Published: 12 April 2017

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Abstract

Seaweed, a popular and abundant food ingredient mainly consumed in Asian countries, is a good source of bioactive compounds with anti-obesity effects. However, the anti-obesity effects of Sargassum thunbergii have not yet been established. In this study, we isolated six indole derivatives (STCs)—indole-2-carboxaldehyde

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Seaweed, a popular and abundant food ingredient mainly consumed in Asian countries, is a good source of bioactive compounds with anti-obesity effects. However, the anti-obesity effects of Sargassum thunbergii have not yet been established. In this study, we isolated six indole derivatives (STCs)—indole-2-carboxaldehyde (STC-1), indole-3-carboxaldehyde (STC-2), indole-4-carboxaldehyde (STC-3), indole-5-carboxaldehyde (STC-4), indole-6-carboxaldehyde (STC-5), and indole-7-carboxaldehyde (STC-6)—from S. thunbergii and evaluated their inhibitory effects on adipocyte differentiation in 3T3-L1 cells. We found that STC-1 and STC-5 resulted in non-toxic inhibition of the differentiation of 3T3-L1 adipocytes and thus selected these compounds for further study. STC-1 and STC-5 significantly inhibited lipid accumulation and downregulated the expression of peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein 1c (SREBP-1c) in a dose-dependent manner. The specific mechanism mediating the effects of STC-1 and STC-5 was shown to be AMP-activated protein kinase (AMPK) activation. Our results demonstrated the inhibitory effect of STC-1 and STC-5 on adipogenesis through the activation of the AMPK signal pathway. Together, these findings suggested that STC-1 and STC-5 may be effective candidates for the prevention of obesity or obesity-related diseases. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessArticle Outdoor Cultivation of Marine Diatoms for Year-Round Production of Biofuels

by Mitsufumi Matsumoto, Daisuke Nojima, Tomomi Nonoyama, Kiichi Ikeda, Yoshiaki Maeda, Tomoko Yoshino and Tsuyoshi Tanaka

Mar. Drugs 2017, 15(4), 94; doi:10.3390/md15040094

Received: 31 January 2017 / Revised: 15 March 2017 / Accepted: 22 March 2017 / Published: 25 March 2017

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Abstract

Biofuel production using microalgae is believed to have the advantage of continuous year-round production over crop plants, which have strong seasonality. However, actual year-round production of microalgal lipids using outdoor mass cultivation has rarely been demonstrated. In our previous study, it was demonstrated

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Biofuel production using microalgae is believed to have the advantage of continuous year-round production over crop plants, which have strong seasonality. However, actual year-round production of microalgal lipids using outdoor mass cultivation has rarely been demonstrated. In our previous study, it was demonstrated that the oleaginous diatom, Fistulifera solaris, was culturable in outdoor bioreactors from spring to autumn, whereas biomass and lipid production in winter failed because F. solaris did not grow below 15 °C. Therefore, another candidate strain that is culturable in winter is required. In this study, a cold-tolerant diatom, Mayamaea sp. JPCC CTDA0820, was selected as a promising candidate for biofuel production in winter. Laboratory-scale characterization revealed that this diatom was culturable at temperatures as low as 10 °C. Subsequently, F. solaris (April–October) and Mayamaea sp. JPCC CTDA0820 (November–March) were cultured in outdoor open-pond bioreactors, wherein year-round production of diatom lipids was successfully demonstrated. The maximal values of areal productivities of biomass and lipids reached to 9.79 and 1.80 g/(m² day) for F. solaris, and 8.62 and 0.92 g/(m² day) for Mayamaea sp. JPCC CTDA0820, respectively. With the combined use of these two diatom species, stable year-round production of microalgal lipids became possible. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessFeature PaperArticle A Place to Call Home: An Analysis of the Bacterial Communities in Two Tethya rubra Samaai and Gibbons 2005 Populations in Algoa Bay, South Africa

by Samantha C. Waterworth, Meesbah Jiwaji, Jarmo-Charles J. Kalinski, Shirley Parker-Nance and Rosemary A. Dorrington

Mar. Drugs 2017, 15(4), 95; doi:10.3390/md15040095

Received: 31 January 2017 / Revised: 8 March 2017 / Accepted: 16 March 2017 / Published: 25 March 2017

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Abstract

Sponges are important sources of bioactive secondary metabolites. These compounds are frequently synthesized by bacterial symbionts, which may be recruited from the surrounding seawater or transferred to the sponge progeny by the parent. In this study, we investigated the bacterial communities associated with

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Sponges are important sources of bioactive secondary metabolites. These compounds are frequently synthesized by bacterial symbionts, which may be recruited from the surrounding seawater or transferred to the sponge progeny by the parent. In this study, we investigated the bacterial communities associated with the sponge Tethya rubra Samaai and Gibbons 2005. Sponge specimens were collected from Evans Peak and RIY Banks reefs in Algoa Bay, South Africa and taxonomically identified by spicule analysis and molecular barcoding. Crude chemical extracts generated from individual sponges were profiled by ultraviolet high performance liquid chromatography (UV-HPLC) and subjected to bioactivity assays in mammalian cells. Next-generation sequencing analysis of 16S rRNA gene sequences was used to characterize sponge-associated bacterial communities. T. rubra sponges collected from the two locations were morphologically and genetically indistinguishable. Chemical extracts from sponges collected at RIY banks showed mild inhibition of the metabolic activity of mammalian cells and their UV-HPLC profiles were distinct from those of sponges collected at Evans Peak. Similarly, the bacterial communities associated with sponges from the two locations were distinct with evidence of vertical transmission of symbionts from the sponge parent to its embryos. We conclude that these distinct bacterial communities may be responsible for the differences observed in the chemical profiles of the two Algoa Bay T. rubra Samaai and Gibbons 2005 populations. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessArticle Tuberatolide B Suppresses Cancer Progression by Promoting ROS-Mediated Inhibition of STAT3 Signaling

by Youn Kyung Choi, Junseong Kim, Kang Min Lee, Yu-Jeong Choi, Bo-Ram Ye, Min-Sun Kim, Seong-Gyu Ko, Seung-Hong Lee, Do-Hyung Kang and Soo-Jin Heo

Mar. Drugs 2017, 15(3), 55; doi:10.3390/md15030055

Received: 29 December 2016 / Revised: 6 February 2017 / Accepted: 17 February 2017 / Published: 25 February 2017

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Abstract

Tuberatolide B (TTB, C₂₇H₃₄O₄) is a diastereomeric meroterpenoid isolated from the Korean marine algae Sargassum macrocarpum. However, the anticancer effects of TTB remain unknown. In this study, we demonstrate that TTB inhibits tumor growth in breast,

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Tuberatolide B (TTB, C₂₇H₃₄O₄) is a diastereomeric meroterpenoid isolated from the Korean marine algae Sargassum macrocarpum. However, the anticancer effects of TTB remain unknown. In this study, we demonstrate that TTB inhibits tumor growth in breast, lung, colon, prostate, and cervical cancer cells. To examine the mechanism by which TTB suppresses cell growth, we determined the effect of TTB on apoptosis, ROS generation, DNA damage, and signal transduction. TTB induced ROS production in MDA-MB-231, A549, and HCT116 cells. Moreover, TTB enhanced DNA damage by inducing γH2AX foci formation and the phosphorylation of DNA damage-related proteins such as Chk2 and H2AX. Furthermore, TTB selectively inhibited STAT3 activation, which resulted in a reduction in cyclin D1, MMP-9, survivin, VEGF, and IL-6. In addition, TTB-induced ROS generation caused STAT3 inhibition, DNA damage, and apoptotic cell death. Therefore, TTB suppresses cancer progression by promoting ROS-mediated inhibition of STAT3 signaling, suggesting that TTB is useful for the treatment of cancer. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessArticle A Saponification Method for Chlorophyll Removal from Microalgae Biomass as Oil Feedstock

by Tao Li, Jin Xu, Hualian Wu, Guanghua Wang, Shikun Dai, Jiewei Fan, Hui He and Wenzhou Xiang

Mar. Drugs 2016, 14(9), 162; doi:10.3390/md14090162

Received: 29 April 2016 / Revised: 31 August 2016 / Accepted: 1 September 2016 / Published: 7 September 2016

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Abstract

Microalgae oil is an optimal feedstock for nutraceutical, pharmaceutical and biodiesel production, but its high levels of chlorophyll limit its large-scale application. To date, few effective approaches have been developed to remove chlorophyll from microalgae oil. The main purpose of this study was

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Microalgae oil is an optimal feedstock for nutraceutical, pharmaceutical and biodiesel production, but its high levels of chlorophyll limit its large-scale application. To date, few effective approaches have been developed to remove chlorophyll from microalgae oil. The main purpose of this study was to present a preprocessing method of algae oil feedstock (Scenedesmus) to remove chlorophyll by saponification. The results showed that 96% of chlorophyll in biomass was removed. High quality orange transparent oil could be extracted from the chlorophyll reduced biomass. Specifically, the proportion of neutral lipids and saturation levels of fatty acids increased, and the pigments composition became carotenoids-based. The critical parameters of chlorophyll reduced biodiesel conformed to the standards of the USA, China and EU. Sodium copper chlorophyllin could be prepared from the bleaching effluent. The results presented herein offer a useful pathway to improve the quality of microalgae oil and reduce the cost of microalgae biodiesel. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessReview The Understanding of the Metazoan Skeletal System, Based on the Initial Discoveries with Siliceous and Calcareous Sponges

by Werner E. G. Müller, Heinz C. Schröder and Xiaohong Wang

Mar. Drugs 2017, 15(6), 172; doi:10.3390/md15060172

Received: 31 March 2017 / Revised: 3 June 2017 / Accepted: 8 June 2017 / Published: 12 June 2017

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Abstract

Initiated by studies on the mechanism of formation of the skeletons of the evolutionary oldest still extant multicellular animals, the sponges (phylum Porifera) have provided new insights into the mechanism of formation of the Ca-phosphate/hydroxyapatite skeleton of vertebrate bone. Studies on the formation

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Initiated by studies on the mechanism of formation of the skeletons of the evolutionary oldest still extant multicellular animals, the sponges (phylum Porifera) have provided new insights into the mechanism of formation of the Ca-phosphate/hydroxyapatite skeleton of vertebrate bone. Studies on the formation of the biomineral skeleton of sponges revealed that both the formation of the inorganic siliceous skeletons (sponges of the class of Hexactinellida and Demospongiae) and of the calcareous skeletons (class of Calcarea) is mediated by enzymes (silicatein: polymerization of biosilica; and carbonic anhydrase: deposition of Ca-carbonate). Detailed studies of the initial mineralization steps in human bone-forming cells showed that this process is also controlled by enzymes, starting with the deposition of Ca-carbonate bio-seeds, mediated by carbonic anhydrases-II and -IX, followed by non-enzymatic transformation of the formed amorphous Ca-carbonate deposits into amorphous Ca-phosphate and finally hydroxyapatite crystals. The required phosphate is provided by enzymatic (alkaline phosphatase-mediated) degradation of an inorganic polymer, polyphosphate (polyP), which also acts as a donor for chemically useful energy in this process. These new discoveries allow the development of novel biomimetic strategies for treatment of bone diseases and defects. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessFeature PaperReview The Rising Tide of Antimicrobial Resistance in Aquaculture: Sources, Sinks and Solutions

by Joy E. M. Watts, Harold J. Schreier, Lauma Lanska and Michelle S. Hale

Mar. Drugs 2017, 15(6), 158; doi:10.3390/md15060158

Received: 31 March 2017 / Revised: 22 May 2017 / Accepted: 25 May 2017 / Published: 1 June 2017

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Abstract

As the human population increases there is an increasing reliance on aquaculture to supply a safe, reliable, and economic supply of food. Although food production is essential for a healthy population, an increasing threat to global human health is antimicrobial resistance. Extensive antibiotic

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As the human population increases there is an increasing reliance on aquaculture to supply a safe, reliable, and economic supply of food. Although food production is essential for a healthy population, an increasing threat to global human health is antimicrobial resistance. Extensive antibiotic resistant strains are now being detected; the spread of these strains could greatly reduce medical treatment options available and increase deaths from previously curable infections. Antibiotic resistance is widespread due in part to clinical overuse and misuse; however, the natural processes of horizontal gene transfer and mutation events that allow genetic exchange within microbial populations have been ongoing since ancient times. By their nature, aquaculture systems contain high numbers of diverse bacteria, which exist in combination with the current and past use of antibiotics, probiotics, prebiotics, and other treatment regimens—singularly or in combination. These systems have been designated as “genetic hotspots” for gene transfer. As our reliance on aquaculture grows, it is essential that we identify the sources and sinks of antimicrobial resistance, and monitor and analyse the transfer of antimicrobial resistance between the microbial community, the environment, and the farmed product, in order to better understand the implications to human and environmental health. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

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Open AccessCommentary Bioethical Considerations of Advancing the Application of Marine Biotechnology and Aquaculture

by Reginal M. Harrell

Mar. Drugs 2017, 15(7), 197; doi:10.3390/md15070197

Received: 17 April 2017 / Revised: 14 June 2017 / Accepted: 20 June 2017 / Published: 24 June 2017

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Abstract

Normative ethical considerations of growth of the marine biotechnology and aquaculture disciplines in biopharming, food production, and marine products commercialization from a bioethical perspective have been limited. This paucity of information begs the question of what constitutes a bioethical approach (i.e., respect for

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Normative ethical considerations of growth of the marine biotechnology and aquaculture disciplines in biopharming, food production, and marine products commercialization from a bioethical perspective have been limited. This paucity of information begs the question of what constitutes a bioethical approach (i.e., respect for individuals or autonomy; beneficence, nonmaleficence, and justice) to marine biotechnology and aquaculture, and whether it is one that is appropriate for consideration. Currently, thoughtful discussion on the bioethical implications of use, development, and commercialization of marine organisms or their products, as well as potential environmental effects, defaults to human biomedicine as a model. One must question the validity of using human bioethical principlism moral norms for appropriating a responsible marine biotechnology and aquaculture ethic. When considering potential impacts within these disciplines, deference must be given to differing value systems in order to find common ground to advance knowledge and avoid emotive impasses that can hinder the science and its application. The import of bioethical considerations when conducting research and/or production is discussed. This discussion is directed toward applying bioethical principles toward technology used for food, biomedical development (e.g., biopharming), or as model species for advancement of knowledge for human diseases. Full article

(This article belongs to the Special Issue Advances and New Perspectives in Marine Biotechnology II 2016)

Guest Editor Prof. Dr. Paul Long Institute of Pharmaceutical Science & Department of Chemistry, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom E-Mail Interests: biochemical adaptations; streptomyces genetics; natural products discovery; bioinformatics
Guest Editor Prof. Dr. Allen Place Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Sciences, Columbus Center, 701 East Pratt Street, Baltimore, MD 21202, USA E-Mail Phone: 410-234-8828
Guest Editor Assoc. Prof. Dr. Rosemary Jagus Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Sciences, Columbus Center, 701 East Pratt Street, Baltimore, MD 21202, USA E-Mail Phone: 410-234-8822
Guest Editor Dr. Joy Watts School of Biological Sciences, University of Portsmouth, King Henry Building, King Henry Street, Portsmouth PO1 2DY, United Kingdom E-Mail Phone: +44 (0)23 9284 6211 Fax: +44 (0)23 9284 2070

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