| 1. |
- Al-Alawi, Ahmed Ali, et al.
(författare)
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Characterization of Carrageenan Extracted from Hypnea bryoides in Oman.
- 2011
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Ingår i: Marine biotechnology (New York, N.Y.). - : Springer Science and Business Media LLC. - 1436-2236 .- 1436-2228. ; 10:1007
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Tidskriftsartikel (refereegranskat)abstract
- Carrageenophyte red seaweed from Oman, Hypnea bryoides, extracted using three different processes: an aqueous, a mild alkaline, and a more vigorous alkaline extraction was investigated. The resulting extract precipitated by alcohol was subject to chemical and rheological measurements. The total carbohydrate [ranged from 36.78 to 41.65g/100g], and ash [39.04 to 43.11 g/100 g] were the most abundant components in H. bryoides and contrary to the two, lipid content was found at a minimum [ranging from 2.95 to 3.38g/100g]. Alkali treatment with NaOH allowed complete conversion of kappa (κ) carrageenan form as detected by FTIR analysis. Total yield by alkali treatments gave higher yields (33%) compared with aqueous treatments (12%). However, subsequent aqueous treatment produced mixed carrageenan (μ and κ) with higher molecular weight compared with the alkali treatments which produced single carrageenan form (κ) with molecular weight of 4.1×10(5)Da. The effects of thermal history on gel-sol and sol-gel transition were investigated by differential scanning calorimeter (DSC) and rheology on a pure sample and 1.5% κ-carrageenan mixture added with 30mM KCl. Transition temperatures from DSC and rheology showed comparable results and were in good agreement with those previously reported.
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| 2. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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Genomic Characterization of the Barnacle Balanus improvisus Reveals Extreme Nucleotide Diversity in Coding Regions
- 2021
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Ingår i: Marine Biotechnology. - : Springer Science and Business Media LLC. - 1436-2228 .- 1436-2236. ; 23, s. 402-416
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Tidskriftsartikel (refereegranskat)abstract
- Barnacles are key marine crustaceans in several habitats, and they constitute a common practical problem by causing biofouling on man-made marine constructions and ships. Despite causing considerable ecological and economic impacts, there is a surprising void of basic genomic knowledge, and a barnacle reference genome is lacking. We here set out to characterize the genome of the baybarnacle Balanus improvisus (= Amphibalanus improvisus) based on short-read whole-genome sequencing and experimental genome size estimation. We show both experimentally (DNA staining and flow cytometry) and computationally (k-mer analysis) that B. improvisus has a haploid genome size of ~ 740 Mbp. A pilot genome assembly rendered a total assembly size of ~ 600 Mbp and was highly fragmented with an N50 of only 2.2 kbp. Further assembly-based and assembly-free analyses revealed that the very limited assembly contiguity is due to the B. improvisus genome having an extremely high nucleotide diversity (π) in coding regions (average π ≈ 5% and average π in fourfold degenerate sites ≈ 20%), and an overall high repeat content (at least 40%). We also report on high variation in the α-octopamine receptor OctA (average π = 3.6%), which might increase the risk that barnacle populations evolve resistance toward antifouling agents. The genomic features described here can help in planning for a future high-quality reference genome, which is urgently needed to properly explore and understand proteins of interest in barnacle biology and marine biotechnology and for developing better antifouling strategies. © 2021, The Author(s).
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| 3. |
- Badary, Amr, et al.
(författare)
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Glycogen Production in Marine Cyanobacterial Strain Synechococcus sp NKBG 15041c
- 2018
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Ingår i: Marine Biotechnology. - : Springer Science and Business Media LLC. - 1436-2228 .- 1436-2236. ; 20:2, s. 109-117
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Tidskriftsartikel (refereegranskat)abstract
- An important feature offered by marine cyanobacterial strains over freshwater strains is the capacity to grow in seawater, replacing the need for often-limited freshwater. However, there are only limited numbers of marine cyanobacteria that are available for genetic manipulation and bioprocess applications. The marine unicellular cyanobacteria Synechococcus sp. strain NKBG 15041c (NKBG15041c) has been extensively studied. Recombinant DNA technologies are available for this strain, and its genomic information has been elucidated. However, an investigation of carbohydrate production, such as glycogen production, would provide information for inevitable biofuel-related compound production, but it has not been conducted. In this study, glycogen production by marine cyanobacterium NKBG15041c was investigated under different cultivation conditions. NKBG15041c yielded up to 399 mu g/ml/OD730 when cells were cultivated for 168 h in nitrogen-depleted medium (marine BG11(Delta N)) after medium replacement (336 h after inoculation). Cultivation under nitrogen-limited conditions also yielded an accumulation of glycogen in NKBG15041c cells (1 mM NaNO3, 301 mu g/ml/OD730; 3 mM NaNO3, 393 mu g/ml/OD730; and 5 mM NaNO3, 328 mu g/ml/OD730) under ambient conditions. Transcriptional analyses were carried out for 13 putative genes responsible for glycogen synthesis and catabolism that were predicted based on homology analyses with Synechocystis sp. PCC 6803 (PCC6803) and Synechococcus sp. PCC7002 (PCC7002). The transcriptional analyses revealed that glycogen production in NKBG15041c under nitrogen-depleted conditions can be explained by the contribution of both increased carbon flux towards glycogen synthesis, similar to PCC6803 and PCC7002, and increased transcriptional levels of genes responsible for glycogen synthesis, which is different from the conventionally reported phenomenon, resulting in a relatively high amount of glycogen under ambient conditions compared to PCC6803 and PCC7002.
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| 4. |
- Doan Van, Thuoc, et al.
(författare)
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Ectoine Production by Halomonas boliviensis: Optimization Using Response Surface Methodology.
- 2010
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Ingår i: Marine Biotechnology. - : Springer Science and Business Media LLC. - 1436-2236 .- 1436-2228. ; 12, s. 586-593
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Tidskriftsartikel (refereegranskat)abstract
- Two cultivation steps were used for production of biomass and ectoine by Halomonas boliviensis, respectively. The optimization of some nutrient parameters in each step was investigated by using response surface methodology. Twenty and 12 experiments were performed to attain optimal conditions for biomass and ectoine production, respectively. The model predicted a maximum biomass concentration of 3.34 g/L on optimization of NH(4)Cl, K(2)HPO(4), and MgSO(4)*7H(2)O concentrations during the first cultivation, while a maximum ectoine concentration of 1.27 g/L was predicted on optimizing NaCl and monosodium glutamate concentrations in the second cultivation. The experimental values obtained (3.36 g biomass/L and 1.25 g ectoine/L) were in good agreement with the predicted values. The optimized conditions were also used for two-step 1.5-L fed-batch fermentations. In the first step, biomass concentration of 28.7 g/L was obtained while in the second step biomass concentration increased to 63 g/L. Ectoine concentration of 9.2 g/L was obtained, and the overall ectoine productivity was 6.3 g/L/day, being among the highest reported so far.
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| 5. |
- Godhe, Anna, et al.
(författare)
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Polymerase chain reaction in detection of Gymnodinium mikimotoi and Alexandrium minutum in field samples from Southwest India
- 2001
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Ingår i: Marine Biotechnology. - 1436-2228 .- 1436-2236. ; 3:2, s. 152-162
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Tidskriftsartikel (refereegranskat)abstract
- Polymerase chain reaction (PCR) primers were constructed for the detection of two toxic dinoflagellate species, Gymnodinium mikimotoi and Alexandrium minutum. The primers amplified a product of expected size from cultured cells of G. mikimotoi and A. minutum. The species-specific primers targeting G. mikimotoi did not yield any product with a wide range of other cultured algae used as negative controls. Primers designed for A. minutum were species-group-specific since it PCR yielded a product from the closely related species A. ostenfeldii and A. andersonii, but not from other species of this genus tested. The confirmation of PCR products was performed by digestion of the products with restriction enzymes. Sensitivity analyses of the primers on DNA template from cultured cells was positive by PCR at a DNA template concentration of 1.5 x 10(-4) ng/microl (0.3 cells/L) for A. minutum, and at a DNA concentration of 2.5 x 10(-2) ng/microl (697 cells/L) for G. mikimotoi. The PCR method for detection of G. mikimotoi and A. minutum was applied on field samples collected with a plankton net. Gymnodinium mikimotoi could be detected in 11 field samples by microscopy, and all these field samples were positive by PCR. The cell counts of G. mikimotoi in simultaneously collected water samples ranged from 306 to 2077/L. Alexandrium minutum could be detected by microscopy in 3 different field samples. The cell counts in water samples collected at the same time as the net samples ranged from 115 to 1115 cells/L. Alexandrium minutum was detected by PCR in these field samples, with the exception of the sample displaying the lowest cell count (115 cells/L). Plankton samples that were negative by microscopy for any of the two target species were also negative by PCR. All the PCR products from field samples were confirmed by restriction enzyme digestion. The application of PCR-based detection of harmful algal bloom species for aquaculture and monitoring purposes in natural field samples is discussed.
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| 6. |
- Hanssen, Kine Œ, et al.
(författare)
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The Bromotyrosine derivative Ianthelline isolated from the arctic marine sponge Stryphnus fortis inhibits marine micro- and macrobiofouling
- 2014
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Ingår i: Marine Biotechnology. - : Springer Science and Business Media LLC. - 1436-2228 .- 1436-2236. ; 16:6, s. 684-694
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Tidskriftsartikel (refereegranskat)abstract
- The inhibition of marine biofouling by the bromotyrosine derivative ianthelline, isolated from the Arctic marine sponge Stryphnus fortis, is described. All major stages of the fouling process are investigated. The effect of ianthelline on adhesion and growth of marine bacteria and microalgae is tested to investigate its influence on the initial microfouling process comparing with the known marine antifoulant barettin as a reference. Macrofouling is studied via barnacle (Balanus improvisus) settlement assays and blue mussel (Mytilus edulis) phenoloxidase inhibition. Ianthelline is shown to inhibit both marine micro- and macrofoulers with a pronounced effect on marine bacteria (minimum inhibitory concentration (MIC) values 0.1–10 μg/mL) and barnacle larval settlement (IC50=3.0 μg/mL). Moderate effects are recorded on M. edulis (IC50=45.2 μg/mL) and microalgae, where growth is more affected than surface adhesion. The effect of ianthelline is also investigated against human pathogenic bacteria. Ianthelline displayed low micromolar MIC values against several bacterial strains, both Gram positive and Gram negative, down to 2.5 μg/mL. In summary, the effect of ianthelline on 20 different representative marine antifouling organisms and seven human pathogenic bacterial strains is presented.
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| 7. |
- Ibarz, A., et al.
(författare)
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Proteomic Approach to Skin Regeneration in a Marine Teleost: Modulation by Oestradiol-17 beta
- 2013
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Ingår i: Marine Biotechnology. - : Springer Science and Business Media LLC. - 1436-2228 .- 1436-2236. ; 15:6, s. 629-646
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Tidskriftsartikel (refereegranskat)abstract
- Skin and scale formation and regeneration in teleosts have mainly been described from a morphological perspective, and few studies of the underlying molecular events exist. The present study evaluates (1) the change in the skin proteome during its regeneration in a marine teleost fish (gilthead sea bream, Sparus aurata) and (2) the impact of oestradiol-17 beta (I center dot(2)) on regeneration and the involvement of oestrogen receptor (ER) isoforms. Thirty-five candidate proteins were differentially expressed (p < 0.05) between intact and regenerated skin proteome 5 days after scale removal, and 27 proteins were differentially expressed after E-2 treatment. Agglomerative hierarchical clustering of the skin proteome revealed that the skin treated with E-2 clustered most closely to intact skin, while regenerating untreated skin formed an independent cluster. Gene Ontology classification associated the differentially expressed proteins in E-2-treated skin with developmental processes and cellular morphogenesis. The proteins modified during skin regeneration suggest a balance exists between immune response and anatomical repair. Overall, the results indicate that, even after 5 days regeneration, the composition of mature skin is not attained, and endocrine factors, in particular E-2, can accelerate wound repair acting possibly via ER beta s expressed in the skin-scales. Several candidate proteins probably involved in scale development, osteoglycin, lipocalin2 and lamin A and the transcription factors PHD and grainyhead were identified. Future studies of fish skin regeneration will be required to provide further insight into this multistage process, and the present study indicates it will be useful to explore immune adaptations of epithelia permanently exposed to an aqueous environment.
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| 8. |
- Jasiecki, J., et al.
(författare)
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Construction and use of a broad-host-range plasmid expressing the lamB gene for utilization of bacteriophage lambda vectors in the marine bacterium Vibrio harveyi
- 2001
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Ingår i: Marine Biotechnology. - : Springer Science and Business Media LLC. - 1436-2228 .- 1436-2236. ; 3:4, s. 336-345
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Tidskriftsartikel (refereegranskat)abstract
- The remarkable success of Escherichia coli as a model organism in molecular genetics was dependent, among other things, on its susceptibility to genetic manipulation. Many versatile and sophisticated genetic tools for molecular biology studies are derived from bacteriophage lambda. However, this bacteriophage is specific for E. coli, and thus lambda -based techniques have been restricted to this bacterium. Plasmids expressing the E. coli gene coding for bacteriophage lambda receptor were reported previously, and introduction of such plasmids into cells of some other bacteria made them sensitive to phage lambda infection. However, we found that these systems were not efficient for Vibrio harveyi, one of the most frequently investigated species of marine bacteria. Here we describe construction of a broad-host-range plasmid expressing the lamB gene. Introduction of this plasmid to V. harveyi cells and expression of lamB made this strain susceptible to bacteriophage lambda adsorption and lambda DNA injection. Foreign genetic material could be introduced into cells of this strain using a cosmid vector.
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| 9. |
- Karlsson, Johnny, et al.
(författare)
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Generating transparent zebrafish : a refined method to improve detection of gene expression during embryonic development
- 2001
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Ingår i: Marine Biotechnology. - : Springer Science and Business Media LLC. - 1436-2228 .- 1436-2236. ; 3:6, s. 522-527
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Tidskriftsartikel (refereegranskat)abstract
- In zebrafish (Danio rerio) pigmentation is initiated during embryogenesis and begins in the retinal epithelium and in the melanophores. The pigment cells develop rapidly, and within hours they constitute a prominent feature of the embryo. In order to improve signal detection by whole mount in situ hybridization, confocal microscopy, or expression of GFP, embryos may be treated with 1-phenyl 2-thiourea (PTU) during embryogenesis. PTU inhibits melanogenesis by blocking all tyrosinase-dependent steps in the melanin pathway but can be toxic at high concentrations. The embryos remain transparent as long as the PTU treatment is continued. However, PTU treatment must be initiated before the initial pigmentation because it does not remove already formed pigment. Here we provide a protocol for generating transparent zebrafish while avoiding the toxic and teratogenic effects of PTU treatment.
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| 10. |
- Labriere, C., et al.
(författare)
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Structure-Activity Relationship Probing of the Natural Marine Antifoulant Barettin
- 2021
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Ingår i: Marine Biotechnology. - : Springer Science and Business Media LLC. - 1436-2228 .- 1436-2236. ; 23:6, s. 904-916
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Tidskriftsartikel (refereegranskat)abstract
- The sponge derived 2,5-diketopiperazine metabolite barettin is a potent antifouling compound effective against the settlement and metamorphosis of barnacles. Simplified derivatives of barettin have previously been shown to display similar inhibitory properties. The synthetic derivative benzo[g]dipodazine has been reported to display significantly improved antifouling properties in comparison with the native barettin with inhibitory activities as low a 0.034 mu M reported against barnacle cyprid settlement. In the current study we report the antifouling activity of 29 synthetic analogs designed and inspired by the potent antifouling effect seen for benzo[g]dipodazine. The library contains mainly not only dipodazine derivatives but also disubstituted diketopiperazines and compounds incorporating alternative heterocyclic cores such as hydantoin, creatinine, and rhodanine. Several of the prepared compounds inhibit the settlement of Amphibalanus improvisus cyprids at low micromolar concentrations, in parity with the natural barettin. While several highly active compounds were prepared by incorporating the benzo[g]indole as hydrophobic substituent, the remarkable antifouling effect reported for benzo[g]dipodazine was not observed when evaluated in our study.
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