| 1. |
- Dånmark, Staffan, et al.
(author)
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In vitro and in vivo degradation profile of aliphatic polyesters subjected to electron beam sterilization
- 2011
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In: ACTA BIOMATERIALIA. - : Elsevier BV. - 1742-7061. ; 7:5, s. 2035-2046
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Journal article (peer-reviewed)abstract
- Degradation characteristics in response to electron beam sterilization of designed and biodegradable aliphatic polyester scaffolds are relevant for clinically successful synthetic graft tissue regeneration Scaffold degradation in vitro and in vivo were documented and correlated to the macroscopic structure and chemical design of the original polymer The materials tested were of inherently diverse hydrophobicity and crystallinity poly(L-lactide) (poly(LLA)) and random copolymers from L-lactide and epsilon-caprolactone or 1.5-dioxepan-2-one, fabricated into porous and non-porous scaffolds After sterilization, the samples underwent hydrolysis in vitro for up to a year In vivo, scaffolds were surgically implanted into rat calvarial defects and retrieved for analysis after 28 and 91 days In vitro, poly(L-lactide-co-1, 5-dioxepan-2-one) (poly(LLA-co-DXO)) samples degraded most rapidly during hydrolysis, due to the pronounced chain-shortening reaction caused by the sterilization. This was indicated by the rapid decrease in both mass and molecular weight of poly(LLA-co-DXO). Poly(L-lactide-co-epsilon-caprolactone) (poly(LLA-co-CL)) samples were also strongly affected by sterilization, but mass loss was more gradual; molecular weight decreased rapidly during hydrolysis Least affected by sterilization were the poly(LLA) samples, which subsequently showed low mass loss rate and molecular weight decrease during hydrolysis. Mechanical stability varied greatly. poly(LLA-co-CL) withstood mechanical testing for up to 182 days, while poly(LLA) and poly(LLA-co-DXO) samples quickly became too brittle Poly(LLA-co-DXO) samples unexpectedly degraded more rapidly in vitro than in vivo. After sterilization by electron beam irradiation, the three biodegradable polymers present widely diverse degradation profiles, both in vitro and in vivo. Each exhibits the potential to be tailored to meet diverse clinical tissue engineering requirements
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| 2. |
- Dahlgren, Thomas G., 1963, et al.
(author)
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Molecular phylogeny of the model annelid Ophryotrocha
- 2001
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In: Biological Bulletin. - 0006-3185. ; 201:2, s. 193-203
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Journal article (peer-reviewed)abstract
- Annelids of the genus Ophryotrocha are small opportunistic worms commonly found in polluted and nutrient-rich habitats such as harbors. Within this small group of about a, 40 described taxa a large variety of reproductive strategies are found, ranging from gonochoristic broadcast spawners to sequential hermaphroditic brooders. Many of the species have a short generation time and are easily maintained as laboratory cultures. Thus they have become a popular system for exploring a variety of biological questions including developmental genetics, ethology, and sexual selection. Despite considerable behavioral, reproductive, and karyological studies, a phylogenetic framework is lacking because most taxa are morphologically similar. In this study we use 16S mitochondrial gene sequence data to infer the phylogeny of Ophryotrocha strains commonly used in the laboratory. The resulting mtDNA topologies are generally well resolved and support a genetic split between hermaphroditic and gonochoristic species. Although the ancestral state could not be unambiguously identified, a change in reproductive strategy (i.e., hermaphroditism and gonochorism) occurred once within Ophryotrocha. Additionally, we show that sequential hermaphroditism evolved from a simultaneous hermaphroditic ancestor, and that characters previously used in phylogenetic reconstruction (i.e., jaw morphology and shape of egg mass) are homoplasic within the group.
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| 3. |
- Kvalø Heggøy, K, et al.
(author)
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The phylogeny of the annelid genus Ophryotrocha (Dorvilleidae)
- 2007
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In: Marine Biology Research. - : Informa UK Limited. - 1745-1000 .- 1745-1019. ; 3:6, s. 412-420
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Journal article (peer-reviewed)abstract
- Ophyotrocha is easy to keep in the laboratory and has therefore been used in several studies of evolution and speciation. The phylogenetic relationships within the group are, however, still not clear and morphological and molecular data are contradictory. Here we attempt to shed light on the phylogeny by adding an additional gene (cytochrome c oxidase subunit I) to the previous analyses of the group. However, the results are still incongruent with the results from the morphological data. We also include a species of the genus Iphitime, and conclude that this species falls within the Ophryotrocha clade. The implications are discussed.
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| 4. |
- Schander, C, 1960, et al.
(author)
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The fauna of hydrothermal vents on the Mohn Ridge (North Atlantic)
- 2010
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In: Marine Biology Research. - 1745-1000. ; 6:2, s. 155-171
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Journal article (peer-reviewed)abstract
- The macrofauna of the newly discovered hydrothermal vent field on the Mohn Ridge at 71 degrees N was investigated. Samples were collected during the cruise BIODEEP 2006 using the ROV 'Bathysaurus'. A total of 180 species-level taxa were identified. The region contains very few vent-endemic species, but some species of Porifera, Crustacea and Mollusca may be vent-associated. Dense aggregations of motile non-vent species such as Heliometra glacialis and Gorgonocephalus eucnemis surrounded the vent area, but the area in general only held small numbers of sedentary animals. Calcareous sponges comprised an unusually high portion of the sponge species found and they constitute one of the first pioneers among the sessile invertebrates settling on these vents. Possible explanations for the structure of the fauna in the region are discussed.
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| 5. |
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