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  • 2020-2022  (8)
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  • 1
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    Coping with the “dirt”: brown shrimp and the microplastic threat (2020)
    ELSEVIER GMBH
    In:  EPIC3Zoology, ELSEVIER GMBH, 143, ISSN: 0944-2006
    Details
    Publication Date: 2020-11-19
    Description: Microplastic pollution is an emerging threat to marine biota. Uptake of microplastics can impair nutrition and affect the performance of organisms. However, the vulnerability to microplastics seems to vary between species for yet widely unexplored reasons. We investigated the stomach content of the brown shrimp, Crangon crangon, from the southern North Sea and performed feeding experiments and anatomical studies of the digestive organs to comprehend the distribution of fluorescent microparticles within the shrimp. Shrimp collected in their natural environment contained between 51 and more than 3,000 sand grains and fragments of bivalve shells in their stomachs. Sand grains may have been ingested to exploit the associated biofilm or to support maceration of food. Bivalve shell fragments were particularly abundant in summer when shrimp fed on freshly settled mussels. Shrimps’ stomach can be cleaned from ingested particles by regurgitation. In an experimental approach, we administered fluorescent microbeads of 0.1, 2.1, and 9.9 μm diameter. Only the smallest particles (0.1 μm) entered the midgut gland, which is the principal site of nutrient resorption in crustaceans. A fine-meshed chitinous filter system in the stomach of the shrimp prevents the passage of particles larger than about 1 μm. C. crangon appears well adapted to handle natural microscopic particles. This trait might also be advantageous in coping with microplastic pollution.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 2
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    Molecular aspects of lipid metabolism in the midgut gland of the brown shrimp Crangon crangon (2020)
    In:  EPIC3Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 248-24, pp. 110465, ISSN: 10964959
    Details
    Publication Date: 2020-07-21
    Description: The brown shrimp, Crangon crangon, is well adapted to the variable environmental conditions in the southern North Sea. It is very abundant, has high reproduction rates, and holds a key position in coastal ecosystems. This species has very low lipid deposits in the midgut gland, suggesting that the main function of the midgut gland is metabolic turnover rather than energy storage. Based on seasonal gene expression studies and established transcriptome data, we investigated key components of lipid metabolic pathways. Gene expression of triacylglycerol lipase, phospholipase, and fatty acid desaturase were analyzed and compared with that of other digestive enzymes involved in lipid, carbohydrate, and protein catabolism. Our results suggest that gene expression of digestive enzymes involved in lipid metabolism is modulated by the lipid content in the midgut gland and is related to food availability. Brown shrimp seem to be capable of using cellular phospholipids during periods of food paucity but high energetic (lipid) requirements. Two of three isoforms of fatty acid binding proteins (FABPs) from the midgut gland involved in fatty acid transport showed specific mutations of the binding site. We hypothesize that the mutations in FABPs and deficiencies in anabolic pathways limit lipid storage capacities in the midgut gland of C. crangon. In turn, food utilization, including lipid catabolism, has to be efficient to fulfill the energetic requirements of brown shrimp.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 3
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    Preparation of Microparticles for Microplastic Research by Cryo-Milling (2020)
    In:  EPIC3IcyMare 2020, 2020-08-26-2020-08-27
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    Publication Date: 2020-09-08
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 4
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    Dietary preferences of brachyuran crabs from Taiwan for marine or terrestrial food sources: evidence based on fatty acid trophic markers (2021)
    BIOMED CENTRAL LTD
    In:  EPIC3Frontiers in Zoology, BIOMED CENTRAL LTD, 18(26), pp. 1-11, ISSN: 1742-9994
    Details
    Publication Date: 2021-05-25
    Description: Background: Trophic interactions are key processes, which determine the ecological function and performance of organisms. Many decapod crustaceans feed on plant material as a source for essential nutrients, e.g. polyunsaturated fatty acids. Strictly herbivorous feeding appears only occasionally in marine decapods but is common in land crabs. To verify food preferences and to establish trophic markers, we studied the lipid and fatty acid composition of the midgut glands of two marine crab species (Grapsus albolineatus and Percnon affine), one semi-terrestrial species (Orisarma intermedium, formerly Sesarmops intermedius), and one terrestrial species (Geothelphusa albogilva) from Taiwan. Results: All species showed a wide span of total lipid levels ranging from 4 to 42% of the dry mass (%DM) in the marine P. affine and from 3 to 25%DM in the terrestrial G. albogilva. Triacylglycerols (TAG) were the major storage lipid compound. The fatty acids 16:0, 18:1(n-9), and 20:4(n-6) prevailed in all species. Essential fatty acids such as 20:4(n-6) originated from the diet. Terrestrial species also showed relatively high amounts of 18:2(n-6), which is a trophic marker for vascular plants. The fatty acid compositions of the four species allow to clearly distinguish between marine and terrestrial herbivorous feeding due to significantly different amounts of 16:0, 18:1(n-9), and 18:2(n-6). Conclusions: Based on the fatty acid composition, marine/terrestrial herbivory indices were defined and compared with regard to their resolution and differentiating capacity. These indices can help to reveal trophic preferences of unexplored species, particularly in habitats of border regions like mangrove intertidal flats and estuaries.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 5
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    Extracellular phosphoesterases of invertebrate origin: underrated actors in phosphorus recycling? (2020)
    SPRINGER
    In:  EPIC3Marine Biology, SPRINGER, 167(47), pp. 1-14, ISSN: 0025-3162
    Details
    Publication Date: 2020-03-06
    Description: Extracellular enzymes contribute substantially to the remineralisation of organic matter in aquatic systems. Marine invertebrates release endogenous enzymes through activities such as sloppy feeding or egestion, but the significance of such processes is widely unexplored. We compared functional key properties such as activity, stability, and apparent molecular masses of extracellular phosphatases from faeces of the marine crustaceans Idotea balthica, Palaemon varians, and Homarus gammarus with those of their digestive organs. A fluorescent substrate was used to examine enzyme activity qualitatively on agarose plates and quantitatively in microplate assays. Apparent molecular masses and enzyme stability were examined by native substrate gel electrophoresis (NSGE). Active extracellular phosphatase were present in the faeces of all tested species. NSGE activity band patterns were similar in digestive tissue extracts and faeces extracts. The initial enzyme activity retained for about 2 days, but thereafter rapidly decreased. Activity band patterns of digestive organs and faeces of I. balthica remained consistent for up to 72 h. Antibiotic treatment did not reduce phosphatase activity in the faeces of I. balthica and H. gammarus but in the faeces P. varians. Because of the comparatively high activities in the faeces, the electrophoretic similarity between faeces and digestive organs, and the limited durability of the enzymes in faeces extracts, we conclude that the studied crustaceans release predominantly endogenous, rather than bacterial phosphatases through faeces. These can substantially contribute to the pool of active extracellular phosphatases and the recycling of phosphorus in aquatic systems. The wider physiological and ecological context is discussed.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 6
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    Coping with synthetic and natural microparticles: brown shrimp and antioxidant defence (2020)
    In:  EPIC3Micro2020, Fate and Impacts of Microplastics: Knowledge and Responsibilities, Lanzarote and beyond, 2020-11-23-2020-11-27
    Details
    Publication Date: 2020-12-04
    Description: Industrialization and unconscious consumerism introduced plastic into our every day’s life. Due to poor recycling strategies, synthetic material is now one of the greatest challengers in the marine environment. Under suitable environmental conditions, plastic is prone to degrade further into microplastics. The wide size range make the microplastics available to different marine fauna. Apart from the synthetic microparticles, marine organisms are in their habitat persistently surrounded by various suspended organic microparticles (remains of bivalves, cellulose fibers, chitinous remains) and inorganic microparticles (silica frustules, sediment grains). The goal of this doctoral project is to determine the differences in antioxidant defense of specimen, subjected to the microparticles of different origin. To investigate this issue, the brown shrimp were exposed to 20 mg L-1 of natural (clay, diatoms) and synthetic (TiO2, PVC, PLA) microparticles. Incubation lasted for 6, 12, 24 and 48 h, until the shrimp were dissected, and the midgut gland was withdrawn. Analyses of antioxidant enzymes such as superoxide dismutase, glutathione peroxidase and reductase followed. Additionally, antioxidant potential was measured. The preliminary results show that the microparticle origin was not detrimental for the cellular stress in the brown shrimp, but the exposure time. Early findings suggest, C. crangon better copes with microplastic pollution then others marine organisms. Similar exposure experiments with crustaceans of other habitual or feeding traits would be advised, to better understand the high stress resistance towards microplastic pollution in the brown shrimp.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 7
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    Sand grains in the stomach of brown shrimp, Crangon crangon: Crunchy garnish, supportive macerator, or simply dirt? (2021)
    ELSEVIER SCIENCE BV
    In:  EPIC3Journal of Sea Research, ELSEVIER SCIENCE BV, 170, pp. 102020, ISSN: 1385-1101
    Details
    Publication Date: 2021-03-02
    Description: Brown shrimp, Crangon crangon, inhabit highly productive sandy and muddy grounds of the southern North Sea. The stomachs of the shrimp contain variable and often high numbers of sediment grains. The function of sediment grains inside the stomach and the purpose of their ingestion are only poorly understood. We tested in laboratory experiments whether sediment and associated organic material complement the natural food of C. crangon or if sand grains may be used by the shrimp to support trituration and maceration of ingested food. The shrimp showed no notable preference for sediment with natural organic content over sediment with reduced organic content, limited ingestion of sediment upon starvation, and no additional uptake of sand grains after feeding. Instead, C. crangon took up sediment only while feeding on regular food, suggesting that sand grains are not ingested intentionally but rather incidentally as a side effect of hasty gobbling. This conclusion is supported by the highly variable uptake of sand grains among individuals. Under experimental conditions, sand grains from sediments do not seem to have a crucial function in food processing and digestion in brown shrimp.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 8
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    pH-Stat Titration: A Rapid Assay for Enzymatic Degradability of Bio-Based Polymers (2021)
    MDPI
    In:  EPIC3Polymers, MDPI, 13(6), ISSN: 2073-4360
    Details
    Publication Date: 2021-05-28
    Description: Bio-based polymers have been suggested as one possible opportunity to counteract the progressive accumulation of microplastics in the environments. The gradual substitution of conventional plastics by bio-based polymers bears a variety of novel materials. The application of bioplastics is determined by their stability and bio-degradability, respectively. With the increasing implementation of bio-based plastics, there is also a demand for rapid and non-elaborate methods to determine their bio-degradability. Here, we propose an improved pH Stat titration assay optimized for bio-based polymers under environmental conditions and controlled temperature. Exemplarily, suspensions of poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) microparticles were incubated with proteolytic and lipolytic enzymes. The rate of hydrolysis, as determined by counter-titration with a diluted base (NaOH), was recorded for two hours. PLA was hydrolyzed by proteolytic enzymes but not by lipase. PBS, in contrast, showed higher hydrolysis rates with lipase than with proteases. The thermal profile of PLA hydrolysis by protease showed an exponential increase from 4 to 30 °C with a temperature quotient Q10 of 5.6. The activation energy was 110 kJ·mol−1. pH-Stat titration proved to be a rapid, sensitive, and reliable procedure supplementing established methods of determining the bio-degradability of polymers under environmental conditions.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
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