Articles de revues : « Soft-tissue marine biological pump »

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Galbraith, Eric D., et Luke C. Skinner. « The Biological Pump During the Last Glacial Maximum ». Annual Review of Marine Science 12, n^o 1 (3 janvier 2020) : 559–86. http://dx.doi.org/10.1146/annurev-marine-010419-010906.

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Much of the global cooling during ice ages arose from changes in ocean carbon storage that lowered atmospheric CO2. A slew of mechanisms, both physical and biological, have been proposed as key drivers of these changes. Here we discuss the current understanding of these mechanisms with a focus on how they altered the theoretically defined soft-tissue and biological disequilibrium carbon storage at the peak of the last ice age. Observations and models indicate a role for Antarctic sea ice through its influence on ocean circulation patterns, but other mechanisms, including changes in biological processes, must have been important as well, and may have been coordinated through links with global air temperature. Further research is required to better quantify the contributions of the various mechanisms, and there remains great potential to use the Last Glacial Maximum and the ensuing global warming as natural experiments from which to learn about climate-driven changes in the marine ecosystem.

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Swann, G. E. A., et A. M. Snelling. « Photic zone changes in the North West Pacific Ocean from MIS 4-5e ». Climate of the Past Discussions 10, n^o 4 (29 août 2014) : 3631–60. http://dx.doi.org/10.5194/cpd-10-3631-2014.

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Abstract. In comparison to other sectors of the marine system, the palaeoceanography of the subarctic North Pacific Ocean is poorly constrained. New diatom isotope records of δ13C, δ18O, δ30Si (δ13Cdiatom, δ18Odiatom, δ30Sidiatom), are presented alongside existing geochemical and isotope records to document changes in photic zone conditions, including nutrient supply and the efficiency of the soft-tissue biological pump, between Marine Isotope Stage (MIS) 4 and MIS 5e. Peaks in opal productivity in MIS 5b/c and MIS 5e are both associated with the breakdown of the regional halocline stratification and increased nutrient supply to the photic zone. Whereas the MIS 5e peak is associated with low rates of nutrient utilisation, the MIS 5b/c peak is associated with significantly higher rates of nutrient utilisation. Both peaks, together with other smaller increases in productivity in MIS 4 and 5a culminate with a~significant increase in freshwater input which strengthens/re-establishes the halocline and limits further upwelling of sub-surface waters to the photic zone. Whilst δ30Sidiatom and previously published records of diatom δ15N (δ15Ndiatom) (Brunelle et al., 2007, 2010) show similar trends until the latter half of MIS 5a, the records become anti-correlated after this juncture and into MIS 4, suggesting a possible change in photic zone state such as may occur with a shift to iron or silicon limitation.

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Swann, G. E. A., et A. M. Snelling. « Photic zone changes in the north-west Pacific Ocean from MIS 4–5e ». Climate of the Past 11, n^o 1 (6 janvier 2015) : 15–25. http://dx.doi.org/10.5194/cp-11-15-2015.

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Abstract. In comparison to other sectors of the marine system, the palaeoceanography of the subarctic North Pacific Ocean is poorly constrained. New diatom isotope records of δ13C, δ18O, δ30Si (δ13Cdiatom, δ18Odiatom, and δ30Sidiatom) are presented alongside existing geochemical and isotope records to document changes in photic zone conditions, including nutrient supply and the efficiency of the soft-tissue biological pump, between Marine Isotope Stage (MIS) 4 and MIS 5e. Peaks in opal productivity in MIS 5b/c and MIS 5e are both associated with the breakdown of the regional halocline stratification and increased nutrient supply to the photic zone. Whereas the MIS 5e peak is associated with low rates of nutrient utilisation, the MIS 5b/c peak is associated with significantly higher rates of nutrient utilisation. Both peaks, together with other smaller increases in productivity in MIS 4 and 5a, culminate with a significant increase in freshwater input which strengthens/re-establishes the halocline and limits further upwelling of sub-surface waters to the photic zone. Whilst δ30Sidiatom and previously published records of diatom δ15N (δ15Ndiatom) (Brunelle et al., 2007, 2010) show similar trends until the latter half of MIS 5a, the records become anti-correlated after this juncture and into MIS 4, suggesting a possible change in photic zone state such as may occur with a shift to iron or silicon limitation.

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de Boer, A. M., A. J. Watson, N. R. Edwards et K. I. C. Oliver. « A multi-variable box model approach to the soft tissue carbon pump ». Climate of the Past 6, n^o 6 (21 décembre 2010) : 827–41. http://dx.doi.org/10.5194/cp-6-827-2010.

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Abstract. The canonical question of which physical, chemical or biological mechanisms were responsible for oceanic uptake of atmospheric CO2 during the last glacial is yet unanswered. Insight from paleo-proxies has led to a multitude of hypotheses but none so far have been convincingly supported in three dimensional numerical modelling experiments. The processes that influence the CO2 uptake and export production are inter-related and too complex to solve conceptually while complex numerical models are time consuming and expensive to run which severely limits the combinations of mechanisms that can be explored. Instead, an intermediate inverse box model approach of the soft tissue pump is used here in which the whole parameter space is explored. The glacial circulation and biological production states are derived from these using proxies of glacial export production and the need to draw down CO2 into the ocean. We find that circulation patterns which explain glacial observations include reduced Antarctic Bottom Water formation and high latitude upwelling and mixing of deep water and to a lesser extent reduced equatorial upwelling. The proposed mechanism of CO2 uptake by an increase of eddies in the Southern Ocean, leading to a reduced residual circulation, is not supported. Regarding biological mechanisms, an increase in the nutrient utilization in either the equatorial regions or the northern polar latitudes can reduce atmospheric CO2 and satisfy proxies of glacial export production. Consistent with previous studies, CO2 is drawn down more easily through increased productivity in the Antarctic region than the sub-Antarctic, but that violates observations of lower export production there. The glacial states are more sensitive to changes in the circulation and less sensitive to changes in nutrient utilization rates than the interglacial states.

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Althagbi, Hanan I., Walied M. Alarif, Khalid O. Al-Footy et Ahmed Abdel-Lateff. « Marine-Derived Macrocyclic Alkaloids (MDMAs) : Chemical and Biological Diversity ». Marine Drugs 18, n^o 7 (17 juillet 2020) : 368. http://dx.doi.org/10.3390/md18070368.

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The curiosity and attention that researchers have devoted to alkaloids are due to their bioactivities, structural diversity, and intriguing chemistry. Marine-derived macrocyclic alkaloids (MDMAs) are considered to be a potential source of drugs. Trabectedin, a tetrahydroisoquinoline derivative, has been approved for the treatment of metastatic soft tissue sarcoma and ovarian cancers. MDMAs displayed potent activities that enabled them to be used as anticancer, anti-invasion, antimalarial, antiplasmodial, and antimicrobial. This review presents the reported chemical structures, biological activities, and structure–activity relationships of macrocyclic alkaloids from marine organisms that have been published since their discovery until May 2020. This includes 204 compounds that are categorized under eight subclasses: pyrroles, quinolines, bis-quinolizidines, bis-1-oxaquinolizidines, 3-alkylpiperidines, manzamines, 3-alkyl pyridinium salts, and motuporamines.

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Labes, Antje. « Marine Resources Offer New Compounds and Strategies for the Treatment of Skin and Soft Tissue Infections ». Marine Drugs 21, n^o 7 (29 juin 2023) : 387. http://dx.doi.org/10.3390/md21070387.

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Bioprospecting of the marine environment for drug development has gained much attention in recent years owing to its massive chemical and biological diversity. Drugs for the treatment of skin and soft tissue infections have become part of the search, mainly with respect to enlarging the number of available antibiotics, with a special focus on multidrug-resistant Gram-positive bacteria, being the major causative agents in this field. Marine resources offer novel natural products with distinct biological activities of pharmaceutical importance, having the chance to provide new chemical scaffolds and new modes of action. New studies advance the field by proposing new strategies derived from an ecosystemic understanding for preventive activities against biofilms and new compounds suitable as disinfectants, which sustain the natural flora of the skin. Still, the development of new compounds is often stuck at the discovery level, as marine biotechnology also needs to overcome technological bottlenecks in drug development. This review summarizes its potential and shows these bottlenecks and new approaches.

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Raff, Rudolf A., et Elizabeth C. Raff. « The Role of Biology in the Fossilization of Embryos and Other Soft-Bodied Organisms : Microbial Biofilms and Lagerstätten ». Paleontological Society Papers 20 (octobre 2014) : 83–100. http://dx.doi.org/10.1017/s1089332600002813.

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Soft-tissue fossils are among the most striking and informative remains of extinct organisms. Although relatively rare, they are diverse, ranging from single microbial cells to nuclei and chromosomes; algae; metazoan embryos and larvae; flowers; complete, small, soft-bodied metazoans, metazoan tissues; integumentary structures such as melanosomes; skin texture, vertebrate feathers and hair, insect wings with color patterns, and sometimes even the entire bodies of large animals. The susceptibility of newly dead soft tissues to physical destruction, consumption, and microbial decay makes their preservation unlikely under most taphonomic conditions. In addition, their vulnerability to rapid autolysis, bioturbation, and destructive physical processes requires that rapid biological events must occur as the critical first steps of fossilization. An understanding of the processes by which biological remains enter the fossil record is important in inferring what non-microbial and microbial processes were operative in Lagerstätten. Paleontologists have recognized that microbial biofilms often accompany soft-tissue fossils, and have suggested that bacteria play an active role in soft tissue fossilization, but that role must be determined experimentally with living bacteria and dead tissue.Marine embryos and marine bacteria are used to investigate the processes that mediate early steps in soft-tissue preservation because they offer simple systems for laboratory investigation of the roles of autolysis-blocking environments, microbial interactions, biofilm formation, and authigenic mineralization in taphonomy. Understanding microbially mediated preservation of embryos may supply new insights into a more general biology of fossilization.

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Khatiwala, S., A. Schmittner et J. Muglia. « Air-sea disequilibrium enhances ocean carbon storage during glacial periods ». Science Advances 5, n^o 6 (juin 2019) : eaaw4981. http://dx.doi.org/10.1126/sciadv.aaw4981.

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The prevailing hypothesis for lower atmospheric carbon dioxide (CO2) concentrations during glacial periods is an increased efficiency of the ocean’s biological pump. However, tests of this and other hypotheses have been hampered by the difficulty to accurately quantify ocean carbon components. Here, we use an observationally constrained earth system model to precisely quantify these components and the role that different processes play in simulated glacial-interglacial CO2 variations. We find that air-sea disequilibrium greatly amplifies the effects of cooler temperatures and iron fertilization on glacial ocean carbon storage even as the efficiency of the soft-tissue biological pump decreases. These two processes, which have previously been regarded as minor, explain most of our simulated glacial CO2 drawdown, while ocean circulation and sea ice extent, hitherto considered dominant, emerge as relatively small contributors.

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Schmidt, Charlotte Vinther, et Ole G. Mouritsen. « Cephalopods as Challenging and Promising Blue Foods : Structure, Taste, and Culinary Highlights and Applications ». Foods 11, n^o 17 (24 août 2022) : 2559. http://dx.doi.org/10.3390/foods11172559.

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Foods are complex systems due to their biological origin. Biological materials are soft matter hierarchically structured on all scales from molecules to tissues. The structure reflects the biological constraints of the organism and the function of the tissue. The structural properties influence the texture and hence the mouthfeel of foods prepared from the tissue, and the presence of flavour compounds is similarly determined by biological function. Cephalopods, such as squid, cuttlefish, and octopuses, are notoriously known for having challenging texture due to their muscles being muscular hydrostats with highly cross-linked collagen. Similar with other marine animals such as fish and crustaceans, cephalopods are rich in certain compounds such as free amino acids and free 5′-ribonucleotides that together elicit umami taste. Scientific investigations of culinary applications of cephalopods as foods must therefore involve mechanical studies (texture analysis), physicochemical measurements of thermodynamic properties (protein denaturation), as well as chemical analysis (taste and aroma compounds). The combination of such basic science investigations of food as a soft material along with an exploration of the gastronomic potential has been termed gastrophysics. In this review paper, we reviewed available gastrophysical studies of cephalopod structure, texture, and taste both as raw, soft material and in certain preparations.

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Kang, Moon Sung, Hyo Jung Jo, Hee Jeong Jang, Bongju Kim, Tae Gon Jung et Dong-Wook Han. « Recent Advances in Marine Biomaterials Tailored and Primed for the Treatment of Damaged Soft Tissues ». Marine Drugs 21, n^o 12 (25 novembre 2023) : 611. http://dx.doi.org/10.3390/md21120611.

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The inherent self-repair abilities of the body often fall short when it comes to addressing injuries in soft tissues like skin, nerves, and cartilage. Tissue engineering and regenerative medicine have concentrated their research efforts on creating natural biomaterials to overcome this intrinsic healing limitation. This comprehensive review delves into the advancement of such biomaterials using substances and components sourced from marine origins. These marine-derived materials offer a sustainable alternative to traditional mammal-derived sources, harnessing their advantageous biological traits including sustainability, scalability, reduced zoonotic disease risks, and fewer religious restrictions. The use of diverse engineering methodologies, ranging from nanoparticle engineering and decellularization to 3D bioprinting and electrospinning, has been employed to fabricate scaffolds based on marine biomaterials. Additionally, this review assesses the most promising aspects in this field while acknowledging existing constraints and outlining necessary future steps for advancement.

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Voegele, Kristyn K., Zachary M. Boles, Paul V. Ullmann, Elena R. Schroeter, Wenxia Zheng et Kenneth J. Lacovara. « Soft Tissue and Biomolecular Preservation in Vertebrate Fossils from Glauconitic, Shallow Marine Sediments of the Hornerstown Formation, Edelman Fossil Park, New Jersey ». Biology 11, n^o 8 (2 août 2022) : 1161. http://dx.doi.org/10.3390/biology11081161.

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Endogenous biomolecules and soft tissues are known to persist in the fossil record. To date, these discoveries derive from a limited number of preservational environments, (e.g., fluvial channels and floodplains), and fossils from less common depositional environments have been largely unexplored. We conducted paleomolecular analyses of shallow marine vertebrate fossils from the Cretaceous–Paleogene Hornerstown Formation, an 80–90% glauconitic greensand from Jean and Ric Edelman Fossil Park in Mantua Township, NJ. Twelve samples were demineralized and found to yield products morphologically consistent with vertebrate osteocytes, blood vessels, and bone matrix. Specimens from these deposits that are dark in color exhibit excellent histological preservation and yielded a greater recovery of cells and soft tissues, whereas lighter-colored specimens exhibit poor histology and few to no cells/soft tissues. Additionally, a well-preserved femur of the marine crocodilian Thoracosaurus was found to have retained endogenous collagen I by immunofluorescence and enzyme-linked immunosorbent assays. Our results thus not only corroborate previous findings that soft tissue and biomolecular recovery from fossils preserved in marine environments are possible but also expand the range of depositional environments documented to preserve endogenous biomolecules, thus broadening the suite of geologic strata that may be fruitful to examine in future paleomolecular studies.

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Schmittner, A., et C. J. Somes. « Complementary constraints from carbon ( 13 C) and nitrogen ( 15 N) isotopes on the glacial ocean's soft‐tissue biological pump ». Paleoceanography 31, n^o 6 (juin 2016) : 669–93. http://dx.doi.org/10.1002/2015pa002905.

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Cavaleiro, Catarina, Antje H. L. Voelker, Heather Stoll, Karl-Heinz Baumann et Michal Kucera. « Coccolithophore productivity at the western Iberian Margin during the Middle Pleistocene (310–455 ka) – evidence from coccolith Sr∕Ca data ». Climate of the Past 16, n^o 6 (3 novembre 2020) : 2017–37. http://dx.doi.org/10.5194/cp-16-2017-2020.

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Abstract. Coccolithophores contribute significantly to marine primary productivity and play a unique role in ocean biogeochemistry by using carbon for photosynthesis (soft-tissue pump) and for calcification (carbonate counter pump). Despite the importance of including coccolithophores in Earth system models to allow better predictions of the climate system's responses to planetary change, the reconstruction of coccolithophore productivity mostly relied on proxies dependent on accumulation and sedimentation rates and preservation conditions. In this study we used an independent proxy, based on the coccolith fraction (CF) Sr∕Ca ratio, to reconstruct coccolithophore productivity. We studied the marine sediment core MD03-2699 from the western Iberian margin (IbM), concentrating on glacial–interglacial cycles of Marine Isotopic Stage (MIS) 12 to MIS 9. We found that IbM coccolithophore productivity was controlled by changes in the oceanographic conditions, such as in sea surface temperature (SST) and nutrient availability, and by competition with other phytoplankton groups. Long-term coccolithophore productivity was primarily affected by variations in the dominant surface water mass. Polar and subpolar surface waters during glacial substages were associated with decreased coccolithophore productivity, with the strongest productivity minima concomitant with Heinrich-type events (HtEs). Subtropical, nutrient-poorer waters, increased terrigenous input, and moderate to strong upwelling during the deglaciation and early MIS11 are hypothesized to have attributed a competitive advantage to diatoms to the detriment of coccolithophores, resulting in intermediate coccolithophore productivity levels. During the progression towards full glacial conditions an increasing presence of nutrient-richer waters, related to the growing influence of transitional surface waters and/or intensified upwelling, probably stimulated coccolithophore productivity to maxima following the rapid depletion of silica by diatoms. We present conceptual models of the carbon and carbonate cycle components for the IbM in different time slices that might serve as a basis for further investigation and modelling experiments.

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Morley, Simon A., Terri A. Souster, Belinda J. Vause, Laura Gerrish, Lloyd S. Peck et David K. A. Barnes. « Benthic Biodiversity, Carbon Storage and the Potential for Increasing Negative Feedbacks on Climate Change in Shallow Waters of the Antarctic Peninsula ». Biology 11, n^o 2 (17 février 2022) : 320. http://dx.doi.org/10.3390/biology11020320.

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The importance of cold-water blue carbon as biological carbon pumps that sequester carbon into ocean sediments is now being realised. Most polar blue carbon research to date has focussed on deep water, yet the highest productivity is in the shallows. This study measured the functional biodiversity and carbon standing stock accumulated by shallow-water (<25 m) benthic assemblages on both hard and soft substrata on the Antarctic Peninsula (WAP, 67° S). Soft substrata benthic assemblages (391 ± 499 t C km−2) contained 60% less carbon than hard substrata benthic assemblages (648 ± 909). In situ observations of substrata by SCUBA divers provided estimates of 59% hard (4700 km) and 12% soft (960 km) substrata on seasonally ice-free shores of the Antarctic Peninsula, giving an estimate of 253,000 t C at 20 m depth, with a sequestration potential of ~4500 t C year−1. Currently, 54% of the shoreline is permanently ice covered and so climate-mediated ice loss along the Peninsula is predicted to more than double this carbon sink. The steep fjordic shorelines make these assemblages a globally important pathway to sequestration, acting as one of the few negative (mitigating) feedbacks to climate change. The proposed WAP marine protected area could safeguard this ecosystem service, helping to tackle the climate and biodiversity crises.

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Zhang, Xi-Guang, Martin R. Smith, Jie Yang et Jin-Bo Hou. « Onychophoran-like musculature in a phosphatized Cambrian lobopodian ». Biology Letters 12, n^o 9 (septembre 2016) : 20160492. http://dx.doi.org/10.1098/rsbl.2016.0492.

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The restricted, exclusively terrestrial distribution of modern Onychophora contrasts strikingly with the rich diversity of onychophoran-like fossils preserved in marine Cambrian Lagerstätten . The transition from these early forebears to the modern onychophoran body plan is poorly constrained, in part owing to the absence of fossils preserving details of the soft anatomy. Here, we report muscle tissue in a new early Cambrian (Stage 3) lobopodian, Tritonychus phanerosarkus gen. et sp. nov., preserved in the Orsten fashion by three-dimensional replication in phosphate. This first report of Palaeozoic onychophoran musculature establishes peripheral musculature as a characteristic of the ancestral panarthropod, but documents an unexpected muscular configuration. Phylogenetic analysis reconstructs T. phanerosarkus as one of a few members of the main onychophoran lineage—which was as rare and as cryptic in the Cambrian period as it is today.

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Gehlen, M., L. Bopp, N. Emprin, O. Aumont, C. Heinze et O. Ragueneau. « Reconciling surface ocean productivity, export fluxes and sediment composition in a global biogeochemical ocean model ». Biogeosciences 3, n^o 4 (9 novembre 2006) : 521–37. http://dx.doi.org/10.5194/bg-3-521-2006.

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Abstract. This study focuses on an improved representation of the biological soft tissue pump in the global three-dimensional biogeochemical ocean model PISCES. We compare three parameterizations of particle dynamics: (1) the model standard version including two particle size classes, aggregation-disaggregation and prescribed sinking speed; (2) an aggregation-disaggregation model with a particle size spectrum and prognostic sinking speed; (3) a mineral ballast parameterization with no size classes, but prognostic sinking speed. In addition, the model includes a description of surface sediments and organic carbon early diagenesis. Model output is compared to data or data based estimates of ocean productivity, pe-ratios, particle fluxes, surface sediment bulk composition and benthic O2 fluxes. Model results suggest that different processes control POC fluxes at different depths. In the wind mixed layer turbulent particle coagulation appears as key process in controlling pe-ratios. Parameterization (2) yields simulated pe-ratios that compare well to observations. Below the wind mixed layer, POC fluxes are most sensitive to the intensity of zooplankton flux feeding, indicating the importance of zooplankton community composition. All model parameters being kept constant, the capability of the model to reproduce yearly mean POC fluxes below 2000 m and benthic oxygen demand does at first order not dependent on the resolution of the particle size spectrum. Aggregate formation appears essential to initiate an intense biological pump. At great depth the reported close to constant particle fluxes are most likely the result of the combined effect of aggregate formation and mineral ballasting.

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Ben-Nissan, Besim. « Biomimetics and Marine Materials in Drug Delivery and Tissue Engineering : From Natural Role Models to Bone Regeneration ». Key Engineering Materials 587 (novembre 2013) : 229–32. http://dx.doi.org/10.4028/www.scientific.net/kem.587.229.

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During the last two decades learning from nature has given us new directions for the use of natural organic and inorganic skeletons, drug delivery devices, new medical treatment methods initiating unique designs and devices ranging from nanoto macro scale. These materials and designs have been instrumental to introduce the simplest remedies to vital problems in regenerative medicine, providing frameworks and highly accessible sources of osteopromotive analogues, naofibres, micro and macrospheres and mineralising proteins. This is exemplified by the biological effectiveness of marine structures such as corals and shells and sponge skeletons to house self-sustaining musculoskeletal tissues and to the promotion of bone formation by extracts of spongin and nacre seashells. Molecules pivotal to the regulation and guidance of bone morphogenesis and particularly the events in mineral metabolism and deposition similarly exist in the earliest marine organisms because they represent the first molecular components established for calcification, morphogenesis and wound healing. It emerges that bone morphogenic protein (BMP) molecules-the main cluster of bone growth factors for human bone morphogenesis-are secreted by endodermal cells into the developing skeleton. Signalling proteins, TGF and Wnt-prime targets in bone therapeutics-are present in early marine sponge development. Furthermore, ready-made organic and inorganic marine skeletons possess a habitat suitable for proliferating added mesenchymal stem cell populations and promoting clinically acceptable bone formation. In this paper we review the nature, morphology and extent of this association and use of these structures for bone grafts, drug delivery and extracts such as proteins for regenerative medicine. As an example, in human biology a study of matrix vesicles will teach us valuable lessons on how proteins are captured and coated; and how the vesicle is able to dock and fuse with their target. We will describe significant technological trends aimed at producing delivery vehicles using natural-origin soft and hard organized matter; fabricated into capsules and cell-delineated assemblies.Therole model for this specific biomimicry is the filtering microskeleton ofForaminifera. We will outline new selected strategies based on our and others works for the engineering of new bone, based on biomimicry themes using these bioceramics building blocks.

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Isaza, Jesica Andrea, Damien Lacroix et Juan Ramírez. « Influence of indentation test factors on the mechanical response of the skin ». Universitas Scientiarum 24, n^o 1 (9 avril 2019) : 49–72. http://dx.doi.org/10.11144/javeriana.sc24-1.ioit.

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This study proposes in vivo tests and design of experiments to determine the influence of experimental factors on the mechanical response of the soft tissue. The experimental factors considered are: room temperature (A), indentation velocity (B), indenter temperature (C), pump pressure (D) and muscle activation (E). An inverse method was developed to obtain the constants for constitutive equations of a multilayer biological model (skin, hypodermis, and muscle) through the use of indentation tests in combination with a finite element method. For each combination of the experimental factors, two groups of constants were established from the inverse method. Sixteen combinations of experimental conditions and their corresponding constants for the Mooney-Rivlin constitutive equations were obtained to be used in further numerical models. The factor D and factor interactions ADE, CDE, and ACDE were statistically significant with respect to skin mechanical response. Therefore, it can be concluded that there is not a current equation able to represent the mechanical properties of the skin under all the experimental conditions considered in this study.

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Kapsenberg, L., A. Miglioli, M. C. Bitter, E. Tambutté, R. Dumollard et J. P. Gattuso. « Ocean pH fluctuations affect mussel larvae at key developmental transitions ». Proceedings of the Royal Society B : Biological Sciences 285, n^o 1893 (19 décembre 2018) : 20182381. http://dx.doi.org/10.1098/rspb.2018.2381.

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Coastal marine ecosystems experience dynamic fluctuations in seawater carbonate chemistry. The importance of this variation in the context of ocean acidification requires knowing what aspect of variability biological processes respond to. We conducted four experiments (ranging from 3 to 22 days) with different variability regimes (pH T 7.4–8.1) assessing the impact of diel fluctuations in carbonate chemistry on the early development of the mussel Mytilus galloprovincialis . Larval shell growth was consistently correlated to mean exposures, regardless of variability regimes, indicating that calcification responds instantaneously to seawater chemistry. Larval development was impacted by timing of exposure, revealing sensitivity of two developmental processes: development of the shell field, and transition from the first to the second larval shell. Fluorescent staining revealed developmental delay of the shell field at low pH, and abnormal development thereof was correlated with hinge defects in D-veligers. This study shows, for the first time, that ocean acidification affects larval soft-tissue development, independent from calcification. Multiple developmental processes additively underpin the teratogenic effect of ocean acidification on bivalve larvae. These results explain why trochophores are the most sensitive life-history stage in marine bivalves and suggest that short-term variability in carbonate chemistry can impact early larval development.

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Bosio, Giulia, Alberto Collareta, Claudio Di Celma, Olivier Lambert, Felix G. Marx, Christian de Muizon, Anna Gioncada et al. « Taphonomy of marine vertebrates of the Pisco Formation (Miocene, Peru) : Insights into the origin of an outstanding Fossil-Lagerstätte ». PLOS ONE 16, n^o 7 (15 juillet 2021) : e0254395. http://dx.doi.org/10.1371/journal.pone.0254395.

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The Miocene Pisco Formation, broadly exposed in the Ica Desert of southern Peru, is among the most outstanding Cenozoic marine Fossil-Lagerstätten worldwide. It is renowned for its exceptional preservation and abundance of vertebrate fossils, including a rich assemblage of whales and dolphins (Cetacea). Here, we integrate taphonomic data on 890 marine vertebrate fossils, gathered through 16 different localities. Our observations range from the taxonomic distribution, articulation, completeness, disposition and orientation of skeletons, to the presence of bite marks, associations with shark teeth and macro-invertebrates, bone and soft tissue preservation, and the formation of attendant carbonate concretions and sedimentary structures. We propose that the exceptional preservation characterising many Pisco vertebrates, as well as their exceptionally high abundance, cannot be ascribed to a single cause like high sedimentation rates (as proposed in the past), but rather to the interplay of several favourable factors including: (i) low levels of dissolved oxygen at the seafloor (with the intervention of seasonal anoxic events); (ii) the early onset of mineralisation processes like apatite dissolution/recrystallisation and carbonate mineral precipitation; (iii) rapid burial of carcasses in a soupy substrate and/or a novel mechanism involving scour-induced self-burial; and (iv) original biological richness. Collectively, our observations provide a comprehensive overview of the taphonomic processes that shaped one of South America’s most important fossil deposits, and suggest a model for the formation of other marine vertebrate Fossil-Lagerstätten.

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Nakhlé, K., D. Cossa, D. Claisse, B. Beliaeff et S. Simon. « Cadmium and mercury in Seine Estuary flounders and mussels : the results of two decades of monitoring ». ICES Journal of Marine Science 64, n^o 5 (5 avril 2007) : 929–38. http://dx.doi.org/10.1093/icesjms/fsm031.

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Abstract Nakhlé, K., Cossa, D., Claisse, D., Beliaeff, B., and Simon, S. 2007. Cadmium and mercury in Seine Estuary flounders and mussels: the results of two decades of monitoring. – ICES Journal of Marine Science, 64: 929–938. The flounder (Platichthys flesus) is a flatfish that inhabits marine coastal environments, especially estuaries. It is an alternative quantitative biological indicator to the common marine mussel (Mytilus spp.), which is currently used as a sentinel species to monitor chemical contamination in numerous monitoring programmes. Findings from two decades of monitoring cadmium (Cd) and mercury (Hg) using both sentinel species in the Seine Estuary (France) are reported. For comparison, time-series of water concentrations for the same two metals at the mouth of the River Seine are given. Cd concentrations in the liver of the fish and in the soft tissue of mussels show similar temporal trends, consistent with the major temporal variations of Cd concentrations recorded in river water and with changes in industrial discharge of Cd (phosphogypsum waste) within the Seine Estuary. On the other hand, Hg concentrations in the muscles of flounders show temporal variations with no link to that observed in mussels or fluvial Hg contributions, which are in fact nearly covariant. It is concluded that optimization of the use of flounders as sentinel organisms for monitoring temporal trends of metal contamination in estuarine environments requires in-depth knowledge of its ecology within the area studied. An adapted sampling strategy based on this knowledge should provide results that are easier to interpret.

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Schmittner, Andreas, et Nathaniel J. Fillman. « Carbon and carbon-13 in the preindustrial and glacial ocean ». PLOS Climate 3, n^o 7 (8 juillet 2024) : e0000434. http://dx.doi.org/10.1371/journal.pclm.0000434.

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Despite their importance for Earth’s climate and paleoceanography, the cycles of carbon (C) and its isotope 13C in the ocean are not well understood. Models typically do not decompose C and 13C storage caused by different physical, biological, and chemical processes, which makes interpreting results difficult. Consequently, basic observed features, such as the decreased carbon isotopic signature (δ13CDIC) of the glacial ocean remain unexplained. Here, we review recent progress in decomposing Dissolved Inorganic Carbon (DIC) into preformed and regenerated components, extend a precise and complete decomposition to δ13CDIC, and apply it to data-constrained model simulations of the Preindustrial (PI) and Last Glacial Maximum (LGM) oceans. Regenerated components, from respired soft-tissue organic matter and dissolved biogenic calcium carbonate, are reduced in the LGM, indicating a decrease in the active part of the biological pump. Preformed components increase carbon storage and decrease δ13CDIC by 0.55 ‰ in the LGM. We separate preformed into saturation and disequilibrium components, each of which have biological and physical contributions. Whereas the physical disequilibrium in the PI is negative for both DIC and δ13CDIC, and changes little between climate states, the biological disequilibrium is positive for DIC but negative for δ13CDIC, a pattern that is magnified in the LGM. The biological disequilibrium is the dominant driver of the increase in glacial ocean C and the decrease in δ13CDIC, indicating a reduced sink of biological carbon. Overall, in the LGM, biological processes increase the ocean’s DIC inventory by 355 Pg more than in the PI, reduce its mean δ13CDIC by an additional 0.52 ‰, and contribute 60 ppm to the lowering of atmospheric CO2. Spatial distributions of the δ13CDIC components are presented. Commonly used approximations based on apparent oxygen utilization and phosphate are evaluated and shown to have large errors.

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Moutin, Thierry, Thibaut Wagener, Mathieu Caffin, Alain Fumenia, Audrey Gimenez, Melika Baklouti, Pascale Bouruet-Aubertot et al. « Nutrient availability and the ultimate control of the biological carbon pump in the western tropical South Pacific Ocean ». Biogeosciences 15, n^o 9 (16 mai 2018) : 2961–89. http://dx.doi.org/10.5194/bg-15-2961-2018.

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Abstract. Surface waters (0–200 m) of the western tropical South Pacific (WTSP) were sampled along a longitudinal 4000 km transect (OUTPACE cruise, DOI: 10.17600/15000900) during the austral summer (stratified) period (18 February to 3 April 2015) between the Melanesian Archipelago (MA) and the western part of the SP gyre (WGY). Two distinct areas were considered for the MA, the western MA (WMA), and the eastern MA (EMA). The main carbon (C), nitrogen (N), and phosphorus (P) pools and fluxes provide a basis for the characterization of the expected trend from oligotrophy to ultra-oligotrophy, and the building of first-order budgets at the daily and seasonal timescales (using climatology). Sea surface chlorophyll a well reflected the expected oligotrophic gradient with higher values obtained at WMA, lower values at WGY, and intermediate values at EMA. As expected, the euphotic zone depth, the deep chlorophyll maximum, and nitracline depth deepen from west to east. Nevertheless, phosphaclines and nitraclines did not match. The decoupling between phosphacline and nitracline depths in the MA allows for excess P to be locally provided in the upper water by winter mixing. We found a significant biological “soft tissue” carbon pump in the MA sustained almost exclusively by dinitrogen (N2) fixation and essentially controlled by phosphate availability in this iron-rich environment. The MA appears to be a net sink for atmospheric CO2, while the WGY is in quasi-steady state. We suggest that the necessary excess P, allowing the success of nitrogen fixers and subsequent carbon production and export, is mainly brought to the upper surface by local deep winter convection at an annual timescale rather than by surface circulation. While the origin of the decoupling between phosphacline and nitracline remains uncertain, the direct link between local P upper water enrichment, N2 fixation, and organic carbon production and export, offers a possible shorter timescale than previously thought between N input by N2 fixation and carbon export. The low iron availability in the SP gyre and P availability in the MA during the stratified period may appear as the ultimate control of N input by N2 fixation. Because of the huge volume of water to consider, and because the SP Ocean is the place of intense denitrification in the east (N sink) and N2 fixation in the west (N source), precise seasonal C, N, P, and iron (Fe) budgets would be of prime interest to understand the efficiency, at the present time and in the future, of the oceanic biological carbon pump.

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Su, Bor-Chyuan, Giun-Yi Hung, Yun-Chieh Tu, Wei-Chen Yeh, Meng-Chieh Lin et Jyh-Yih Chen. « Marine Antimicrobial Peptide TP4 Exerts Anticancer Effects on Human Synovial Sarcoma Cells via Calcium Overload, Reactive Oxygen Species Production and Mitochondrial Hyperpolarization ». Marine Drugs 19, n^o 2 (5 février 2021) : 93. http://dx.doi.org/10.3390/md19020093.

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Synovial sarcoma is a rare but aggressive soft-tissue sarcoma associated with translocation t(X;18). Metastasis occurs in approximately 50% of all patients, and curative outcomes are difficult to achieve in this group. Since the efficacies of current therapeutic approaches for metastatic synovial sarcoma remain limited, new therapeutic agents are urgently needed. Tilapia piscidin 4 (TP4), a marine antimicrobial peptide, is known to exhibit multiple biological functions, including anti-bacterial, wound-healing, immunomodulatory, and anticancer activities. In the present study, we assessed the anticancer activity of TP4 in human synovial sarcoma cells and determined the underlying mechanisms. We first demonstrated that TP4 can induce necrotic cell death in human synovial sarcoma AsKa-SS and SW982 cells lines. In addition, we saw that TP4 initiates reactive oxygen species (ROS) production and downregulates antioxidant proteins, such as uncoupling protein-2, superoxide dismutase (SOD)-1, and SOD-2. Moreover, TP4-induced mitochondrial hyperpolarization is followed by elevation of mitochondrial ROS. Calcium overload is also triggered by TP4, and cell death can be attenuated by a necrosis inhibitor, ROS scavenger or calcium chelator. In our experiments, TP4 displayed strong anticancer activity in human synovial sarcoma cells by disrupting oxidative status, promoting mitochondrial hyperpolarization and causing calcium overload.

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Gehlen, M., L. Bopp, N. Emprin, O. Aumont, C. Heinze et O. Ragueneau. « Reconciling surface ocean productivity, export fluxes and sediment composition in a global biogeochemical ocean model ». Biogeosciences Discussions 3, n^o 3 (28 juin 2006) : 803–36. http://dx.doi.org/10.5194/bgd-3-803-2006.

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Abstract. This study focuses on an improved representation of the biological soft tissue pump in the global three-dimensional biogeochemical ocean model PISCES. We compare three parameterizations of particle dynamics: (1) the model standard version including two particle size classes, aggregation-disaggregation and prescribed sinking speed; (2) an aggregation-disaggregation model with a particle size spectrum and prognostic sinking speed; (3) a mineral ballast parameterization with no size classes, but prognostic sinking speed. In addition, the model includes a description of surface sediments and organic carbon early diagenesis. The integrated representation of material fluxes from the productive surface ocean down to the sediment-water interface allows taking advantage of surface ocean observations, sediment trap data and exchange fluxes at the sediment-water interface. The capability of the model to reproduce yearly averaged particulate organic carbon fluxes and benthic oxygen demand does at first order not dependent on the resolution of the particle size spectrum. Model results obtained with the standard version and with the one including a particle size spectrum and prognostic sinking speed are not significantly different. Both model versions overestimate particulate organic carbon between 1000 and 2000 m, while deep fluxes are of the correct order of magnitude. Predicted benthic oxygen fluxes correspond with respect to their large scale distribution and magnitude to data based estimates. Modeled particulate organic C fluxes across the mesopelagos are most sensitive to the intensity of zooplankton flux feeding. An increase of the intensity of flux feeding in the standard version results in lower mid- and deep-water particulate organic carbon fluxes, shifting model results to an underestimation of particulate organic carbon fluxes in the deep. The corresponding benthic oxygen fluxes are too low. The model version including the mineral ballast parameterization yields an improved fit between modeled and observed particulate organic carbon fluxes below 2000 m and down to the sediment-water interface. Our results suggest that aggregate formation alone might not be sufficient to drive an intense biological pump. The later is most likely driven by the combined effect of aggregate formation and mineral ballasting.

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Fioravanti, Tatiana, Andrea Splendiani, Tommaso Righi, Nicola Maio, Sabrina Lo Brutto, Antonio Petrella et Vincenzo Caputo Barucchi. « A Mediterranean Monk Seal Pup on the Apulian Coast (Southern Italy) : Sign of an Ongoing Recolonisation ? » Diversity 12, n^o 6 (25 juin 2020) : 258. http://dx.doi.org/10.3390/d12060258.

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The Mediterranean monk seal (Monachus monachus) is one of the most endangered marine mammals in the world. This species has been threatened since ancient times by human activities and currently amounts to approximately 700 individuals distributed in the Eastern Mediterranean Sea (Aegean and Ionian Sea) and Eastern Atlantic Ocean (Cabo Blanco and Madeira). In other areas, where the species is considered “probably extinct”, an increase in sporadic sightings has been recorded during recent years. Sightings and accidental catches of Mediterranean monk seals have become more frequent in the Adriatic Sea, mainly in Croatia but also along the coasts of Montenegro, Albania and Southern Italy. A Mediterranean monk seal pup was recovered on 27 January 2020 on the beach of Torre San Gennaro in Torchiarolo (Brindisi, Apulia, Italy). DNA was extracted from a tissue sample and the hypervariable region I (HVR1) of the mitochondrial DNA control region was amplified and sequenced. The alignment performed with seven previous published haplotypes showed that the individual belongs to the haplotype MM03, common in monk seals inhabiting the Greek islands of the Ionian Sea. This result indicates the Ionian Islands as the most probable geographical origin of the pup, highlighting the need to intensify research and conservation activities on this species even in areas where it seemed to be extinct.

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Fabrello, Jacopo, Michela Dalla Fontana, Noemi Gaiani, Maria Ciscato, Marco Roverso, Sara Bogialli et Valerio Matozzo. « Assessing the Effects of a Diet of BPA Analogue-Exposed Microalgae in the Clam Ruditapes philippinarum ». Journal of Xenobiotics 14, n^o 3 (6 septembre 2024) : 1221–37. http://dx.doi.org/10.3390/jox14030069.

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In our previous study, we demonstrated that the microalgae Phaeodactylum tricornutum can bioaccumulate bisphenol A analogues. Since this microalgae species is part of the diet of marine filter-feeding organisms, such as bivalves, in this study we tested the hypothesis that a diet based on exposed microalgae can exert negative effects on the clam Ruditapes philippinarum. Microalgae were exposed for 7 days to 300 ng/L of bisphenol AF (BPAF), bisphenol F (BPF), and bisphenol S (BPS), alone or as a mixture (MIX), to allow bioaccumulation. Microalgae were then supplied as food to bivalves. After 7 and 14 days of diet, the effects of exposed microalgae were evaluated on a battery of biomarkers measured in haemolymph/haemocytes, gills and digestive glands of clams. In addition, bioaccumulation of the three bisphenols was investigated in clams by UHPLC-HRMS. The results obtained demonstrated that total haemocyte count (THC) increased in clams following ingestion for 7 days of BPAF- and BPF-exposed microalgae, while BPS-exposed microalgae significantly reduced THC after 14 days of diet. MIX- and BPS-exposed microalgae increased haemocyte proliferation. The diet of exposed microalgae affected acid and alkaline phosphatase activity in clams, with an opposite response between haemolymph and haemocytes. Regarding antioxidants, an increase in catalase activity was observed in clams after ingestion of BPA analogue-exposed microalgae. The results also demonstrated marked oxidative stress in gills, the first tissue playing an important role in the feeding process. Oxidative damage was recorded in both the gills and digestive glands of clams fed BPA analogue-exposed microalgae. Alterations in epigenetic-involved enzyme activity were also found, demonstrating for the first time that BPA analogue-exposed food can alter epigenetic mechanisms in marine invertebrates. No bioaccumulation of BPA analogues was detected in clam soft tissues. Overall, this study demonstrated that a diet of BPA analogue-exposed microalgae can induce significant alterations of some important biological responses of R. philippinarum. To our knowledge, this is the first study demonstrating the effects of ingestion of BPA analogue-exposed microalgae in the clam R. philippinarum, suggesting a potential ecotoxicological risk for the marine food chain, at least at the first levels.

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Shukhairi, Sarah Syazwani, Nurzafirah Mazlan, Miftahul Jannah Muhammad Husin, Jemimah Shalom, Safaa Najah Saud, Muhammad Shirwan Adbullah Sanie, Ong Meng Chuan et Naveen Kumar Naidu Chandra Mohan. « Microplastics Isolated from Saltwater Clam Paratapes undulatus from Wet Market at Shah Alam, Selangor, Malaysia ». Malaysian Journal of Fundamental and Applied Sciences 20, n^o 1 (8 février 2024) : 89–99. http://dx.doi.org/10.11113/mjfas.v20n1.2893.

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Plastic waste has become a serious environmental threat because of large scale demand and poor disposal methods. Microplastics, defined defined as plastic waste with a diameter spanning from 5 mm to 1 μm, may easily enter the ocean and cumulatively ingested by marine life, which will eventually be consumed by humans. The goal of this study is to determine the types of microplastic that can be found in the saltwater clam Paratapes undulatus collected in Kuala Selangor, a fishery hub in Peninsular Malaysia. A total of 30 P. undulatus samples were collected and the soft tissue inside was dissected and digested using NaOH. The digestates were then vacuum-filtered to obtain the microplastics. Microplastics were identified based on their physical characteristics under microscopic examination (colour, shape and size). Fourier Transform Infrared Spectroscopy (FTIR) was used to determine the polymers based on the functional group of the plastics’ molecular structure. A total of 2,072 microplastic particles were isolated from all clam samples. In terms of colour and shape, the majority of microplastics were black (64.48 %) and in the form of fibres (97.2 %). Most of the microplastic particles had sizes ranging from 0.5 to 1 µm and 1 to 2 µm. Polystyrene (PS) and polymethyl methacrylate (PMMA) were two common polymers. This study indicates that clams harvested off the coast Kuala Selangor may be contaminated with microplastics from their habitat. More research is needed to assess the toxicity and potential threat of microplastics to human health when consuming seafood.

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El-Hossary, Dalia, Asmaa Mahdy, Eman Y. T. Elariny, Ahmed Askora, Abdallah M. A. Merwad, Taisir Saber, Hesham Dahshan, Nora Y. Hakami et Rehab A. Ibrahim. « Antibiotic Resistance, Virulence Gene Detection, and Biofilm Formation in Aeromonas spp. Isolated from Fish and Humans in Egypt ». Biology 12, n^o 3 (10 mars 2023) : 421. http://dx.doi.org/10.3390/biology12030421.

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The genus Aeromonas is widely distributed in aquatic environments and is recognized as a potential human pathogen. Some Aeromonas species are able to cause a wide spectrum of diseases, mainly gastroenteritis, skin and soft-tissue infections, bacteremia, and sepsis. The aim of the current study was to determine the prevalence of Aeromonas spp. in raw fish markets and humans in Zagazig, Egypt; identify the factors that contribute to virulence; determine the isolates’ profile of antibiotic resistance; and to elucidate the ability of Aeromonas spp. to form biofilms. The examined samples included fish tissues and organs from tilapia (Oreochromis niloticus, n = 160) and mugil (Mugil cephalus, n = 105), and human skin swabs (n = 51) and fecal samples (n = 27). Based on biochemical and PCR assays, 11 isolates (3.2%) were confirmed as Aeromonas spp. and four isolates (1.2%) were confirmed as A. hydrophila. The virulence genes including haemolysin (hyl A) and aerolysin (aer) were detected using PCR in A. hydrophila in percentages of 25% and 50%, respectively. The antimicrobial resistance of Aeromonas spp. was assessed against 14 antibiotics comprising six classes. The resistance to cefixime (81.8%) and tobramycin (45.4%) was observed. The multiple antibiotic resistance (MAR) index ranged between 0.142–0.642 with 64.2% of the isolates having MAR values equal to 0.642. Biofilm formation capacity was assessed using a microtiter plate assay, and two isolates (18.1%) were classified as biofilm producers. This study establishes a baseline for monitoring and controlling the multidrug-resistant Aeromonas spp. and especially A. hydrophila in marine foods consumed in our country to protect humans and animals.

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Nneoyi-Egbe, Ada Francesca. « Assessment of Heavy Metal Contamination in Shrimp and Water from the Great Kwa River : Implications for Human Health and Aquatic Ecosystems ». International Journal of Biochemistry Research & ; Review 33, n^o 3 (9 mars 2024) : 27–35. http://dx.doi.org/10.9734/ijbcrr/2024/v33i3861.

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The aftermath of heavy metal pollution can be hazardous to humans, considering the level of consumption of shellfish in riverine areas - which is relatively high. There is a growing concern about the quality of aquatic food (e.g. periwinkle and shrimp) in several parts of the world. The determination of toxic elements in food has prompted studies on toxicological effects of heavy metals in foods. Due to man’s industrialization activities such as oil exploration, the levels of toxicants in marine environments have increased over the years. This study aimed at evaluating heavy metal contents (lead, cadmium, nickel, manganese, chromium and copper) in shrimp and water obtained from Great Kwa River, Calabar, Cross River State, Nigeria. Fresh shrimp and water samples were collected from the river in Calabar metropolis, Cross River State. In the sample preparation, the soft tissue (edible part) of the shrimps were extracted, dried in the oven (at 80°C) for 72hours then, after which the weights of the shrimps and water from each sampling point were measured. Digestion of the samples were carried out before an Atomic Absorption Spectrophotometer was used to determine the concentrations of the heavy metals. Graph pad Prism Version 7 was used for statistical analysis and Microsoft Excel Application. The results indicate contamination of both the shrimps and water from the Great Kwa River by some heavy metals, which also pose a health risk to aquatic ecosystem and humans. Among the heavy metals studied, chromium had the highest concentrations in both shrimps (30.07 ± 0.67ppm) and water (27.68 ± 0.34ppm). The heavy metals were found in higher concentrations in the shrimp than in water, except for manganese which had a significantly (p<0.05) higher concentration in water (15.05 ± 0.67ppm as against 14.02 ± 0.93ppm in shrimp). Certain minerals have biological uses, but concentrations above recommended levels become detrimental to consumers. The levels of some of these heavy metals in this study, call for more investigation and regulation of their anthropogenic sources in order to reduce risk of public health issues.

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Reinecke, Koot, Werner Schoeman et Sophié Reinecke. « Cellular biomarker responses of limpets (Mollusca) as measure of sensitivity to cadmiumcontamination ». Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 27, n^o 2 (16 septembre 2008) : 123–42. http://dx.doi.org/10.4102/satnt.v27i2.86.

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Due to the availability and chemical nature of some heavy metals, sub-lethal toxicant levels may persist in the ocean waters and may cause physiological problems and toxicity in invertebrates and other marine organisms. Although studies of metal concentrations in False Bay showed relatively low mean concentrations of Cd, invertebrates such as molluscs, crustaceans and many other groups are able to accumulate high levels of heavy metals in their tissues and still survive in the heaviest polluted areas. They can accumulate numerous pollutants from natural waters in quantities that are many orders of magnitude higher than background levels. Bioaccumulation ofcadmium in intertidal species could cause stress which may be measurable at the cellular level. A variety of limpet species that may serve as suitable ecotoxicological monitoring species occur in abundance on rocky shores along the South African coastline. The aim of this study was to obtain sensitivity data which could contribute to the selection of a suitable monitoring species and the eventual establishment of a species sensitivity distribution model (SSD) with a biomarker responseas endpoint. The limpets Cymbula oculus, Scutellastra longicosta, Cymbula granatina and Scutellastragranularis as well as water samples were collected at two localities in False Bay, South Africa. Analysis of water and biological samples were done by atomic absorption spectrometry. Exposures were done to three different sublethal concentrations of cadmium in the laboratory in static flow tanks over three days. There was a moderate increase in cadmium body concentrations over time. Results obtained at three exposure concentrations showed no significant differences in metal concentrations between the different C. oculus samples. Significant differences were obtained between the control and the exposure groups for each exposure time except between the control and the 1mg/L CdCl2 exposure group after 24 and 72 hours of exposure. Cd body concentrations(soft tissue) varied between 4.56 and 21.41µg/g (wet mass).Mean Cd concentrations in soft tissue of S. longicosta was considerably lower (varying between 1.18 and 19.58 µg/g Cd ) than in the tissues of C. oculus. The control group differed significantly from the 0.8 and 1 mg/L CdCl2 exposures after 48 and 72 hours. Mean Cd body concentrations in S. granular is were the highest of all exposed species, reaching a level of 148 µg/g Cd at the highest exposure concentration and differed significantly from the means of the other samples of the 0.8 mg/L CdCl2 exposure group after 72 hours and from the 1 mg/L CdCl2 group after 24 hours. Significant differences were also obtained between theCd body concentrations of C. granatina for the three exposure concentrations and three exposure times. Lysosomal membrane integrity was determined for both exposed and control animals, using the neutral red retention assay. Three of the four species showed a significant decrease in retention times with an increase in Cd concentration. Inter-species differences in sensitivity to environmentally relevant cadmium concentrations were reflected in the biomarker responses. Based on reduction of NRR times, the order of relative sensitivity to cadmium was S. granularis >C. oculus> S. longicosta.> C.granatina.

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Xu, Ningning, Wenlei Wang, Yan Xu, Dehua Ji, Changsheng Chen, Chaotian Xie et Kai Xu. « Effects of Nutrient Availability on the Release of Dissolved and Particulate Organic Carbon by Pyropia haitanensis and Its Implications ». Frontiers in Marine Science 8 (5 juillet 2021). http://dx.doi.org/10.3389/fmars.2021.696938.

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As an important component of the coastal-offshore ecosystem, Pyropia haitanensis aquaculture is continually being challenged due to rapid environmental changes because of global climate change and anthropogenic pressures. To explore the effect of nutrient availability on carbon metabolism by P. haitanensis, two strains of thalli were incubated for 15 days under four different concentrations of nitrogen and phosphorus. Significant increases in carbon, nitrogen, and phosphorus contents were observed in the algal tissue after the nitrates and phosphates enrichment, leading to elemental stoichiometry gradually approaching the Redfield ratio. Our results also showed a positive correlation between carbon or phosphorous accumulation and growth rate. Furthermore, under the natural seawater conditions, the release rates of dissolved organic carbon (DOC) and particulate organic carbon (POC) were highest, and more DOC was released than POC. The release rates tended to decrease with nutrient enrichment. The average proportions of DOC compared to total carbon were 6.3%–25.7%, while the average proportions of POC compared to total carbon were 2.1%–5.4%. Our results support the proposed importance of P. haitanensis in contributing the DOC and POC that play a significant role in the biological carbon pump and in sustaining marine aquaculture ecosystems in eutrophic environments.

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Rasmussen, Tine L., Tove Nielsen, Siri Ofstad, Emmelie Åström, Naima El bani Altuna, Troels Laier, Arunima Sen, Cheshtaa Chitkara, Anastasiia Frolova et Anna Mamadzhanian. « CAGE-18-3 Cruise to the Barents Sea, Storfjorden Trough, East Greenland Ridge (Leg 1, 2), Arctic Ocean Vestnesa Ridge, and PKF, (Leg 3) ». CAGE – Centre for Arctic Gas Hydrate, Environment and Climate Report Series 6 (15 décembre 2022). http://dx.doi.org/10.7557/cage.6849.

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From the evening of June 29th to the evening of July 10th 2018, CAGE at the Department of Geology Uit, the Arctic University of Norway, arranged a scientific cruise aimed at investigating methane seep sites by surface sediment sampling, sediment core sampling, plankton sampling and water sampling. The areas for investigation were the Barents Sea (Crater area), Storfjorden Trough (Pingo area),East Greenland Ridge (non-seep, for IODP-proposal) (Leg 1 and 2) and the western Svalbard margin, Vestnesa Ridge, Arctic Ocean and Prins Karls Forland (Leg 3) on R/V “Helmer Hanssen”. The scientific sampling was done within the framework of several ongoing projects at the Department of Geology, University of Tromsø: “CAGE -Centre for Arctic Gas Hydrate, Environment and Climate”-WP6: “Methane Release, Ocean Acidification and CO2” hereunder ocean acidification impact on marine calcifiers (planktic foraminifera and pteropods, methane seeping impact on ocean acidification and productivity, the state of the inorganic and organic biological pump from foraminifera, bottom water temperature change and impact on release of methane, living benthic microfauna studies from seep sites for geochemical investigations for calibrations for paleostudies. A total of 15 gravity cores (c. 60 m),and 31 CTD (conductivity-temperature-depth) casts were performed, 11 plankton net (no. 12 failed because the net was torn completely), 22 boxcore samples x 6 surface samples for each. A total of 137 lines of acoustics and seismics together were performed. Chirp profiles and multi-beam lines were acquired during transits and in surveys mapping of new seep sites northeast of “Crater” area, seep sites in Storfjorden Trough, East Greenland Ridge, seeps in Hinlopen trough and Norske Banken, the east slope of Yermak Plateau, active and inactive pockmarks at Vestnesa Ridge and a small patch off PKF for WP4. All acoustic and seismic investigations were performed with soft-start of all instruments (Echo-sounders, deep-penetrating echosounder (‘Chirp’), Multi-beam echosounder and mini-air gun). The cruise may be known as: CAGE18_3_leg1 CAGE18_3_leg2 CAGE18_3_leg3

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Parekh, P., M. J. Follows, S. Dutkiewicz et T. Ito. « Physical and biological regulation of the soft tissue carbon pump ». Paleoceanography 21, n^o 3 (14 juillet 2006). http://dx.doi.org/10.1029/2005pa001258.

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Xiao, Peng, Ziwei Wang, Kangpeng Zhou, Xinwei Fan, Yuhan Zhang, Guangkai Sun et Lianqing Zhu. « Hypostomus plecostomus-inspired soft sucker to adsorb slippery tissues : A stabilizing post-valvular cavity and stiffness gradient materials provide excellent adsorption performance ». Bioinspiration & ; Biomimetics, 14 août 2024. http://dx.doi.org/10.1088/1748-3190/ad6f88.

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Abstract The hard suckers commonly used in surgical operations often cause adsorption extrusion damage to the biological tissue. To tackle this problem, from the perspective of bionics, through in-depth observation and research on the special sucker adsorption process and adsorption mechanism of hypostomus plecostomus (HP), this paper proposes a bionic soft hypostomus plecostomus sucker (BSHPS) with a variable stiffness gradient structure with a good adsorption performance on soft moist irregular biological tissues. The BSHPS comprises a lip disc, a pre-valvular cavity, and a post-valvular cavity. Through the volume changes of the pre- and post-valvular cavities, a pressure difference is generated between the inside and outside of the sucker, enabling the lip disc to remain sealed. The experiments were carried out by an automatic tensile force measurement system equipped with a vacuum pump, and the results showed that in slippery environment, the adsorption performance of the BSHPS is improved by a maximum of 61.9% compared to that in dry environment. On a biological tissue surface, the adsorption force is as high as 13.7765 N. The most important advantage of the proposed BSHPS is that it can be firmly adsorbed the surface of soft moist irregular biological tissues, effectively slowing down or avoiding adsorption extrusion damage to the biological tissue. Therefore, the BSHPS is expected to have good application prospects in modern surgical medicine.

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Ozkan, Cengiz S., Erhan Ata, Mihrimah Ozkan et Sadik C. Esener. « Optical Manipulation of Inorganic and Organic Objects in Soft Microfluidic Devices ». MRS Proceedings 657 (2000). http://dx.doi.org/10.1557/proc-657-ee5.2.

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ABSTRACTWe describe a technique for trapping and manipulation of inorganic and organic objects in microfluidic channels, based on photonic momentum transfer using an optical tweezers arrangement. Microfluidic devices have been fabricated by polydimethylsiloxane (PDMS) elastomer molding of patterns lithographically defined on a thick negative photoresist. Polystyrene microspheres dispersed in water were transferred into the fluidic channels using a syringe pump. Microspheres and live biological cells are trapped and redirected by optical manipulation within the fluidic channels. Optical trapping and patterning will have applications in creation of active cellular arrays for cell biology research, tissue engineering, cell sorting and drug discovery.

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Davis, Elizabeth J., et Vicki L. Keedy. « Recent Advances in the Treatment of Metastatic Soft Tissue Sarcoma ». EMJ Oncology, 6 décembre 2018, 91–101. http://dx.doi.org/10.33590/emjoncol/10310137.

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Soft tissue sarcomas (STS) are a rare group of heterogeneous malignancies with >50 histologic subtypes that have varying biological behaviour and responsiveness to systemic therapy. The mainstay of therapy for metastatic STS in recent decades has been doxorubicin. To improve survival outcomes, numerous agents have been combined with doxorubicin; however, no combination has led to a survival benefit over doxorubicin alone until the recent use of olaratumab, a monoclonal antibody targeting platelet-derived growth factor-α. In addition to olaratumab, several other new drugs have surfaced as promising treatment options. Marine-derived chemotherapy agents, eribulin and trabectedin, are active in selecting STS subtypes. Both agents are effective in liposarcoma, while trabectedin also has activity in leiomyosarcoma. Further understanding of the importance of STS subtype-directed therapy, as well as the genomic complexities of STS, has led to development of several small molecule inhibitors for specific STS histologies. Agents targeting vascular endothelial growth factors, platelet-derived growth factors, and cyclin-dependent kinases 4 and 6 have all shown some efficacy in various STS subtypes. Similar to the selective activity of cytotoxic agents and small molecule inhibitors, immunotherapy, which has revolutionised management of numerous cancers, has also demonstrated activity in select STS subtypes. Collectively, these novel therapies highlight the importance of histology-directed approaches and of a greater understanding of the genomic landscape of STS. This review describes advances in chemotherapy, molecularly targeted, and immunotherapy agents for STS.

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Peerlinck, Sam, Frauke Willemyns, Dominiek Reynaerts et Benjamin Gorissen. « Biomimetic Small Intestinal Peristalsis Simulator Using Circumferential Pneumatic Artificial Muscles (cirPAM) ». Advanced Materials Technologies, 21 décembre 2023. http://dx.doi.org/10.1002/admt.202301662.

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AbstractSurgical simulators offer clinicians an environment to train techniques before transitioning to on‐patient procedures. The realism with which a certain procedure can be mimicked is limited by the used simulator model. While for certain procedures surgical simulators are well established, other procedures lack a sufficiently realistic hardware model. The field of soft robotics is especially suited to act as a platform for developing soft tissue surgical simulators, matching both stiffness and extent of deformation of biological soft tissue. Here, an integrated, pneumatically actuated intestinal peristalsis simulator is developed that mimics a section of the small intestines. This simulator is able the mimic both the peristalsis functionality and the intestinal morphology. The simulator incorporates novel circumferential pneumatic artificial muscles (cirPAM) that radially contract and expand when exposed to respectively negative and positive pressures while keeping their cross‐sectional thickness constant. By sequencing the inflation of these cirPAM actuators, a global peristaltic motion is created with a peristaltic wave propagating at 20 mm s −1, which is in accordance with human physiology. Finally, the simulator is shown to pump viscous liquids, confirming that besides the morphological semblance, it also functionally resembles human small intestine, and can offer a platform for medical device testing and surgical training.

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Nowicki, Michael, Tim DeVries et David A. Siegel. « The Influence of Air‐Sea CO₂ Disequilibrium on Carbon Sequestration by the Ocean's Biological Pump ». Global Biogeochemical Cycles 38, n^o 2 (29 janvier 2024). http://dx.doi.org/10.1029/2023gb007880.

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AbstractThe ocean's biological carbon pump (BCP) affects the Earth's climate by sequestering CO2 away from the atmosphere for decades to millennia. One primary control on the amount of carbon sequestered by the biological pump is air‐sea CO2 disequilibrium, which is controlled by the rate of air‐sea CO2 exchange and the residence time of CO2 in surface waters. Here, we use a data‐assimilated model of the soft tissue BCP to quantify carbon sequestration inventories and time scales from remineralization in the water column to equilibration with the atmosphere. We find that air‐sea CO2 disequilibrium enhances the global biogenic carbon inventory by ∼35% and its sequestration time by ∼70 years compared to identical calculations made assuming instantaneous air‐sea CO2 exchange. Locally, the greatest enhancement occurs in the subpolar Southern Ocean, where air‐sea disequilibrium increases sequestration times by up to 600 years and the biogenic dissolved inorganic carbon inventory by >100% in the upper ocean. Contrastingly, in deep‐water formation regions of the North Atlantic and Antarctic margins, where biological production creates undersaturated surface waters which are subducted before fully equilibrating with the atmosphere, air‐sea CO2 disequilibrium decreases the depth‐integrated sequestration inventory by up to ∼150%. The global enhancement of carbon sequestration by air‐sea disequilibrium is particularly important for carbon respired in deep waters that upwell in the Southern Ocean. These results highlight the importance of accounting for air‐sea CO2 disequilibrium when evaluating carbon sequestration by the biological pump and for assessing the efficacy of ocean‐based CO2 removal methods.

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Simonet Roda, Maria, Erika Griesshaber, Lucia Angiolini, Claire Rollion-Bard, Elizabeth M. Harper, Maria Aleksandra Bitner, Sara Milner Garcia et al. « The architecture of Recent brachiopod shells : diversity of biocrystal and biopolymer assemblages in rhynchonellide, terebratulide, thecideide and craniide shells ». Marine Biology 169, n^o 1 (20 novembre 2021). http://dx.doi.org/10.1007/s00227-021-03962-4.

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AbstractBiological hard tissues are a rich source of design concepts for the generation of advanced materials. They represent the most important library of information on the evolution of life and its environmental conditions. Organisms produce soft and hard tissues in a bottom-up process, a construction principle that is intrinsic to biologically secreted materials. This process emerged early on in the geological record, with the onset of biological mineralization. The phylum Brachiopoda is a marine animal group that has an excellent and continuous fossil record from the early Cambrian to the Recent. Throughout this time interval, the Brachiopoda secreted phosphate and carbonate shells and populated many and highly diverse marine habitats. This required great flexibility in the adaptation of soft and hard tissues to the different marine environments and living conditions. This review presents, juxtaposes and discusses the main modes of mineral and biopolymer organization in Recent, carbonate shell-producing, brachiopods. We describe shell tissue characteristics for taxa of the orders Rhynchonellida, Terebratulida, Thecideida and Craniida. We highlight modes of calcite and organic matrix assembly at the macro-, micro-, and nano-scales based on results obtained by Electron Backscatter Diffraction, Atomic Force Microscopy, Field Emission Scanning Electron Microscopy and Scanning Transmission Electron Microscopy. We show variation in composite hard tissue organization for taxa with different lifestyles, visualize nanometer-scale calcite assemblies for rhynchonellide and terebratulide fibers, highlight thecideide shell microstructure, texture and chemistry characteristics, and discuss the feasibility to use thecideide shells as archives of proxies for paleoenvironment and paleoclimate reconstructions.

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Zawadzka-Knefel, Anna, Agnieszka Rusak, Monika Mrozowska, Tomasz Machałowski, Andrzej Żak, Katarzyna Haczkiewicz-Leśniak, Michał Kulus, Piotr Kuropka, Marzenna Podhorska-Okołów et Katarzyna Skośkiewicz-Malinowska. « Chitin scaffolds derived from the marine demosponge Aplysina fistularis stimulate the differentiation of dental pulp stem cells ». Frontiers in Bioengineering and Biotechnology 11 (14 novembre 2023). http://dx.doi.org/10.3389/fbioe.2023.1254506.

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The use of stem cells for tissue regeneration is a prominent trend in regenerative medicine and tissue engineering. In particular, dental pulp stem cells (DPSCs) have garnered considerable attention. When exposed to specific conditions, DPSCs have the ability to differentiate into osteoblasts and odontoblasts. Scaffolds are critical for cell differentiation because they replicate the 3D microenvironment of the niche and enhance cell adhesion, migration, and differentiation. The purpose of this study is to present the biological responses of human DPSCs to a purified 3D chitin scaffold derived from the marine demosponge Aplysina fistularis and modified with hydroxyapatite (HAp). Responses examined included proliferation, adhesion, and differentiation. The control culture consisted of the human osteoblast cell line, hFOB 1.19. Electron microscopy was used to examine the ultrastructure of the cells (transmission electron microscopy) and the surface of the scaffold (scanning electron microscopy). Cell adhesion to the scaffolds was determined by neutral red and crystal violet staining methods. An alkaline phosphatase (ALP) assay was used for assessing osteoblast/odontoblast differentiation. We evaluated the expression of osteogenic marker genes by performing ddPCR for ALP, RUNX2, and SPP1 mRNA expression levels. The results show that the chitin biomaterial provides a favorable environment for DPSC and hFOB 1.19 cell adhesion and supports both cell proliferation and differentiation. The chitin scaffold, especially with HAp modification, isolated from A. fistularis can make a significant contribution to tissue engineering and regenerative medicine.

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Davtyan, Rubina, et Narine A. Sarvazyan. « Output of a valveless Liebau pump with biologically relevant vessel properties and compression frequencies ». Scientific Reports 11, n^o 1 (1 juin 2021). http://dx.doi.org/10.1038/s41598-021-90820-4.

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AbstractLiebau pump is a tubular, non-peristaltic, pulsatile pump capable of creating unidirectional flow in the absence of valves. It requires asymmetrical positioning of the pincher relative to the attachment sites of its elastic segment to the rest of the circuit. Biological feasibility of such valveless pumps remains a hotly debated topic. To test the feasibility of the Liebau-based pumping in vessels with biologically relevant properties we quantified the output of Liebau pumps with their compliant segments made of a silicone rubber that mimicked the Young modulus of soft tissues. The lengths, the inner diameters, thicknesses of the tested compliant segments ranged from 1 to 5 cm, 3 to 8 mm and 0.3 to 1 mm, respectively. The compliant segment of the setup was compressed at 0.5–2.5 Hz frequencies using a 3.5-mm-wide rectangular piston. A nearest-neighbor tracking algorithm was used to track movements of 0.5-mm carbon particles within the system. The viscosity of the aqueous solution was varied by increased percentage of glycerin. Measurements yielded quantitative relationships between viscosity, frequency of compression and the net flowrate. The use of the Liebau principle of valveless pumping in conjunction with physiologically sized vessel and contraction frequencies yields flowrates comparable to peristaltic pumps of the same dimensions. We conclude that the data confirm physiological feasibility of Liebau-based pumping and warrant further testing of its mechanism using excised biological conduits or tissue engineered components. Such biomimetic pumps can serve as energy-efficient flow generators in microdevices or to study the function of embryonic heart during its normal development or in diseased states.

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Kim, Sora L., Meghan A. Balk, Elizabeth C. Sibert et Lisa Whitenack. « Diving Deeper : Leveraging the Chondrichthyan Fossil Record to Investigate Environmental, Ecological, and Biological Change ». Annual Review of Earth and Planetary Sciences, 23 décembre 2024. https://doi.org/10.1146/annurev-earth-040523-010455.

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The extensive chondrichthyan fossil record spans 400+ million years and has a global distribution. Paleontological studies provide a foundation of description and taxonomy to support deeper forays into ecology and evolution considering geographic, morphologic, and functional changes through time with nonanalog species and climate states. Although chondrichthyan teeth are most studied, analyses of dermal denticle metrics and soft tissue imprints are increasing. Recent methodological advances in morphology and geochemistry are elucidating fine-scale details, whereas large datasets and ecological modeling are broadening taxonomic, temporal, and geographic perspectives. The combination of ecological metrics and modeling with environmental reconstruction and climate simulations is opening new horizons to explore form and function, demographic dynamics, and food web structure in ancient marine ecosystems. Ultimately, the traits and taxa that endured or perished during the many catastrophic upheaval events in Earth's history contribute to conservation paleobiology, which is a much-needed perspective for extant chondrichthyans. ▪ The longevity and abundance of the chondrichthyan fossil record elucidates facets of ecological, evolutionary, and environmental histories. ▪ Though lacking postcranial, mineralized skeletons, dental enameloid and dermal denticles exquisitely preserve morphology and geochemistry. ▪ Technical advances in imaging, geochemistry, and modeling clarify the linkages between form and function with respect to physiology, diet, and environment. ▪ Conservation efforts can benefit from the temporal and spatial perspective of chondrichthyan persistence through past global change events.

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Martin, Jeremy E., Guillaume Suan, Baptiste Suchéras-Marx, Louis Rulleau, Jan Schlögl, Kevin Janneau, Matt Williams et al. « Stenopterygiids from the lower Toarcian of Beaujolais and a chemostratigraphic context for ichthyosaur preservation during the Toarcian Oceanic Anoxic Event ». Geological Society, London, Special Publications, 1 mars 2021, SP514–2020–232. http://dx.doi.org/10.1144/sp514-2020-232.

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AbstractWe report new ichthyosaur material excavated in lower Toarcian levels of the LafargeHolcim Val d'Azergues quarry in Beaujolais, SE France. A partially articulated skull and a smaller, unprepared but likely subcomplete skeleton preserved in a carbonate concretion are identified as stenopterygiids, a family of wide European distribution during the Early Jurassic. These specimens are among the finest preserved Toarcian exemplars known from Europe and, in one of them, soft tissue preservation is suspected. Their state of preservation is attributed to the combination of prolonged anoxic conditions near the water–sediment interface and early carbonate cementation resulting from the activity of sulfate-reducing bacteria. We also present carbon and strontium isotope values obtained from the study site that allow detailed temporal comparisons with other Toarcian vertebrate-yielding sites and environmental perturbations associated with the Toarcian Oceanic Anoxic Event (T-OAE). These comparisons suggest that the relatively high abundance and good preservation state of Toarcian vertebrates was favoured by a prolonged period of low bottom water oxygenation and accumulation rates. The environmental conditions that prevailed during the T-OAE were probably responsible for the extensive nature of Lagerstätte-type deposits with exceptional preservation of marine organisms. Testing whether the T-OAE had a biological impact on marine vertebrates requires a precise chemostratigraphic context of the fossil record spanning the Pliensbachian–Toarcian interval.

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McMahon, S., J. J. Matthews, A. Brasier et J. Still. « Late Ediacaran life on land : desiccated microbial mats and large biofilm streamers ». Proceedings of the Royal Society B : Biological Sciences 288, n^o 1962 (3 novembre 2021). http://dx.doi.org/10.1098/rspb.2021.1875.

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The Ediacaran period witnessed transformational change across the Earth–life system, but life on land during this interval is poorly understood. Non-marine/transitional Ediacaran sediments preserve a variety of probable microbially induced sedimentary structures and fossil matgrounds, and the ecology, biogeochemistry and sedimentological impacts of the organisms responsible are now ripe for investigation. Here, we report well-preserved fossils from emergent siliciclastic depositional environments in the Ediacaran of Newfoundland, Canada. These include exquisite, mouldically preserved microbial mats with desiccation cracks and flip-overs, abundant Arumberia -type fossils and, most notably, assemblages of centimetre-to-metre-scale, subparallel, branching, overlapping, gently curving ribbon-like features preserved by aluminosilicate and phosphate minerals, with associated filamentous microfossils. We present morphological, petrographic and taphonomic evidence that the ribbons are best interpreted as fossilized current-induced biofilm streamers, the earliest record of an important mode of life (macroscopic streamer formation) for terrestrial microbial ecosystems today. Their presence shows that late Ediacaran terrestrial environments could produce substantial biomass, and supports recent interpretations of Arumberia as a current-influenced microbial mat fossil, which we here suggest existed on a ‘streamer–arumberiamorph spectrum’. Finally, the absence of classic Ediacaran macrobiota from these rocks despite evidently favourable conditions for soft tissue preservation upholds the consensus that those organisms were exclusively marine.

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López Gutiérrez, Lersy, Martha Torres, Esteban Zarza, Alejandro Henao-Castro et Laura Contreras Vega. « Composition of the culturable bacterial community associated with the water column and soft tissues from oysters of the mangrove ecosystem at Honda Swamp, Colombian Caribbean ». Universitas Scientiarum 28, n^o 1 (17 mars 2023). http://dx.doi.org/10.11144/javeriana.sc281.cotc.

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The study of bacterial communities is highly relevant in relation to the knowledge of global biological biodiversity and the biogeochemical cycles of the planet. Microbiological activity is the basis of ecosystems functioning, among these are the mangroves, which offer a wide variety of goods and services to humanity. Nevertheless, they have been severely impacted by anthropogenic activities such as felling, heavy metal pollution, water enrichment, overexploitation of resources, among others. This research aimed to characterize the culturable bacterial community from the water column and the oyster Crassostrea rhizophorae muscle tissue in a mangrove ecosystem from the Cartagena Bay, Colombian Caribbean as a baseline for future studies on bioremediation treatments. To accomplish this, four samplings were conducted over the course of a year, including contrasting climatic seasons (e.g., windy and rainy), collecting oyster individuals from mangroves and samples from superficial water. The bacterial community comprised 25 species, from which 9 were exclusive for the oyster tissue, 7 for the water column, and 9 generalists isolated from both types of samples. Enterobacter cloacae was the most frequent species during the year, followed by Escherichia coli and Erwinia sp.There were significant differences in the species composition between the sampling months (ANOSIM, R = 0:492; p=D 0:001), because of the presence of a higher number of exclusive species in December than in the other months. Furthermore, the physicochemical variables that presented a major influence on the bacterial community composition were the wind velocity and the dissolved oxygen. The review of this research findings will allow to detect if any of the identified species could be exploited for bioremediation treatments, and it will contribute to the preservation of marine-coastal water bodies biodiversity.

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