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Marine phytoplankton acts as a considerable sink of atmospheric CO 2 as it sequesters large quantities of this greenhouse gas for biomass production. To assess microalgae's counterbalancing of global warming, the quantities of CO 2 they fix need to be determined. For this task, it is mandatory to understand which environmental and physiological parameters govern this transformation from atmospheric CO 2 to microalgal biomass. However, experimental analyses are challenging as it has been found that the chemical environment has a major impact on the physiological properties of the microalgae cells (diameter typ. 5–20 μm). Moreover, the cells can only chemically interact with their immediate vicinity and thus compound sequestration needs to be studied on a microscopic spatial scale. Due to these reasons, computer simulations are a more promising approach than the experimental studies. Modeling software has been developed that describes the dissolution of atmospheric CO 2 into oceans followed by the formation of HCO 3 − which is then transported to individual microalgae cells. The second portion of this model describes the competition of different cell species for this HCO 3 − , a nutrient, as well as its uptake and utilization for cell production. Two microalgae species, i.e. Dunaliella salina and Nannochloropsis oculata , were cultured individually and in a competition situation under different atmospheric CO 2 conditions. It is shown that this novel model's predictions of biomass production are in very good agreement with the experimental flow cytometry results. After model validation, it has been applied to long-term prediction of phytoplankton generation. These investigations were motivated by the question whether or not cell production slows down as cultures grow. This is of relevance as a reduced cell production rate means that the increase in a culture's CO 2 -sinking capacity slows down as well. One implication resulting from this is that an increase in anthropogenic CO 2 may not be counterbalanced by an increase in phytoplankton production. Modeling studies have found that for several different atmospheric CO 2 levels provided to single-species cultures as well as to species in competing scenarios the cell production rate does slow down over time.
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Peptide nanosponges designed for rapid uptake by leukocytes and neural stem cells
The structure of novel binary nanosponges consisting of (cholesterol-(K/D) n DEVDGC) 3 -trimaleimide units possessing a trigonal maleimide linker, to which either lysine (K) 20 or aspartic acid (D) 20 are tethered, has been elucidated by means of TEM. A high degree of agreement between these findings and structure predictions through explicit solvent and then coarse-grained molecular dynamics (MD) simulations has been found. Based on the nanosponges' structure and dynamics, caspase-6 mediated release of the model drug 5(6)-carboxyfluorescein has been demonstrated. Furthermore, the binary (DK20) nanosponges have been found to be virtually non-toxic in cultures of neural progenitor cells. It is of a special importance for the future development of cell-based therapies that DK20 nanosponges were taken up efficiently by leucocytes (WBC) in peripheral blood within 3 h of exposure. The percentage of live cells among the WBC was not significantly decreased by the DK20 nanosponges. In contrast to stem cell or leucocyte cell cultures, which have to be matched to the patient, autologous cells are optimal for cell-mediated therapy. Therefore, the nanosponges hold great promise for effective cell-based tumor targeting.
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- Award ID(s):
- 1656968
- PAR ID:
- 10079017
- Date Published:
- Journal Name:
- RSC Advances
- Volume:
- 8
- Issue:
- 29
- ISSN:
- 2046-2069
- Page Range / eLocation ID:
- 16052 to 16060
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C8RA00717A
