Protein-protein interactions with G3BPs drive stress granule condensation and gene expression changes under cellular stress.

Stress granules (SGs) are macromolecular assemblies that form under cellular stress. Formation of these condensates is driven by the condensation of RNA and RNA-binding proteins such as G3BPs. G3BPs condense into SGs following stress-induced translational arrest. Three G3BP paralogs (G3BP1, G3BP2A, and G3BP2B) have been identified in vertebrates. However, the contribution of different G3BP paralogs to stress granule formation and stress-induced gene expression changes is incompletely understood. Here, we identified key residues for G3BP condensation such as V11. This conserved amino acid is required for formation of the G3BP-Caprin-1 complex, hence promoting SG assembly. Total RNA sequencing and ribosome profiling revealed that disruption of G3BP condensation corresponds to changes in mRNA levels and ribosome engagement during the integrated stress response (ISR). Moreover, we found that G3BP2B preferentially condenses and promotes changes in mRNA expression under endoplasmic reticulum (ER) stress. Together, this work suggests that stress granule assembly promotes changes in gene expression under cellular stress, which is differentially regulated by G3BP paralogs.

Iron modified biochar enables recovery and recycling of phosphorus from wastewater through column filters and flow reactors.

Controlling water pollution by phosphorus (P) and satisfying high demand of P fertilizer in agriculture are two global challenges for sustainable development. This paper presents a novel application of iron modified biochar as an adsorbent to recover P from wastewater and reuse it as P fertilizer. Granular iron biochar (GIB) and ball milled powder iron biochar (PIB) were prepared from pinewood pretreated with iron salt. The biochars were characterized to determine their surface properties. Their effectiveness in P removal from wastewater was evaluated with packed column filters for GIB and continuous flow reactors for PIB. The spent biochar was tested to determine if it is safe for agricultural application as alternative P fertilizer. The results showed that GIB and PIB were highly porous, had high specific surface area (385 and 331 m2 g-1, respectively), and contained high levels of iron (mainly γ-Fe2O3). Both GIB and PIB showed excellent performance for P removal from wastewater. The P adsorption capacity of GIB in the column filter was 16 times larger than that of sand. A fast P adsorption kinetic rate (0.144 min-1) was observed for PIB in the flow reactor. The spent biochars showed no negative effects on bean germination or even some positive effects on seedling growth, indicating they can be safely used as P fertilizer. This study provides the technical basis of a sustainable wastewater treatment strategy that can capture the full values of water, P, and biochar.

Life cycle assessment of environmental impact of disposable drinking straws: A trade-off analysis with marine litter in the United States.

Sound environmental management to control marine plastic pollution requires a careful assessment of environmental costs and benefits of replacing single-use plastics with their biodegradable counterparts. This research employs the standard life cycle assessment (LCA) approach to assess and compare the environmental impact of plastic straws made from polypropylene (PP), and its biodegradable alternatives made from polylactic acid (PLA) and paper (PA) in the United States. Eight environmental impact categories, not including marine litter, were analyzed and a composite relative environmental impact index (REI) was derived for quantitative comparison. The results show that US daily consumption of disposable drinking straws (500 million straws daily) may carry significant environmental burdens regardless of straw types, with the feedstock manufacture stage of the life cycle creating most of the contribution. The REI index values were 2.4 for PP straws, 6.4 for PLA straws, and 5.1 for PA straws with landfill and 3.2 for PP straws, 6.8 for PLA straws, and 4.9 for PA straws with incineration. A sensitivity analysis did not show much change in REI with increasing marine litter rate, demonstrating that replacing PP straws with PLA or PA straws for controlling marine plastic pollution would come with environmental costs in other categories. The trade-off can be quantitatively represented by the difference in REI between PP straws and PA or PLA straws. Our analysis also indicates close-loop recycling can greatly reduce the environmental impact of PP straws, serving as a technological development to control plastic pollution. While disposable straws were used as a case study in this work, the findings are extensive to other single-use products.