Modulating Lipid Membrane Morphology by Dynamic DNA Origami Networks.

Membrane morphology and its dynamic adaptation regulate many cellular functions, which are often mediated by membrane proteins. Advances in DNA nanotechnology have enabled the realization of various protein-inspired structures and functions with precise control at the nanometer level, suggesting a viable tool to artificially engineer membrane morphology. In this work, we demonstrate a DNA origami cross (DOC) structure that can be anchored onto giant unilamellar vesicles (GUVs) and subsequently polymerized into micrometer-scale reconfigurable one-dimensional (1D) chains or two-dimensional (2D) lattices. Such DNA origami-based networks can be switched between left-handed (LH) and right-handed (RH) conformations by DNA fuels and exhibit potent efficacy in remodeling the membrane curvatures of GUVs. This work sheds light on designing hierarchically assembled dynamic DNA systems for the programmable modulation of synthetic cells for useful applications.

3D DNA origami pincers that multitask on giant unilamellar vesicles.

Proteins self-assemble to function in living cells. They may execute essential tasks in the form of monomers, complexes, or supramolecular cages via oligomerization, achieving a sophisticated balance between structural topology and functional dynamics. The modularity and programmability make DNA origami unique in mimicking these key features. Here, we demonstrate three-dimensional reconfigurable DNA origami pincers (DOPs) that multitask on giant unilamellar vesicles (GUVs). By programmably adjusting their pinching angle, the DOPs can dynamically control the degree of GUV remodeling. When oligomerized on the GUV to form origami cages, the DOP units interact with one another and undergo reorganization, resulting in the capture, compartmentalization, and detachment of lipid fragments. This oligomerization process is accompanied with membrane disruptions, enabling the passage of cargo across the membrane. We envisage that interfacing synthetic cells with engineered, multifunctional DNA nanostructures may help to confer customized cellular properties, unleashing the potential of both fields.

Aging of polypropylene plastic and impacts on microbial community structure in constructed wetlands.

The COVID-19 pandemic has resulted in a substantial surge in the usage of disposable plastic masks, generating a significant volume of waste and contributing to environmental pollution. Wetland ecosystems function as crucial repositories for terrestrial pollutants and are highly effective in retaining disposable masks composed mainly of PP material. These masks can endure extended periods in wetlands, experiencing natural degradation that may have potential implications on wetland ecosystems. Our findings demonstrate the natural aging process of disposable masks, resulting in the generation of microplastics (MPs) ranging in diameter from 10 to 30 µm over a 180-day timeframe. Examination of 16S rDNA data unveiled temporal fluctuations in microbial diversity in the wetland ecosystem. Initially, microbial diversity displayed a modest incline, which was succeeded by a subsequent decrease. With the progressive accumulation of plastic within the wetland, an ongoing decline in microbial diversity linked to nitrogen transformation was observed. This study provides valuable insights into the retention of disposable masks by wetlands amidst the COVID-19 pandemic, along with their consequential effects on wetland ecosystems, specifically pertaining to nitrogen cycling. It underscores the urgency of augmenting the safeguarding measures for wetland ecosystems.

Surface engineering of colloidal nanoparticles.

Synthesis of engineered colloidal nanoparticles (NPs) with delicate surface characteristics leads to well-defined physicochemical properties and contributes to multifunctional applications. Surface engineering of colloidal NPs can improve their stability in diverse solvents by inhibiting the interparticle attractive forces, thus providing a prerequisite for further particle manipulation, fabrication of the following materials and biological applications. During the last decades, surface engineering methods for colloidal NPs have been well-developed by numerous researchers. However, accurate control of surface properties is still an important topic. The emerging DNA/protein nanotechnology offers additional possibility of surface modification of NPs and programmable particle self-assembly. Here, we first briefly review the recent progress in surface engineering of colloidal NPs, focusing on the improved stability by grafting suitable small molecules, polymers or biological macromolecules. We then present the practical strategies for nucleic acid surface encoding of NPs and subsequent programmable assembly. Various exciting applications of these unique materials are summarized with a specific focus on the cellular uptake, bio-toxicity, imaging and diagnosis of colloidal NPs in vivo. With the growing interest in colloidal NPs in nano-biological research, we expect that this review can play an instructive role in engineering the surface properties for desired applications.

Characteristics analysis of plastisphere biofilm and effect of aging products on nitrogen metabolizing flora in microcosm wetlands experiment.

The marsh, a significant terrestrial ecosystem, has steadily developed the capacity to act as a microplastics collection place (MPs). Here, 180 days of exposure to three different polymer kinds of plastics: polyethylene (PE), polystyrene (PS), and polyvinyl chloride (PVC), were conducted in miniature wetlands (CWs). Water contact angle (WCA), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and High-throughput sequencing were used to study the succession of microbial community structure and function on MPs after 0, 90, and 180 days of exposure. The results showed that different polymers were degrading and aging differing degrees; PVC contained new functional groups with the symbols -CC-, -CO-, and -OH, while PE had the biggest range of contact angles (74.0-45.5°). Bacteria colonization was discovered on plastic surfaces, and as time went on, it became increasingly evident that the surfaces' composition had altered, and their hydrophobicity had diminished. The plastisphere's microbial community structure as well as water nitrification and denitrification were altered by MPs. In general, our study created a vertical flow-built wetland environment, monitored the impacts of plastic aging and breakdown products on nitrogen metabolizing microorganisms in wetland water, and offered a reliable site for the screening of plastic-degrading bacteria.

Effects of land use on soil microplastic distribution adjacent to Danjiangkou reservoir, China.

As a new type of pollutant, microplastics (MPs) are an increasingly prominent threat to terrestrial ecosystems. However, the distribution, sources and influencing factors of MPs need to be further studied, especially in reservoir surrounding soil, a hot zone for MPs accumulation and a source of MPs in the watershed. Here, we detected MPs in 120 soil samples collected around Danjiangkou reservoir, with their amount ranging from 645 to 15,161 items/kg. The topsoil layer at 0-20 cm had lower levels of MPs (mean 3989 items/kg) than subsoils at 20-40 cm (mean 5620 items/kg). The most commonly detected types of MPs were polypropylene (26.4%) and polyamide (20.2%), with sizes ranging from 0.05 to 0.5 mm. With regard to shape, most MPs (67.7%) were fragmented, while fibers make up 25.3% of the MPs. Further analysis revealed that the number of villages had the highest driving force for the abundance of MPs with 51%, followed by pH 25% and land use types 10%. The water and sediment of reservoirs are important sources of agricultural soil microplastics. Paddy lands showed higher microplastics levels than orchards and dry croplands. The polymer risk index indicated that the agricultural soil near Danjiangkou reservoir had the highest MPs risk. This study highlights the importance of assessing MPs contamination in the agroecosystems surrounding reservoirs and provides valuable insight into clarify the ecological risks of MPs in the reservoir area.

Recent advances in mitigating membrane biofouling using carbon-based materials.

Biofouling is the Achilles Heel of membrane processes. The accumulation of organic foulants and growth of microorganisms on the membrane surface reduce the permeability, shorten the membrane life, and increase the energy consumption. Advancements in novel carbon-based materials (CBMs) present significant opportunities in mitigating biofouling of membrane processes. This article provides a comprehensive review of the recent progress in the application of CBMs in antibiofouling membrane. It starts with a detailed summary of the different antibiofouling mechanisms of CBM-containing membrane systems. Next, developments in membrane modification using CBMs, especially carbon nanotubes and graphene family materials, are critically reviewed. Further, the antibiofouling potential of next-generation carbon-based membranes is surveyed. Finally, the current problems and future opportunities of applying CBMs for antibiofouling membranes are discussed.

Soil biofilm formation enhances microbial community diversity and metabolic activity.

Biofilms have been extensively studied in aquatic and clinical environments. However, the complexity of edaphic microenvironment hinders the advances toward understanding the environmental functionalities and ecological roles of soil biofilms. In this work, artificial soil was employed to investigate the soil biofilm formation and corresponding impacts on community structure and microbial activities. Our results showed that extracellular polymeric substances (EPS) production was significantly enhanced and micro-meter sized cell aggregates formed with high glucose amendment. Biofilm development exhibited significant effects on the soil microbial processes. 16S rRNA gene sequencing demonstrated the soils with biofilms and free-living cells shared similar microbial communities. But the Shannon diversity and evenness indices of communities with soil biofilms were significantly enhanced by 18.2% and 17.1%. The soil with biofilms also revealed a rapid response to nutrient provision and robust microbial activity, which consumed 65.4% more oxygen in the topsoil (0-1.5 mm). Kinetic respiration analysis showed that the enhanced metabolic activity was attributed to 23-times more active microbes in soil biofilms. In summary, this study revealed that soil biofilms can sustain a diverse and robust community to drive soil biogeochemical processes.