Construction of target-specific virus-like particles for the delivery of algicidal compounds to harmful algae

Protein Cages: From Fundamentals to Advanced Applications

Proteins that self-assemble into polyhedral shell-like structures are useful molecular containers both in nature and in the laboratory. Here we review efforts to repurpose diverse protein cages, including viral capsids, ferritins, bacterial microcompartments, and designed capsules, as vaccines, drug delivery vehicles, targeted imaging agents, nanoreactors, templates for controlled materials synthesis, building blocks for higher-order architectures, and more. A deep understanding of the principles underlying the construction, function, and evolution of natural systems has been key to tailoring selective cargo encapsulation and interactions with both biological systems and synthetic materials through protein engineering and directed evolution. The ability to adapt and design increasingly sophisticated capsid structures and functions stands to benefit the fields of catalysis, materials science, and medicine.

The biomedical and bioengineering potential of protein nanocompartments

Protein nanocompartments (PNCs) are self-assembling biological nanocages that can be harnessed as platforms for a wide range of nanobiotechnology applications. The most widely studied examples of PNCs include virus-like particles, bacterial microcompartments, encapsulin nanocompartments, enzyme-derived nanocages (such as lumazine synthase and the E2 component of the pyruvate dehydrogenase complex), ferritins and ferritin homologues, small heat shock proteins, and vault ribonucleoproteins. Structural PNC shell proteins are stable, biocompatible, and tolerant of both interior and exterior chemical or genetic functionalization for use as vaccines, therapeutic delivery vehicles, medical imaging aids, bioreactors, biological control agents, emulsion stabilizers, or scaffolds for biomimetic materials synthesis. This review provides an overview of the recent biomedical and bioengineering advances achieved with PNCs with a particular focus on recombinant PNC derivatives.

Effect of aquatic macrophyte growth on landscape water quality improvement

The water of urban landscape park is often confronted with microalgal blooms due to its stagnancy. Bioremediation using the combined emergent and submerged plants to control the microalgae growth was investigated in the present study. Two water bodies (Bei and Xin) of Yuyuantan Park in Beijing were selected for the field experiments, and the other lakes with different vegetation of macrophytes were selected as the comparison. The concentrations of chlorophyll a (chl a), chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP), and water temperature and transparency were monitored before and after bioremediation from 2015 to 2017. Results showed that the effects of microalgal inhibition were more significant 2 years after bioremediation. Specifically, the chl a of Dong Lake without any vegetation of macrophytes was up to 65.1 μg/L in summer of 2017, while the Bei and Xin Lakes was only 6.2 and 11.3 μg/L, respectively. In addition, the water quality and transparency also improved, with water bodies being crystal clear. Submerged plants played major roles in microalgal control and water quality improvement, compared to the lakes with only emergent plants. The intensity of humic acid-like substances in three-dimensional fluorescent spectra was stronger for the lakes with submerged plants.

Biodegraded mackerel wastewater selectively inhibits harmful algal blooms

Functional substances from mackerel wastewater were biodegraded and tested for inhibitory activity against harmful algal blooms (HABs) that are detrimental to aquaculture. The supernatant from a 48 h culture of mackerel wastewater had a half-maximal inhibitory concentration of 0.54-0.68 mg/ml for the three tested HAB organisms (Heterocapsa triquetra, Alexandrium fundyense and Prorocentrum minimum). This inhibitory effect was not observed form 48-h biodegraded nutrient broth culture supernatant, indicating inhibitory substances did not originate from bacterial metabolites. Rough estimation of molecular weight using ultrafiltration indicated that the inhibitory substance was less than 2 kDa, and it did not inhibit the non-HAB organism (Skeletonema costatum), which is essential for preserving marine ecosystems in real-world applications. Furthermore, this inhibitory effect against HABs was not observed for biodegraded culture supernatants of other protein sources (skim milk and okara), indicating that the inhibitory substances were derived from a particular source present only in raw mackerel wastewater. To the best of our knowledge, this is the first report describing the selective inhibitory effects of the culture supernatant of mackerel wastewater against HABs.