Biosynthesis of linear protein nanoarrays using the flagellar axoneme

Applications in biotechnology and synthetic biology often make use of soluble proteins, but there are many potential advantages to anchoring enzymes to a stable substrate, including stability and the possibility for substrate channeling. To avoid the necessity of protein purification and chemical immobilization, there has been growing interest in bio-assembly of protein-containing nanoparticles, exploiting the self-assembly of viral capsid proteins or other proteins that form polyhedral structures. But these nanoparticle are limited in size which constrains the packaging and the accessibility of the proteins. The axoneme, the insoluble protein core of the eukaryotic flagellum or cilium, is a highly ordered protein structure that can be several microns in length, orders of magnitude larger than other types of nanoparticles. We show that when proteins of interest are fused to specific axonemal proteins and expressed in living cells, they become incorporated into linear arrays which have the advantages of high protein loading capacity, high stability, and single-step purification with retention of biomass. The arrays can be isolated as membrane enclosed vesicle or as exposed protein arrays. The approach is demonstrated for both fluorescent proteins and enzymes, and in the latter case it is found that incorporation into axoneme arrays provides increased stability for the enzyme.

Study on Solidification of Chromium-Containing Sludge With Alkali Slag Combined With Attapulgite

In order to solve the harm of hazardous waste chromium-containing sludge to humans and the environment, this paper uses attapulgite to strengthen alkali slag to prepare cementitious materials to solidify/stabilize chromium-containing sludge. Single-factor and orthogonal experiments were used to optimize the preparation parameters of alkali slag cementitious materials. The compressive strength, heavy metal leaching toxicity, and microscopic characterization of chromium-containing sludge solidified body were tested to investigate the solidification effect and mechanism of chromium-containing sludge. The results show that: The best content of attapulgite is 4%. The compressive strength of the solidified body decreased with the increase of chromium sludge content, and the leaching concentration of Cr and Cu increased with the rise of chromium-sludge content. The addition of attapulgite enhanced the compressive strength. Compared with the original chromium-containing sludge, the leaching concentration of heavy metals in the solidified body is significantly reduced. The XRD and FTIR analysis showed that the solidified body might solidify/stabilize heavy metals by physical encapsulation of amorphous form and chemical immobilization. This research realizes the use of waste to treat waste and provides the possibility for the application of solidified products in construction.

Case Report: Subclinical Verminous Pneumonia and High Ambient Temperatures Had Severe Impact on the Anesthesia of Semi-domesticated Eurasian Tundra Reindeer (Rangifer tarandus tarandus) With Medetomidine–Ketamine

Semidomesticated Eurasian tundra reindeer (Rangifer tarandus tarandus, n = 21) were scheduled twice for chemical immobilization with medetomidine–ketamine as part of a scientific experiment in June 2014. During the first round of immobilizations, seven animals developed severe respiratory depression (RD). Three individuals died, and 4 recovered. The ambient temperature during the 2 days of immobilization (June 3 and 4) was high (mean 13.9–17.6°C) compared to the normal mean temperature for these 2 days (7–8°C) based on statistical records. During the second round of immobilizations, using the same anesthetic protocol for the remaining animals as in the first round but conducted under cooler conditions (mean 6.6°C for the period June 9–18), no signs of RD were observed. Clinical and pathological investigations indicated that the animals suffered from circulatory changes possibly caused by high ambient temperatures and granulomatous interstitial pneumonia due to Elaphostrongylus rangiferi larvae. These conditions, together with the cardiovascular effects of medetomidine, were likely causes of RD and the fatal outcome. We conclude that chemical immobilization of reindeer with medetomidine–ketamine should be avoided in May–June due to the potential risk when animals partly in winter coats encounter rising ambient temperatures and usually have parasites developing in their airways.

Polymer-Coated Magnetite Nanoparticles for Protein Immobilization

Since their discovery, magnetic nanoparticles (MNPs) have become materials with great potential, especially considering the applications of biomedical sciences. A series of works on the preparation, characterization, and application of MNPs has shown that the biological activity of such materials depends on their size, shape, core, and shell nature. Some of the most commonly used MNPs are those based on a magnetite core. On the other hand, synthetic biopolymers are used as a protective surface coating for these nanoparticles. This review describes the advances in the field of polymer-coated MNPs for protein immobilization over the past decade. General methods of MNP preparation and protein immobilization are presented. The most extensive section of this article discusses the latest work on the use of polymer-coated MNPs for the physical and chemical immobilization of three types of proteins: enzymes, antibodies, and serum proteins. Where possible, the effectiveness of the immobilization and the activity and use of the immobilized protein are reported. Finally, the information available in the peer-reviewed literature and the application perspectives for the MNP-immobilized protein systems are summarized as well.

Blocking polysulfides with a Janus Fe3C/N-CNF@RGO electrode via physiochemical confinement and catalytic conversion for high-performance lithium–sulfur batteries

A novel Janus Fe3C/N-CNF@RGO electrode was successfully constructed, which realizes the co-existence of chemical immobilization, catalytic ability, and physical barrier in 3D conductive networks, enabling robust cycling stability of Li–S battery