A Chloride-Doped Silver-Sulfide Cluster [Ag148S26Cl30(C≡CBut)60]6+: Hierarchical Assembly, Enhanced Luminescence and Cytotoxicity to Cancer Cells

The formation of high-nuclear silver(I) clusters remains elusive and their potential applications are still underdeveloped. Herein, we report a unprecedented gigantic Ag148 ([Ag148S26Cl30(C≡CBut)60](SbF6)6) cluster co-templated by Cl- and S2-, which...

Biomass-Derived Carbon Heterostructures Enable Environmentally Adaptive Wideband Electromagnetic Wave Absorbers

Although advances in wireless technologies such as miniature and wearable electronics have improved the quality of our lives, the ubiquitous use of electronics comes at the expense of increased exposure to electromagnetic (EM) radiation. Up to date, extensive efforts have been made to develop high-performance EM absorbers based on synthetic materials. However, the design of an EM absorber with both exceptional EM dissipation ability and good environmental adaptability remains a substantial challenge. Here, we report the design of a class of carbon heterostructures via hierarchical assembly of graphitized lignocellulose derived from bamboo. Specifically, the assemblies of nanofibers and nanosheets behave as a nanometer-sized antenna, which results in an enhancement of the conductive loss. In addition, we show that the composition of cellulose and lignin in the precursor significantly influences the shape of the assembly and the formation of covalent bonds, which affect the dielectric response-ability and the surface hydrophobicity (the apparent contact angle of water can reach 135°). Finally, we demonstrate that the obtained carbon heterostructure maintains its wideband EM absorption with an effective absorption frequency ranging from 12.5 to 16.7 GHz under conditions that simulate the real-world environment, including exposure to rainwater with slightly acidic/alkaline pH values. Overall, the advances reported in this work provide new design principles for the synthesis of high-performance EM absorbers that can find practical applications in real-world environments.

A more complex basal complex: novel components mapped to the Toxoplasma gondii cytokinesis machinery portray an expanded hierarchy of its assembly and function

The basal complex (BC) of Toxoplasma gondii has an essential role in cell division but details on the mechanism are lacking. To promote insights in this process, reciprocal proximity based biotinylation was used to map the basal complex proteome. An assembled protein map was interrogated by spatiotemporal characterization of critical components as well as functionally by disrupting the expression of the components. Spatially, this revealed four proteins sub-complexes with distinct sub-structural BC localization. Temporally, several patterns were differentiated based on their first appearance and/or disappearance from the BC corresponding with different steps in BC development (initiation, expansion, constriction, maturation). We also identified a protein pre-ceding BC formation (BCC0) laid out in a 5-fold symmetry. This symmetry marks the apical annuli and site of alveolar suture formation. From here, it was determined that the apical cap is assembled in the apical direction, whereas the rest of the IMC expands in the basal direction, inspiring a new bi-directional daughter budding process. Furthermore, we discovered BCC4, an essential protein exclusively localizing to the BC during cell division. Although depletion of BCC4 did not prevent BC formation, it led to BC fragmentation at the mid-point of cell division. Based on these data, a model is presented wherein BCC4 and MORN1 stabilize each other and form a rubber band that implies an essential role for the BC in preventing the fraying of the basal end of the assembling daughter cytoskeleton scaffolds. Furthermore, one new component of the Myosin J and Centrin2 cluster was BCC1, a hypothetical protein whose depletion prevents the non-essential last step of BC constriction. Overall, the BC is a highly dynamic, multi-functional structure that is critical to the hierarchical assembly of the daughter parasites.

Anthropization Affects the Assembly of Bat-Bat Fly Interaction Networks

Increasing anthropization is detrimental to the natural environment and the quality of life, affecting populations, communities, and the relationships between organisms. One of the most unique relationships in the animal world is parasitism, which often involves tightly specialized interactions between pairs of species. Bat flies, for example, are obligate ectoparasites represented by two highly adapted dipteran families that usually parasite a single bat species or genus. Recent studies have shown that bat flies could carry pathogens such as bacteria and viruses, transmitting them among bat individuals in a colony. Because host roost characteristics can influence bat-fly parasitism, we aimed to assess whether the ecological networks between parasites and their host bats are influenced by the degree of habitat anthropization. Our hypothesis was that bat-fly interaction networks would be less specialized and more nested in highly anthropized sites. We collected bat fly individuals from bats captured at 21 sampling sites located in the Federal District of Brazil and quantified the amount of natural and anthropized area within a 3-km buffer from the sampling site. Areas consisting of agriculture, construction, mining, roads, or any man-made structure were considered anthropized. Sites presented different degrees of anthropization, with areas ranging from 100% anthropized to areas retaining full natural cover. We built bat-bat fly networks for each of the sites and excluded those with less than 0.7% of sampling completeness. We calculated key weighted structural metrics for each network, such as nestedness, specialization, and modularity. The effect of the reduction in natural cover on structural metrics was assessed through GLMMs, controlling for network size and ectoparasite diversity. Nestedness increased with the amount of anthropization, while specialization and modularity did not change and were overall high in all networks. This result suggests that anthropization may influence the assembly of bat-bat fly networks, leading to the emergence of a hierarchical assembly of interactions as parasites become less specialized and interact with a wider variety of hosts. Less specialized relationships could influence parasite fitness or even increase the likelihood of transmitting pathogens between populations of different bat species.

Encoding hierarchical assembly pathways of proteins with DNA

The structural and functional diversity of materials in nature depends on the controlled assembly of discrete building blocks into complex architectures via specific, multistep, hierarchical assembly pathways. Achieving similar complexity in synthetic materials through hierarchical assembly is challenging due to difficulties with defining multiple recognition areas on synthetic building blocks and controlling the sequence through which those recognition sites direct assembly. Here, we show that we can exploit the chemical anisotropy of proteins and the programmability of DNA ligands to deliberately control the hierarchical assembly of protein–DNA materials. Through DNA sequence design, we introduce orthogonal DNA interactions with disparate interaction strengths (“strong” and “weak”) onto specific geometric regions of a model protein, stable protein 1 (Sp1). We show that the spatial encoding of DNA ligands leads to highly directional assembly via strong interactions and that, by design, the first stage of assembly increases the multivalency of weak DNA–DNA interactions that give rise to an emergent second stage of assembly. Furthermore, we demonstrate that judicious DNA design not only directs assembly along a given pathway but can also direct distinct structural outcomes from a single pathway. This combination of protein surface and DNA sequence design allows us to encode the structural and chemical information necessary into building blocks to program their multistep hierarchical assembly. Our findings represent a strategy for controlling the hierarchical assembly of proteins to realize a diverse set of protein–DNA materials by design.

α-/γ-Taxilin are required for centriolar subdistal appendage assembly and microtubule organization

The centrosome, composed of a pair of centrioles (mother and daughter centrioles) and pericentriolar material, is mainly responsible for microtubule nucleation and anchorage in animal cells. The subdistal appendage (SDA) is a centriolar structure located at the subdistal region on the mother centriole, and it functions in microtubule anchorage. However, the molecular composition and detailed structure of SDA remain largely unknown. Here, we identified a-taxilin and r-taxilin as new SDA components, which form a complex via their coiled-coil domains and serve as a new subgroup during SDA hierarchical assembly. Their SDA localization is dependent on ODF2, and α-taxilin recruits CEP170 to the SDA. Functional analyses suggest that α-taxilin and γ-taxilin are responsible for centrosomal microtubule anchorage during interphase, as well as for proper spindle orientation during metaphase. Altogether, our results shed light on the molecular components and functional understanding of the SDA hierarchical assembly and microtubule organization.