Structural and Functional Analysis of PGRP-LC Indicates Exclusive Dap-Type PGN Binding in Bumblebees.

Peptidoglycan recognition proteins (PGRPs) play an important role in the defense against invading microbes via the recognition of the immunogenic substance peptidoglycan (PGN). Bees possess fewer PGRPs than Drosophila melanogaster and Anopheles gambiae but retain two important immune pathways, the Toll pathway and the Imd pathway, which can be triggered by the recognition of Dap-type PGN by PGRP-LCx with the assistance of PGRP-LCa in Drosophila. There are three isoforms of PGRP-LC including PGRP-LCx, PGRP-LCa and PGRP-LCy in Drosophila. Our previous study showed that a single PGRP-LC exists in bumblebees. In this present study, we prove that the bumblebee Bombus lantschouensis PGRP-LC (Bl-PGRP-LC) can respond to an infection with Gram-negative bacterium Escherichia coli through binding to the Dap-type PGNs directly, and that E. coli infection induces the quick and strong upregulation of PGRP-LC, abaecin and defensin. Moreover, the Bl-PGRP-LC exhibits a very strong affinity for the Dap-type PGN, much stronger than the affinity exhibited by the PGRP-LC from the more eusocial honeybee Apis mellifera (Am-PGRP-LC). In addition, mutagenesis experiments showed that the residue His390 is the anchor residue for the binding to the Dap-type PGN and forms a hydrogen bond with MurNAc rather than meso-Dap, which interacts with the anchor residue Arg413 of PGRP-LCx in Drosophila. Therefore, bumblebee PGRP-LC possesses exclusive characteristics for the immune response among insect PGRPs.

Sol-Gel Preparation of Laser Damage Resistant and Moisture-Proof Antireflective Coatings for KDP Crystals.

Surface fogging induced degradation has been a bottleneck problem in potassium dihydrogen phosphate (KDP) crystals due to they are grown from aqueous solution. In this paper, we developed a facile method to prepare a double-layer antireflective coating with moisture-proof and laser damage resistant properties for KDP crystals. The bottom layer was a poly siloxane coating with dense structure and silanol side groups, while the top layer was a hexamethyl-disilazane (HMDS) modified nanoporous SiO2 coating. Both of the sols were nonalkaline and nonaqueous to make sure those are harmless to KDP crystals. The double-layer coated KDP crystal exhibited a maximum transmittance of 99.9% with an average increase of transmitted light of 6-7% over the wavelength range between 351 and 1053 nm. After exposure in a 55% relative humidity environment for 6 months, the double-layer HMDS_SiO2/PS coating coated KDP crystal displayed nearly the same optical transmittance as the original one, whereas the single-layer HMDS_SiO2 coated KDP crystal had a transmittance loss of ∼5%. Moreover, the laser-induced damage threshold of the double-layer coating on KDP crystal reached 11.5 J/cm2 (355 nm, 3 ns). This multifunctional antireflective coating not only can be used for KDP crystals, but also can be applied to thermal-sensitive polymeric substrates.

Combating Atherosclerosis with Chirality/Phase Dual-Engineered Nanozyme Featuring Microenvironment-Programmed Senolytic and Senomorphic Actions.

Senescence plays a critical role in the development and progression of various diseases. This study introduces an amorphous, high-entropy alloy (HEA)-based nanozyme designed to combat senescence. By adjusting the nanozyme's composition and surface properties, this work analyzes its catalytic performance under both normal and aging conditions, confirming that peroxide and superoxide dismutase (SOD) activity are crucial for its anti-aging therapeutic function. Subsequently, the chiral-dependent therapeutic effect is validated and the senolytic performance of D-handed PtPd2CuFe across several aging models is confirmed. Through multi-Omics analyses, this work explores the mechanism underlying the senolytic action exerted by nanozyme in depth. It is confirm that exposure to senescent conditions leads to the enrichment of copper and iron atoms in their lower oxidation states, disrupting the iron-thiol cluster in mitochondria and lipoic acid transferase, as well as oxidizing unsaturated fatty acids, triggering a cascade of cuproptosis and ferroptosis. Additionally, the concentration-dependent anti-aging effects of nanozyme is validated. Even an ultralow dose, the therapeutic can still act as a senomorphic, reducing the effects of senescence. Given its broad-spectrum action and concentration-adjustable anti-aging potential, this work confirms the remarkable therapeutic capability of D-handed PtPd2CuFe in managing atherosclerosis, a disease involving various types of senescent cells.

Ligand Phase Separation-Promoted, "Squeezing-Out" Mode Explaining the Mechanism and Implications of Neutral Nanoparticles That Escaped from Lysosomes.

Neutral nanomaterials functionalized with PEG or similar molecules have been popularly employed as nanomedicines. Compared to positive counterparts that are capable of harnessing the well-known proton sponge effect to facilitate their escape from lysosomes, it is yet unclear how neutral substances got their entry into the cytosol. In this study, by taking PEGylated, neutral Au nanospheres as an example, we systematically investigated their time-dependent translocation postuptake. Specifically, we harnessed dissipative particle dynamics simulations to uncover how nanospheres bypass lysosomal entrapment, wherein a mechanism termed as "squeezing-out" mode was discovered. We next conducted a comprehensive investigation on how nanomaterials implicate lysosomes in terms of integrity and functionality. By using single-molecule imaging, specific preservation of PEG-terminated with targeting moieties in lysosomes supports the "squeezing-out" mode as the mechanism underlying the lysosomal escape of nanomaterials. All evidence points out that such a process is benign to lysosomes, wherein the escape of nanomaterials proceeds at the expense of targeting moieties loss. Furthermore, we proved that by fine-tuning of the efficacy of nanomaterials escaping from lysosomes, modulation of distinct pathways and metabolic machinery can be achieved readily, thereby offering us a simple and robust tool to implicate cells.

Embedding constructed refractive index graded antireflective coating with high abrasion resistance and environmental stability for polycarbonate glass.

Polycarbonate (PC) is a durable and transparent optical plastic material commonly used as shatter-resistant alternative to traditional optical glass. Broadband antireflective (AR) coatings with excellent mechanical strength and environmental stability are essential for PC to achieve high light transmission and visual quality. In this work, chloroform vapor treatment was employed to partially embed the silica coating into the PC substrate for adhesion enhancement, which also divided the silica coating layer into bottom and middle layers with different refractive indices. The contact between the silica nanoparticles and the substrate was transformed from "point-contact" to "area-contact", which enhanced the adhesion between coating and PC substrate. After the deposition of a top layer coating consisted of silica nanoparticles with smaller diameter, a triple-layer refractive index graded AR structure was constructed. Hexamethyldisilazane vapor surface modification was performed to decrease the surface free energy of top coating layer. The triple-layer coating coated PC exhibits superior antireflection property with an average reflectance of only 0.43% over a wide wavelength range of 400-1000 nm. After 100 times of friction or 5 months of exposure to a contaminated environment, the reflectance of coated PC shows barely noticeable difference, indicating its excellent mechanical strength and environmental stability.

Worker-Born Males Are Smaller but Have Similar Reproduction Ability to Queen-Born Males in Bumblebees.

Queen-worker conflict over the reproduction of males exists in the majority of haplodiplioidy hymenpteran species such as bees, wasps, and ants, whose workers lose mating ability but can produce haploid males in colony. Bumblebee is one of the representatives of primitively eusocial insects with plastic division labor and belongs to monandrous and facultative low polyandry species that have reproductive totipotent workers, which are capable of competing with mother queen to produce haploid males in the queenright colony compared to higher eusocial species, e.g., honeybees. So, bumblebees should be a better material to study worker reproduction, but the reproductive characteristics of worker-born males (WMs) remain unclear. Here, we choose the best-studied bumblebee Bombus terrestris to evaluate the morphological characteristics and reproductive ability of WMs from the queenless micro-colonies. The sexually matured WMs showed smaller in forewing length and weight, relatively less sperm counts but equally high sperm viability in comparison with the queen-born males (QMs) of the queenright colony. Despite with smaller size, the WMs are able to successfully mate with the virgin queens in competition with the QMs under laboratory conditions, which is quite different from the honeybees reported. In addition, there was no difference in the colony development, including the traits such as egg-laying rate, colony establishment rate, and populations of offspring, between the WM- and the QM-mated queens. Our study highlights the equivalent reproductive ability of worker-born males compared to that of queens, which might exhibit a positive application or special use of bumblebee rearing, especially for species whose males are not enough for copulation. Further, our finding contributes new evidence to the kin selection theory and suggests worker reproduction might relate to the evolution of sociality in bees.

Factors Influencing the Reproductive Ability of Male Bees: Current Knowledge and Further Directions.

Bumblebees and honeybees are very important pollinators and play a vital role in agricultural and natural ecosystems. The quality of their colonies is determined by the queens and the reproductive drones of mother colonies, and mated drones transmit semen, including half of the genetic materials, to queens and enhance their fertility. Therefore, factors affecting drone fecundity will also directly affect progeny at the colony level. Here, we review environmental and bee-related factors that are closely related to drone reproductive ability. The environmental factors that mainly affect the sperm count and the viability of males include temperature, nutrients and pesticides. In addition, the inherent characteristics of male bees, such as body size, weight, age, seminal fluid proteins and proteins of the spermathecal fluid, contribute to mating success, sperm quality during long-term storage in the spermathecae and the reproductive behaviors of queens. Based on the results of previous studies, we also suggest that the effects of somatotype dimorphism in bumblebee males on sperm quality and queen fecundity and the indispensable and exploitable function of gland proteins in the fecundity of males and queens should be given more attention in further studies.

De Novo Transcriptomic and Metabolomic Analyses Reveal the Ecological Adaptation of High-Altitude Bombus pyrosoma.

Bombus pyrosoma is one of the most abundant bumblebee species in China, with a distribution range of very varied geomorphology and vegetation, which makes it an ideal pollinator species for research into high-altitude adaptation. Here, we sequenced and assembled transcriptomes of B. pyrosoma from the low-altitude North China Plain and the high-altitude Tibet Plateau. Subsequent comparative analysis of de novo transcriptomes from the high- and low-altitude groups identified 675 common upregulated genes (DEGs) in the high-altitude B. pyrosoma. These genes were enriched in metabolic pathways and corresponded to enzyme activities involved in energy metabolism. Furthermore, according to joint analysis with comparative metabolomics, we suggest that the metabolism of coenzyme A (CoA) and the metabolism and transport of energy resources contribute to the adaptation of high-altitude B. pyrosoma. Meanwhile, we found many common upregulated genes enriched in the Toll and immune deficiency (Imd)signaling pathways that act as important immune defenses in insects, and hypoxia and cold temperatures could induce the upregulation of immune genes in insects. Therefore, we suppose that the Toll and Imd signaling pathways also participated in the high-altitude adaptation of B. pyrosoma. Like other organisms, we suggest that the high-altitude adaptation of B. pyrosoma is controlled by diverse mechanisms.

Low-Temperature Preparation of Mechanically Robust and Contamination-Resistant Antireflective Coatings for Flexible Polymeric Glasses via Embedding of Silica Nanoparticles and HMDS Modification.

Mechanical and contamination-resistant properties are the most crucial and challenging issues that impede the practical applications of sol-gel antireflective (AR) coating. In this paper, we report a low-temperature vapor surface treatment strategy for the partial embedding and surface functionalization of silica nanoparticles (SNPs) on flexible polymeric glass substrates. SNPs, which were synthesized via the Stöber method, were partially embedded into the polymeric glass substrates by vapor-phase surface treatment using volatile chloroform. Further vapor-phase surface treatments by water and hexamethyldisilazane (HMDS) were applied successively to achieve high trimethylsilyl coverage of the SNPs. The HMDS modification could convert the polar surface of SNPs to a nonpolar surface for contamination resistance, while ammonia, as a byproduct generated, could help to cross-link the SNPs via self-condensation of silanol groups, thus hardening the coating. The SNP-CWH coated polymethylmethacrylate (PMMA) substrate shows an average transmittance of 98.62% in the wavelength region of 400-800 nm, which is 6.32% higher than that of the uncoated bare PMMA. The AR performance of SNP-CWH coated PMMA shows almost no degradation after 100 times of rubbing or bending, indicating the greatly enhanced abrasion resistance and flexibility. Furthermore, the SNP-CWH coating exhibits superior contamination-resistant property, where the transmittance curve of the coated substrate displays a barely noticeable change after exposure to a "dirty" environment with water and organic contaminants for 6 months. This work paves a new way for developing mechanically robust and contamination-resistant AR coating for polymeric substrates.

Surface free energy and microstructure dependent environmental stability of sol-gel SiO2 antireflective coatings: Effect of combined vapor phase surface treatment.

Environmental stability is of great interest for sol-gel porous antireflective (AR) coatings. In this work, sol-gel silica AR coatings with excellent environmental stability were prepared via ammonia vapor treatment (AVT) combined with organosilane (hexamethyldisilazane (HMDS) or hexadecyltrimethoxysilane (HTMS)) vapor treatment. The surface free energy (SFE) of the coatings treated with different approaches was estimated through Owens-Wendt method combined with Wenzel equation from the contact angles of water, glycerol and diiodomethane. Scanning electron microscope and Fourier transform infrared spectroscopy were employed to study the surface morphology and chemical composition of the silica coatings treated with different methods. The silica coatings treated by combined vapor phase method possess the SFE of 24.11 mJ·m-2 for N-HD-SiO2 and 34.18 mJ·m-2 for N-HT-SiO2. After being placed in a 90%RH humid environment for 2 months, the peak transmittance of BK7 glasses coated with N-HD-SiO2 and N-HT-SiO2 only decreases by 0.58% and 0.95%, respectively. Meanwhile, N-HD-SiO2 and N-HT-SiO2 coated BK7 glasses also show quite stable optical transmittance after exposure to a vacuum oil environment for 2 months. The mechanism of the combined vapor phase surface treatment is discussed based on the combination analysis of surface morphology, chemical composition and SFE of the coatings.