Insect chitin deacetylases (CDAs) are carbohydrate esterases that catalyze N‐deacetylation of chitin to generate chitosan, a process essential for chitin organization and compactness during the ...formation of extracellular chitinous structure. Here we identified two CDA2 splice variants (LdCDA2a and LdCDA2b) in Leptinotarsa decemlineata. Both splices were abundantly expressed in larval foregut, rectum, and epidermis; their levels peaked immediately before ecdysis within each instar. In vivo results revealed that the two isoforms transcriptionally responded, positively and negatively respectively, to 20‐hydroxyecdysone and juvenile hormone signaling pathways. RNA interference (RNAi)‐aided knockdown of the two LdCDA2 variants (hereafter LdCDA2) or LdCDA2b, rather than LdCDA2a, resulted in three negative effects. First, foliage consumption was significantly reduced, larval developing period was lengthened, and larval growth was retarded. Second, chitin contents were reduced, whereas glucose, trehalose, and glycogen contents were increased in the LdCDA2 and LdCDA2b RNAi larvae. Third, approximately 20% of LdCDA2 and LdCDA2b RNAi larvae were trapped within the exuviae and finally died. About 60% of the abnormal pupae died as pharate adults. Around 20% of the RNAi pupae emerged as deformed adults, with small size and wrinkled wings. These adults eventually died within 1 week after molting. Our results reveal that knockdown of CDA2 affects chitin accumulation. Consequently, LdCDA2 may be a potential target for control of L. decemlineata larvae.
Rapid, simple, and cost-effective diagnostics are needed to improve healthcare at the point of care (POC). However, the most widely used POC diagnostic, the lateral flow immunoassay (LFA), is ...∼1000-times less sensitive and has a smaller analytical range than laboratory tests, requiring a confirmatory test to establish truly negative results. Here, a rational and systematic strategy is used to design the LFA contrast label (i.e., gold nanoparticles) to improve the analytical sensitivity, analytical detection range, and antigen quantification of LFAs. Specifically, we discovered that the size (30, 60, or 100 nm) of the gold nanoparticles is a main contributor to the LFA analytical performance through both the degree of receptor interaction and the ultimate visual or thermal contrast signals. Using the optimal LFA design, we demonstrated the ability to improve the analytical sensitivity by 256-fold and expand the analytical detection range from 3 log10 to 6 log10 for diagnosing patients with inflammatory conditions by measuring C-reactive protein. This work demonstrates that, with appropriate design of the contrast label, a simple and commonly used diagnostic technology can compete with more expensive state-of-the-art laboratory tests.
Electronic structures of graphene oxide (GO) and hydro-thermally reduced graphene oxides (rGOs) processed at low temperatures (120-180°C) were studied using X-ray absorption near-edge structure ...(XANES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). C K-edge XANES spectra of rGOs reveal that thermal reduction restores C = C sp(2) bonds and removes some of the oxygen and hydroxyl groups of GO, which initiates the evolution of carbonaceous species. The combination of C K-edge XANES and Kα XES spectra shows that the overlapping π and π* orbitals in rGOs and GO are similar to that of highly ordered pyrolytic graphite (HOPG), which has no band-gap. C Kα RIXS spectra provide evidence that thermal reduction changes the density of states (DOSs) that is generated in the π-region and/or in the gap between the π and π* levels of the GO and rGOs. Two-dimensional C Kα RIXS mapping of the heavy reduction of rGOs further confirms that the residual oxygen and/or oxygen-containing functional groups modify the π and σ features, which are dispersed by the photon excitation energy. The dispersion behavior near the K point is approximately linear and differs from the parabolic-like dispersion observed in HOPG.
Using quantitative models to predict the biological interactions of nanoparticles will accelerate the translation of nanotechnology. Here, we characterized the serum protein corona ‘fingerprint’ ...formed around a library of 105 surface-modified gold nanoparticles. Applying a bioinformatics-inspired approach, we developed a multivariate model that uses the protein corona fingerprint to predict cell association 50% more accurately than a model that uses parameters describing nanoparticle size, aggregation state, and surface charge. Our model implicates a set of hyaluronan-binding proteins as mediators of nanoparticle–cell interactions. This study establishes a framework for developing a comprehensive database of protein corona fingerprints and biological responses for multiple nanoparticle types. Such a database can be used to develop quantitative relationships that predict the biological responses to nanoparticles and will aid in uncovering the fundamental mechanisms of nano–bio interactions.
The volatile flavor substances in traditional fermented yak milk samples collected from 5 ecoregions (A: coniferous forests and grasslands of the Qilian Qingdong Mountains; B: alpine grasslands ...surrounding the lakes in the Qiangtang Plateau; C: alpine shrubs and meadows of the Guoluo-Nagqu Highlands; D: coniferous forests along the alpine valley in East Tibet; E: shrubs and grasslands along the alpine valley in South Tibet) of the Qinghai-Tibetan plateau were comparatively analyzed. The relative percentage composition of volatile flavor substances varied among the different ecoregions. In samples collected from region E, more than 50% of the volatile flavor compounds were esters comprising mainly n-butyl acetate, butyl butyrate, and ethyl octanoate, and a considerable proportion of acetoin was found in samples from regions B and E. Greater proportions of 2-heptanone and 2-nonanone were observed in samples collected from regions A, C, and D compared with regions B and E.
A heterodimer of ultraspiracle (USP) and ecdysone receptor (EcR) mediates 20‐hydroxyecdysone (20E) signalling cascade to regulate insect moulting and metamorphosis. However, at least two questions ...remain to be addressed in terms of the molecular importance of USP in insect species. First, is USP involved in both regulation of ecdysteroidogenesis and mediation of 20E signalling in non‐drosophilid insects, as in Drosophila melanogaster? Second, does USP play any role in larval metamorphosis except as the partner of heterodimeric receptor to activate the downstream 20E signalling genes? In this paper, we found that RNA interference (RNAi) of LdUSP in the final (fourth) instar larvae reduced the messenger RNA levels of four ecdysteroidogenesis genes (Ldspo, Ldphm, Lddib and Ldsad) and 20E titre, and repressed the expression of five 20E signal genes (EcRA, HR3, HR4, E74 and E75) in Leptinotarsa decemlineata. The LdUSP RNAi larvae remained as prepupae, with developing antennae, legs and discs of forewings and hindwings. Dietary supplement with 20E restored the expression of the five 20E signal genes, but only partially alleviated the decreased pupation rate in LdUSP RNAi beetles. Knockdown of LdUSP at the penultimate (third) instar larvae did not affect third–fourth instar moulting. However, silencing LdUSP caused similar but less severe impairments on pupation. Accordingly, we propose that USP is undoubtedly necessary for ecdysteroidogenesis, for mediation of 20E signalling and for initiation of metamorphosis in L. decemlineata.
Intermetallic alloys have traditionally been characterized by their inherent brittleness due to their lack of sufficient slip systems and absence of strain hardening. However, here we developed a ...single-phase B2 high-entropy intermetallic alloy that is both strong and plastic. Unlike conventional intermetallics, this high-entropy alloy features a highly distorted crystalline lattice with complex chemical order, leading to multiple slip systems and high flow stress. In addition, the alloy exhibits a dynamic hardening mechanism triggered by dislocation gliding that preserves its strength across a wide range of temperatures. As a result, this high-entropy intermetallic circumvents precipitous thermal softening, with extensive plastic flows even at high homologous temperatures, outperforming a variety of both body-centered cubic and B2 alloys. These findings reveal a promising direction for the development of intermetallic alloys with broad engineering applications.Intermetallics are traditionally characterised by their inherent brittleness due to a lack of sufficient slip systems and the absence of strain hardening. Here authors show that a single-phase distorted high entropy B2 intermetallic alloy displays notable strength and plasticity at room temperature, along with stable plastic flow at high homologous temperatures.
Delivery and toxicity are critical issues facing nanomedicine research. Currently, there is limited understanding and connection between the physicochemical properties of a nanomaterial and its ...interactions with a physiological system. As a result, it remains unclear how to optimally synthesize and chemically modify nanomaterials for in vivo applications. It has been suggested that the physicochemical properties of a nanomaterial after synthesis, known as its “synthetic identity”, are not what a cell encounters in vivo. Adsorption of blood components and interactions with phagocytes can modify the size, aggregation state, and interfacial composition of a nanomaterial, giving it a distinct “biological identity”. Here, we investigate the role of size and surface chemistry in mediating serum protein adsorption to gold nanoparticles and their subsequent uptake by macrophages. Using label-free liquid chromatography tandem mass spectrometry, we find that over 70 different serum proteins are heterogeneously adsorbed to the surface of gold nanoparticles. The relative density of each of these adsorbed proteins depends on nanoparticle size and poly(ethylene glycol) grafting density. Variations in serum protein adsorption correlate with differences in the mechanism and efficiency of nanoparticle uptake by a macrophage cell line. Macrophages contribute to the poor efficiency of nanomaterial delivery into diseased tissues, redistribution of nanomaterials within the body, and potential toxicity. This study establishes principles for the rational design of clinically useful nanomaterials.
A nanoparticle’s physical and chemical properties at the time of cell contact will determine the ensuing cellular response. Aggregation and the formation of a protein corona in the extracellular ...environment will alter nanoparticle size, shape, and surface properties, giving it a “biological identity” that is distinct from its initial “synthetic identity”. The biological identity of a nanoparticle depends on the composition of the surrounding biological environment and determines subsequent cellular interactions. When studying nanoparticle–cell interactions, previous studies have ignored the dynamic composition of the extracellular environment as cells deplete and secrete biomolecules in a process known as “conditioning”. Here, we show that cell conditioning induces gold nanoparticle aggregation and changes the protein corona composition in a manner that depends on nanoparticle diameter, surface chemistry, and cell phenotype. The evolution of the biological identity in conditioned media enhances the cell membrane affinity, uptake, and retention of nanoparticles. These results show that dynamic extracellular environments can alter nanoparticle–cell interactions by modulating the biological identity. The effect of the dynamic nature of biological environments on the biological identity of nanoparticles must be considered to fully understand nano–bio interactions and prevent data misinterpretation.
Using gas chromatography mass spectrometry and the PacBio single molecule with real-time sequencing technology (SMRT), we analyzed the detailed metabolomic profiles and microbial community dynamics ...involved in ensiled Medicago sativa (alfalfa) inoculated without or with the homofermenter Lactobacillus plantarum or heterofermenter Lactobacillus buchneri. Our results revealed that 280 substances and 102 different metabolites were present in ensiled alfalfa. Inoculation of L. buchneri led to remarkable up-accumulation in concentrations of 4-aminobutyric acid, some free amino acids, and polyols in ensiled alfalfa, whereas considerable down-accumulation in cadaverine and succinic acid were observed in L. plantarum-inoculated silages. Completely different microbial flora and their successions during ensiling were observed in the control and two types of inoculant-treated silages. Inoculation of the L. plantarum or L. buchneri alters the microbial composition dynamics of the ensiled forage in very different manners. Our study demonstrates that metabolomic profiling analysis provides a deep insight in metabolites in silage. Moreover, the PacBio SMRT method revealed the microbial composition and its succession during the ensiling process at the species level. This provides information regarding the microbial processes underlying silage formation and may contribute to target-based regulation methods to achieve high-quality silage production.
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