Ultrathin quantum light source with van der Waals NbOCl2 crystal.

Interlayer electronic coupling in two-dimensional materials enables tunable and emergent properties by stacking engineering. However, it also results in significant evolution of electronic structures and attenuation of excitonic effects in two-dimensional semiconductors as exemplified by quickly degrading excitonic photoluminescence and optical nonlinearities in transition metal dichalcogenides when monolayers are stacked into van der Waals structures. Here we report a van der Waals crystal, niobium oxide dichloride (NbOCl2), featuring vanishing interlayer electronic coupling and monolayer-like excitonic behaviour in the bulk form, along with a scalable second-harmonic generation intensity of up to three orders higher than that in monolayer WS2. Notably, the strong second-order nonlinearity enables correlated parametric photon pair generation, through a spontaneous parametric down-conversion (SPDC) process, in flakes as thin as about 46 nm. To our knowledge, this is the first SPDC source unambiguously demonstrated in two-dimensional layered materials, and the thinnest SPDC source ever reported. Our work opens an avenue towards developing van der Waals material-based ultracompact on-chip SPDC sources as well as high-performance photon modulators in both classical and quantum optical technologies1-4.

Halofilins as emerging bactofilin families of archaeal cell shape plasticity orchestrators.

Bactofilins are rigid, nonpolar bacterial cytoskeletal filaments that link cellular processes to specific curvatures of the cytoplasmic membrane. Although homologs of bactofilins have been identified in archaea and eukaryotes, functional studies have remained confined to bacterial systems. Here, we characterize representatives of two families of archaeal bactofilins from the pleomorphic archaeon Haloferax volcanii, halofilin A (HalA) and halofilin B (HalB). HalA and HalB polymerize in vitro, assembling into straight bundles. HalA polymers are highly dynamic and accumulate at positive membrane curvatures in vivo, whereas HalB forms more static foci that localize in areas of local negative curvatures on the outer cell surface. Gene deletions and live-cell imaging show that halofilins are critical in maintaining morphological integrity during shape transition from disk (sessile) to rod (motile). Morphological defects in ΔhalA result in accumulation of highly positive curvatures in rods but not in disks. Conversely, disk-shaped cells are exclusively affected by halB deletion, resulting in flatter cells. Furthermore, while ΔhalA and ΔhalB cells imprecisely determine the future division plane, defects arise predominantly during the disk-to-rod shape remodeling. The deletion of halA in the haloarchaeon Halobacterium salinarum, whose cells are consistently rod-shaped, impacted morphogenesis but not cell division. Increased levels of halofilins enforced drastic deformations in cells devoid of the S-layer, suggesting that HalB polymers are more stable at defective S-layer lattice regions. Our results suggest that halofilins might play a significant mechanical scaffolding role in addition to possibly directing envelope synthesis.

CD19 occupancy with tafasitamab increases therapeutic index of CART19 cell therapy and diminishes severity of CRS.

ABSTRACT: In the development of various strategies of anti-CD19 immunotherapy for the treatment of B-cell malignancies, it remains unclear whether CD19 monoclonal antibody therapy impairs subsequent CD19-targeted chimeric antigen receptor T-cell (CART19) therapy. We evaluated the potential interference between the CD19-targeting monoclonal antibody tafasitamab and CART19 treatment in preclinical models. Concomitant treatment with tafasitamab and CART19 showed major CD19 binding competition, which led to CART19 functional impairment. However, when CD19+ cell lines were pretreated with tafasitamab overnight and the unbound antibody was subsequently removed from the culture, CART19 function was not affected. In preclinical in vivo models, tafasitamab pretreatment demonstrated reduced incidence and severity of cytokine release syndrome and exhibited superior antitumor effects and overall survival compared with CART19 alone. This was associated with transient CD19 occupancy with tafasitamab, which in turn resulted in the inhibition of CART19 overactivation, leading to diminished CAR T apoptosis and pyroptosis of tumor cells.

Integrated Manipulation and Addressing of Spin Defect in Diamond.

Scalable and addressable integrated manipulation of qubits is crucial for practical quantum information applications. Different waveguides have been used to transport the optical and electrical driving pulses, which are usually required for qubit manipulation. However, the separated multifields may limit the compactness and efficiency of manipulation and introduce unwanted perturbation. Here, we develop a tapered fiber-nanowire-electrode hybrid structure to realize integrated optical and microwave manipulation of solid-state spins at nanoscale. Visible light and microwave driving pulses are simultaneously transported and concentrated along an Ag nanowire. Studied with spin defects in diamond, the results show that the different driving fields are aligned with high accuracy. The spatially selective spin manipulation is realized. And the frequency-scanning optically detected magnetic resonance (ODMR) of spin qubits is measured, illustrating the potential for portable quantum sensing. Our work provides a new scheme for developing compact, miniaturized quantum sensors and quantum information processing devices.

Involvement of ArlI, ArlJ, and CirA in archaeal type IV pilin-mediated motility regulation.

Many prokaryotes use swimming motility to move toward favorable conditions and escape adverse surroundings. Regulatory mechanisms governing bacterial flagella-driven motility are well-established; however, little is yet known about the regulation underlying swimming motility propelled by the archaeal cell surface structure, the archaella. Previous research showed that the deletion of the adhesion pilins (PilA1-6), subunits of the type IV pili cell surface structure, renders the model archaeon Haloferax volcanii non-motile. In this study, we used ethyl methanesulfonate mutagenesis and a motility assay to identify motile suppressors of the ∆pilA[1-6] strain. Of the eight suppressors identified, six contain missense mutations in archaella biosynthesis genes, arlI and arlJ. In trans expression of arlI and arlJ mutant constructs in the respective multi-deletion strains ∆pilA[1-6]∆arlI and ∆pilA[1-6]∆arlJ confirmed their role in suppressing the ∆pilA[1-6] motility defect. Additionally, three suppressors harbor co-occurring disruptive missense and nonsense mutations in cirA, a gene encoding a proposed regulatory protein. A deletion of cirA resulted in hypermotility, while cirA expression in trans in wild-type cells led to decreased motility. Moreover, quantitative real-time PCR analysis revealed that in wild-type cells, higher expression levels of arlI, arlJ, and the archaellin gene arlA1 were observed in motile early-log phase rod-shaped cells compared to non-motile mid-log phase disk-shaped cells. Conversely, ∆cirA cells, which form rods during both early- and mid-log phases, exhibited similar expression levels of arl genes in both growth phases. Our findings contribute to a deeper understanding of the mechanisms governing archaeal motility, highlighting the involvement of ArlI, ArlJ, and CirA in pilin-mediated motility regulation.IMPORTANCEArchaea are close relatives of eukaryotes and play crucial ecological roles. Certain behaviors, such as swimming motility, are thought to be important for archaeal environmental adaptation. Archaella, the archaeal motility appendages, are evolutionarily distinct from bacterial flagella, and the regulatory mechanisms driving archaeal motility are largely unknown. Previous research has linked the loss of type IV pili subunits to archaeal motility suppression. This study reveals three Haloferax volcanii proteins involved in pilin-mediated motility regulation, offering a deeper understanding of motility regulation in this understudied domain while also paving the way for uncovering novel mechanisms that govern archaeal motility. Understanding archaeal cellular processes will help elucidate the ecological roles of archaea as well as the evolution of these processes across domains.

Ferrostatin-1 Inhibits Toll-Like Receptor 4/NF-κB Signaling to Alleviate Intervertebral Disc Degeneration in Rats.

Ferrostatin-1 (Fer-1), an inhibitor of ferroptosis, is implicated in intervertebral disc degeneration (IDD). The current study explored the role of Fer-1 in IDD via the toll-like receptor 4 (TLR4)/NF-κB signaling pathway. IDD-related gene expression microarray GSE124272 and high-throughput sequencing data set GSE175710 were obtained through the Gene Expression Omnibus database. Differentially expressed genes in IDD were identified, followed by implementation of protein-protein interaction network analysis and receiver operating characteristic curve analysis. The main pathways in IDD were obtained through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional analyses, and target genes of Fer-1 were obtained through PubChem and PharmMapper websites. Finally, GPX4, FTH, and TLR4 expression was determined in a IDD rat model. Three key co-expression modules involved in IDD were obtained through Weighted Gene Co-Expression Network Analysis. Thirteen differentially expressed genes were found to be associated with IDD, and eight key genes (TLR4, BCL2A1, CXCL1, IL1R1, NAMPT, SOCS3, XCL1, and IRAK3) were found to affect IDD. These eight key genes had the diagnostic potential for IDD. The NF-κB signaling pathway was shown to play a predominant role in IDD development. Network pharmacologic analysis indicated a role of Fer-1 in suppressing ferroptosis and ameliorating IDD via the TLR4/NF-κB signaling pathway, which was verified by an in vivo animal experiment. The study showed that Fer-1 down-regulates TLR4 to inactivate NF-κB signaling pathway, suppressing ferroptosis and ultimately alleviating IDD in rats.

Optomechanical squeezing with strong harmonic mechanical driving.

In this paper, we propose an optomechanical scheme for generating mechanical squeezing over the 3 dB limit, with the mechanical mirror being driven by a strong and linear harmonic force. In contrast to parametric mechanical driving, the linearly driven force shakes the mechanical mirror periodically oscillating at twice the mechanical eigenfrequency with large amplitude, where the mechanical mirror can be dissipatively stabilized by the engineered cavity reservoir to a dynamical squeezed steady state with a maximum degree of squeezing over 8 dB. The mechanical squeezing of more than 3 dB can be achieved even for a mechanical thermal temperature larger than 100 mK. The scheme can be implemented in a cascaded optomechanical setup, with potential applications in engineering continuous variable entanglement and quantum sensing.

Design and synthesis of TH19P01-Camptothecin based hybrid peptides inducing effective anticancer responses on sortilin positive cancer cells.

Recently, the sortilin receptor (SORT1) was found to be preferentially over-expressed on the surface of many cancer cells, which makes SORT1 a novel anticancer target. The SORT1 binding proprietary peptide TH19P01 could achieve the SORT1-mediated cancer cell binding and subsequent internalization. Inspired by the peptide-drug conjugate (PDC) strategy, the TH19P01-camptothecin (CPT) conjugates were designed, efficiently synthesized, and evaluated for their anticancer potential in this study. The water solubility, in vitro anticancer activity, time-kill kinetics, cellular uptake, anti-migration activity, and hemolysis effects were systematically estimated. Besides, in order to monitor the release of CPT from conjugates in real-time, the CPT/Dnp-based "turn on" hybrid peptide was designed, which indicted that CPT could be sustainably released from the hybrid peptide in both human serum and cancer cellular environments. Strikingly, compared with free CPT, the water solubility, cellular uptake, and selectivity towards cancer cells of hybrid peptide LYJ-2 have all been significantly enhanced. Moreover, unlike free CPT or TH19P01, LYJ-2 exhibited selective anti-proliferative and anti-migration effects against SORT1-positive MDA-MB-231 cells. Collectively, this study not only established efficient strategies to improve the solubility and anticancer potential of chemotherapeutic agent CPT, but also provided important references for the future development of TH19P01 based PDCs targeting SORT1.

Synthesis and structural optimization of oncolytic peptide LTX-315.

Oncolytic peptides represented potential novel candidates for anticancer treatments especially drug-resistant cancer cell lines. One of the most promising and extensively studied is LTX-315, which is considered as the first in class oncolytic peptide and has entered phase I/II clinical trials. Nevertheless, the shortcomings including poor proteolytic stability, moderate anticancer durability and high synthesis costs may hinder the widespread clinical applications of LTX-315. In order to reduce the synthesis costs, as well as develop derivatives possessing both high protease-stability and durable anticancer efficiency, twenty LTX-315-based derived-peptides were designed and efficiently synthesized. Especially, through solid-phase S-alkylation, as well as the optimized peptide cleavage condition, the derived peptides could be prepared with drastically reduced synthesis cost. The in vitro anticancer efficiency, serum stability, anticancer durability, anti-migration activity, and hemolysis effect were systematically investigated. It was found that derived peptide MS-13 exhibited comparable anticancer efficiency and durability to those of LTX-315. Strikingly, the D-type peptide MS-20, which is the enantiomer of MS-13, was demonstrated to possess significantly high proteolytic stability and sustained anticancer durability. In general, the cost-effective synthesis and stability-guided structural optimizations were conducted on LTX-315, affording the highly hydrolysis resistant MS-20 which possessed durable anticancer activity. Meanwhile, this study also provided a reliable reference for the future optimization of anticancer peptides through the solid-phase S-alkylation and L-type to D-type amino acid substitutions.

d-type peptides based fluorescent probes for "turn on" sensing of heparin.

Developing "turn on" fluorescent probes was desirable for the detection of the effective anticoagulant agent heparin in clinical applications. Through combining the aggregation induced emission (AIE) fluorogen tetraphenylethene (TPE) and heparin specific binding peptide AG73, the promising "turn on" fluorescent probe TPE-1 has been developed. Nevertheless, although TPE-1 could achieve the sensitive and selective detection of heparin, the low proteolytic stability and undesirable poor solubility may limit its widespread applications. In this study, seven TPE-1 derived fluorescent probes were rationally designed, efficiently synthesized and evaluated. The stability and water solubility were systematically estimated. Especially, to achieve real-time monitoring of proteolytic stability, the novel Abz/Dnp-based "turn on" probes that employ the internally quenched fluorescent (IQF) mechanism were designed and synthesized. Moreover, the detection ability of synthetic fluorescent probes for heparin were systematically evaluated. Importantly, the performance of d-type peptide fluorescent probe XH-6 indicated that d-type amino acid substitutions could significantly improve the proteolytic stability without compromising its ability of heparin sensing, and attaching solubilizing tag 2-(2-aminoethoxy) ethoxy) acid (AEEA) could greatly enhance the solubility. Collectively, this study not only established practical strategies to improve both the water solubility and proteolytic stability of "turn on" fluorescent probes for heparin sensing, but also provided valuable references for the subsequent development of enzymatic hydrolysis-resistant d-type peptides based fluorescent probes.

Engineering Co-N-Cr Cross-Interfacial Electron Bridges to Break Activity-Stability Trade-Off for Superdurable Bifunctional Single Atom Oxygen Electrocatalysts.

Atomically dispersed metal-nitrogen-carbon (M-N-C) catalysts have exhibited encouraging oxygen reduction reaction (ORR) activity. Nevertheless, the insufficient long-term stability remains a widespread concern owing to the inevitable 2-electron byproducts, H2O2. Here, we construct Co-N-Cr cross-interfacial electron bridges (CIEBs) via the interfacial electronic coupling between Cr2O3 and Co-N-C, breaking the activity-stability trade-off. The partially occupied Cr 3d-orbitals of Co-N-Cr CIEBs induce the electron rearrangement of CoN4 sites, lowering the Co-OOH* antibonding orbital occupancy and accelerating the adsorption of intermediates. Consequently, the Co-N-Cr CIEBs suppress the two-electron ORR process and approach the apex of Sabatier volcano plot for four-electron pathway simultaneously. As a proof-of-concept, the Co-N-Cr CIEBs is synthesized by the molten salt template method, exhibiting dominant 4-electron selectively and extremely low H2O2 yield confirmed by Damjanovic kinetic analysis. The Co-N-Cr CIEBs demonstrates impressive bifunctional oxygen catalytic activity (▵E=0.70 V) and breakthrough durability including 100 % current retention after 10 h continuous operation and cycling performance over 1500 h for Zn-air battery. The hybrid interfacial configuration and the understanding of the electronic coupling mechanism reported here could shed new light on the design of superdurable M-N-C catalysts.

BMP7 ameliorates intervertebral disc degeneration in type 1 diabetic rats by inhibiting pyroptosis of nucleus pulposus cells and NLRP3 inflammasome activity.

BACKGROUND: Accumulating evidence indicates that intervertebral disc degeneration (IDD) is associated with diabetes mellitus (DM), while the underlying mechanisms still remain elusive. Herein, the current study sought to explore the potential molecular mechanism of IDD in diabetic rats based on transcriptome sequencing data. METHODS: Streptozotocin (STZ)-induced diabetes mellitus type 1 (T1DM) rats were used to obtain the nucleus pulposus tissues for transcriptome sequencing. Next, differentially expressed genes (DEGs) in transcriptome sequencing data and GSE34000 microarray dataset were obtained and intersected to acquire the candidate genes. Moreover, GO and KEGG enrichment analyses were performed to analyze the cellular functions and molecular signaling pathways primarily regulated by candidate DEGs. RESULTS: A total of 35 key genes involved in IDD of T1DM rats were mainly enriched in the extracellular matrix (ECM) and cytokine adhesion binding-related pathways. NLRP3 inflammasome activation promoted the pyroptosis of nucleus pulposus cells (NPCs). Besides, BMP7 could affect the IDD of T1DM rats by regulating the inflammatory responses. Additionally, NPCs were isolated from STZ-induced T1DM rats to illustrate the effects of BMP7 on IDD of T1DM rats using the ectopic expression method. Both in vitro and in vivo experiments validated that BMP7 alleviated IDD of T1DM rats by inhibiting NLRP3 inflammasome activation and pyroptosis of NPCs. CONCLUSION: Collectively, our findings provided novel mechanistic insights for understanding of the role of BMP7 in IDD of T1DM, and further highlighted BMP7 as a potential therapeutic target for preventing IDD in T1DM.

Design, synthesis and anticancer evaluation of novel oncolytic peptide-chlorambucil conjugates.

Nitrogen mustards (NMs) are an important class of chemotherapeutic drugs and have been widely employed for the treatment of various cancers. However, due to the high reactivity of nitrogen mustard, most NMs react with proteins and phospholipids within the cell membrane. Therefore, only a very small fraction of NMs can reach the reach nucleus, alkylating and cross-linking DNA. To efficiently penetrate the cell membrane barrier, the hybridization of NMs with a membranolytic agent may be an effective strategy. Herein, the chlorambucil (CLB, a kind of NM) hybrids were first designed by conjugation with membranolytic peptide LTX-315. However, although LTX-315 could help large amounts of CLB penetrate the cytomembrane and enter the cytoplasm, CLB still did not readily reach the nucleus. Our previous work demonstrated that the hybrid peptide NTP-385 obtained by covalent conjugation of rhodamine B with LTX-315 could accumulate in the nucleus. Hence, the NTP-385-CLB conjugate, named FXY-3, was then designed and systematically evaluated both in vitro and in vivo. FXY-3 displayed prominent localization in the cancer cell nucleus and induced severe DNA double-strand breaks (DSBs) to trigger cell apoptosis. Especially, compared with CLB and LTX-315, FXY-3 exhibited significantly increased in vitro cytotoxicity against a panel of cancer cell lines. Moreover, FXY-3 showed superior in vivo anticancer efficiency in the mouse cancer model. Collectively, this study established an effective strategy to increase the anticancer activity and the nuclear accumulation of NMs, which will provide a valuable reference for future nucleus-targeting modification of nitrogen mustards.

Efficient synthesis and anticancer evaluation of spider toxin peptide LVTX-8-based analogues with enhanced stability.

Cytotoxic peptides derived from spider venoms have been considered as promising candidates for anticancer treatment. The novel cell penetrating peptide LVTX-8, which is a 25-residue amphipathic α-helical peptide isolated from spider Lycosa vittata, exhibited potent cytotoxicity and is a potential precursor for further anticancer drug development. Nevertheless, LVTX-8 may be easily degraded by multiple proteases, inducing the proteolytic stability problem and short half-life. In this study, ten LVTX-8-based analogs were rationally designed and the efficient manual synthetic method was established by the DIC/Oxyma based condensation system. The cytotoxicity of synthetic peptides was systematically evaluated against seven cancer cell lines. Seven of the derived peptides exhibited high cytotoxicity towards tested cancer in vitro, which was better than or comparable to that of natural LVTX-8. In particular, both N-acetyl and C-hydrazide modified LVTX-8 (825) and the conjugate methotrexate (MTX)-GFLG-LVTX-8 (827) possessed more durable anticancer efficiency, higher proteolytic stability, as well as lower hemolysis. Finally, we confirmed that LVTX-8 could disrupt the integrity of cell membrane, target the mitochondria and reduce the mitochondrial membrane potential to induce the cell death. Taken together, the structural modifications were conducted on LVTX-8 for the first time and the stability significantly improved derivatives 825 and 827 may provide useful references for the modifications of cytotoxic peptides.

The hybrid oncolytic peptide NTP-385 potently inhibits adherent cancer cells by targeting the nucleus.

The use of oncolytic peptides with activity against a wide range of cancer entities as a new and promising cancer therapeutic strategy has drawn increasing attention. The oncolytic peptide LTX-315 derived from bovine lactoferricin (LfcinB) was found to be highly effective against suspension cancer cells, but not adherent cancer cells. In this study, we tactically fused LTX-315 with rhodamine B through a hybridization strategy to design and synthesize a series of nucleus-targeting hybrid peptides and evaluated their activity against adherent cancer cells. Thus, four hybrid peptides, NTP-212, NTP-217, NTP-223 and NTP-385, were synthesized. These hybrid peptides enhanced the anticancer activity of LTX-315 in a panel of adherent cancer cell lines by 2.4- to 37.5-fold. In model mice bearing B16-F10 melanoma xenografts, injection of NTP-385 (0.5 mg per mouse for 3 consecutive days) induced almost complete regression of melanoma, prolonged the median survival time and increased the overall survival. Notably, the administered dose of NTP-385 was only half the effective dose of LTX-315. We further revealed that unlike LTX-315, which targets the mitochondria, NTP-385 disrupted the nuclear membrane and accumulated in the nucleus, resulting in the transfer of a substantial amount of reactive oxygen species (ROS) from the cytoplasm to the nucleus through the fragmented nuclear membrane. This ultimately led to DNA double-strand break (DSB)-mediated intrinsic apoptosis. In conclusion, this study demonstrates that hybrid peptides obtained from the fusion of LTX-315 and rhodamine B enhance anti-adherent cancer cell activity by targeting the nucleus and triggering DNA DSB-mediated intrinsic apoptosis. This study also provides an advantageous reference for nucleus-targeting peptide modification.

First Report of Panax notoginseng Wilt Disease Caused by Fusarium graminearum in China.

Panax notoginseng is one of the important economic crops under the forest, which is widely planted in Yunnan Province, China. In August of 2022, a survey in Xundian county (25º26' N, 12 103°7' E), was accomplished to verify the occurrence of wilt disease in P. notoginseng and understand its aetiology. The site is an underforest of organic P. notoginseng, covering an area of over 40 ha. Disease symptoms included severe stunting, leaf chlorosis, red or yellow stalks, and rotting roots. The entire plant gradually wilted and died with disease progression (Fig. 1). To identify the causal agent, we collected more than 30 wilted P. notoginseng plants and got the plant tissues from the symptomatic leaves, stalks, and roots. The tissues surface sterilised with 0.5% sodium hypochlorite for 2 min, followed by 75% alcohol for 1 min, and rinsed in sterilised water three times. Upon drying, samples were placed onto potato dextrose agar (PDA) incubated in the dark at 25°C (Bilgi et al. 2011). Isolates were then transferred to carnation leaf agar (CLA) to induce sporulation. Colonies on PDA were yellow, orange to red, with abundant fluffy aerial mycelia with a dark red pigment on the undersides; Colonies on CLA were orange to yellow (Fig. 2). Fusiform macroconidia and bottle-shaped conidiogenous cells were visible under a microscope. Microconidia were not observed. Macroconidia were measured as 18.5-40.5 µm × 3-4.7 µm (n = 60) (Fig. 3), and possessed 2 to 6 septa. These are similar to previously reported morphological characteristics of Fusarium graminearum (Shikur et al. 2018; Martinez et al. 2019). Cetyltrimethylammonium bromide rapid plant genome extraction kit-DN14 was used to obtain genomic DNA from two representative isolate, the ITS, TEF1 and RPB2 gene were amplified by Polymerase Chain Reaction using primers ITS5/ITS4 (White et al, 1990), EF1-983F/EF1-2218R (Rehner et al, 2005), bRPB2-6F/bRPB2-7.1R (Matheny et al, 2002), respectively. BLAST homology search for nucleotide sequences revealed > 99% similarity to F. graminearum ITS (550bp; MG274308, KU847854), TEF1 (1000bp; MH572248, MH572252) and RPB2 (1000bp; KT855203, KT855206) sequences. All sequences from this study were deposited in GenBank (OP617343 and OP617344 for ITS; OP930951 and OP930952 for TEF1; OP930953 and OP930954 for RPB2). In the phylogenetic tree, the isolates (SWFU 0000116, SWFU 0000117) clustered with the representative strains of F. graminearum. The morphology and multi-gene phylogenetic analysis indicated that the new isolate is F. graminearum. Koch's postulates were used to confirm that the symptoms in wilted P. notoginseng were attributable to F. graminearum. First, healthy leaves were gently wounded with a needle and sprayed with spore suspension (1.0 × 106 spores mL-1) in a hand sprayer (Martinez et al, 2019). All P. notoginseng plants were then replanted in pots with a diameter of 20 cm (1 plants/pot) filled with mixture of sterilised soil, and incubated at 25-27°C. The blank control comprised sterile cotton soaked in sterile water and inactivated mycelia sprayed on the leaves. After 7d of incubation, all inoculated leaves and stalks developed necrosis and developed pale red mycelia, while control plants remained symptomless (Fig. 4-5). The pathogen was successfully isolated from these inoculated plants and identified as F. graminearum. Koch's postulates were implemented. To the best of our knowledge, this is the first report from China with evidence of F. graminearum infecting P. notoginseng.

Near-Field Modulation of Differently Oriented Single Photon Emitters with A Plasmonic Probe.

Single photon emitters (SPEs) are critical components of photon-based quantum technology. Recently, the interaction between surface plasmons and emitters has attracted increasing attention because of its potential to improve the quality of single-photon sources through stronger light-matter interactions. In this work, we use a hybrid plasmonic probe composed of a fiber taper and silver nanowire to controllably modulate the radiation properties of SPEs with differently oriented polarization. For out-of-plane oriented SPEs such as single CdSe quantum dots, the radiation lifetime could be reduced by a factor as large as seven; for in-plane oriented SPEs such as hBN defect SPEs, the average modulation amplitude varied from 0.69 to 1.23, depending on the position of the probe. The experimental results were highly consistent with the simulations and theory. This work provides an efficient approach for optimizing the properties of SPEs for quantum photonic integration.

Discovery, synthesis, and optimization of teixobactin, a novel antibiotic without detectable bacterial resistance.

Discovering new antibiotics with novel chemical scaffolds and antibacterial mechanisms presents a challenge for medicinal scientists worldwide as the ever-increasing bacterial resistance poses a serious threat to human health. A new cyclic peptide-based antibiotic termed teixobactin was discovered from a screen of uncultured soil bacteria through iChip technology in 2015. Teixobactin exhibits excellent antibacterial activity against all the tested gram-positive pathogens and Mycobacterium tuberculosis, including drug-resistant strains. Given that teixobactin targets the highly conserved lipid II and lipid III, which induces the simultaneous inhibition of both peptidoglycan and teichoic acid synthesis, the emergence of resistance is considered to be rather difficult. The novel structure, potent antibacterial activity, and highly conservative targets make teixobactin a promising lead compound for further antibiotic development. This review provides a comprehensive treatise on the advances of teixobactin in the areas of discovery processes, antibacterial activity, mechanisms of action, chemical synthesis, and structural optimizations. The synthetic methods for the key building block l-allo-End, natural teixobactin, representative teixobactin analogs, as well as the structure-activity relationship studies will be highlighted and discussed in details. Finally, some insights into new trends for the generation of novel teixobactin analogs and tips for future work and directions will be commented.

Comparison of different strategies towards the chemical synthesis of long-chain scorpion toxin AaH-II.

Long-chain scorpion toxin AaH-II isolated from Androctonus australis Hector can selectively inhibit mammalian voltage-gated sodium ion channel Nav 1.7 responsible for pain sensation. Efficient chemical synthesis of AaH-II and its derivatives is beneficial to the study of the function and mechanism of Nav 1.7 and the development of potential peptide inhibitors. Herein, we compared three different strategies, namely, direct solid-phase peptide synthesis, hydrazide-based two-segment native chemical ligation, and hydrazide-based three-segment native chemical ligation for the synthesis of AaH-II. The hydrazide-based two-segment native chemical ligation affords the target toxin with the optimal efficiency, which provides a practically robust procedure for the preparation of tool molecules derived from AaH-II to study the biological functions and modulation of Nav 1.7. Our work highlights the importance of selecting suitable segment condensation approach in the chemical synthesis of protein toxins.

DIC/Oxyma-based accelerated synthesis and oxidative folding studies of centipede toxin RhTx.

Coupling reagents play crucial roles in the iterative construction of amide bonds for the synthesis of peptides and peptide-based derivatives. The novel DIC/Oxyma condensation system featured with the low risk of explosion displayed remarkable abilities to inhibit racemization, along with efficient coupling efficiency in both manual and automated syntheses. Nevertheless, an ideal reaction molar ratio in DIC/Oxyma condensation system and the moderate reaction temperature by manual synthesis remain to be further investigated. Herein, the synthetic efficiencies of different reaction ratios between DIC and Oxyma under moderate reaction temperature were systematically evaluated. The robustness and efficiency of DIC/Oxyma condensation system are validated by the rapid synthesis of linear centipede toxin RhTx. Different folding strategies were applied for the construction of disulfide bridges in RhTx, which was further confirmed in assays of circular dichroism and patch-clamp electrophysiology evaluation. This work establishes the DIC/Oxyma-based accelerated synthesis of peptides under moderate condensation conditions, which is especially useful for the manual synthesis of peptides. Besides, the strategy presented here provides robust technical supports for the large-scale synthesis and oxidative folding of RhTx.