Three amphioxus reference genomes reveal gene and chromosome evolution of chordates.

The slow-evolving invertebrate amphioxus has an irreplaceable role in advancing our understanding of the vertebrate origin and innovations. Here we resolve the nearly complete chromosomal genomes of three amphioxus species, one of which best recapitulates the 17 chordate ancestor linkage groups. We reconstruct the fusions, retention, or rearrangements between descendants of whole-genome duplications, which gave rise to the extant microchromosomes likely existed in the vertebrate ancestor. Similar to vertebrates, the amphioxus genome gradually establishes its three-dimensional chromatin architecture at the onset of zygotic activation and forms two topologically associated domains at the Hox gene cluster. We find that all three amphioxus species have ZW sex chromosomes with little sequence differentiation, and their putative sex-determining regions are nonhomologous to each other. Our results illuminate the unappreciated interspecific diversity and developmental dynamics of amphioxus genomes and provide high-quality references for understanding the mechanisms of chordate functional genome evolution.

RNA base editing therapy cures hearing loss induced by OTOF gene mutation.

Otoferlin (OTOF) gene mutations represent the primary cause of hearing impairment and deafness in auditory neuropathy. The c.2485C>T (p. Q829X) mutation variant is responsible for approximately 3% of recessive prelingual deafness cases within the Spanish population. Previous studies have used two recombinant AAV vectors to overexpress OTOF, albeit with limited efficacy. In this study, we introduce an enhanced mini-dCas13X RNA base editor (emxABE) delivered via an AAV9 variant, achieving nearly 100% transfection efficiency in inner hair cells. This approach is aimed at treating OTOFQ829X, resulting in an approximately 80% adenosine-to-inosine conversion efficiency in humanized OtofQ829X/Q829X mice. Following a single scala media injection of emxABE targeting OTOFQ829X (emxABE-T) administered during the postnatal day 0-3 period in OtofQ829X/Q829X mice, we observed OTOF expression restoration in nearly 100% of inner hair cells. Moreover, auditory function was significantly improved, reaching similar levels as in wild-type mice. This enhancement persisted for at least 7 months. We also investigated P5-P7 and P30 OtofQ829X/Q829X mice, achieving auditory function restoration through round window injection of emxABE-T. These findings not only highlight an effective therapeutic strategy for potentially addressing OTOFQ829X-induced hearing loss but also underscore emxABE as a versatile toolkit for treating other monogenic diseases characterized by premature termination codons.

Targeted chemical profiling for p-HAP glycosides by using molecular networking and comparative analysis of their contents between Artemisia japonica and Artemisia capillaris.

A total of 65 phenolic acid compounds were annotated or identified by UHPLC-MS/MS method, among them, 17 p-HAP (p-hydroxyacetophenone) glycosides were firstly targeted profiled based on molecular networking. Their characteristic product ions of MS/MS spectra were found and examined on the guideline of targeted isolation. As a result, a new p-HAP glycoside was thus obtained and determined as 2'-O-caffeoyl-p-HAP-4-O-ß-D-glucopyranoside (33) based on 1D and 2D NMR data. Besides, multicomponents quantitative analysis indicated the distinct regional variability in chemicals distribution of A. japonica, and meanwhile, the contents of p-HAP glycosides from A. japonica were higher than those in A. capillaris as a whole, which further suggested the potential medicinal value of A. japonica.

The antennal transcriptome analysis and characterizations of odorant-binding proteins in Megachile saussurei (Hymenoptera, Megachilidae).

BACKGROUND: Odorant-binding proteins (OBPs) are essential in insect's daily behaviors mediated by olfactory perception. Megachile saussurei Radoszkowski (Hymenoptera, Megachilidae) is a principal insect pollinating alfalfa (Medicago sativa) in Northwestern China. The olfactory function have been less conducted, which provides a lot of possibilities for our research. RESULTS: Our results showed that 20 OBPs were identified in total. Multiple sequence alignment analysis indicated MsauOBPs were highly conserved with a 6-cysteine motif pattern and all belonged to the classic subfamily, coding 113-196 amino acids and sharing 41.32%-99.12% amino acid identity with known OBPs of other bees. Phylogenetic analysis indicated there were certain homologies existed among MsauOBPs and most sequences were clustered with that of Osmia cornuta (Hymenoptera, Megachilidae). Expression analysis showed the identified OBPs were mostly enriched in antennae instead of other four body parts, especially the MsauOBP2, MsauOBP3, MsauOBP4, MsauOBP8, MsauOBP11 and MsauOBP17, in which the MsauOBP2, MsauOBP4 and MsauOBP8 presented obvious tissue-biased expression pattern. Molecular docking results indicated MsauOBP4 might be the most significant protein in recognizing alfalfa flower volatile 3-Octanone, while MsauOBP13 might be the most crucial protein identifying (Z)-3-hexenyl acetate. It was also found the lysine was a momentous hydrophilic amino acid in docking simulations. CONCLUSION: In this study, we identified and analyzed 20 OBPs of M. saussurei. The certain homology existed among these OBPs, while some degree of divergence could also be noticed, indicating the complex functions that different MsauOBPs performed. Besides, the M. saussurei and Osmia cornuta were very likely to share similar physiological functions as most of their OBPs were clustered together. MsauOBP4 might be the key protein in recognizing 3-Octanone, while MsauOBP13 might be the key protein in binding (Z)-3-hexenyl acetate. These two proteins might contribute to the alfalfa-locating during the pollination process. The relevant results may help determine the highly specific and effective attractants for M. saussurei in alfalfa pollination and reveal the molecular mechanism of odor-evoked pollinating behavior between these two species.

Effectiveness and tolerability of camrelizumab combined with molecular targeted therapy for patients with unresectable or advanced HCC.

There is a lack of effective programmed cell death protein 1 (PD-1)-targeted immunotherapy with good tolerability in patients with advanced hepatocellular carcinoma (HCC) and severely compromised liver function. We assessed patient outcomes after combined camrelizumab and molecular targeted therapy in a multicenter cohort study in China. The study included 99 patients with advanced HCC (58 Child-Pugh A and 41 Child-Pugh B), 84 of them received camrelizumab combined with molecular targeted therapy from January 10, 2019, to March 31, 2021. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and adverse events (AEs) were assessed. The median follow-up was 12.1 months. For patients with Child-Pugh B, the OS probability at 12-months, ORR and DCR were 49.7%, 31.7% and 65.9%, respectively, and the median PFS was 5.1 months [95% confidence interval (CI) 3.0-7.1], which were comparable with Child-Pugh A patients, although median OS was shorter in Child-Pugh B patients (20.5 vs.13.4 months, P = 0.12). In multivariate analysis, macrovascular infiltration (MVI), but not sex, age, hepatitis B virus etiology, extrahepatic metastasis, Child-Pugh B, or AFP > 400 ng/ml, was associated with 12-months OS [hazard ratio (HR) 2.970, 95% CI 1.276-6.917, P = 0.012] and ORR (HR 2.906, 95% CI 1.18-7.16, P = 0.020). Grade 3/4 immune-related AEs occurred in 26.8% of Child-Pugh B patients, including one potentially treatment-related death. In both groups, the most common AEs were immune thrombocytopenia and hepatotoxicity. Camrelizumab combined with targeted therapy showed favorable effectiveness and tolerability with manageable toxicities in Chinese HCC patients, regardless of Child-Pugh A/B liver function. MVI was associated with suboptimal immunotherapy response and poor prognosis.

Preparation of Polyethylene/α-Zirconium Phosphate Nanocomposites via a Well-Controlled Polyethylene-Grafted Interface.

It is a daunting task to prepare polyolefin nanocomposites that contain well-exfoliated nanoplatelets due to the nonpolar and high crystallinity nature of polyolefins. In this research, a robust approach was developed to prepare polyethylene (PE) nanocomposites by grafting maleated polyethylene (MPE) onto pre-exfoliated α-zirconium phosphate (ZrP) nanoplatelets via a simple amine-anhydride reaction to form ZrP-g-MPE. Several variables, including maleic anhydride (MA) content, MPE graft density, MPE molecular weight, and PE matrix crystallinity, were investigated to determine how they influence ZrP-g-MPE dispersion in PE. It was found that grafted PE has a different morphology and that the long PE brushes with medium graft density on ZrP can achieve sufficient chain entanglement and cocrystallization with PE matrix to stabilize and maintain ZrP-g-MPE dispersion after solution or melt mixing. This leads to enhanced Young's modulus, yield stress, and ductility. The structure-property relationship of PE/ZrP-g-MPE nanocomposites and usefulness of this study for the preparation of high-performance polyolefin nanocomposites are discussed.

Multi-scale molecular simulation of random peptide phase separation and its extended-to-compact structure transition driven by hydrophobic interactions.

Intrinsically disordered proteins (IDPs) often undergo liquid-liquid phase separation (LLPS) and form membraneless organelles or protein condensates. One of the core problems is how do electrostatic repulsion and hydrophobic interactions in peptides regulate the phase separation process? To answer this question, this study uses random peptides composed of positively charged arginine (Arg, R) and hydrophobic isoleucine (Ile, I) as the model systems, and conduct large-scale simulations using all atom and coarse-grained model multi-scale simulation methods. In this article, we investigate the phase separation of different sequences using a coarse-grained model. It is found that the stronger the electrostatic repulsion in the system, the more extended the single-chain structure, and the more likely the system forms a low-density homogeneous phase. In contrast, the stronger the hydrophobic effect of the system, the more compact the single-chain structure, the easier phase separation, and the higher the critical temperature of phase separation. Overall, by taking the random polypeptides composed of two types of amino acid residues as model systems, this study discusses the relationship between the protein sequence and phase behaviour, and provides theoretical insights into the interactions within or between proteins. It is expected to provide essential physical information for the sequence design of functional IDPs, as well as data to support the diagnosis and treatment of the LLPS-associated diseases.

Comparison of two novel diagnostic criteria for bronchopulmonary dysplasia in predicting adverse outcomes of preterm infants: a retrospective cohort study.

BACKGROUND: This study aimed to compare the predictive value of two diagnostic criteria for bronchopulmonary dysplasia (BPD) in preterm infants with gestational age (GA) < 32 weeks for death or severe respiratory morbidity at corrected age of 18-24 months. METHODS: In this retrospective cohort study, clinical data from July 2019 to September 2021 were classified by 2018 National Institute of Child Health and Human Development (NICHD) and 2019 Jensen definitions of BPD. Based on the follow-up results, the enrolled population was divided into adverse outcome group and normal outcome group. Logistic regression and receiver operating characteristic (ROC) curve analyses were conducted to explore the risk factors of adverse outcomes and evaluate the predictive value of both diagnostic criteria. RESULTS: Of 451 infants, 141 (31.3%) had adverse outcomes, which increased with increasing severity of BPD. Logistic regression analysis showed only BPD was an independent risk factor for adverse outcomes in preterm infants. ROC analysis revealed that both diagnostic criteria showed similar predictive values (2018 NICHD definition AUC = 0.771 vs. 2019 Jensen definition AUC = 0.770), with specificities of 93.5% and 96.8%, respectively; however, combining them separately with GA or birth weight did not improve their predictive values. CONCLUSIONS: The two novel definitions of BPD demonstrate similar predictive values in predicting death or severe respiratory morbidity at corrected age of 18-24 months, with higher specificity observed in both.

Comparison of short-term and long-term clinical effects of modified overlap anastomosis and conventional incision-assisted anastomosis in laparoscopic total gastrectomy.

BACKGROUND: To compare short-term and long-term clinical effects of modified overlap anastomosis and conventional incision-assisted anastomosis for laparoscopic total gastrectomy. METHODS: This retrospective cohort study included patients with gastric cancer admitted to the Second Affiliated Hospital of Fujian Medical University from January 2016 to March 2020. Quality of life, intraoperative and postoperative conditions were analyzed. RESULTS: Compared with the conventional assisted group, the modified overlap group showed a shorter auxiliary incision, milder postoperative pain, shorter time to the first postoperative anal exhaust, shorter time to the first postoperative liquid food intake, and shorter postoperative stay. There were no differences between the two groups regarding operation time, esophagus-jejunum anastomosis time, intraoperative blood loss, number of lymph nodes dissected, and length of the upper incision margin. There were no differences between the two groups regarding postoperative early and late complications. There were no differences between the two groups regarding the QLQ-C30 scale three years after the operation. The scores of the QLQ-STO22 scale 3 years after the operation showed significantly lower scores for dysphagia and feeding limit in the modified overlap group than those in the conventional assisted anastomosis group. There was no recurrence in the modified overlap group but one patient in the conventional assisted group. CONCLUSIONS: Patients undergoing totally laparoscopic total gastrectomy with modified overlap anastomosis have better minimal invasiveness and faster post-operative recovery than conventional incision-assisted anastomosis.

Highly Conjugated Graphitic Carbon Nitride Nanofoam for Photocatalytic Hydrogen Evolution.

As a metal-free photocatalyst, graphitic carbon nitride (g-CN) shows great potential for photocatalytic water splitting, although its performance is significantly limited by structural defects due to incomplete polymerization. In the present work, we successfully synthesize highly conjugated g-CN nanofoam through an iodide substitution technique. The product possesses a high polymerization degree, low defect density, and large specific surface area; as a result, it achieves a hydrogen evolution rate of 9.06 mmol h-1 g-1 under visible light irradiation, with an apparent quantum efficiency (AQE) of 18.9% at 420 nm. Experimental analysis and theoretical calculations demonstrate that the recombination of photogenerated carriers at C-NHx defects was effectively depressed in the nanofoam, giving rise to the high photocatalytic activity.

Systematic research on gallium atom-doped neutral small- and medium-sized gas-phase magnesium clusters: A DFT study of GaMgn (n=2-12) clusters.

Structure, stability, charge transfer, chemical bonding, and spectroscopic properties of Ga atom-doped neutral Mgn (n = 2-12) clusters have been systematically investigated by CALYPSO and density functional theory. All cluster structures are based on "tetrahedral" and "yurt-like" growth except for GaMg2. The ground state isomer of GaMg8 with high symmetry structure is predicted to be the best-fit candidate for the "magic" cluster because of its excellent stability. Natural bond orbital calculations reveal that Ga and Mg atoms play the role of electron acceptor and donor in all ground state isomers, while the orbitals in both Ga and Mg are sp-hybridized. Most importantly, chemical bonding studies based on atom-in-molecular theory have shown that the lowest-energy state of GaMg4 is so special, in that it has not only the critical size for the appearance of Mg-Mg covalent bonds, but also the only cluster that has both Ga-Mg covalent and non-covalent bonds. Finally, theoretical calculations of IR and Raman spectra of all ground state isomers indicate that the spectra of these clusters are observable in the low-frequency band, and thus they can be identified by spectroscopic experiments. Furthermore, the bond heterogeneity of the Ga-Mg in the GaMg4 ground state isomer has also been specifically investigated, including the fixed GaMg4 structure with Mg atoms added in different directions, as well as ab initio molecular dynamics sampling at different temperatures.

C-Reactive Protein-to-Albumin Ratio as an Early Biomarker to Identify Sepsis in Neonates with Pneumonia.

Objectives: Neonates with pneumonia often also have sepsis, and the identifying sepsis from pneumonia may be a challenge for clinicians. However, there are no available data regarding the clinical value C-reactive protein-to-albumin ratio (CAR) in identifying sepsis in neonates with pneumonia. The aim of this study was to evaluate the clinical value of CAR in identifying sepsis in neonates with pneumonia. Methods: 847 neonates with pneumonia were included in this study, of which 511 neonates were diagnosed with sepsis. Neonates were divided into the sepsis group and the nonsepsis group. All neonates underwent extensive and necessary clinical and laboratory tests. CAR was calculated as serum C-reactive protein (ng/ml)/albumin (mg/ml). All statistical analyses were performed using the statistical package SPSS 24.0, as appropriate. Results: Compared with the nonsepsis group, neonates with sepsis have a higher CAR (P < 0.001). Further analysis showed that the prevalence of neonates with sepsis increased significantly from 41.0% in the low CAR group (CAR ≤ 0.024 × 10-3) to 80.0% in the high CAR group (CAR > 0.024 × 10-3) (P < 0.001). Correlation analysis showed that there was a strong positive correlation between CAR and PCT (r = 0.452, P < 0.001), nSOFA (r = 0.267, P < 0.001), and the prolonged length of hospital stay (r = 0.311, P < 0.001). Multiple logistic regression showed that CAR was an independent risk factor for the presence of sepsis in neonates with pneumonia. Receiver operating characteristic curve analysis revealed that CAR had adequate discriminatory power in predicting sepsis in neonates with pneumonia (area under curve (AUC) = 0.76, 95% CI 0.73-0.79, P < 0.001). Conclusions: CAR can be used as a new marker to identify sepsis in neonates with pneumonia.

Discovery of a Thioxanthone-TfOH Complex as a Photoredox Catalyst for Hydrogenation of Alkenes Using p-Xylene as both Electron and Hydrogen Sources.

Hydrogenation of alkenes is one of the most fundamental transformations in organic synthesis, and widely used in the petrochemical, pharmaceutical, and food industries. Although numerous hydrogenation methods have been developed, novel types of catalysis with new mechanisms and new hydrogen sources are still desirable. Thioxanthone (TX) is widely used in energy-transfer photoreactions, but rarely in photoredox processes. Herein we show that a catalytic amount of TfOH as a co-catalyst can tune the properties of TX to make it a photoredox catalyst with highly enhanced oxidative capability in the hydrogenation of carbonylated alkenes with the cheap petroleum industrial product p-xylene serving as the hydrogen source. Deuterium can also be introduced by this method by using D2 O as the D source. To the best of our knowledge, this is the first example of using p-xylene as a hydrogen source.

Evaluation of the clinical effect of an artificial intelligence-assisted diagnosis and treatment system for neonatal seizures in the real world: a multicenter clinical study protocol. / æ–°ç”Ÿå„¿æƒŠåŽ¥æ™ºèƒ½è¯Šç–—ç³»ç»ŸçœŸå®žåœºæ™¯ä¸´åºŠå®žæ–½æ•ˆæžœç»¼åˆè¯„ä»·çš„å¤šä¸­å¿ƒä¸´åºŠç ”ç©¶æ–¹æ¡ˆ.

Neonatal seizures are the most common clinical manifestations of critically ill neonates and often suggest serious diseases and complicated etiologies. The precise diagnosis of this disease can optimize the use of anti-seizure medication, reduce hospital costs, and improve the long-term neurodevelopmental outcomes. Currently, a few artificial intelligence-assisted diagnosis and treatment systems have been developed for neonatal seizures, but there is still a lack of high-level evidence for the diagnosis and treatment value in the real world. Based on an artificial intelligence-assisted diagnosis and treatment systems that has been developed for neonatal seizures, this study plans to recruit 370 neonates at a high risk of seizures from 6 neonatal intensive care units (NICUs) in China, in order to evaluate the effect of the system on the diagnosis, treatment, and prognosis of neonatal seizures in neonates with different gestational ages in the NICU. In this study, a diagnostic study protocol is used to evaluate the diagnostic value of the system, and a randomized parallel-controlled trial is designed to evaluate the effect of the system on the treatment and prognosis of neonates at a high risk of seizures. This multicenter prospective study will provide high-level evidence for the clinical application of artificial intelligence-assisted diagnosis and treatment systems for neonatal seizures in the real world.

Perovskite Light-Emitting Electrochemical Cells Employing Electron Injection/Transport Layers of Ionic Transition Metal Complexes.

Recently, perovskites have attracted intense attention due to their high potential in optoelectronic applications. Employing perovskites as the emissive materials of light-emitting electrochemical cells (LECs) shows the advantages of simple fabrication process, low-voltage operation, and compatibility with inert electrodes, along with saturated electroluminescence (EL) emission. Unlike in previously reported perovskite LECs, in which salts are incorporated in the emissive layer, the ion-transport layer was separated from the emissive layer in this work. The layer of ionic transition metal complex (iTMC) not only provides mobile ions but also serves as an electron-injection/transport layer. Orthogonal solvents are used in spin coating to prevent the intermixing of stacked perovskite and iTMC layers. The blue iTMC with high ionization potential is effective in blocking holes from the emissive layer and thus ensures EL color saturation. In addition, the carrier balance of the perovskite/iTMC LECs can be optimized by adjusting the iTMC layer thickness. The optimized external quantum efficiency of the CsPbBr3 /iTMC LEC reaches 6.8 %, which is among the highest reported values for perovskite LECs. This work successfully demonstrates that, compared with mixing all components in a single emissive layer, separating the layer of ion transport, electron injection and transport from the perovskite emissive layer is more effective in adjusting device carrier balance. As such, solution-processable perovskite/iTMC LECs open up a new way to realize efficient perovskite LECs.

Perovskite Light-Emitting Electrochemical Cells Employing Electron Injection/Transport Layers of Ionic Transition Metal Complexes.

Invited for the cover of this issue are Chin-Wei Lu, Zu-Po Yang, Hai-Ching Su, and co-workers at National Yang Ming Chiao Tung University and Providence University. The image depicts electron transport for light-emitting electrochemical cells. Read the full text of the article at 10.1002/chem.202103739.

Preparation of Well-Exfoliated Poly(ethylene-co-vinyl acetate)/α-Zirconium Phosphate Nanocomposites.

Poly(ethylene-co-vinyl acetate) (PEVAc) nanocomposites containing exfoliated α-zirconium phosphate (ZrP) have been prepared using a simple solution mixing method to improve their barrier and mechanical properties. ZrP was pre-exfoliated with a surfactant, followed by additional targeted surface functionalization and surfactant exchange to allow for hydrogen bonding of ZrP with the acetate functionality on PEVAc and to improve ZrP surface hydrophobicity. The solvent is found to play an important role in stabilizing ZrP exfoliation in the presence of PEVAc to retain full exfoliation and homogeneous dispersion upon the removal of the solvent. The PEVAc/ZrP nanocomposite exhibits greatly improved oxygen barrier, melt strength, and mechanical properties. The usefulness of the present study for the preparation of olefinic polymer nanocomposites is discussed.

Molecular epidemiology of hepatitis B virus genotypes and subgenotypes in ethnic minority populations, Yunnan province, China.

The aim of our study was to determine the distribution of hepatitis B virus (HBV) genotypes and subgenotypes in ethnic minorities in Yunnan province to provide evidence supporting the theoretical basis for hepatitis B prevention and control. We obtained serum samples and demographic data from 765 individuals reported by Yunnan province who had either acute or chronic HBV infection and were from one of 20 ethnic minority populations: Achang, Bai, Brown, Tibetan, Dai, Deang, Dulong, Hani, Hui, Jingpo, Lahu, Yi, Lisu Miao, Naxi, Nu, Pumi, Wa, Yao, or Zhuang people. We sequenced the HBV DNA and determined the genotypes and subgenotypes of the isolated HBVs. We mapped the genotype and subgenotype distribution by ethnic minority population and conducted descriptive analyses. There were four genotypes among the 20 ethnic groups: genotype B (21.3% of samples), C (76.6%), D (1.8%) and I (0.3%). The most common subgenotype was C1. There were no genotype differences by gender (P = 0.954) or age (P = 0.274), but there were differences by region (P < 0.001). There were differences in genotype distribution (P < 0.001) and subgenotype distribution (P = 0.011) by ethnic group. Genotype D was most prominent in Tibet and most HBV isolates were C/D recombinant viruses. The only two genotype I virus isolates were in Zhuang people. Susceptibility and geographic patterns may influence HBV prevalence in different ethnic populations, but additional research is needed for such a determination.

Adeno-associated virus vector enables safe and efficient Cas9 activation in neonatal and adult Cas9 knockin murine cochleae.

Adeno-associated virus (AAV)-mediated gene delivery systems have been shown to be effective tools for gene manipulation in the inner ear. For example, hair cells (HCs) and multiple other cell types can be transduced by the local injection of AAVs into the inner ear. However, application of the AAV-mediated CRISPR/Cas9 gene-editing approach to the inner ear in adult mice has not yet been studied. Based on our previous work, we investigated several AAV serotypes in neonatal and adult mice in parallel, and found that AAV8 had the top efficiency to transduce inner HCs. We then tested the ability of Cre-expressing AAV8 to activate Cas9 in floxed-Cas9 knockin mice, and observed significant Cas9 activation in the inner ear of both neonatal and adult animals. Neither the AAV8 virus itself nor the surgical procedures used to deliver it-cochleostomy for neonatal mice and canalostomy for adult mice-caused any damage to HCs or impaired normal hearing. Our studies indicate that the local injection of AAV8-Cre can induce Cas9 activation to perform safe and efficient gene editing in the inner ear, expanding the repertoire of gene-editing tools for regulating gene expression in the inner ear as a part of efforts to rescue genetic hearing loss, initiate regeneration of HCs, or develop gene therapy techniques.

Characterization of Miharamycin Biosynthesis Reveals a Hybrid NRPS-PKS to Synthesize High-Carbon Sugar from a Complex Nucleoside.

Miharamycins are peptidyl nucleoside antibiotics with a unique branched C9 pyranosyl amino acid core and a rare 2-aminopurine moiety. Inactivation of 19 genes in the biosynthetic gene cluster and identification of several unexpected intermediates suggest an alternative biosynthetic pathway, which is further supported by feeding experiments and in vitro characterization of an unusual adenylation domain recognizing a complex nucleoside derivative as the substrate. These results thereby provide an unprecedented biosynthetic route of high-carbon sugar catalyzed by atypical hybrid nonribosomal peptide synthetase-polyketide synthase.