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Abstract In the United States, Black individuals have higher rates of cancer mortality than any other racial group. Here, we examine chromosome copy number changes in cancers from more than 1800 self-reported Black patients. We find that tumors from self-reported Black patients are significantly more likely to exhibit whole-genome duplications (WGDs), a genomic event that enhances metastasis and aggressive disease, compared to tumors from self-reported white patients. This increase in WGD frequency is observed across multiple cancer types, including breast, endometrial, and lung cancer, and is associated with shorter patient survival. We further demonstrate that combustion byproducts are capable of inducing WGDs in cell culture, and cancers from self-reported Black patients exhibit mutational signatures consistent with exposure to these carcinogens. In total, these findings identify a type of genomic alteration that is associated with environmental exposures and that may influence racial disparities in cancer outcomes.

As a benzoylurea insecticide, diflubenzuron (DFB) has been widely used in the prevention and control of diseases and insect pests in vegetables, fruits, grain cultivation, and other fields in recent years. In addition, because of its low acute toxicity, excellent biological activity, and specific action mechanism, DFB has been widely used in aquaculture to kill bacteria and lice. With its large-scale production and widespread use, its partial residue remains in environmental media, such as water, soil, and the atmosphere, and causes direct or indirect chronic toxicity to aquatic organisms. The residual DFB enters the human body along the food chain and poses a threat to human health when it reaches a certain concentration through chronic exposure and long-term accumulation. At present, research on DFB insecticides has been limited to the usage and dosage, residual metabolism, and its toxicological effects on the environment. There have been no reports, to our knowledge, on the effect of DFB on gene expression in carp liver in China. The purpose of this study was to explore the differential expression of genes in carp liver under DFB stress.In this study, carp (Cyprinus carpio) was selected as the research subject, and three exposure experiments for 15 days under 0.1 and 1.0 mg/L medicated bath concentrations were carried out in parallel for each concentration. High-throughput sequencing of the liver was performed using the Illumina NovaSeq 6000. Differentially expressed genes (DEGs) were screened by Padj < 0.05 and |log2FoldChange| ≥1, and bioinformatics analysis, such as Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, were performed. The transcriptome analysis results showed that 2 406 and 2 688 DEGs changed significantly at 0.1 and 1.0 mg/L exposure concentrations, respectively, and 821 DEGs were co-expressed between the two groups. GO analysis results showed that DEGs in the DFB exposure group were enriched in biological processes, cell compositions, and molecular functions. KEGG enrichment analysis showed that DEGs in the low DFB concentration exposure group were significantly enriched in metabolic pathways, such as biodegradation and metabolism of xenobiotics, lipid metabolism, carbohydrate metabolism, amino acid metabolism, signal molecules and interactions, endocrine system, and immune system. In addition to the above metabolic pathways, DEGs in the high DFB concentration exposure group were significantly enriched in metabolic pathways, such as folding, classification and degradation, transport, and catabolism.Studies have shown that DFB exposure causes the biodegradation and metabolism of xenobiotics, lipid metabolism, carbohydrate metabolism, and amino acid metabolism, and generates endoplasmic reticulum stress, inflammatory response, and immune toxicity. In summary, the results of this study provide basic data and a theoretical basis for further research on the molecular mechanism of DFB stress in carp.

Histones play crucial roles in both promoting and repressing gene expression, primarily regulated through post-translational modifications (PTMs) at specific amino acid residues. Histone PTMs, including methylation, acetylation, ubiquitination, phosphorylation, lactylation, butyrylation, and propionylation, act as important epigenetic markers. These modifications influence not only chromatin compaction but also gene expression. Their importance extends to the treatment and prevention of various human diseases, particularly cancer, due to their involvement in key cellular processes. Abnormal histone modifications and the enzymes responsible for these alterations often serve as critical drivers in tumor cell proliferation, invasion, apoptosis, and stemness. This review introduces key histone PTMs and the enzymes responsible for these modifications, examining their impact on tumorigenesis and cancer progression. Furthermore, it explores therapeutic strategies targeting histone PTMs and offers recommendations for identifying new potential therapeutic targets.

ABSTRACT Carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) is a significant pathogen causing major public health problems worldwide. This study characterized a novel sequence type 6417 (ST6471) CR-hvKP strain recovered from the blood of a male patient with septicemia. Strain CR2021 is not susceptible to carbapenems, cephalosporin, sulfonamides, quinolones, or levofloxacin and is susceptible to amikacin and tigecycline. Molecular typing indicated that ST6417 is derived from the most dominant hypervirulent K. pneumoniae (hvKP) clone in China, ST23, with a single-locus variation in tonB. The genomic characterization of CR2021, which contains three plasmids, was performed through whole-genome sequencing. The plasmid pCR2021_IncFII contains 12 antibiotic resistance genes [blaCTX-M-3, blaTEM-1B, blaDHA-1, aac (3)-Ild, aadA16, sul1, sul2, qnrB4, ARR-3, dfrA27, qacE, merACDE], all of which are associated with genetic elements. The plasmid pCR2021_IncFIB carries crucial virulence-related genes, while the plasmid pCR2021_IncX3 only harbors the blaNDM-5 resistance gene and exhibits 99% similarity with two other blaNDM-5-carrying IncX3 plasmids (pSHX180-NDM5, pNDM-K725), with coverage of 87% and 100%, respectively. The blaNDM-5 genetic region contains an additional IS26-Tn3 genetic module. Serum killing and anti-human neutrophil phagocytosis tests indicated that CR2021 exhibits high virulence, which was further confirmed in a Galleria mellonella larvae infection model. CR-hvKP is becoming more prevalent in China; however, the majority have evolved from the multidrug resistance clone ST11 and its variants by acquiring virulence factors. Conversely, CR-hvKP derived from hvKP, such as the clone ST23, remains relatively rare. Therefore, the discovery of ST6417 underscores the need for further research into the genetic characteristics and evolution of bacteria.IMPORTANCEST11 and its variants, which often exhibit drug resistance, represent popular clones of carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) in China, often leading to high morbidity and mortality rates owing to their high virulence and robust drug resistance. Conversely, CR-hvKP, originating from the high-virulence sequence type ST23, remains rarely reported. In this study, we identified a novel ST6417 CR-hvKP strain derived from ST23, carrying blaNDM-5 on an IncX3 plasmid conferring resistance to carbapenems. In addition, we elucidate its virulence, resistance to drugs, and genetic characteristics. The discovery of ST6417 highlights the diverse pathways in the evolution of CR-hvKP, warranting increased attention.

Abstract Intercropping with Pleurotus ostreatus has been demonstrated to increase the tea yield and alleviate soil acidification in tea gardens. However, the underlying mechanisms remain elusive. Here, high-throughput sequencing and Biolog Eco analysis were performed to identify changes in the community structure and abundance of soil microorganisms in the P. ostreatus intercropped tea garden at different seasons (April and September). The results showed that the soil microbial diversity of rhizosphere decreased in April, while rhizosphere and non-rhizosphere soil microbial diversity increased in September in the P. ostreatus intercropped tea garden. The diversity of tea tree root microorganisms increased in both periods. In addition, the number of fungi associated with organic matter decomposition and nutrient cycling, such as Penicillium, Trichoderma, and Trechispora, was significantly higher in the intercropped group than in the control group. Intercropping with P. ostreatus increased the levels of total nitrogen (TN), total phosphorus (TP), and available phosphorus (AP) in the soil. It also improved the content of secondary metabolites, such as tea catechins, and polysaccharides in tea buds. Microbial network analysis showed that Unclassified_o__Helotiales, and Devosia were positively correlated with soil TN and pH, while Lactobacillus, Acidothermus, and Monascus were positively correlated with flavone, AE, and catechins in tea trees. In conclusion, intercropping with P. ostreatus can improve the physical and chemical properties of soil and the composition and structure of microbial communities in tea gardens, which has significant potential for application in monoculture tea gardens with acidic soils.

Abstract Base editors (BEs) are a recent generation of genome editing tools that couple a cytidine or adenosine deaminase activity to a catalytically impaired Cas9 moiety (nCas9) to enable specific base conversions at the targeted genomic loci. Given their strong application potential, BEs are under active developments toward greater levels of efficiency and safety. Here, a previously overlooked nCas9‐centric strategy is explored for enhancement of BE. Based on a cytosine BE (CBE), 20 point mutations associated with nCas9‐target interaction are tested. Subsequently, from the initial positive X‐to‐arginine hits, combinatorial modifications are applied to establish further enhanced CBE variants (1.1–1.3). Parallel nCas9 modifications in other versions of CBEs including A3A‐Y130F‐BE4max, YEE‐BE4max, CGBE, and split‐AncBE4max, as well as in the context of two adenine BEs (ABE), likewise enhance their respective activities. The same strategy also substantially improves the efficiencies of high‐fidelity nCas9/BEs. Further evidence confirms that the stabilization of nCas9‐substrate interactions underlies the enhanced BE activities. In support of their translational potential, the engineered CBE and ABE variants respectively enable 82% and 25% higher rates of editing than the controls in primary human T‐cells. This study thus demonstrates a highly adaptable strategy for enhancing BE, and for optimizing other forms of Cas9‐derived tools.

Asthma comprises one of the most common chronic inflammatory conditions, yet still lacks effective diagnostic markers and treatment targets. To gain deeper insights, we comprehensively analyzed microarray datasets of airway epithelial samples from asthmatic patients and healthy subjects in the Gene Expression Omnibus database using three machine learning algorithms. Our investigation identified a pivotal gene, STEAP4. The expression of STEAP4 in patients with allergic asthma was found to be reduced. Furthermore, it was found to negatively correlate with the severity of the disease and was subsequently validated in asthmatic mice in this study. A ROC analysis of STEAP4 showed the AUC value was greater than 0.75. Functional enrichment analysis of STEAP4 indicated a strong correlation with IL-17, steroid hormone biosynthesis, and ferroptosis signaling pathways. Subsequently, intercellular communication analysis was performed using single-cell RNA sequencing data obtained from airway epithelial cells. The results revealed that samples exhibiting low levels of STEAP4 expression had a richer MIF signaling pathway in comparison to samples with high STEAP4 expression. Through both in vitro and in vivo experiments, we further confirmed the overexpression of STEAP4 in airway epithelial cells resulted in decreased expression of MIF, which in turn caused a decrease in the levels of the cytokines IL-33, IL-25, and IL-4; In contrast, when the STEAP4 was suppressed in airway epithelial cells, there was an upregulation of MIF expression, resulting in elevated levels of the cytokines IL-33, IL-25, and IL-4. These findings suggest that STEAP4 in the airway epithelium reduces allergic asthma Th2-type inflammatory reactions by inhibiting the MIF signaling pathway.

Summary: Enhancer-derived RNAs (eRNAs) play critical roles in diverse biological processes by facilitating their target gene expression. However, the abundance and function of eRNAs in early embryos are not clear. Here, we present a comprehensive eRNA atlas by systematically integrating publicly available datasets of mouse early embryos. We characterize the transcriptional and regulatory network of eRNAs and show that different embryo developmental stages have distinct eRNA expression and regulatory profiles. Paternal eRNAs are activated asymmetrically during zygotic genome activation (ZGA). Moreover, we identify an eRNA, MZGAe1, which plays an important function in regulating mouse ZGA and early embryo development. MZGAe1 knockdown leads to a developmental block from 2-cell embryo to blastocyst. We create an online data portal, M2ED2, to query and visualize eRNA expression and regulation. Our study thus provides a systematic landscape of eRNA and reveals the important role of eRNAs in regulating mouse early embryo development.

Porcine epidemic diarrhea virus (PEDV) is considered the cause for porcine epidemic diarrhea (PED) outbreaks and hefty losses in pig farming. However, no effective commercial vaccines against PEDV mutant strains are available nowadays. Here, we constructed three native-like trimeric candidate nanovaccines, i.e., spike 1 trimer (S1-Trimer), collagenase equivalent domain trimer (COE-Trimer), and receptor-binding domain trimer (RBD-Trimer) for PEDV based on Trimer-Tag technology. And evaluated its physical properties and immune efficacy. The result showed that the candidate nanovaccines were safe for mice and pregnant sows, and no animal death or miscarriage occurred in our study. S1-Trimer showed stable physical properties, high cell uptake rate and receptor affinity. In the mouse, sow and piglet models, immunization of S1-Trimer induced high-level of humoral immunity containing PEDV-specific IgG and IgA. S1-Trimer-driven mucosal IgA responses and systemic IgG responses exhibited high titers of virus neutralizing antibodies (NAbs) in vitro. S1-Trimer induced Th1-biased cellular immune responses in mice. Moreover, the piglets from the S1-Trimer and inactivated vaccine groups displayed significantly fewer microscopic lesions in the intestinal tissue, with only one and two piglets showing mild diarrhea. The viral load in feces and intestines from the S1-Trimer and inactivated vaccine groups were significantly lower than those of the PBS group. For the first time, our data demonstrated the protective efficacy of Trimer-Tag-based nanovaccines used for PEDV. The S1-Trimer developed in this study was a competitive vaccine candidate, and Trimer-Tag may be an important platform for the rapid production of safe and effective subunit vaccines in the future.

ABSTRACTThe internal ribosome entry site (IRES) element constitutes a cis-acting RNA regulatory sequence that recruits the ribosomal initiation complex in a cap-independent manner, assisted by various RNA-binding proteins and IRES trans-acting factors. Foot-and-mouth disease virus (FMDV) contains a functional IRES element and takes advantage of this element to subvert host translation machinery. Our study identified a novel mechanism wherein RALY, a member of the heterogeneous nuclear ribonucleoproteins (hnRNP) family belonging to RNA-binding proteins, binds to the domain 3 of FMDV IRES via its RNA recognition motif residue. This interaction results in the downregulation of FMDV replication by inhibiting IRES-driven translation. Furthermore, our findings reveal that the inhibitory effect exerted by RALY on FMDV replication is not attributed to the FMDV IRES-mediated assembly of translation initiation complexes but rather to the impediment of 80S ribosome complex formation after binding with 40S ribosomes. Conversely, 3Cpro of FMDV counteracts RALY-mediated inhibition by the ubiquitin-proteasome pathway. Therefore, these results indicate that RALY, as a novel critical IRES-binding protein, inhibits FMDV replication by blocking the formation of 80S ribosome, providing a deeper understanding of how viruses recruit and manipulate host factors.IMPORTANCEThe translation of FMDV genomic RNA driven by IRES element is a crucial step for virus infections. Many host proteins are hijacked to regulate FMDV IRES-dependent translation, but the regulatory mechanism remains unknown. Here, we report for the first time that cellular RALY specifically interacts with the IRES of FMDV and negatively regulates viral replication by blocking 80S ribosome assembly on FMDV IRES. Conversely, RALY-mediated inhibition is antagonized by the viral 3C protease by the ubiquitin-proteasome pathway. These results would facilitate further understanding of virus-host interactions and translational control during viral infection.

Abstract Quantitatively establishing the correlation between nanoparticle size and fluorescence is essential for understanding the behavior and functionality of fluorescent nanoparticles (FNPs). However, such exploration focusing on organic FNPs has not been achieved to date. Herein, we employ the use of supramolecular polymeric FNPs prepared from tetraphenylethylene‐based bis‐ureidopyrimidinone monomers (bis‐UPys) to relate the size to the fluorescence of organic nanoparticles. At an equal concentration of bis‐UPys, a logarithmic relationship between them is built with a correlation coefficient higher than 0.96. Theoretical calculations indicate that variations in fluorescence intensity among FNPs of different sizes are attributed to the distinct molecular packing environments at the surface and within the interior of the nanoparticles. This leads to different nonradiative decay rates of the embedded and exposed bis‐UPys and thereby changes the overall fluorescence quantum yield of nanoparticles due to their different specific surface areas. The established fluorescence intensity‐size correlation possesses fine universality and reliability, and it is successfully utilized to estimate the sizes of other nanoparticles, including those in highly diluted dispersions of FNPs. This work paves a new way for the simple and real‐time determination of nanoparticle sizes and offers an attractive paradigm to optimize nanoparticle functionalities by the size effect.

ABSTRACT Mass spectrometry imaging (MSI) technologies are widely used today to study the in situ spatial distributions for a variety of analytes. As these technologies advance, the pursuit of higher resolution in MSI has intensified. The limitation of direct desorption/ionization is its insufficient ionization, posing a constraint on the advancement of high‐resolution MSI technologies. The introduction of postionization process compensates the low ionization efficiency caused by sacrificing the desorption area while pursuing high spatial resolution, resolving the conflict between high spatial resolution and high sensitivity in direct desorption/ionization method. Here, we discuss the sampling and ionization steps of MSI separately, and review the postionization methods in MSI according to three different sampling modes: laser sampling, probe sampling, and ion beam sampling. Postionization technology excels in enhancing ionization efficiency, boosting sensitivity, mitigating discrimination effect, simplifying sample preparation, and expanding the scope of applicability. These advantages position postionization technology as a promising tool for biomedical sciences, materials sciences, forensic analysis and other fields. [ABSTRACT FROM AUTHOR]

Dielectric barrier discharge ionization is increasingly used for rapid detection in ambient mass spectrometry, although more often for gaseous and highly volatile samples than for solids and liquids. In this project, we present a rapid and sensitive method for detecting mycotoxins and demonstrate its capability for the detection of aflatoxin B1, zearalenone, and ochratoxin A in food samples. Our method is based on thermal desorption coupled to dielectric barrier discharge ionization mass spectrometry (TD-DBDI-MS), which we show generates minimal interferences and produces almost exclusively molecular ions. We detected mycotoxins in various food samples, including corn, peanuts, millet, and rice. Our method has a linear dynamic range of 1 μg kg−1 to 100 μg kg−1 for all three mycotoxins and a limit of detection (LOD) of 0.31 μg kg−1, 0.28 μg kg−1 and 0.43 μg kg−1, respectively. It is simple, rapid, reduces the pretreatment steps and has significant potential for practical applications. [ABSTRACT FROM AUTHOR]

The emergence of carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKp) is a growing concern due to its high mortality and limited treatment options. Although hypermucoviscosity is crucial for CR-hvKp infection, the role of changes in bacterial mucoviscosity in the host colonization and persistence of CR-hvKp is not clearly defined. Herein, we observed a phenotypic switch of CR-hvKp from a hypermucoviscous to a hypomucoviscous state in a patient with scrotal abscess and urinary tract infection (UTI). This switch was attributed to decreased expression of rmpADC, the regulator of mucoid phenotype, caused by deletion of the upstream insertion sequence ISKpn26. Postswitching, the hypomucoid variant showed a 9.0-fold decrease in mice sepsis mortality, a >170.0-fold reduction in the ability to evade macrophage phagocytosis in vitro, and an 11.2-to 40.9-fold drop in growth rate in normal mouse serum. Conversely, it exhibited an increased residence time in the mouse urinary tract (21 vs. 6 d), as well as a 216.4-fold boost in adhesion to bladder epithelial cells and a 48.7% enhancement in biofilm production. Notably, the CR-hvKp mucoid switch was reproduced in an antibiotic-free mouse UTI model. The in vivo generation of hypomucoid variants was primarily associated with defective or low expression of rmpADC or capsule synthesis gene wcaJ, mediated by ISKpn26 insertion/deletion or base-pair insertion. The spontaneous hypomucoid variants also outcompeted hypermucoid bacteria in the mouse urinary tract. Collectively, the ISKpn26-associated mucoid switch in CR-hvKp signifies the antibiotic-independent host adaptive evolution, providing insights into the role of mucoid switch in the persistence of CR-hvKp. [ABSTRACT FROM AUTHOR]

The economic burden of brucellosis care on patients can lead to significant financial strain, despite partial coverage by medical insurance. However, there is limited research on the out‐of‐pocket costs faced by brucellosis patients. Therefore, our study aimed to investigate the costs and out‐of‐pocket expenses of brucellosis care, specifically examining the varying socioeconomic status of patients in Xinjiang, China. We collected cost and demographic data from 563 respondents and their hospital bills and employed latent variable analysis to assess socioeconomic status. The majority of patients belonged to the middle and lower socioeconomic status categories (85.97%), and they were primarily farmers and herders (82.77%). The median direct cost per brucellosis episode was USD 688.65, with out‐of‐pocket expenses amounting to USD 391.44. These costs exceeded both the 2020 Xinjiang and national per capita health expenditures (USD 233.66 and USD 267.21, respectively). Notably, the overall medical reimbursement rate was 48.60%, and for outpatient costs, it was merely 12.82%. Despite higher out‐of‐pocket costs among high socioeconomic status patients, the percentage of income spent was higher (37.23%) for patients in the lower socioeconomic status group compared to other groups (16.25% and 12.96%). In conclusion, our findings highlight that brucellosis patients are predominantly from the middle and lower socioeconomic status, with high out‐of‐pocket expenses placing them under significant financial pressure. Moreover, there is notable inequity in economic consequences across different socioeconomic status groups. These results call for policy interventions aimed at reducing brucellosis‐related poverty and promoting equitable access to care. [ABSTRACT FROM AUTHOR]

Background: Entomopathogenic fungi can live in insects to cause disease and death and are the largest group of entomopathogenic microorganisms. Therefore, these fungi are best known for their microbial control potential. Importantly, they also have other beneficial effects, including promoting plant growth and development by colonizing plant. Here, the study sought to identify specific strains of the entomopathogenic fungus, Cordyceps cateniannulata that would form endophytic associations with tobacco, thus benefiting plant growth and resistance to abiotic stresses, thereby highlighting the application of entomopathogenic fungi in tobacco. Methods: The C. cateniannulata-tobacco symbiont was constructed by root irrigation. The effects of C. cateniannulata on tobacco growth were evaluated by measuring the maximum leaf length, maximum leaf width, number of leaves, plant height, stem thickness, stem circumference, dry and fresh shoot weight 7, 14, 21, and 28 days after colonization. The peroxidase, catalase, superoxide dismutase, and malondialdehyde were measured to observe the impact of C. cateniannulata on tobacco defense enzyme activity. Finally, high-throughput sequencing was used to access microbial communities in the rhizosphere, with data subsequently linked to growth indicators. Results: After tobacco was inoculated with C. cateniannulata X8, which significantly promoted growth and related enzyme activity, malondialdehyde was decreased. The most significant impact was on peroxidase, with its activity being upregulated by 98.20, 154.42, 180.65, and 170.38% in the four time periods, respectively. The high throughput sequencing results indicated that C. cateniannulata had changed the rhizosphere microbial relative abundances, such as increasing Acidobacteria and Ascomycetes, and decreasing Actinomycetes and Basidiomycetes. The redundancy analysis showed that C. cateniannulata significantly boosted tobacco growth by reducing the abundance of specific dominant genera such as Stachybotrys, Cephalotrichum, Streptomyces, Isoptericola, and Microbacterium. Conclusion: Specific strains of C. cateniannulata can be introduced into host plants as endophytes, resulting in promotion of host plant growth and increased resistance to abiotic stress and microbial pathogens. The study provides a foundation for future studies of C. cateniannulata as an ecological agent. [ABSTRACT FROM AUTHOR]

Lymphocyte activation gene-3 (LAG-3) is an inhibitory receptor expressed on activated T cells and an emerging immunotherapy target. Domain 1 (D1) of LAG-3, which has been purported to directly interact with major histocompatibility complex class II (MHCII) and fibrinogen-like protein 1 (FGL1), has been the major focus for the development of therapeutic antibodies that inhibit LAG-3 receptor-ligand interactions and restore T cell function. Here, we present a high-resolution structure of glycosylated mouse LAG-3 ectodomain, identifying that cis-homodimerization, mediated through a network of hydrophobic residues within domain 2 (D2), is critically required for LAG-3 function. Additionally, we found a previously unidentified key protein-glycan interaction in the dimer interface that affects the spatial orientation of the neighboring D1 domain. Mutation of LAG-3 D2 residues reduced dimer formation, dramatically abolished LAG-3 binding to both MHCII and FGL1 ligands, and consequentially inhibited the role of LAG-3 in suppressing T cell responses. Intriguingly, we showed that antibodies directed against D1, D2, and D3 domains are all capable of blocking LAG-3 dimer formation and MHCII and FGL-1 ligand binding, suggesting a potential allosteric model of LAG-3 function tightly regulated by dimerization. Furthermore, our work reveals unique epitopes, in addition to D1, that can be targeted for immunotherapy of cancer and other human diseases., Competing Interests: Competing interests statement:Authors are inventors on intellectual property related to this work that is owned by Stanford University and New York University. J.W. is on the Scientific Advisory Board of Rootpath Genomics and is a consultant for BMS (Relatlimab Advisory Council) and Beijing Hanmi Pharmaceutical Co., LTD. J.R.C. is a cofounder and equity holder of Combangio, Inc. (now Kala Bio), xCella Biosciences (now OmniAb), Charged Biotherapeutics, TwoStep Therapeutics, and Red Tree Venture Capital; has financial interests in Aravive, Inc.; is a member of the Board of Directors of OmniAb, Revel Pharmaceuticals, Excellergy Therapeutics, Rondo Therapeutics, Tachyon Therapeutics, and Biograph 55; and is a Board Observer at Acrigen Biosciences. The other authors have no competing interests.

This paper demonstrates a high-energy, single-longitudinal-mode (SLM), actively Q -switched fiber laser based on the injection seeding technique. The large-mode-area double-cladding fiber is used as the gain medium to improve energy storage. Simultaneously, by using the linear electro-optic effect of the negative uniaxial crystal ( β - B a B 2 O 4 , BBO), a matching frequency-shift-free Q -switch with high damage threshold and high extinction-ratio is designed. Before reaching the stimulated Brillouin scattering threshold, the SLM Q -switched pulses can be achieved with energy higher than 15 µJ over a wide range of repetition rates from 10 to 80 kHz, and the maximum output power reaches 1.2 W at the repetition rate of 80 kHz, which may be the highest output pulse energy for such a SLM Q -switched fiber laser so far, to our best knowledge.