Hepsin as a potential therapeutic target for alleviating acetaminophen-induced hepatotoxicity via gap-junction regulation and oxidative stress modulation.

Acetaminophen (APAP) overdose is a leading cause of drug-induced liver damage, highlighting the limitations of current emergency treatments that primarily involve administering the glutathione precursor N-acetylcysteine and supportive therapy. This study highlights the essential protective role of the type II transmembrane serine protease (TTSP), hepsin, in mitigating acetaminophen-induced liver injury, particularly through its regulation of gap junction (GJ) abundance in response to reactive oxygen stress in the liver. We previously reported that reduced levels of activated hepatocyte growth factor and the c-Met receptor tyrosine kinase-both of which are vital for maintaining cellular redox balance-combined with increased expression of GJ proteins in hepsin-deficient mice. Here, we show that hepsin deficiency in mice exacerbates acetaminophen toxicity compared to wild-type mice, leading to more severe liver pathology, elevated oxidative stress, and greater mortality within 6 h after exposure. Administering hepsin had a protective effect in both mouse models, reducing hepatotoxicity by modulating GJ abundance. Additionally, transcriptome analysis and a functional GJ inhibitor have highlighted hepsin's mechanism for managing oxidative stress. Combining hepsin with relatively low doses of N-acetylcysteine had a synergistic effect that was more efficacious than high-dose N-acetylcysteine alone. Our results illustrate the crucial role of hepsin in modulating the abundance of hepatic GJs and reducing oxidative stress, thereby offering early protection against acetaminophen-induced hepatotoxicity and a new, combination approach. Emerging as a promising therapeutic target, hepsin holds potential for combination therapy with N-acetylcysteine, paving the way for novel approaches in managing drug-induced liver injury.

PIAS1 S510G variant acts as a genetic modifier of spinocerebellar ataxia type 3 by selectively impairing mutant ataxin-3 proteostasis.

Dysregulated protein homeostasis, characterized by abnormal protein accumulation and aggregation, is a key contributor to the progression of neurodegenerative disorders such as Huntington's disease and spinocerebellar ataxia type 3 (SCA3). Previous studies have identified PIAS1 gene variants in patients with late-onset SCA3 and Huntington's disease. This study aims to elucidate the role of PIAS1 and its S510G variant in modulating the pathogenic mechanisms of SCA3. Through in vitro biochemical analyses and in vivo assays, we demonstrate that PIAS1 stabilizes both wild-type and mutant ataxin-3 (ATXN3). The PIAS1 S510G variant, however, selectively reduces the stability and SUMOylation of mutant ATXN3, thereby decreasing its aggregation and toxicity while maintaining the stability of wild-type ATXN3. This effect is mediated by a weakened interaction with the SUMO-conjugating enzyme UBC9 in the presence of mutant ATXN3. In Drosophila models, downregulation of dPIAS1 resulted in reduced levels of mutant ATXN3 and alleviated associated phenotypes, including retinal degeneration and motor dysfunction. Our findings suggest that the PIAS1 S510G variant acts as a genetic modifier of SCA3, highlighting the potential of targeting SUMOylation as a therapeutic strategy for this disease.

Developing a plant microbial fuel cell by planting water spinach in a hanging-submerged plant pot system.

To plant crops (especially dry crops such as water spinach) with concomitant electricity recovery, a hanging-submerged-plant-pot system (HSPP) is developed. The HSPP consists of a soil pot (anodic) partially submerged under the water surface of a cathode tank. The microbial communities changed with conditions were also investigated. It was found that with chemical fertilizers the closed-circuit voltage (CCV, with 1 kΩ) was stable (approximately 250 mV) within 28 d; however, without fertilizer, the water spinach could adjust to the environment to obtain a better power output (approximately 3 mW m-2) at day 28. The microbial-community analyses revealed that the Pseudomonas sp. was the only exoeletrogens found in the anode pots. Using a secondary design of HSPP, for a better water-level adjustment, the maximum power output of each plant was found to be approximately 27.1 mW m-2. During operation, high temperature resulted in low oxygen solubility, and low CCV as well. At this time, it is yet to be concluded whether the submerged water level significantly affects electricity generation.

Femtogram-Sensitive Cantilever Platform for Dynamic Graphene Oxide Nanosheet Monitoring.

This study introduces a new approach to optimizing graphene oxide (GO) properties using liquid-phase plasma treatment in a microenvironment. Our innovation exploits atomic force microscopy (AFM) cantilever frequency tracking to monitor mass variations in GO, which are indicative of surface oxidation-reduction processes or substituent doping (boron/nitrogen). Complementary in situ Raman spectroscopy has observed D/G band shifts, and X-ray photoelectron spectroscopy (XPS) determined the C/O ratio and B/N doping levels pre- and post-treatment, confirming chemical tuning to GO. We can achieve femtogram-level precision in detecting nanomaterial mass changes by correlating elemental ratios with AFM cantilever frequency measurements. This multifaceted approach not only enhances our understanding of the chemical properties of GO but also establishes a new, versatile method for monitoring, modifying, and optimizing the properties of nanomaterials.

Differences in characteristics and outcomes between early-onset colorectal cancer and late-onset colorectal cancers.

INTRODUCTION: Colorectal cancer (CRC) represents a significant health burden worldwide, with a notable increase in early-onset colorectal cancer (EOCRC) cases, defined as those diagnosed before the age of 50 years. MATERIALS AND METHODS: Using data from Taiwan's national cancer registry and a retrospective cohort from Chang Gung Memorial Hospital, this study analyzed CRC cases diagnosed between 2008 and 2019. The analysis compared the EOCRC and late-onset CRC (LOCRC) groups in terms of clinicopathological characteristics, pre-diagnostic symptoms, and survival outcomes. RESULTS: The analysis revealed a continuous increase in the annual incidence of EOCRC, with colon cancer and rectal cancer rising by 3.2 % and 3.3 %, respectively. Patients with EOCRC presented with more aggressive disease characteristics, such as signet-ring cell adenocarcinoma, mucinous adenocarcinoma, and poorly differentiated grade. Advanced stages at diagnosis, stages III and IV, were more common with EOCRC (62.4 %) than with LOCRC (50.3 %). Patients with EOCRC reported rectal bleeding, changes in bowel habits, and abdominal pain more frequently than those in the LOCRC group. There is a strong association between stool-related symptoms and left-sided CRC. Despite similar surgical outcomes, the 5-year cancer-specific survival rate of patients with stage IV EOCRC was significantly lower than that of patients with LOCRC (32.8 % vs. 51.9 %, p = 0.012). CONCLUSION: This study highlights a persistent rise in the incidence of EOCRC, with patients presenting with more aggressive disease and experiencing inferior survival. These findings underscore the importance of heightened awareness and early detection strategies for CRC, especially in younger populations, to improve the prognosis.

Associations of Polygenic Risk for Depression, Traditional Chinese Medicine Constitution, and Depression: A Population-Based Study in Taiwan.

To comprehensively investigate the risk factors associated with depression, traditional Chinese medicine constitution (TCMC) has been found to be related to depression. However, the underlying mechanism remains unclear. This study examined the association between the concept of unbalanced TCMCs and major depressive disorder (MDD), investigated the overlapping polygenic risks between unbalanced TCMC and MDD, and performed a mediation test to establish potential pathways. In total, 11,030 individuals were recruited from the Taiwan Biobank, and the polygenic risk score (PRS) for MDD for each participant was calculated using the data from the Psychiatric Genomics Consortium. Unbalanced TCMC were classified as yang-deficiency, yin-deficiency, and stasis. The MDD PRS was associated with yang-deficiency odds ratio [OR] per standard deviation increase in standardized (PRS = 1.07, p = 0.0080), yin-deficiency (OR = 1.07, p = 0.0030), and stasis constitution (OR = 1.06, p = 0.0331). Yang-deficiency (OR = 2.07, p < 0.0001) and stasis constitutions (OR = 1.65, p = 0.0015) were associated with an increased risk of MDD. A higher number of unbalanced constitutions was associated with MDD (p < 0.0001). The effect of MDD PRS on MDD was partly mediated by yang-deficiency (10.21%) and stasis (8.41%) constitutions. This study provides evidence for the shared polygenic risk mechanism underlying depression and TCMC and the potential mediating role of TCMC in the polygenic liability for MDD.

Short-term outcomes of Transrectal Natural Orifice Specimen extraction compared with conventional minimally invasive surgery for selected patients with colorectal cancer: a propensity score matching analysis and literature review.

PURPOSE: Conventional minimally invasive surgery requires mini-laparotomy to extract the pathological specimen. However, by using a natural orifice as the delivery route, natural orifice specimen extraction (NOSE) surgery avoids the need for a large incision. This study analyzed the short-term outcome of NOSE compared with conventional mini-laparotomy (CL) for colorectal cancer surgery. METHODS: We conducted a retrospective analysis of 1,189 patients who underwent surgery for primary colorectal cancer between the cecum and upper rectum. Propensity score analyses were applied to the NOSE and CL groups in a 1:1 matched cohort. RESULTS: After propensity score matching, each group included 201 patients. The NOSE group and CL group did not differ significantly in terms of baseline characteristics. Postoperative morbidity and mortality rates were comparable. Compared with the CL group, the NOSE group experienced a shorter time to first flatus (1.6 ± 0.8 vs. 2.0 ± 1.2 days, p < 0.001), first stool (2.7 ± 1.5 vs. 4.1 ± 1.9, p < 0.001), liquid diet (2.3 ± 1.3 vs. 3.6 ± 1.8 days, p < 0.001), soft diet (3.9 ± 2.0 vs. 5.2 ± 1.9 days, p < 0.001) and a shorter hospital stay (5.1 ± 3.5 vs. 7.4 ± 4.8 days, p < 0.001). The NOSE group exhibited lower mean pain intensity and lower highest pain intensity on postoperative days 1, 2, and 3. CONCLUSION: NOSE has several advantages over conventional mini-laparotomy following minimally invasive surgery for colon cancer. These advantages include reduced time to oral intake, shorter hospital stays, and less postoperative pain. NOSE can be adopted and applied to highly selective patients without additional risk of short-term complications.

Phylogenetic relationships and historical biogeography of silkmoths (Lepidoptera: Bombycidae) suggest an origin in Southern Gondwana.

Silkmoths (Bombycidae) have a disjunct distribution predominantly in the Southern Hemisphere and Asia. Here we reconstruct the phylogenetic history of the family to test competing hypotheses on their origin and assess how vicariance and long-distance dispersal shaped their current distribution. We sequenced up to 5,074 base pairs from six loci (COI, EF1-α, wgl, CAD, GAPDH, and RpS5) to infer the historical biogeography of Bombycidae. The multilocus dataset covering 20 genera (80 %) of the family, including 17 genera (94 %) of Bombycinae and 3 genera (43 %) of Epiinae, was used to estimate phylogenetic patterns, divergence times and biogeographic reconstruction. Dating estimates extrapolated from secondary calibration sources indicate the Bombycidae stem-group originated approximately 64 Mya. The subfamilies Epiinae (South America) and Bombycinae (Australia, Asia, East Palaearctic, and Africa) were reciprocally monophyletic, diverging at c. 56 Mya (95 % credibility interval: 66-46 Mya). The 'basal' lineage of Bombycinae - Gastridiota + Elachyophtalma - split from the rest of Bombycinae c. 53 Mya (95 % credibility interval: 63-43 Mya). Gastridiota is a monobasic genus with a relictual distribution in subtropical forests of eastern Australia. The Oriental and African genera comprised a monophyletic group: the Oriental region was inferred to have been colonized from a long-distance dispersal event from Australia to South-East Asia c. 53 Mya or possibly later (c. 36-26 Mya); Africa was subsequently colonized by dispersal from Asia c. 16 Mya (95 % credibility interval: 21-12 Mya). Based on the strongly supported phylogenetic relationships and estimates of divergence times, we conclude that Bombycidae had its origin in the fragment of Southern Gondwana consisting of Australia, Antarctica and South America during the Paleocene. The disjunction between South America (Epiinae) and Australia (Bombycinae) is best explained by vicariance in the Eocene, whereas the disjunct distribution in Asia and Africa is best explained by more recent dispersal events.

Anti-inflammatory potential of low-molecular-weight and high-sulfation-degree sulfated polysaccharides extracted from Antrodia cinnamomea.

Two novel sulfated polysaccharides (SPs), N10 and K5 were isolated from ammonium sulfate or potassium sulfate at concentrations of 10 mM and 5 mM in liquid cultures of Antrodia cinnamomea, respectively. N10 and K5 were galactoglucans with a galactose:glucose molar ratio of approximately 1:3. In lipopolysaccharide (LPS)-stimulated RAW264.7 cells, N10 and K5 exhibited strong anti-inflammatory potential, of 56 % and 23 % maximal inhibition of IL-6 and TNF-α production, respectively. Mechanical analysis revealed differences between N10 and K5, with N10 inhibiting the LPS-stimulated phosphorylation of ERK and p38 in RAW264.7 cells. K5 inhibited the LPS-stimulated phosphorylation of AKT and TGFßR-II. N10 and K5 were fragmented into F1, F2, and F3, the molecular weights of which were 455, 24, 0.9, and 327, 36, 1.9 kDa, respectively. K5 F2 and K5 F3 exhibited high degrees of sulfation of 1:3 and 1:8, resulting in strong anti-inflammation, of 83 % and 37 % highest inhibition of IL-6 and TNF-α production, respectively. Therefore, low-molecular-weight and high-sulfation-degree SPs exhibited strong anti-inflammatory activity. Specifically, K5 F2 inhibited the phosphorylation of p38, and K5 F3 suppressed the signaling pathway of p38/JNK. Overall, the sulfation degree of SPs is concluded to affect the anti-inflammatory responses.

Light Activated Release of Nitrile Ligands from trans-Ru(L)(PPh3)2(nitrile) Complexes.

A series of trans-RuL(PPh3)2(nitrile) and {RuL(PPh3)2}.2-µ-(nitrile)-based complexes [where L = 2,2'-(3,4-diphenyl-pyrrole-2,5-diyl)dipyridine (dpp), di(pyridin-2-yl)isoindoline-1,3-diimine (bpi), or 4-(4-methoxyphenyl)-6-phenyl-2,2'-bipyridine (Pbpy); and nitrile = 1,4-dibenzontirile, 4-ethynylbenzonitrile, or dicyanamide] were synthesized and characterized, and their electrochemical and photochemical behaviors were investigated. Those complexes that contained a significant nitrile contribution to their 3MLLCT show a release of their nitrile ligand (when L = dpp or Pbpy and the nitrile ligand = 4-dibenzontirile, or 4-ethynylbenzonitrile) with dissociation constants up to 8.09 × 10-4 s-1.

Performance comparison of flip-chip blue-light microLEDs with various passivation.

In this study, arrays of µLEDs in four different sizes (5 × 5 µm2, 10 × 10 µm2, 25 × 25 µm2, 50 × 50 µm2) were fabricated using a flip-chip bonding process. Two passivation processes were investigated with one involving a single layer of SiO2 deposited using plasma-enhanced chemical vapor deposition (PECVD) and the other incorporating Al2O3 deposited by atomic layer deposition (ALD) beneath the SiO2 layer. Owing to superior coverage and protection, the double-layers passivation process resulted in a three-order lower leakage current of µLEDs in the 5 µm chip-sized µLED arrays. Furthermore, higher light output power of µLEDs was observed in each chip-sized µLED array with double layers passivation. Particularly, the highest EQE value 21.9% of µLEDs array with 5 µm × 5 µm chip size was achieved with the double-layers passivation. The EQE value of µLEDs array was improved by 4.4 times by introducing the double-layers passivation as compared with that of µLEDs array with single layer passivation. Finally, more uniform light emission patterns were observed in the µLEDs with 5 µm × 5 µm chip size fabricated by double-layer passivation process using ImageJ software.

Learning Outcomes of Flipped Classroom on Community Health Nursing Course.

PURPOSE: To improve the quality of community health nursing practice, the learning outcomes of nursing students in community health nursing courses must be enhanced. Although the flipped classroom is considered an effective innovative teaching strategy, evidence of its application in community health nursing courses is limited. Therefore, this study aimed to examine the effects of a flipped classroom approach on community nursing competence, academic performance, course engagement, and learning satisfaction for a community health nursing course. DESIGN: A quasi-experimental study design was adopted between September 2021 and January 2022. METHODS: Two classes of nursing students (n = 92) from a 2-year nursing program at a university in Taiwan were recruited. The classes were randomly assigned to the intervention group (n = 50) that attended a flipped classroom and the control group (n = 42) that received traditional lecture-based instruction. FINDINGS: Compared with the control group, the intervention group demonstrated significantly greater improvements in community nursing competence (p = .012) and significantly higher academic performance (p = .005). In addition, the course engagement and learning satisfaction of the two groups were high, but not significantly different. CONCLUSIONS: A flipped classroom can be an important strategy to enhance community nursing competence and academic performance. CLINICAL EVIDENCE: The flipped classroom strategy can enhance community nursing competence of nursing students, which may improve the quality of population-based healthcare.

Flavopereirine exerts anti-cancer activities in various human thyroid cancer cells.

Thyroid cancer (TC) stands out as the most prevalent endocrine malignancy globally, with a steadily increasing incidence. Its clinical manifestations include enlarged thyroid nodules, dysphagia, enophthalmos, and various other symptoms. While standard treatments such as thyroidectomy and radioiodine therapy effectively manage most cases of differentiated thyroid cancers (DTC), some recurrent cases of DTC or those involving poorly differentiated thyroid cancers (PDTC) require specialized interventions. However, existing drugs primarily address symptom management without offering a curative solution. Therefore, the development of a new therapeutic agent for these challenging cases is of utmost importance. Flavopereirine, derived from Geissospermum vellosii, has demonstrated promise as a potential anti-cancer agent across various human cancers. However, its specific anti-cancer effects on human thyroid cancer (TC) have remained unclear. Therefore, this study aims to investigate the anti-cancer activity of flavopereirine in human TC. The research findings revealed that flavopereirine effectively hinders the growth of human TC cells, induces cell cycle arrest, promotes apoptosis, and modulates autophagy. Moreover, the study delved into the underlying mechanisms by which flavopereirine influenced signaling pathways. To validate these anti-cancer effects, an in vivo zebrafish model was utilized, confirming the efficacy of flavopereirine against human TC cells. In summary, this study establishes that flavopereirine exhibits notable anti-human TC activities, positioning it as a promising therapeutic candidate for the treatment of human thyroid cancer.

Impact of photoaging on the chemical and cytotoxic properties of nanoscale zeolitic imidazolate framework-8.

This study investigated the influence of photoaging on a nanoscale metal-organic framework (MOF), truncated rhombic dodecahedron nano-zeolitic imidazolate framework-8 (nZIF-8), focusing on its oxidative stress, inflammation, and implications for pulmonary diseases. We observed significant photodegradation-induced transformations in nZIF-8, characterized by a reduction in particle size from 200.5 to 101.4 nm and notable structural disintegration after prolonged exposure to simulated solar radiation. This alteration resulted in a marked decrease in oxidative cytotoxicity in BEAS-2B cells, which was attributed to changes in surface properties and reduced reactive oxygen species (ROS) production. Gene expression analysis further revealed a decrease in cytotoxic and inflammatory responses, which potentially lowers the risk of chronic obstructive pulmonary disease (COPD). Aged nZIF-8 also showed diminished capacity to induce pro-inflammatory cytokines and influence COPD-related gene expression, reducing its potential to exacerbate COPD pathogenesis. Our findings highlight the critical need for comprehensive safety evaluations of these materials, while considering their long-term environmental and biological impacts. The diminished cytotoxicity and inflammatory potential of aged nZIF-8 highlighted its enhanced suitability for broader applications, indicating that photoaging may lead to safer and more sustainable material utilization.

Clinical Features and Vaccination Effects among Children with Post-Acute Sequelae of COVID-19 in Taiwan.

BACKGROUND: Post-acute sequelae of SARS-CoV-2 infection (PASC) affects patients after recovering from acute coronavirus disease 2019 (COVID-19). This study investigates the impact of SARS-CoV-2 vaccination on PASC symptoms in children in Taiwan during the Omicron pandemic. METHODS: We enrolled children under 18 years with PASC symptoms persisting for more than 4 weeks. Data collected included demographics, clinical information, vaccination status, and symptom persistence. We used logistic regression models to compare symptoms in the acute and post-COVID-19 phases and to assess the association between vaccination and these symptoms. RESULTS: Among 500 PASC children, 292 (58.4%) were vaccinated, 282 (52.8%) were male, and the mean (SD) age was 7.6 (4.6) years. Vaccinated individuals exhibited higher odds of experiencing symptoms in the previous acute phase, such as cough (adjusted odds ratio [AOR] = 1.57; 95% confidence interval [CI]: 1.02-2.42), rhinorrhea/nasal congestion (AOR = 1.74; 95% CI: 1.13-2.67), sneezing (AOR = 1.68; 95% CI: 1.02-2.76), sputum production (AOR = 1.91; 95% CI: 1.15-3.19), headache/dizziness (AOR = 1.73; 95% CI: 1.04-2.87), and muscle soreness (AOR = 2.33; 95% CI: 1.13-4.80). In contrast, there were lower odds of experiencing abdominal pain (AOR = 0.49; 95% CI: 0.25-0.94) and diarrhea (AOR = 0.37; 95% CI: 0.17-0.78) in children who had received vaccination during the post-COVID-19 phase. CONCLUSIONS: This study revealed clinical features and vaccination effects in PASC children in Taiwan. Vaccination may reduce some gastrointestinal symptoms in the post-COVID-19 phase.

Disparities in medical recommendations from AI-based chatbots across different countries/regions.

This study explores disparities and opportunities in healthcare information provided by AI chatbots. We focused on recommendations for adjuvant therapy in endometrial cancer, analyzing responses across four regions (Indonesia, Nigeria, Taiwan, USA) and three platforms (Bard, Bing, ChatGPT-3.5). Utilizing previously published cases, we asked identical questions to chatbots from each location within a 24-h window. Responses were evaluated in a double-blinded manner on relevance, clarity, depth, focus, and coherence by ten experts in endometrial cancer. Our analysis revealed significant variations across different countries/regions (p < 0.001). Interestingly, Bing's responses in Nigeria consistently outperformed others (p < 0.05), excelling in all evaluation criteria (p < 0.001). Bard also performed better in Nigeria compared to other regions (p < 0.05), consistently surpassing them across all categories (p < 0.001, with relevance reaching p < 0.01). Notably, Bard's overall scores were significantly higher than those of ChatGPT-3.5 and Bing in all locations (p < 0.001). These findings highlight disparities and opportunities in the quality of AI-powered healthcare information based on user location and platform. This emphasizes the necessity for more research and development to guarantee equal access to trustworthy medical information through AI technologies.

Rational protein engineering to enhance MHC-independent T cell receptors.

Chimeric antigen receptor (CAR)-based therapies have pioneered synthetic cellular immunity but remain limited in their long-term efficacy. Emerging data suggest that dysregulated CAR-driven T cell activation causes T cell dysfunction and therapeutic failure. To re-engage the precision of the endogenous T cell response, we designed MHC-independent T cell receptors (miTCRs) by linking antibody variable domains to TCR constant chains. Using predictive modeling, we observed that this standard "cut and paste" approach to synthetic protein design resulted in myriad biochemical conflicts at the hybrid variable-constant domain interface. Through iterative modeling and sequence modifications we developed structure-enhanced miTCRs which significantly improved receptor-driven T cell function across multiple tumor models. We found that 41BB costimulation specifically prolonged miTCR T cell persistence and enabled improved leukemic control in vivo compared to classic CAR T cells. Collectively, we have identified core features of hybrid receptor structure responsible for regulating function.

Oral mucosal lesions triage via YOLOv7 models.

BACKGROUND/PURPOSE: The global incidence of lip and oral cavity cancer continues to rise, necessitating improved early detection methods. This study leverages the capabilities of computer vision and deep learning to enhance the early detection and classification of oral mucosal lesions. METHODS: A dataset initially consisting of 6903 white-light macroscopic images collected from 2006 to 2013 was expanded to over 50,000 images to train the YOLOv7 deep learning model. Lesions were categorized into three referral grades: benign (green), potentially malignant (yellow), and malignant (red), facilitating efficient triage. RESULTS: The YOLOv7 models, particularly the YOLOv7-E6, demonstrated high precision and recall across all lesion categories. The YOLOv7-D6 model excelled at identifying malignant lesions with notable precision, recall, and F1 scores. Enhancements, including the integration of coordinate attention in the YOLOv7-D6-CA model, significantly improved the accuracy of lesion classification. CONCLUSION: The study underscores the robust comparison of various YOLOv7 model configurations in the classification to triage oral lesions. The overall results highlight the potential of deep learning models to contribute to the early detection of oral cancers, offering valuable tools for both clinical settings and remote screening applications.

Towards a better future for DNA barcoding: Evaluating monophyly- and distance-based species identification using COI gene fragments of Dacini fruit flies.

The utility of a universal DNA 'barcode' fragment (658 base pairs of the Cytochrome C Oxidase I [COI] gene) has been established as a useful tool for species identification, and widely criticized as one for understanding the evolutionary history of a group. Large amounts of COI sequence data have been produced that hold promise for rapid species identification, for example, for biosecurity. The fruit fly tribe Dacini holds about a thousand species, of which 80 are pests of economic concern. We generated a COI reference library for 265 species of Dacini containing 5601 sequences that span most of the COI gene using circular consensus sequencing. We compared distance metrics versus monophyly assessments for species identification and although we found a 'soft' barcode gap around 2% pairwise distance, the exceptions to this rule dictate that a monophyly assessment is the only reliable method for species identification. We found that all fragments regularly used for Dacini fruit fly identification >450 base pairs long provide similar resolution. 11.3% of the species in our dataset were non-monophyletic in a COI tree, which is mostly due to species complexes. We conclude with recommendations for the future generation and use of COI libraries. We revise the generic assignment of Dacus transversus stat. rev. Hardy 1982, and Dacus perpusillus stat. rev. Drew 1971 and we establish Dacus maculipterus White 1998 syn. nov. as a junior synonym of Dacus satanas Liang et al. 1993.