Systematic identification of barriers to human iPSC generation.

Reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) holds enormous promise for regenerative medicine. To elucidate endogenous barriers limiting this process, we systematically dissected human cellular reprogramming by combining a genome-wide RNAi screen, innovative computational methods, extensive single-hit validation, and mechanistic investigation of relevant pathways and networks. We identify reprogramming barriers, including genes involved in transcription, chromatin regulation, ubiquitination, dephosphorylation, vesicular transport, and cell adhesion. Specific a disintegrin and metalloproteinase (ADAM) proteins inhibit reprogramming, and the disintegrin domain of ADAM29 is necessary and sufficient for this function. Clathrin-mediated endocytosis can be targeted with small molecules and opposes reprogramming by positively regulating TGF-ß signaling. Genetic interaction studies of endocytosis or ubiquitination reveal that barrier pathways can act in linear, parallel, or feedforward loop architectures to antagonize reprogramming. These results provide a global view of barriers to human cellular reprogramming.

Melatonin, a potentially effective drug for the treatment of infected bone nonunion.

Osteomyelitis (OM), characterized by heterogeneity and complexity in treatment, has a high risk of infection recurrence which may cause limb disability. Management of chronic inactive osteomyelitis (CIOM) without typical inflammatory symptoms is a great challenge for orthopedic surgeons. On the basis of data analysis of 1091 OM cases, we reported that latent osteogenic decline in CIOM patients was the main cause of secondary surgery. Our research shows that impairment of osteoblasts capacity in CIOM patients is associated with ferroptosis of osteoblasts caused by internalization of Staphylococcus aureus. Further studies show that melatonin could alleviate ferroptosis of osteoblasts in infected states through Nox4/ROS/P38 axis and protect the osteogenic ability of CIOM patients. Knockout of NADPH oxidase 4 (Nox4) in vivo could effectively relieve ferroptosis of osteoblasts in the state of infection and promote osteogenesis. Through a large number of clinical data analyses combined with molecular experiments, this study clarified that occult osteogenic disorders in CIOM patients were related to ferroptosis of osteoblasts. We revealed that melatonin might be a potential therapeutic drug for CIOM patients and provided a new insight for the treatment of OM.

Lipotoxicity: The missing link between diabetes and periodontitis?

Lipotoxicity refers to the accumulation of lipids in tissues other than adipose tissue (body fat). It is one of the major pathophysiological mechanisms responsible for the progression of diabetes complications such as non-alcoholic fatty liver disease and diabetic nephropathy. Accumulating evidence indicates that lipotoxicity also contributes significantly to the toxic effects of diabetes on periodontitis. Therefore, we reviewed the current in vivo, in vitro, and clinical evidence of the detrimental effects of lipotoxicity on periodontitis, focusing on its molecular mechanisms, especially oxidative and endoplasmic reticulum stress, inflammation, ceramides, adipokines, and programmed cell death pathways. By elucidating potential therapeutic strategies targeting lipotoxicity and describing their associated mechanisms and clinical outcomes, including metformin, statins, liraglutide, adiponectin, and omega-3 PUFA, this review seeks to provide a more comprehensive and effective treatment framework against diabetes-associated periodontitis. Furthermore, the challenges and future research directions are proposed, aiming to contribute to a more profound understanding of the impact of lipotoxicity on periodontitis.

Impact of hyperoxia on the gut during critical illnesses.

Molecular oxygen is typically delivered to patients via oxygen inhalation or extracorporeal membrane oxygenation (ECMO), potentially resulting in systemic hyperoxia from liberal oxygen inhalation or localized hyperoxia in the lower body from peripheral venoarterial (VA) ECMO. Consequently, this exposes the gastrointestinal tract to excessive oxygen levels. Hyperoxia can trigger organ damage due to the overproduction of reactive oxygen species and is associated with increased mortality. The gut and gut microbiome play pivotal roles in critical illnesses and even small variations in oxygen levels can have a dramatic influence on the physiology and ecology of gut microbes. Here, we reviewed the emerging preclinical evidence which highlights how excessive inhaled oxygen can provoke diffuse villous damage, barrier dysfunction in the gut, and gut dysbiosis. The hallmark of this dysbiosis includes the expansion of oxygen-tolerant pathogens (e.g., Enterobacteriaceae) and the depletion of beneficial oxygen-intolerant microbes (e.g., Muribaculaceae). Furthermore, we discussed potential impact of oxygen on the gut in various underlying critical illnesses involving inspiratory oxygen and peripheral VA-ECMO. Currently, the available findings in this area are somewhat controversial, and a consensus has not yet to be reached. It appears that targeting near-physiological oxygenation levels may offer a means to avoid hyperoxia-induced gut injury and hypoxia-induced mesenteric ischemia. However, the optimal oxygenation target may vary depending on special clinical conditions, including acute hypoxia in adults and neonates, as well as particular patients undergoing gastrointestinal surgery or VA-ECMO support. Last, we outlined the current challenges and the need for future studies in this area. Insights into this vital ongoing research can assist clinicians in optimizing oxygenation for critically ill patients.

Prevalence and risk factors for astigmatism in 7 to 19-year-old students in Xinjiang, China: a cross-sectional study.

BACKGROUND: To investigate the prevalence and risk factors for astigmatism in 7-19-year-old students in Xinjiang, China. METHODS: A school-based, cross-sectional study was conducted on students who underwent refraction examination in Xinjiang, China, between May and December 2019. The prevalence of astigmatism was determined. Astigmatism was defined as cylinder power (C) ≤-0.75 D, undefined astigmatism as ≤-1.50 D, and high astigmatism as C ≤-3.00 D. Astigmatism types were: against-the-rule astigmatism (maximum refraction of the main meridian in 180° ± 30°), with-the-rule astigmatism (maximum refraction of the main meridian at 90°±30°), and oblique astigmatism (all other cases). RESULTS: Of the 71,838 students examined (51.0% boys, 7 - 19 years old), 25,945 (36.1%, 95%CI: 35.52-36.68%) had astigmatism and 1267 (1.8%, 95%CI: 1.07-2.53%) had high astigmatism. The prevalence of astigmatism was greater in Han individuals (39.6%) compared with the Hui (34.0%), Kazakh (34.0%), Kyrgyz (32.1%), and Uyghur (26.4%) populations. Among the 25,945 students with astigmatism, 19,947 had with-the-rule astigmatism (76.9%), 3405 had against-the-rule astigmatism (13.1%), and 2593 had oblique astigmatism (10.0%). Multivariable logistic regression analysis showed that ethnicity (Han individuals more susceptible), male gender, age, and refractive errors (myopia and hyperopia) were independently associated with astigmatism, high astigmatism, and with-the-rule astigmatism (all P < 0.05). CONCLUSIONS: The prevalence of astigmatism among children and adolescents in Xinjiang was 36.1%, including 1.8% of high astigmatism. In this population, astigmatism was mainly of the with-the-rule astigmatism type (76.9%). Han ethnicity, male gender, and myopia or hyperopia were independently associated with a high risk of astigmatism.

Syndecan-4 inhibition attenuates cartilage degeneration in temporomandibular joint osteoarthritis.

BACKGROUND: Syndecan 4 (SDC4), a type I transmembrane proteoglycan, serves as a critical link between chondrocytes and the extracellular matrix. OBJECTIVE: This study aimed to explore the role of SDC4 in cartilage degeneration of temporomandibular joint osteoathritis (TMJOA). METHODS: Condylar chondrocytes were stimulated with varying concentrations of recombinant rat interleukin-1ß (rrIL-1ß) and SDC4 small interfering RNA (si-SDC4). Anti-SDC4 ectodomain-specific antibodies or IgG were intra-articularly administrated in a TMJOA model rats. SDC4 conditional knockout (SDC4-cKO) and Sdc4flox/flox mice were induced TMJOA. Cartilage degeneration was assessed using haematoxylin & eosin (H&E) and safranin O (SO) staining. Protein levels of SDC4, matrix metalloproteinases (MMPs), a disintegrin and metalloproteinase with a thrombospondin motifs 5 (ADAMTS5), tumour necrosis factor α (TNFα), type II collagen (Col-II), aggrecan (ACAN), cleaved caspase 3 (CASP3), Ki67 and related pathways in condylar cartilage were evaluated by immunohistochemical (IHC) staining or western blot assays. RESULTS: SDC4 expression was evidently increased in MIA-model animals compared to control groups. rrIL-1ß stimulation increased the expression of SDC4, MMP3 and ADAMTS5 expression in chondrocytes, while decreasing the expression of Col-II. These effects were reversed by si-SDC4 in vitro. In vivo, SDC4 blockade reduced the death of chondrocytes and the loss of cartilage matrix, which was evidenced by increased expression of Col-II and ACAN, and a decrease in SDC4, MMP13 and cleaved-CASP3-positive cells. Furthermore, the protein levels of ACAN and Ki67 were elevated, and the ERK1/2 and P38 signalling pathways were activated following SDC4 inhibition. CONCLUSIONS: SDC4 inhibition significantly ameliorates condylar cartilage degeneration, which was mediated, at least partly, through P38 and ERK1/2 signalling. Inhibition of SDC4 may be of great value for the treatment of TMJOA.

Clinical profile in relation to age and gender of patients with temporomandibular disorders: a retrospective study.

BACKGROUND: The present study is to evaluate the clinical characteristics of patients with temporomandibular disorders (TMD). METHODS: A total of 3362 TMD patients were included. Each participant had complete medical records according to the diagnostic criteria for temporomandibular disorders (DC/TMD). The clinical characteristics including symptoms and signs in relation to age and gender were analyzed. RESULTS: The mean age of the patients seeking care was 29.89 ± 13.73Y, and 68.6% of patients were aged 16-35 years. The female-to-male ratio of patients was 2.2: 1, and the average age of males was significantly lower than that of females. The prevalence of clicking symptoms decreased with age, while the prevalence of pain symptoms and limitations in jaw movement increased with age. Females were more likely to have limitations in jaw movement than males. Among the patients with pain, the average visual analogue scale (VAS) was 2.96 ± 1.23. The average VAS score of acute TMD patients (≤ 3 months) was significantly higher than that of chronic TMD patients (> 3 months). CONCLUSIONS: The majority of TMD patients seeking care were young people. The number and average age of female patients was higher than the males. Female patients were more likely to have limitations in jaw movement than males.

Multiple paternally inherited chloroplast capture events associated with Taxus speciation in the Hengduan Mountains.

Mountainous regions provide a multitude of habitats and opportunities for complex speciation scenarios. Hybridization leading to chloroplast capture, which can be revealed by incongruent phylogenetic trees, is one possible outcome. Four allopatric Taxus lineages (three species and an undescribed lineage) from the Hengduan Mountains, southwest China, exhibit conflicting phylogenetic relationships between nuclear and chloroplast phylogenies. Here, we use multi-omic data at the population level to investigate their historical speciation processes. Population genomic analysis based on ddRAD-seq data revealed limited contemporary inter-specific gene flow involving only populations located close to another species. In a historical context, chloroplast and nuclear data (transcriptome) consistently showed conflicting phylogenetic relationships for T. florinii and the Emei type lineage. ILS and chloroplast recombination were excluded as possible causes, and transcriptome and ddRAD-seq data revealed an absence of the mosaic nuclear genomes that characterize hybrid origin scenarios. Therefore, T. florinii appears to have originated when a lineage of T. florinii captured the T. chinensis plastid type, whereas plastid introgression in the opposite direction generated the Emei Type. All four species have distinct ecological niche based on community investigations and ecological niche analyses. We propose that the origins of both species represent very rare examples of chloroplast capture events despite the paternal cpDNA inheritance of gymnosperms. Specifically, allopatrically and/or ecologically diverged parental species experienced a rare secondary contact, subsequent hybridization and reciprocal chloroplast capture, generating two new lineages, each of which acquired a unique ecological niche. These events might have been triggered by orogenic activities of the Hengduan Mountains and an intensification of the Asian monsoon in the late Miocene, and may represent a scenario more common in these mountains than presently known.

Expression, purification and refolding of pro-MMP-2 from inclusion bodies of E. coli.

MMP-2 has been reported as the most validated target for cancer progression and deserves further investigation. However, due to the lack of methods for obtaining large amounts of highly purified and bioactive MMP-2, identifying specific substrates and developing specific inhibitors of MMP-2 remains extremely difficult. In this study, the DNA fragment coding for pro-MMP-2 was inserted into plasmid pET28a in an oriented manner, and the resulting recombinant protein was effectively expressed and led to accumulation as inclusion bodies in E. coli. This protein was easy to purify to near homogeneity by the combination of common inclusion bodies purification procedure and cold ethanol fractionation. Then, our results of gelatin zymography and fluorometric assay revealed that pro-MMP-2 at least partially restored its natural structure and enzymatic activity after renaturation. We obtained approximately 11 mg refolded pro-MMP-2 protein from 1 L LB broth, which was higher than other strategies previously reported. In conclusion, a simple and cost-effective procedure for obtaining high amounts of functional MMP-2 was developed, which would contribute to the progress of studies on the gamut of biological action of this important proteinase. Furthermore, our protocol should be appropriate for the expression, purification, and refolding of other bacterial toxic proteins.

Myocardial Protection by Desflurane: From Basic Mechanisms to Clinical Applications.

ABSTRACT: Coronary heart disease is an affliction that is common and has an adverse effect on patients' quality of life and survival while also raising the risk of intraoperative anesthesia. Mitochondria are the organelles most closely associated with the pathogenesis, development, and prognosis of coronary heart disease. Ion abnormalities, an acidic environment, the production of reactive oxygen species, and other changes during abnormal myocardial metabolism cause the opening of mitochondrial permeability transition pores, which disrupts electron transport, impairs mitochondrial function, and even causes cell death. Differences in reliability and cost-effectiveness between desflurane and other volatile anesthetics are minor, but desflurane has shown better myocardial protective benefits in the surgical management of patients with coronary artery disease. The results of myocardial protection by desflurane are briefly summarized in this review, and biological functions of the mitochondrial permeability transition pore, mitochondrial electron transport chain, reactive oxygen species, adenosine triphosphate-dependent potassium channels, G protein-coupled receptors, and protein kinase C are discussed in relation to the protective mechanism of desflurane. This article also discusses the effects of desflurane on patient hemodynamics, myocardial function, and postoperative parameters during coronary artery bypass grafting. Although there are limited and insufficient clinical investigations, they do highlight the possible advantages of desflurane and offer additional suggestions for patients.

A simulation study on the phase transition behavior of solid nitrogen under extreme conditions.

There are numerous examples of materials that exhibit interesting phenomena at extremely low temperatures, but the difficulty of obtaining absolute zero at high pressure in experiments is sometimes a hurdle to reveal the exact explanation of these low temperature phenomena. Based on the calculations of the phonon spectrum and Gibbs free energy of α-N2 and γ-N2 under different pressures, we found that solid nitrogen at 0 K showed a re-entrant phase transition under continuously increasing pressure. The extremely low temperature in this pressure range turned out to be the main external condition for inducing phase transition as well as phase reversal.

Validation of a physiological type 2 diabetes model in human periodontal ligament stem cells.

OBJECTIVES: Type 2 diabetes (T2DM), a recognized risk factor for periodontitis, is characterized by insulin resistance. However, the molecular mechanisms concerning the role of insulin resistance in linking T2DM and periodontitis remain poorly elucidated due to the absence of an appropriate T2DM cell model. We aimed to explore an appropriate model of T2DM in human periodontal ligament stem cells (hPDLSCs) and uncover the involved mechanisms. MATERIALS AND METHODS: hPDLSCs were incubated with common reagents for recapitulating insulin resistance state including high glucose (HG) (15, 25, 35, 45 mM), glucosamine (0.8, 8, 18, 28, 38 mM), or palmitic acid (PA; 100, 200, 400, 800 µM), combined with LPS for 48 h. The insulin signaling pathway, inflammation, and pyroptosis were detected by western blots and quantitative real-time polymerase chain reaction (RT-qPCR). The effects on osteogenesis were evaluated by alkaline phosphatase staining, alizarin red S staining, RT-qPCR, and western blots. RESULTS: HG failed to recapitulate insulin resistance. Glucosamine was sufficient to induce insulin resistance but failed to trigger inflammation. In total, 100 and 200 µM PA exhibited the most proinflammatory, insulin resistance, and pyroptosis induced role, and inhibited the osteogenic differentiation of hPDLSCs. CONCLUSION: Palmitic acid is a promising candidate for developing T2DM model in hPDLSCs.

Diagnosis of obstructive sleep apnea in children based on the XGBoost algorithm using nocturnal heart rate and blood oxygen feature.

PURPOSE: Obstructive sleep apnea (OSA) is a serious type of obstructive sleep-disordered breathing (SDB) that can cause a series of adverse effects on children's cardiovascular, growth, cognition, etc. The gold standard for diagnosis is polysomnography (PGS), which is used to assess the prevalence of OSA by obtaining the apnea-hypopnea index (AHI), but this diagnosis method is expensive and needs to be performed in a specialized laboratory, making it difficult to be of benefit to children with suspected OSA on a large scale. Our goal was to use a machine learning method to identify children with OSA of varying severity using data on children's nighttime heart rate and blood oxygen data. METHODS: This study included 3139 children who received diagnostic PSG with suspected OSA. Age, sex, BMI, 3 % oxygen depletion index (ODI), average nighttime heart rate and fastest heart rate were used as predictive features. Data sets were established with AHI ≥ 1, AHI ≥ 5, and AHI ≥ 10 as the diagnostic criteria for mild, moderate and severe OSA, and the samples of each data set were randomly divided into a training set and a test set at a ratio of 8:2. An OSA diagnostic model was established based on the XGBoost algorithm, and the ability of the machine learning model to diagnose OSA children with different severities was evaluated through different classification ability evaluation indicators. As a comparison, traditional classifier Logistic Regression was used to perform the same diagnostic task. The SHAP algorithm was used to evaluate the role of these features in the classification task. RESULTS: We established a diagnostic model of OSA in children based on the XGBoost algorithm. On the test set, the AUCs of the model for diagnosing mild, moderate, and severe OSA were 0.95, 0.88, and 0.88, respectively, and the classification accuracy was 90.45 %, 85.67 %, and 89.81 %, respectively, perform better than Logistic Regression classifiers. ODI is the most important feature in all classification tasks, and a higher fastest heart rate and ODI make the model tend to classify samples as positive. A high BMI value caused the model to tend to classify samples as positive in the mild and moderate classification tasks and as negative in the classification task with severe OSA. CONCLUSION: Using heart rate and blood oxygen data as the main features, a machine learning diagnostic model based on the XGBoost algorithm can accurately identify children with OSA at different severities. This diagnostic modality reduces the number of signals and the complexity of the diagnostic process compared to PSG, which could benefit children with suspected OSA who do not have the opportunity to receive a diagnostic PSG and provide a diagnostic priority reference for children awaiting a diagnostic PSG.

SymMap database and TMNP algorithm reveal Huanggui Tongqiao granules for Allergic rhinitis through IFN-mediated neuroimmuno-modulation.

Allergic rhinitis (AR) is a series of reactions to allergen mediated by immunoglobulin E (IgE) and is one of the most common allergic diseases that affects children. Traditional Chinese Medicine, due to its diverse regulatory functions, may offer new strategies for AR therapy. Huanggui Tongqiao Granules (HTG) is a Chinese formula consisting of twelve herbs and has long been prescribed for patients with AR. The aim of this study is to determine the possible targets and action mechanisms of HTG for the AR treatment. SymMap database and TMNP algorithm were employed to show that interferon-gamma (IFN-gamma), acting as a molecular link between immunity and neural circuits, is the involved key target. The enrichment of immune and virus-related signaling pathways indicated the neuroimmunomodulatory potential of HTG. Then, AR mouse model was established by ovalbumin (OVA) challenge and was used to verify the therapeutic effects of HTG in vivo. HTG significantly relieved AR symptoms and nasal mucosal inflammation, reduced OVA-specific IgE levels and balanced IFN-gamma/IL-4 ratio. Moreover, transcriptional profile based on clinical data presented that blood cell-specific IFN-gamma co-expressed gene module (BIM) was underexpressed in AR patients, further validating the potential of IFN-gamma as target for AR. Collectively, these findings suggest that HTG could be a promising candidate drug for AR.

Resolution, conflict and rate shifts: insights from a densely sampled plastome phylogeny for Rhododendron (Ericaceae).

BACKGROUND AND AIMS: Rhododendron is a species-rich and taxonomically challenging genus due to recent adaptive radiation and frequent hybridization. A well-resolved phylogenetic tree would help to understand the diverse history of Rhododendron in the Himalaya-Hengduan Mountains where the genus is most diverse. METHODS: We reconstructed the phylogeny based on plastid genomes with broad taxon sampling, covering 161 species representing all eight subgenera and all 12 sections, including ~45 % of the Rhododendron species native to the Himalaya-Hengduan Mountains. We compared this phylogeny with nuclear phylogenies to elucidate reticulate evolutionary events and clarify relationships at all levels within the genus. We also estimated the timing and diversification history of Rhododendron, especially the two species-rich subgenera Rhododendron and Hymenanthes that comprise >90 % of Rhododendron species in the Himalaya-Hengduan Mountains. KEY RESULTS: The full plastid dataset produced a well-resolved and supported phylogeny of Rhododendron. We identified 13 clades that were almost always monophyletic across all published phylogenies. The conflicts between nuclear and plastid phylogenies suggested strongly that reticulation events may have occurred in the deep lineage history of the genus. Within Rhododendron, subgenus Therorhodion diverged first at 56 Mya, then a burst of diversification occurred from 23.8 to 17.6 Mya, generating ten lineages among the component 12 clades of core Rhododendron. Diversification in subgenus Rhododendron accelerated c. 16.6 Mya and then became fairly continuous. Conversely, Hymenanthes diversification was slow at first, then accelerated very rapidly around 5 Mya. In the Himalaya-Hengduan Mountains, subgenus Rhododendron contained one major clade adapted to high altitudes and another to low altitudes, whereas most clades in Hymenanthes contained both low- and high-altitude species, indicating greater ecological plasticity during its diversification. CONCLUSIONS: The 13 clades proposed here may help to identify specific ancient hybridization events. This study will help to establish a stable and reliable taxonomic framework for Rhododendron, and provides insight into what drove its diversification and ecological adaption. Denser sampling of taxa, examining both organelle and nuclear genomes, is needed to better understand the divergence and diversification history of Rhododendron.

Doping effects on the antibonding states and carriers of two-dimensional PC6.

The absence of a bandgap in pristine graphene severely restricts its application, and there is high demand for other novel two-dimensional (2D) materials. PC6 has recently emerged as a promising 2D material with a direct band gap and ultrahigh carrier mobility. In light of the remarkable properties of an intrinsic PC6 monolayer, it would be intriguing to find out whether a doped PC6 monolayer displays properties superior to the pure system. In this study, we have performed density functional theory calculations to understand the doping effects of both P-site and C-site substitution in PC6 and, for the first time, we discovered doping-related impurity-level anomalies in this system. We successfully explained why no donor or acceptor defect states exist in the band structures of XP-PC6 (X = C, Ge, Sn, O, S, Se, or Te). In group-IV-substituted systems, these dopant states hybridize with host states near the Fermi level rather than act as acceptors, which is deemed to be a potential way to tune the mobility of PC6. In the case of group-VI substitution, the underlying mechanism relating to doping anomalies arises from excess electrons occupying antibonding states.

Impact of COVID-19 on emergency patients in the resuscitation room: A cross-sectional study.

OBJECTIVE: The purpose of this study was to evaluate the impact of COVID-19 outbreaks on emergency patients in a resuscitation room in Nanning, China. METHODS: A single-center cross-sectional retrospective study was conducted in the emergency department of a tertiary public hospital from January 1, 2019, to December 31, 2020, in Nanning, Guangxi, China. We collected the data of patients in the resuscitation room to investigate the number of patients accessing emergency services during the study period. Data in 2020 were compared to the data during the same period in 2019. RESULTS: The number of emergency patients in the resuscitation room during the COVID-19 pandemic has decreased in intrinsic diseases, extrinsic diseases, and pediatric cases, especially in the early stages of the pandemic. Additionally, the length of stay of emergency patients in the resuscitation room was reduced. CONCLUSIONS: The number of emergency patients in the resuscitation room during the pandemic of COVID-19 in 2020 was reduced compared to that in the same period in 2019 in Nanning, China. This situation shows a serious social problem, which should arouse the attention of the medical profession and the government.

Proteome-wide and lysine crotonylation profiling reveals the importance of crotonylation in chrysanthemum (Dendranthema grandiforum) under low-temperature.

BACKGROUND: Low-temperature severely affects the growth and development of chrysanthemum which is one kind of ornamental plant well-known and widely used in the world. Lysine crotonylation is a recently identified post-translational modification (PTM) with multiple cellular functions. However, lysine crotonylation under low-temperature stress has not been studied. RESULTS: Proteome-wide and lysine crotonylation of chrysanthemum at low-temperature was analyzed using TMT (Tandem Mass Tag) labeling, sensitive immuno-precipitation, and high-resolution LC-MS/MS. The results showed that 2017 crotonylation sites were identified in 1199 proteins. Treatment at 4 °C for 24 h and - 4 °C for 4 h resulted in 393 upregulated proteins and 500 downregulated proteins (1.2-fold threshold and P < 0.05). Analysis of biological information showed that lysine crotonylation was involved in photosynthesis, ribosomes, and antioxidant systems. The crotonylated proteins and motifs in chrysanthemum were compared with other plants to obtain orthologous proteins and conserved motifs. To further understand how lysine crotonylation at K136 affected APX (ascorbate peroxidase), we performed a site-directed mutation at K136 in APX. Site-directed crotonylation showed that lysine decrotonylation at K136 reduced APX activity, and lysine complete crotonylation at K136 increased APX activity. CONCLUSION: In summary, our study comparatively analyzed proteome-wide and crotonylation in chrysanthemum under low-temperature stress and provided insights into the mechanisms of crotonylation in positively regulated APX activity to reduce the oxidative damage caused by low-temperature stress. These data provided an important basis for studying crotonylation to regulate antioxidant enzyme activity in response to low-temperature stress and a new research ideas for chilling-tolerance and freezing-tolerance chrysanthemum molecular breeding.

Natural hybridization among three Rhododendron species (Ericaceae) revealed by morphological and genomic evidence.

BACKGROUND: Natural hybridization can influence the adaptive response to selection and accelerate species diversification. Understanding the composition and structure of hybrid zones may elucidate patterns of hybridization processes that are important to the formation and maintenance of species, especially for taxa that have experienced rapidly adaptive radiation. Here, we used morphological traits, ddRAD-seq and plastid DNA sequence data to investigate the structure of a Rhododendron hybrid zone and uncover the hybridization patterns among three sympatric and closely related species. RESULTS: Our results show that the hybrid zone is complex, where bi-directional hybridization takes place among the three sympatric parental species: R. spinuliferum, R. scabrifolium, and R. spiciferum. Hybrids between R. spinuliferum and R. spiciferum (R. ×duclouxii) comprise multiple hybrid classes and a high proportion of F1 generation hybrids, while a novel hybrid taxon between R. spinuliferum and R. scabrifolium dominated the F2 generation, but no backcross individuals were detected. The hybrid zone showed basically coincident patterns of population structure between genomic and morphological data. CONCLUSIONS: Natural hybridization exists among the three Rhododendron species in the hybrid zone, although patterns of hybrid formation vary between hybrid taxa, which may result in different evolutionary outcomes. This study represents a unique opportunity to dissect the ecological and evolutionary mechanisms associated with adaptive radiation of Rhododendron species in a biodiversity hotspot.

Diagnostic accuracy of the Berlin questionnaire and therapeutic effect of nasal continuous positive airway pressure in OSAHS patients with glucose metabolic dysfunction.

PURPOSE: Obstructive sleep apnea-hypopnea syndrome (OSAHS) is associated with alterations in glucose metabolism. The Berlin questionnaire (BQ) is effective in identifying subjects with high risk of OSAHS. However, its validity in patients with glucose metabolic dysfunction remains unclear. Our study aims to examine the diagnostic efficacy of the BQ in detecting OSAHS in patients with glucose metabolic dysfunction and to explore the effect of nasal CPAP on glucose metabolism. METHODS: Patients with glucose metabolic dysregulation were first asked to complete the BQ and then recruited for polysomnogram (PSG). The diagnostic accuracy of the BQ and the relationships between groups with normal glucose tolerance (NGT), elevated fasting blood glucose (IFG), impaired glucose tolerance (IGT), and diabetes mellitus (DM) were analyzed. Subjects with both OSAHS and glucose dysregulation received CPAP treatment and underwent an oral glucose tolerance test. Changes in apnea-hypopnea indices (AHI) and glycemic parameters were calculated to determine the efficacy of CPAP. RESULTS: Glycosylated hemoglobin and insulin levels were statistically different between the high-risk and low-risk groups according to the BQ. For diagnosis of subjects with OSAHS who also had glucose metabolic dysfunction, the sensitivity and specificity of the BQ using AHI cut-off values at 5 events per hour were 73% and 67%. CPAP therapy effectively reduced the blood glucose, HOMA-IR, and insulin levels. CONCLUSIONS: The BQ can be considered to be an effective and economical screening tool for patieints with OSAHS who also have glucose metabolic dysfunction. Treatment with CPAP may improve glycemic parameters.