Site-selective, reversible, pH-induced N-terminal maleylation and its application for proteomics research.

RATIONALE: Compared with traditional labelling reagents used in proteomics, maleic anhydride is milder and can be easily removed under certain conditions, thus simplifying chemical derivatization. METHODS: The proposed strategy combined a site-specific chemical labelling reaction with mass spectrometry. Site-selective, reversible N-terminal maleylation was controlled by pH. RESULTS: Selective maleyl N-terminal labelling was achieved with high efficiency under the optimized reaction conditions. The demaleylation conditions were also optimized. The sequence coverage of histone H4 increased from 77% to 95% after the maleyl labels were removed, and the number of maleylated peptides was five times that of the unlabelled peptides. We further verified the reversible and selective N-terminal labelling properties of maleic anhydride through propionylation labelling at the peptide/protein level. CONCLUSIONS: A new method for site-selective maleylation of the N-terminal amino groups of a peptide was explored. Through the optimization experiment, good efficiency was achieved for this labelling reaction. The reversibility of maleylation labelling was also explored and applied for the identification of post-translational modifications of histones. Thus, site-selective, reversible, pH-induced N-terminal labelling using maleic anhydride has greater potential for application in proteomics than any other labelling methods.

Maleic Anhydride Labeling-Based Approach for Quantitative Proteomics and Successive Derivatization of Peptides.

Chemical derivatization is a simple approach for stable-isotope covalent labeling of proteins in quantitative proteomics. Herein we describe the development of a novel maleyl-labeling-based approach for protein quantification. Under optimized conditions, maleic anhydride can serve as a highly efficient reagent to label the amino groups of tryptic peptides. Furthermore, "click chemistry" was successfully applied to obtain the second modification of maleylated peptides via thiol-Michael addition reaction. Accurate quantification was further achieved via the first or/and second step stable-isotope labeling in this study. Our data thus demonstrate that the maleyl-labeling-based method is simple, accurate, and reliable for quantitative proteomics. The developed method not only enables an enhanced sequence coverage of proteins by improving the identification of small and hydrophilic peptides, but also enables a controllable, successive, second derivatization of labeled peptides or proteins, and therefore holds a very promising potential for in-depth analysis of protein structures and dynamics.

Identification of hydroxylation at aromatic amino acid residues in yeast kinase using mass spectrometry with affinity enrichment.

RATIONALE: Protein kinases represent the key elements in phosphorylation-based signal transmission. Recent studies suggest that hydroxylation may mediate activities of protein kinases. This paper aims to examine the hydroxylation in protein kinases for improving our understanding of the protein modification. METHODS: We combined affinity-based protein purification with MS analysis for identification of novel hydroxylation at aromatic amino acid residues in yeast kinases. RESULTS: We identified 17 hydroxylation at aromatic amino acid residues (10 at Phe, 1 at Tyr and 6 at Trp) using MS analysis. We further characterized the localization and studied the potential significance of these modifications. CONCLUSIONS: This is a new report on the identification of hydroxylation at aromatic amino acid residues in yeast kinases. This study expands the catalog of hydroxylation in kinases and suggests the potential function of hydroxylation. Copyright © 2016 John Wiley & Sons, Ltd.

Development of a DNA-Templated Peptide Probe for Photoaffinity Labeling and Enrichment of the Histone Modification Reader Proteins.

Histone post-translational modifications (HPTMs) provide signal platforms to recruit proteins or protein complexes to regulate gene expression. Therefore, the identification of these recruited partners (readers) is essential to understand the underlying regulatory mechanisms. However, it is still a major challenge to profile these partners because their interactions with HPTMs are rather weak and highly dynamic. Herein we report the development of a HPTM dual probe based on DNA-templated technology and a photo-crosslinking method for the identification of HPTM readers. By using the trimethylation of histone H3 lysine 4, we demonstrated that this HPTM dual probe can be successfully utilized for labeling and enrichment of HPTM readers, as well as for the discovery of potential HPTM partners. This study describes the development of a new chemical proteomics tool for profiling HPTM readers and can be adapted for broad biomedical applications.

Comprehensive profiling of protein lysine acetylation in Escherichia coli.

Protein lysine acetylation plays a key role in regulating chromatin dynamics, gene expression and metabolic pathways in eukaryotes, and, thus, contributes to diverse cellular processes like transcription, cell cycle regulation, and apoptosis. Although recent evidence suggests that acetylated proteins impact broadly cellular functions in prokaryotes, the substrates and localization of this modification remain widely unknown due to the limitations of analytical methods. Comprehensive identification of protein acetylation is a major bottleneck due to its dynamic property and pretty low abundance. A complete atlas of acetylome will significantly advance our understanding of this modification functions in prokaryotes. To achieve this goal, we have developed an intergraded approach to identifying lysine acetylation. Combining immunoaffinity enrichment with high sensitive mass spectrometry, we identified 349 acetylated proteins and addressed 1070 acetylation sites in Escherichia coli. To our knowledge, the acetylated proteins and acetylated sites were increased to 3 times and 8 times, respectively, compared to that in previous report. To further characterize this modification, we classified acetylated proteins into several groups according to cell components, molecular functions and biological process. Additionally, interaction networks and high confident domains architectures of acetylated proteins were investigated with the aid of bioinformatics tools. Finally, the acetylated metabolic enzymes were analyzed on the basis of acetylated proteins identified by proteomic survey in E. coli. Our study has demonstrated that the combined approach is powerful for identification and characterization of protein lysine acetylation on a large scale. These results not only greatly expand the number of acetylated proteins, but also provide a series of important information including localization, networks and characterization of acetylome.

PDINH bridged NH2-UiO-66(Zr) Z-scheme heterojunction for promoted photocatalytic Cr(VI) reduction and antibacterial activity.

Z-scheme mechanism was a promising approach to considerably enhance photocatalytic activity. In this work, the PDINH/NH2-UiO-66(Zr) (PNU) heterojunctions were made using a facile ball-milling method. As expect, the optimum PNU-1 composite acted as highly active photocatalyst with 97% Cr(VI) to be reduced within 60 min of LED light illumination. Moreover, the antibacterial rate almost reached 100% for E. coli and S. aureus in 4 h, which was more conspicuous than the others. The wider light absorption range, promoted charge separation because of Z-scheme mechanism and efficient generation of reactive 1O2, •O2-, and •OH contributed greatly to the enhanced photocatalytic activity. Meanwhile, the superior stability and repeatability of the composites were also demonstrated by five cyclic experiments and related physicochemical characterizations. Therefore, this work provides a novel insight for designing high-efficiency Z-scheme heterostructures between MOFs and organic PDINH for wastewater remediation.

The strong interaction and confinement effect of Ag@NH2-MIL-88B for improving the conversion and durability of photocatalytic Cr(VI) reduction in the presence of a hole scavenger.

Selectively regulating active factors in photocatalytic reactions by designing materials is one of the very important factors. Herein, we prepared spindle-like core-shell Ag@NH2-MIL-88B composites (Ag@NM-88) by a two-step hydrothermal method. The as-prepared Ag@NM-88 displayed superior photocatalytic activity for Cr(VI) reduction under LED light, compared with the activities of pure NH2-MIL-88B (NM-88) and Ag/NM-88 (Ag was deposited on NH2-MIL-88B). The core-shell structure Ag@NM-88 was not only beneficial to the absorption of light but also beneficial to the separation of photogenerated e- and h+. More importantly, it was further confirmed by active radical capture experiments and nitroblue tetrazolium (NBT) conversion experiments that the design of the core-shell structure could effectively prevent photogenerated e- from combing with O2 to form •O2-, so that photogenerated e- directly reduced Cr(VI), thereby improving the reaction rate. In addition, it could still maintain good stability after 5 cycles, indicating that the construction of a core-shell structure is also conducive to improving stability. This work provides a strategy for selectively regulating the active components of photocatalysts, and provides new insights into the relationship between interfacial charge transfer and molecular oxygen activation in photocatalytic reduction Cr(VI) systems.

Acupuncture for the Elsberg Syndrome Secondary to Varicella-Zoster Virus Infection: a Case Report and Brief Review.

Elsberg syndrome (ES) is an infectious syndrome presenting with variable signs of acute lumbosacral radiculomyelitis. Its low recognition rate leads to misdiagnosis and incorrect treatment. Thus, some ES patients may develop neurological sequelae. This case described a 74-year-old woman complained of urinary retention, constipation, and sacral numbness after herpes zoster in the perianal area. She was diagnosed with ES and accepted conventional drug treatments and urethral catheterization. The treatment was ineffective; therefore, she accepted electroacupuncture six times and her symptoms completely disappeared, with no recurrence of neurological disorders during 1-year follow-up. This shows that acupuncture is a safe and effective alternative therapy for ES. Nonetheless, further prospective studies are necessary to prove its efficacy in ES.

Effects of Qihuang Needling on Motor Function for Patients With Parkinson's Disease: Study Protocol for a Multicenter, Randomized Controlled Trial.

Background: Although significant progress has been made in the pharmacologic management of Parkinson's Disease (PD), effective management of movement disorders is still a hurdle for therapeutics targeting PD. Acupuncture is one therapeutic option that could potentially improve the motor function of PD and is widely used as adjuvant therapy. Among the various acupuncture approaches, Qihuang Needling (QHN) therapy has been found to improve motor-function control for patients with PD. However, evidence regarding its efficacy remains scarce. Therefore, to address this need, this study will determine the effects of QHN therapy on motor function in patients with PD and compare it to placebo effects. Methods: This trial is a multicenter, prospective randomized controlled clinical trial. We randomly allocated 144 participants to two groups of 72 patients. Patients in the treatment group were treated with QHN therapy. The control group had undergone insertion of acupuncture needles at sham acupoints not corresponded to acupuncture points. Participants in the verum treatment group and sham-acupuncture control group received 9 sessions over 6 weeks followed by 8 weeks of follow-up. The primary outcome was the change of motor function from baseline to weeks 6 and 14 measured by the PD Rating Scale-Part III Motor Examination (UPDRS-III). Secondary outcome measures included the change of PD daily quality of life-39 (PDQ-39) and Non-Motor Symptoms Scale for PD (NMSS) from baseline to weeks 6 and 14. Discussion: The results of this trial will generate data to improve our general understanding of the efficacy of QHN therapy on motor function in patients with PD and thoroughly compare these responses to the placebo effect. Trial Registration: The trial was registered at the Chinese Clinical Trials Registry (ChiCTR- 2000030871) on 16 March 2020.

Early intervention with acupuncture improves the outcome of patients with Bell's palsy: A propensity score-matching analysis.

Objective: Although acupuncture is widely used as a complementary therapy in the treatment of Bell's palsy (BP) when to initiate acupuncture is still controversial. This study aims to determine the efficacy of the early intervention by acupuncture on BP. Methods: We retrospectively gathered clinical data from the Third Affiliated Hospital of SUN-YAT SEN University between 2016 and 2021. We selected newly diagnosed patients with BP who were diagnosed by registered neurologists or acupuncturists formally. The qualified patients were divided into two groups according to whether or not initial acupuncture treatment was given within 7 days from the onset of palsy. Cohorts were balanced using 1:1 propensity score matching (PSM). Cox proportional hazards modeling and Kaplan-Meier analysis were applied to determine the differences between the two groups. The outcome included time to complete recovery of facial function, the rate of complete recovery, and the occurrence of sequelae in 24 weeks. Results: A total of 345 patients were eligible for this study and were divided into the manual acupuncture/electroacupuncture (MA/EA) group (n = 76) and the EA group (n = 125). In the propensity score-matched cohort, the time to complete recovery was significantly shorter in the MA/EA group compared with the patients in the EA group (hazard ratio 1.505, 95% CI 1.028-2.404, p <0.05). The MA/EA group had a higher rate of favorable outcomes at 12 weeks than the EA group (93.4 vs. 80.3%, p = 0.032), and the occurrence of sequelae at 24 weeks showed a greater reducing trend in the MA/EA group than the EA group (6.6 vs. 16.4%, p = 0.088). Conclusion: Acupuncture intervention at the acute stage of BP could shorten the time to recovery and improve the outcome. Clinical trial registration: http://www.chictr.org.cn, identifier ChiCTR 2200058060.

The Effects of Acupuncture on Pregnancy Outcomes of Recurrent Implantation Failure: A Systematic Review and Meta-Analysis.

OBJECTIVE: To systematically evaluate the efficacy and safety of acupuncture for patients with recurrent implantation failure (RIF) undergoing in vitro fertilization-embryo transfer (IVF-ET) and hopefully provide reliable guidance for clinicians and patients. METHODS: Through searching domestic and foreign medical journals, the literature of randomized controlled trials (RCTs) of acupuncture for RIF undergoing IVF-ET was collected. RevMan 5.3 software was used for meta-analysis and Cochrane's risk of bias assessment tool was used to evaluate the quality of the included studies. RESULTS: Seven documents meeting the criteria were finally included. The results showed that the intervention group contributes more in outcomes including clinical pregnancy rate (RR = 1.90, 95% CI (1.51, 2.40), P < 0.05), biochemical pregnancy rate (RR = 1.59, 95% CI (1.27, 1.99), P < 0.05), embryo implantation rate (RR = 1.89, 95% CI (1.47, 2.45), P < 0.05), and endometrial thickness (MD = 1.11, 95% CI (0.59, 1.63), P < 0.05) when compared with the control group, and the difference is statistically significant. In terms of the number of embryo transfers and the type of endometrium, the difference between the acupuncture group and the control group was not statistically significant. CONCLUSION: Acupuncture therapy on patients with RIF can improve the pregnancy outcome of patients. It is a relatively effective treatment with satisfactory safety and suitable for clinical application. However, as the quality of the included studies is not good enough, the conclusion of this meta-analysis should be treated with caution. More double-blind RCTs equipped with high quality and large samples are expected for the improvement of the level of evidence.

fNIRS Evidence for Distinguishing Patients With Major Depression and Healthy Controls.

In recent years, major depressive disorder (MDD) has been shown to negatively impact physical recovery in a variety of patients. Functional near-infrared spectroscopy (fNIRS) is a tool that can potentially supplement clinical interviews and mental state examinations to establish a psychiatric diagnosis and monitor treatment progress. Thirty-two subjects, including 16 patients clinically diagnosed with MDD and 16 healthy controls (HCs), participated in the study. Brain oxyhemoglobin (HbO) and deoxyhemoglobin (HbR) responses were recorded using a 22-channel continuous-wave fNIRS device while the subjects performed the emotional sound test. This study evaluated the difference between MDD patients and HCs using a variety of methods. In a comparison of the Pearson correlation coefficients between the HbO/HbR responses of each fNIRS channel and four scores, MDD patients and HCs had significantly different Athens Insomnia Scale (AIS) scores. By quantitative evaluation of the functional association, we found that MDD patients had aberrant functional connectivity compared with HCs. Furthermore, we concluded that compared with HCs, there were marked abnormalities in blood oxygen in the bilateral ventrolateral prefrontal cortex (VLPFC) and bilateral dorsolateral prefrontal cortex (DLPFC). Four statistical-based features extracted from HbO signals and four vector-based features from both HbO and HbR served as inputs to four simple neural networks (multilayer neural network (MNN), feedforward neural network (FNN), cascade forward neural network (CFNN) and recurrent neural network (RNN)). Through an analysis of combinations of different features, the combination of 4 common features (mean, STD, area under the receiver operating characteristic curve (AUC) and slope) yielded the highest classification accuracy of 89.74% for fear emotion. The combination of four novel feature (CBV, COE, |L | and K) resulted in a classification accuracy of 99.94% for fear emotion. The top 10 common and novel features were selected by the ReliefF feature selection algorithm, resulting in classification accuracies of 83.52% and 91.99%, respectively. This study identified the AUC and angle K as specific neuromarkers for predicting MDD across specific depression-related regions of the prefrontal cortex (PFC). These findings suggest that the fNIRS measurement of the PFC may serve as a supplementary test in routine clinical practice to further support a diagnosis of MDD.

Automatic epileptic seizure detection via Stein kernel-based sparse representation.

Epileptic seizure detection is of great significance in the diagnosis of epilepsy and relieving the heavy workload of visual inspection of electroencephalogram (EEG) recordings. This paper presents a novel method for seizure detection using the Stein kernel-based sparse representation (SR) for EEG recordings. Different from the traditional SR scheme that works with vector data in Euclidean space, the Stein kernel-based SR framework is constructed for seizure detection in the space of the symmetric positive definite (SPD) matrices, which form a Riemannian manifold. Due to the non-Euclidean geometry of the Riemannian manifold, the Stein kernel on the manifold permits the embedding of the manifold in a high-dimensional reproducing kernel Hilbert space (RKHS) to perform SR. In the Stein kernel-based SR framework, EEG samples are described by SPD matrices in the form of covariance descriptors (CovDs). Then, a test EEG sample is sparsely represented on the training set, and the test sample is classified as a member of the class, which leads to the minimum reconstructed residual. Finally, by using three widely used EEG datasets to evaluate the detection performance of the proposed method, the experimental results demonstrate that it achieves good classification accuracy on each dataset. Furthermore, the fast computational speed of the Stein kernel-based SR also meets the basic requirements for real-time seizure detection.

[Effects of tongyuan acupuncture on pregnancy outcomes of ovarian induction period with clomiphene citrate: a retrospective analysis].

OBJECTIVE: To observe the clinical efficacy and action mechanism of tongyuan acupuncture for ovulatory disorder infertility of ovarian induction period with clomiphene citrate (CC). METHODS: Through retrospective analysis, 36 patients with ovulatory disorder infertility were divided into CC group (16 cases) and tongyuan acupuoture group (20 cases) by method. The patients in the CC group were treated with oral administration of CC (50 mg) for 5 days from the 5th day of menstruation; based on the treatment of CC, patients in the tongyuan acupuncture group were treated with tongyuan acupuncture; the group A of acupoint was mainly consisted of acupoints of the conception vessel and the three yin meridians and front-mu acupoints in abdomen; the group B of acupoint was mainly consisted of acupoints of the governor vessel and back-shu acupoints. The two groups of the acupoints were selected alternately, combined with the si-guan points (Taichong (LR 3)、Hegu (LI 4)) and five-shu points. The needles were inserted with flying needling method, and the needles were retained for 30 min per treatment; acupuncture was given once every other day. All the patients were treated for 2 months, and treatment stopped if pregnancy occurred. The pregnancy rate, cycle ovulation rate, maximum diameter of follicle, endometrial thickness and adverse effects were compared between the two groups. RESULTS: The pregnancy rate of the tongyuan acupuncture group was 75.0% (15/20), which was superior to 37.5% (6/16) in the CC group (P<0.05). The cycle ovulation rates of two groups were 70.4% (19/27, P>0.05). The maximum diameter of follicle and the endometrium thickness in the tongyuan acupuncture group were superior to those in the CC group (both P<0.05). The incidence of adverse effects in the tongyuan acupuncture group was 0% (0/20), which was lower than 18.8% (3/16) in the CC group (P<0.05). CONCLUSION: Tongyuan acupuncture combined with CC could improve the quality of follicle and the receptivity of endometrium in patients with ovulatory disorder infertility, so as to improve the pregnancy rate, which could be used as a safe and effective means to cooperate with modern assisted reproductive technology.

Profiling post-translational modifications of histones in neural differentiation of embryonic stem cells using liquid chromatography-mass spectrometry.

The neural differentiation of embryonic stem cells (ESCs) is of great significance for understanding of the mechanism of diseases. Histone post-translational modifications (HPTMs) play a key role in the regulation of ESCs differentiation. Here, we combined the stable isotope chemical derivatization with nano-HPLC-mass spectrometry (MS) for comprehensive analysis and quantification of histone post-translational modifications (HPTMs) in mouse embryonic stem cells (mESCs) and neural progenitor cells (mNPCs) that was derived from ESCs. We identified 85 core HPTM sites in ESCs and 78HPTM sites in NPCs including some novel lysine modifications. Our quantitative analysis results further revealed the changes of HPTMs from ESCs to NPCs and suggested effect of combinational HPTMs in the differentiation. This study demonstrates that HPLC-MS-based quantitative proteomics has a considerable advantage on quantification of combinational PTMs and expands our understanding of HPTMs in the differentiation.

Identification of Two Novel Modifications at Tryptophan Residues.

Protein post-translational modifications (PTMs) play important roles in cellular physiology. Mass spectrometry (MS) has been developed into a powerful tool to identify all possible protein modifications. Herein, we describe our efforts to deduce the structures of two unknown modifications at tryptophan (Trp) residues (W + 92 Da and W + 108 Da). The two modifications were further confirmed by aligning the MS/MS fragmentation of synthetic peptide with in-vivo peptide identified. Finally, the mimic experiment elucidated how two Trp modifications occur. This study, therefore, expands current knowledge of Trp modifications.