Identification of Key Ubiquitination Sites Involved in the Proteasomal Degradation of AtACS7 in Arabidopsis.

The gaseous hormone ethylene plays pivotal roles in plant growth and development. The rate-limiting enzyme of ethylene biosynthesis in seed plants is 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS). ACS proteins are encoded by a multigene family and the expression of ACS genes is highly regulated, especially at a post-translational level. AtACS7, the only type III ACS in Arabidopsis, is degraded in a 26S proteasome-dependent pathway. Here, by using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) analysis, two lysine residues of AtACS7, lys285 (K285) and lys366 (K366), were revealed to be ubiquitin-modified in young, light-grown Arabidopsis seedlings but not in etiolated seedlings. Deubiquitylation-mimicking mutations of these residues significantly increased the stability of the AtACS7K285RK366R mutant protein in cell-free degradation assays. All results suggest that K285 and K366 are the major ubiquitination sites on AtACS7, providing deeper insights into the post-translational regulation of AtACS7 in Arabidopsis.

Structure of the Arabidopsis JMJ14-H3K4me3 Complex Provides Insight into the Substrate Specificity of KDM5 Subfamily Histone Demethylases.

In chromatin, histone methylation affects the epigenetic regulation of multiple processes in animals and plants and is modulated by the activities of histone methyltransferases and histone demethylases. The jumonji domain-containing histone demethylases have diverse functions and can be classified into several subfamilies. In humans, the jumonji domain-containing Lysine (K)-Specific Demethylase 5/Jumonji and ARID Domain Protein (KDM5/JARID) subfamily demethylases are specific for histone 3 lysine 4 trimethylation (H3K4me3) and are important drug targets for cancer treatment. In Arabidopsis thaliana, the KDM5/JARID subfamily H3K4me3 demethylase JUMONJI14 (JMJ14) plays important roles in flowering, gene silencing, and DNA methylation. Here, we report the crystal structures of the JMJ14 catalytic domain in both substrate-free and bound forms. The structures reveal that the jumonji and C5HC2 domains contribute to the specific recognition of the H3R2 and H3Q5 to facilitate H3K4me3 substrate specificity. The critical acidic residues are conserved in plants and animals with the corresponding mutations impairing the enzyme activity of both JMJ14 and human KDM5B, indicating a common substrate recognition mechanism for KDM5 subfamily demethylases shared by plants and animals and further informing efforts to design targeted inhibitors of human KDM5.

Difunctionalization of the C-N Bond through tert-Butylnitrite-Initiated C-N Cleavage of 1,2,3,4-Tetrahydroisoquinolines and N,N'-Diarylimidazolidines under Transition-Metal-Free Conditions.

Difunctionalization of the saturated C-N bond of 1,2,3,4-tetrahydroisoquinolines and N,N'-diarylimidazolidines was achieved using TBN as the metal-free initiator, providing a series N-nitrosoaminoaldehydes in high yields. Mechanistic study shows that the TBN-derived tBuO radical initiated the sp3 C-H bond activation, and the C-N bond cleavage was mediated by an iminium intermediate. This reaction provided a new way to cleave an inert C-N bond under mild and metal-free conditions, realizing the construction of molecular complexity through difunctionalization of the C-N bond.

C-N Bond Activation of N,N'-Dialkylacylhydrazines Mediated by ß-Fragmentation of Nitrogen-Centered Radical.

In the presence of tert-butylnitrite and dioxygen, the C-N bond activation of N,N'-dialkylacylhydrazines was realized, providing a series of N-nitrosoacylhydrazines in high yields. Different from transition-metal and other radical catalysis, this reaction is mediated by a nitrogen-centered radical of the corresponding N,N'-dialkylacylhydrazine and further ß-fragmentation, which was supported by the mechanistic study.

Endoscopic Dyeing and Plasma Coblation-Assisted Open Neck Surgery for Pyriform Fossa Branchial Apparatus Anomalies in Adults.

Objective: Pyriform fossa (PF) branchial apparatus anomalies (PFBAA) are rare congenital third or fourth branchial apparatus anomalies (TBAA or FBAA). This article summarizes our paradigm in managing this condition by combining endoscopic procedures and open neck surgery. Methods: A retrospective review was undertaken concerning PFBAA cases treated at our tertiary medical institution between July 2020 and November 2023. Data were collected from case records. Three sequential steps were implemented: (1) direct laryngoscopy to identify internal orifice (IO), with injection of methylene blue into it; (2) open neck surgery to resect all inflammatory tissues, focusing on the ligation of the sinus tract out of PF; and (3) plasma coblation of IO mucosa. Results: In total, 7 cases (4 men and 3 women) were included (28-67 years old, median age 53). Presenting symptoms were various, with 6 lesions on the left and 1 on the right side. Preoperative (PO) fiberoptic laryngoscopy identified IO in 6 patients, while PO barium esophageal study identified outflow from PF in 4 patients. A preliminary diagnosis of PFBAA could be established in all cases (2 TBAA and 5 FBAA cases). Direct laryngoscopy after general anesthesia identified IO in all cases (2 on the base of PF and 5 on the apex of PF). All the surgical procedures were successful, with uneventful recovery in all the patients. No postoperative complications were observed. All the patients resumed oral fluid intake after confirmation of no pharyngeal fistula by barium esophageal study on the seventh postoperative day. The duration of follow-up was between 6 and 40 months (with a median duration of 27 months). No recurrence was observed. Conclusion: Open neck surgery, assisted by endoscopic dyeing of sinus tracts and plasma coblation of IO mucosa, is a suitable treatment for PFBAA in adults. This paradigm is effective and safe for senior surgeons.

Carbon nanoparticles beneficial for prophylactic central compartment lymph node dissection in cN0 papillary thyroid carcinoma.

Objective: This study explored prophylactic central compartment lymph node dissection (pCCLND) for patients with cN0 papillary thyroid carcinoma (PTC) and the effect of carbon nanoparticles (CNP) on surgical outcomes. Methods: This retrospective study reviewed PTC cases treated at our tertiary medical institution between January 2019 and December 2022. Only patients with indications for total thyroidectomy and cN0 disease were included. CNP has been associated with a higher number of harvested lymph nodes and a lower rate of accidental parathyroid gland (PTG) removal. Patients who used CNP in this study were classified as group 1, while those who denied its use were classified as group 2. Results: In total, 116 cases were included, with 80 patients in group 1 and 36 in group 2. Most patients were in stage T1, with 68 (85.0 %) patients in group 1 and 31 (86.1 %) in group 2. Postoperative hoarseness occurred in 3 (3.8 %) patients in group 1 and 1 (2.8 %) in group 2, which recovered within two months. In group 2, 250 nodes were harvested, 72 (28.8 %) of which were metastatic; in group 1, 889 nodes were harvested, 316 (35.5 %) of which were metastatic; the difference regarding the rates of metastatic lymph nodes between the 2 groups was statistically significant (P = 0.047). Differences in postoperative blood calcium and parathyroid hormone levels between the two groups were statistically significant (P = 0.035 and P = 0.034, respectively). There were symptoms of hypocalcemia in 6 (16.7 %) patients in group 2 but in only 2 (2.5 %) in group 1, all of which recovered within three months; the difference was statistically significant (p = 0.017). Conclusion: pCCLND is worth undertaking for cN0 PTC. CNP is beneficial for achieving more thorough dissection and reducing temporary hypoparathyroidism.

Fluid-structure interaction study on the causes of mending material damage after sigmoid sinus wall reconstruction.

BACKGROUND AND OBJECTIVE: Sigmoid Sinus (SS) Wall Reconstruction (SSWR) is the mainstream treatment for pulsatile tinnitus (PT), but it has a high risk of recurrence. The damage of mending material is the key cause of recurrence, and its hemodynamic mechanism is still unclear. The purpose of this study was to investigate the hemodynamic causes of mending material breakage. METHODS: In this study, six patient-specific geometric models were reconstructed based on the data of the computed tomography angiography (CTA). The transient fluid-structure coupling method was performed to clarify the hemodynamic state of sigmoid sinus and the biomechanical state of the mending material. The distribution of stress and displacement and the flow pattern were calculated to evaluate the hemodynamic and biomechanics difference at the mending material area. RESULTS: The area of blood flow impact in some patients (2/6) was consistent with the damaged location of the mending material. The average stress (6/6) and average displacement (6/6) of damaged mending material were higher than those of complete mending material. All (6/6) patients showed that the high-stress and high-displacement proportion of the DMM region was higher than that of the CMM region. Moreover, the average stress fluctuation (6/6) and average displacement (6/6) fluctuation degree of damaged mending material is larger than that of complete mending material. CONCLUSIONS: The impact of blood and the uneven stress and displacement fluctuation of the mending material may be the causes of mending material damage. High stress and high displacement might be the key causes of the mending material damage.

Telomere-to-telomere genome of the allotetraploid legume Sesbania cannabina reveals transposon-driven subgenome divergence and mechanisms of alkaline stress tolerance.

Alkaline soils pose an increasing problem for agriculture worldwide, but using stress-tolerant plants as green manure can improve marginal land. Here, we show that the legume Sesbania cannabina is very tolerant to alkaline conditions and, when used as a green manure, substantially improves alkaline soil. To understand genome evolution and the mechanisms of stress tolerance in this allotetraploid legume, we generated the first telomere-to-telomere genome assembly of S. cannabina spanning ∼2,087 Mb. The assembly included all centromeric regions, which contain centromeric satellite repeats, and complete chromosome ends with telomeric characteristics. Further genome analysis distinguished A and B subgenomes, which diverged approximately 7.9 million years ago. Comparative genomic analysis revealed that the chromosome homoeologs underwent large-scale inversion events (>10 Mb) and a significant, transposon-driven size expansion of the chromosome 5A homoeolog. We further identified four specific alkali-induced phosphate transporter genes in S. cannabina; these may function in alkali tolerance by relieving the deficiency in available phosphorus in alkaline soil. Our work highlights the significance of S. cannabina as a green tool to improve marginal lands and sheds light on subgenome evolution and adaptation to alkaline soils.

Hemodynamic assessments of unilateral pulsatile tinnitus with jugular bulb wall dehiscence using 4D flow magnetic resonance imaging.

Background: Pulsatile tinnitus (PT) is a type of tinnitus characterized by a rhythmic sound that is synchronous with the heartbeat. One of the possible causes of PT is the jugular bulb wall dehiscence (JBWD). However, the hemodynamics of this condition are not well understood. To elucidate this issue, the present study aimed to compare the blood flow of PT patients with JBWD, PT patients with sigmoid sinus wall dehiscence (SSWD), and volunteers. Methods: A retrospective case-control study was conducted, which enrolled patients with unilateral PT who had undergone both computed tomography angiography (CTA) and four-dimensional (4D) flow magnetic resonance imaging (MRI) examinations at the Department of Otolaryngology-Head and Neck Surgery of Beijing Friendship Hospital affiliated to Capital Medical University between January 2019 and July 2023. After excluding the possible causes of PT, the patients were divided into the JBWD group and SSWD group according to the presence or absence of JBWD and/or SSWD. Finally, 11 female unilateral PT patients with JBWD (JBWD group, 11sides), 22 age- and side-matched female patients with SSWD (SSWD group, 22 sides), and 22 age-matched female volunteers (volunteer group, 36 sides) were enrolled. The area, maximum voxel velocity (Vv-max), maximum velocity (Vmax), average velocity (Vavg), and average blood flow rate (Q) were measured in the transverse sinuses (TSs), sigmoid sinuses (SSs), and jugular bulb (JB). The vortex flow pattern was also assessed. Fisher's exact test and Bonferroni correction were used for count data, with P<0.017 was considered statistically significant. Shapiro-Wilk test, one-way analysis of variance (ANOVA), Kruskal-Wallis H test, paired-samples t-test, and Wilcoxon matched-pairs signed-rank test were used for continuous variables depending on the distribution and variance of the data. The P<0.05 and corrected P<0.05 was considered statistically significant. Results: The area and Q of TSs and JB on the symptomatic side were higher than those on the contralateral side in the JBWD group (TSs: Parea=0.004, Pflow=0.002; JB: Parea=0.034, Pflow=0.018). The area was larger and velocities were lower in the JBWD group at the TSs than the SSWD group (Parea=0.004, PVv-max=0.009, PVmax=0.021, PVavg=0.026), and velocities were higher at the distal TSs and SSs than the volunteer group (TSs: PVv-max=0.042, PVmax=0.046, PVavg=0.040; SSs: PVv-max=0.007, PVmax=0.001, PVavg=0.001). At the JB, the JBWD group also had higher Vv-max than the volunteer group (P=0.012). The occurrence rate of vortex at JB in the JBWD group was higher than both the JBWD and the volunteer groups (P=0.002<0.017 and P=0.009<0.017, respectively). Conclusions: The blood flow of the intracranial venous sinus was different between the JBWD group and the SSWD group. The indicators that can differentiate include Vv-max, Vmax, Vavg, vortex, and TSs cross-sectional area.

Intracapsular Enucleation of Brachial Plexus Schwannoma With Intraoperative Neuromonitoring: A Case Series Study and a Review of Literature.

OBJECTIVE: Brachial plexus schwannoma (BPS) is a rare clinical entity that poses a significant challenge for head and neck surgeons due to its neuroanatomical complexity and potential severe complications, such as major motor or sensory neurological deficits or pain of the corresponding upper extremity. This article summarizes our experience in its diagnosis and intracapsular enucleation with intraoperative neuromonitoring (INM). METHODS: A retrospective review of BPS cases treated at our tertiary medical institution was conducted between April 2020 and May 2023. The clinical and demographic data were retrieved from case notes. RESULTS: Totally, 3 cases were included. All 3 patients were male, aged 43 to 54 years (median age = 52). The presenting symptom was a palpable supraclavicular mass in all these cases (2 on the left side and 1 on the right side). Neuromonitoring was performed with a 4-channel nerve integrity monitor, with the electrodes placed in the upper arm and forearm muscles, as demonstrated in the literature. After exposing the mass and identifying its origin from the brachial plexus, a unipolar stimulating probe was used to stimulate the tumor surface or the nerves with a 1.0-mA current, and a longitudinal incision into the tumor capsule was made along a carefully mapped line with no INM response. Then the mass was carefully exposed and meticulously dissected from its capsule to achieve an intact enucleation. Immediate postoperative neurological deficit was documented in Case 1 as a mild grasping weakness. The recovery of the other 2 patients was uneventful. The follow-up duration was 7 to 38 months (median = 8 months). The minor motor deficit of Case 1 recovered completely 1 month after surgery. No recurrence of BPS was observed. CONCLUSIONS: Intracapsular enucleation with INM could result in complete removal of BPS and minimal postoperative neurological deficit, whose recovery was quick and satisfactory.

Design of a Multiple Folded-Beam Disk Resonator with High Quality Factor.

This paper proposes a new multiple folded-beam disk resonator whose thermoelastic quality factor is significantly improved by appropriately reducing the beam width and introducing integral-designed lumped masses. The quality factor of the fabricated resonator with (100) single crystal silicon reaches 710 k, proving to be a record in silicon disk resonators. Meanwhile, a small initial frequency split of the order-3 working modes endows the resonator with great potential for microelectromechanical systems (MEMS) gyroscopes application. Moreover, the experimental quality factor of resonators with different beam widths and relevant temperature experiment indicate that the dominating damping mechanism of the multiple folded-beam disk resonator is no longer thermoelastic damping.

Intracapsular Enucleation of Cervical Sympathetic Chain Schwannoma.

OBJECTIVES: Schwannoma arising from cervical sympathetic chain (CSC) is a rare clinical entity. CSC is hard to preserve in CSC schwannoma (CSCS) surgeries, resulting in Horner's syndrome (HS) and first bite syndrome (FBS). This article aims to explore our experience in successful preservation of CSC in CSCS surgeries. METHODS: This is a retrospective review of CSCS cases treated at our tertiary medical institution between Apr 2018 and March 2022. Only cases with successful intraoperative preservation of CSC were included. RESULTS: In total, 3 cases were included. There were 2 male patients and 1 female patient. Their age was between 38 years old and 66 years old (average and median age was 52 and 51 years old, respectively). Presenting symptom was neck mass for all them, 2 of which were on the left side, while 1 was on the right. Intracapsular enucleation of the CSCS was attempted and achieved in all 3 cases. Hemorrhage from the inner surface of capsules was diffuse and heavy. Constant saline irrigation, suction, and bipolar coagulation were needed to achieve hemostasis. Postoperative HS presented between 4 hours and 14 hours after surgery for all 3 patients, which took 1 month to 3 months to recover, whereas FBS did not occur in any patient. Median duration of follow-up was 6 months. No recurrence was observed. CONCLUSIONS: Intracapsular enucleation should be attempted in CSCS surgeries, although hemorrhage might be diffuse and hard to control. When intracapsular enucleation was achieved, postoperative FBS can be avoided, while postoperative HS could occur, but its recovery was satisfactory.

The histone H3K27 demethylase REF6/JMJ12 promotes thermomorphogenesis in Arabidopsis.

Dynamic trimethylation of histone H3 at Lys27 (H3K27me3) affects gene expression and controls plant development and environmental responses. In Arabidopsis thaliana, RELATIVE OF EARLY FLOWERING 6 (REF6)/JUMONJI DOMAIN-CONTAINING PROTEIN 12 demethylates H3K27me3 by recognizing a specific DNA motif. However, little is known about how REF6 activates target gene expression after recognition, especially in environmental responses. In response to warm ambient temperature, plants undergo thermomorphogenesis, which involves accelerated growth, early flowering and changes in morphology. Here we show that REF6 regulates thermomorphogenesis and cooperates with the transcription factor PHYTOCHROME INTERACTING FACTOR 4 to synergistically activate thermoresponsive genes under warm ambient temperature. The ref6 loss-of-function mutants exhibited attenuated hypocotyl elongation at warm temperature, partially due to downregulation of GIBBERELLIN 20-OXIDASE 2 and BASIC HELIX-LOOP-HELIX 87. REF6 enzymatic activity is necessary for warm ambient temperature responses. Together, our results provide direct evidence of an epigenetic modifier and a transcription factor working together to respond to the environment.

Microplastics: A tissue-specific threat to microbial community and biomarkers of discus fish (Symphysodon aequifasciatus).

As detriments in aquatic environments, microplastics (MPs) have been commonly studied on organisms, but tissue-scale effects of MPs were poorly understood. Discus fish (Symphysodon aequifasciatus), herewith, were exposed to polystyrene MPs (0/20/200 µg/L) for 28 d. We found that MPs significantly inhibited growth performance. MPs were observed in skin, gill and intestine after 14/28-d exposure. MPs bioaccumulation was independent of exposure time, but increased with MPs concentrations. Microbial community diversity of fish gill, but not skin and intestine, in MPs treatments was significantly increased. Bacterial community of MP-treated skin and gill were obviously separated from control. Skin dominant phyla changed from Actinobacteriota to Proteobacteria and Firmicutes. Proteobacteria gradually occupied dominance in gill after exposure. Furthermore, MPs-induced skin oxidative stress was demonstrated by the activation of superoxide dismutase and catalase. Skin malondialdehyde also increased and showed significant correlations with four bacterial phyla, e.g., Proteobacteria. Gill Na+/K+-ATPase activity decreased, strongly correlating to microbial community changes caused by MPs. Intestinal digestive enzymes activity (pepsin, lipase and α-amylase) reduced, revealing correlation with bacterial community especially Fibrobacterota. These results suggest a tissue-specific effect of MPs to microbial community and biomarkers in aquatic organism.

Histone methylation in epigenetic regulation and temperature responses.

Methylation of histones on different lysine residues is dynamically added by distinct writer enzymes, interpreted by reader proteins, and removed by eraser enzymes. This epigenetic mark has widespread, dynamic roles in plant development and environmental responses. For example, histone methylation plays a key role in mediating plant responses to temperature, including alterations of flowering time. In this review, we summarize recent advances in understanding the mechanism by which histone methylation regulates these processes, and discuss the role of histone methylation in temperature responses, based on data from Arabidopsis thaliana.

Tunable Functionalization of Saturated C-C and C-H Bonds of N,N'-Diarylpiperazines Enabled by tert-Butyl Nitrite (TBN) and NaNO2 Systems.

A tunable functionalization of saturated C-C and C-H bonds of N,N'-diarylpiperazine derivatives was realized by tert-butyl nitrite (TBN) and NaNO2 systems, respectively. When TBN was employed as the oxidant, C-C bond cleavage occurred smoothly, providing a series of formamides in good yields. In the presence of NaNO2, C-H oxidation was achieved, resulting in efficient synthesis of nitroalkenes. The mechanistic study shows that a mixed mechanism is involved in these reactions, in which a generated enamine might be the key intermediate.

DNA methylation repels targeting of Arabidopsis REF6.

RELATIVE OF EARLY FLOWERING 6 (REF6/JMJ12), a Jumonji C (JmjC)-domain-containing H3K27me3 histone demethylase, finds its target loci in Arabidopsis genome by directly recognizing the CTCTGYTY motif via its zinc-finger (ZnF) domains. REF6 tends to bind motifs located in active chromatin states that are depleted for heterochromatic modifications. However, the underlying mechanism remains unknown. Here, we show that REF6 preferentially bind to hypo-methylated CTCTGYTY motifs in vivo, and that CHG methylation decreases REF6 DNA binding affinity in vitro. In addition, crystal structures of ZnF-clusters in complex with DNA oligonucleotides reveal that 5-methylcytosine is unfavorable for REF6 binding. In drm1 drm2 cmt2 cmt3 (ddcc) quadruple mutants, in which non-CG methylation is significantly reduced, REF6 can ectopically bind a small number of new target loci, most of which are located in or neighbored with short TEs in euchromatic regions. Collectively, our findings reveal that DNA methylation, likely acting in combination with other epigenetic modifications, may partially explain why REF6 binding is depleted in heterochromatic loci.

The seekers: how epigenetic modifying enzymes find their hidden genomic targets in Arabidopsis.

Epigenetic regulation plays fundamental roles in modulating chromatin-based processes and shaping the epigenome in multicellular eukaryotes, including plants. How epigenetic factors recognize their target loci hiding in the vast genomic DNA sequence remains a long-standing mystery. During the past several years, a growing body of work has revealed the complex, dynamic, and diverse chromatin-targeting mechanisms of these epigenetic factors. In this review, we focus on recent advances in understanding the recruitment of epigenetic factors to specific genomic regions, based on data from Arabidopsis thaliana.

Radical Cation Salt-initiated Aerobic C-H Phosphorylation of N-Benzylanilines: Synthesis of α-Aminophosphonates.

A radical cation salt-initiated phosphorylation of N-benzylanilines was realized through an aerobic oxidation of the sp3 C-H bond, providing a series of α-aminophosphonates in high yields. An investigation of the reaction scope revealed that this mild catalyst system is superior in good functional group tolerance and high reaction efficiency. The mechanistic study implied that the cleavage of the sp3 C-H bond was involved in the rate-determining step.

0.04 degree-per-hour MEMS disk resonator gyroscope with high-quality factor (510 k) and long decaying time constant (74.9 s).

The disk resonator gyroscope is an attractive candidate for high-performance MEMS gyroscopes. This gyroscope consists of a sensor and readout electronics, and the characteristics of the sensor directly determine the performance. For the sensor, a high-quality factor and long decaying time constant are the most important characteristics required to achieve high performance. We report a disk resonator gyroscope with a measured quality factor of 510 k and decaying time constant of 74.9 s, which is a record for MEMS silicon disk resonator gyroscopes, to the best of our knowledge. To improve the quality factor of the DRG, the quality factor improvement mechanism is first analyzed, and based on this mechanism two stiffness-mass decoupled methods, i.e., spoke length distribution optimization and lumped mass configuration design, are proposed and demonstrated. A disk resonator gyroscope prototype is fabricated based on these design strategies, and the sensor itself shows an angle random walk as low as 0.001°/√h, demonstrating true potential to achieve navigation-grade performance. The gyroscope with readout electronics shows an angle random walk of 0.01°/√h and a bias instability of 0.04°/h at room temperature without compensation, revealing that the performance of the gyroscope is severely limited by the readout electronics, which should be further improved. We expect that the quality factor improvement methods can be used in the design of other MEMS gyroscopes and that the newly designed DRG can be further improved to achieve navigation-grade performances for high-end industrial, transportation, aerospace, and automotive applications.