Postoperative organ dysfunction is a leading cause of death and disability following hip fracture surgery in older patients. Intraoperative hypotension is a major modifiable risk factor for this complication, yet the optimal management strategy to prevent it remains controversial. We hypothesize that an individualized blood pressure management strategy is superior to standard management in reducing postoperative organ dysfunction. This single-center, randomized, controlled trial will enroll 180 patients aged 65-85 years with hip fractures under general anesthesia. Eligible patients will be randomly allocated in a 1:1 ratio to the individualized management group (targeting systolic blood pressure within ± 10% of baseline) or the standard management group (reactive management, where intervention is initiated only if systolic blood pressure < 90 mmHg or decrease of > 30% from baseline). A universal mean arterial pressure target of ≥ 65 mmHg will be maintained for all patients. The allocated hemodynamic management strategy will be maintained throughout surgery and during the post-anesthesia care unit stay. The primary outcome is a composite of dysfunction in at least one organ system (respiratory, cardiovascular, renal, and neurological) within 7 days after surgery. Secondary outcomes include the components of the primary outcome, intraoperative variables (including hemodynamic management data, fluid balance, blood loss, and serum lactate levels), intensive care unit and hospital stay, and all-cause mortality within 30 days after surgery. This randomized controlled trial aims to determine whether individualized blood pressure management reduces postoperative organ dysfunction more effectively than standard management in older hip fracture surgery patients. If proven effective, this proactive approach may represent a significant advance in clinical practice, moving from reactive hypotension correction to preventive stabilization, potentially reducing major complications, shortening hospital stays, and improving functional recovery. The results will provide important evidence to guide hemodynamic management during general anesthesia in this vulnerable population, contributing to standardized, evidence-based protocols for enhancing perioperative outcomes. Trial registration: Chinese Clinical Trial Registry, ChiCTR2400093838. Registered on 12 December 2024. This manuscript presents the study protocol; participant recruitment is ongoing and results will be reported upon trial completion.
Enteroinvasive Escherichia coli is a gram-negative pathogen closely related to Shigella, and it is one of the leading causes of bacillary dysentery acquired in South Asia and worldwide. The emergence of multidrug-resistant serotypes has severely limited treatment options, with an urgent requirement for vaccines. This study applied immunoinformatics to design a multiepitope vaccine candidate targeting the O96:H19 strain. Here, four invasion plasmid antigens (IpaA, IpaB, IpaC, and IpaD) were taken as targets. Designed vaccine construct integrates three 9-mer PAP (possessing both MHC & B cell inducing properties) linked by proteasomal and lysosomally cleavable spacers. 7-mer TLR4 agonist (RS-04) fused with both its terminals. Computational analysis of the 69-mer vaccine construct predicted strong antigenicity, non-allergenicity and optimum solubility. In Ramachandran's plot, 100% of the residues were located in the most favourable regions. Molecular docking revealed a high affinity of the construct towards the human TLR4 model. Additionally, a 100 ns all-atom molecular dynamics simulation further confirmed the TLR4-vaccine complex formation through 14 H-bonds, 131 non-bonded contacts, and five salt bridges. Post-simulation (100 ns) molecular interaction maps identified specific interactions of TLR4 agonists with the TLR4 model. Immunosimulation for 365 days was associated with rising titers of IgG and IgM antibodies, as well as pro-inflammatory cytokine responses. To express the construct in E.coli expression system, the vaccine sequence was reverse-translated. The codon-optimized sequence was recombined into a modified pET vector using an in-silico method. Hence, laboratory validation was required to assess the real-time efficacy of the EIEC and Shigella cross-protective multiepitope vaccine. The online version contains supplementary material available at 10.1007/s40203-026-00618-3.
Stellate ganglion block is a salvage therapy used for refractory or incessant ventricular tachycardia when conservative measures have failed. This case involves a man in his 60s with a history of hypertension, glaucoma, heart failure with a reduced ejection fraction of 28%, and 2 stents at the mid left anterior descending artery and proximal right coronary artery following a recent myocardial infarction. After his initial presentation, he was found to be in sustained ventricular tachycardia, in addition to having a right brachial vein deep vein thrombosis for which he was started on rivaroxaban. He had several major risk factors, including triple anticoagulant therapy, glaucoma, recent myocardial infarction, and cardiac conduction block. Since he was a poor candidate for heart transplantation and after weighing risks vs benefits, he underwent a stellate ganglion block. No immediate postprocedure complications occurred. He had terminal cardiac sympathectomy afterwards. While stellate ganglion block is not a novel technique, this case demonstrated the feasibility for performing it for refractory ventricular tachycardia in select high-risk patients.
Birth defects are a significant contributor to neonatal and under-five deaths. The majority of birth defects, once diagnosed, need multidisciplinary referrals. A Birth Defect Clinic (BDC) was therefore initiated as a one-stop clinic where all concerned specialists are available at the same place and time. An integrated approach to managing birth defects can possibly improve patient care and outcomes. The objective of the study was to evaluate the effectiveness of a multidisciplinary BDC in managing antenatally diagnosed congenital anomalies. A retrospective study of 1549 antenatal patients counseled at the BDC was conducted. Data on epidemiology, prognosis, management options, and follow-up outcomes were analyzed. The most common anomalies diagnosed were of the genitourinary system (35.95%), followed by cardiovascular system (21.82%), central nervous system (19.75%), and gastrointestinal (7.74%) anomalies. 61.8% of patients could be contacted for postnatal follow-up, with 21.5% not undergoing any postnatal evaluation. 12.58% of patients underwent Medical Termination of Pregnancy. The BDC provides a comprehensive and integrated approach to managing birth defects, improving patient care and outcomes.
Connexin 43 (Cx43) exhibits remarkable functional diversity that is precisely dictated by its dynamic subcellular localization. Beyond its canonical role at the plasma membrane, where it assembles into gap junctions (GJs) and hemichannels (HCs) to mediate intercellular communication, Cx43 translocates to the nucleus and mitochondria, where it exerts non-channel functions including transcriptional regulation and metabolic adaptation. At the plasma membrane, dysregulation of Cx43 trafficking, anchoring, or turnover leads to excessive HC opening and impaired GJ communication, contributing to cardiovascular arrhythmias, ischemia-reperfusion injury, neuroinflammation, osteoporosis, and retinopathy. In the nucleus, Cx43 or its C-terminal fragment enters through importin-dependent pathways, functioning as a non-canonical transcriptional regulator; its mislocalization is implicated in cancer (context-dependent suppression or promotion), hepatic gluconeogenesis in diabetes, and tissue fibrosis. Within mitochondria, Cx43 is imported via Hsp90/TOM complex- or GJA1-20 k-dependent pathways, where it regulates K+ transport, respiratory chain activity, and redox balance; this mitochondrial pool exerts cardioprotection under preconditioning but exacerbates diabetic cardiomyopathy and neurological injury under pathological stress. This review synthesizes current knowledge on the trafficking mechanisms, pathological outcomes, and therapeutic targeting of Cx43 in these three subcellular compartments. We further discuss peptide-based inhibitors (e.g., Gap19, αCT1), small molecules (e.g., tonabersat, danegaptide), and natural product-derived modulators, highlighting challenges in specificity, bioavailability, and clinical translation. By linking compartment-specific functions to distinct disease entities, this review establishes subcellular localization as a central determinant of Cx43 biology and a promising axis for precision medicine.
A light-driven method for the enantioselective contrathermodynamic positional isomerization of olefins based on excited-state electron transfer is reported. Sequential oxidation and deprotonation of a tetrasubstituted enol ether generates an allylic radical which is captured by a Cr(II) cocatalyst bearing a chiral bioxazoline (BiOX) ligand. Regio- and enantioselective protodemetalation of the nascent Cr(III) allyl complex by methanol yields the terminal olefin product with enantioselectivities of up to 95:5 er. Kinetic and isotopic labeling studies support an enantiodetermining protodemetalation and reveal the presence of two primary KIEs within the same catalytic manifold.
Arising from epidermal keratinocytes, cutaneous squamous cell carcinoma (cSCC) is the second most common human tumor. Transformed keratinocytes in cSCC retain partial ability to execute terminal-differentiation, forming keratinized, cyst-like structures called 'keratin pearls' rather than normal stratified epidermis. It is readily appreciated that well-differentiated tumors have better prognosis than poorly differentiated ones; however, molecular mechanisms governing terminal differentiation in cSCC remain incompletely understood. Delineating these mechanisms promises to identify additional differentiation-associated molecules that could serve as histologic markers for prognostic stratification. In this study, we demonstrate that FWE (Flower), a newly described regulator of lamellar body trafficking in normal epidermis, is specifically expressed in highly differentiated cSCC layers. Genetic knockout of FWE dysregulates cornification and lamellar body-related gene expression, causing abnormal keratinization, whereas ectopic hFWE4 expression drives G1 arrest and exit from the proliferative basal keratinocyte population. Poorly differentiated human cSCC exhibit minimal FWE positivity, whereas well-differentiated regions show readily detectable FWE. We propose that, as in normal epidermis, FWE facilitates late stages of cornification in cSCC and represents a differentiation marker that can classify differentiation status to improve prognostic stratification of these tumors.
Fragile X messenger ribonucleoprotein 1 (FMRP) is a multidomain RNA-binding protein highly expressed in neurons. It comprises a structured N-terminal region (NTR) containing five RNA/protein interaction domains and a large intrinsically disordered C-terminal region. A limited number of fragile X syndrome (FXS)-associated point mutations have been identified in the NTR, leading to the expression of mutated protein variants. Here, we show that the destabilizing effects of these mutations on the NTR region are less severe than those previously observed in the isolated domains, suggesting the presence of inter-domain interactions that stabilize the overall NTR architecture. Moreover, we demonstrate that the NTR structured region has an intrinsic propensity to undergo liquid-liquid phase separation (LLPS) and amyloid fibril formation in vitro, depending on protein concentration, and we characterize how three FXS-associated mutations (R138Q, G266E, and I304N) affect these processes. We show that the mutations either destabilize the entire NTR (G266E/I304N), markedly affect the kinetics of LLPS and suppress the droplet liquid nature (R138Q/G266E), or promote solid or gel-like non-amyloid aggregation (G266E), thus providing mechanistic insights into how they may alter protein function, contributing to the pathogenic mechanism. These findings suggest that the interplay between protein stability, LLPS, and fibrillization is finely regulated and may be critical for understanding FMRP function and its dysfunction in disease.
The progressive skeletal muscle degeneration observed in Duchenne Muscular Dystrophy (DMD) patients requires multiple cycles of satellite cells (SCs) activation to promote tissue regeneration. Dystrophic SCs present intrinsic defects, and the disrupting fibrotic niche hinders appropriate muscle recovery. Traditional 2D culture systems face challenges in modeling the DMD muscle niche and SCs behavior. Our aim was to validate a 3D culture of skeletal muscle spheroids (iSMS) for DMD modeling, as compared to the traditional 2D culture, while investigating the pathophysiological mechanisms of dystrophin deficiency in vitro. To compare iSMS with traditional 2D myogenic differentiation, we differentiated wild-type (WT), dystrophic (DMD) isogenic induced pluripotent stem cells (iPSCs), as well as iPSCs derived from DMD patients, characterized myogenic markers levels and assessed differences in proliferation and differentiation using RT-qPCR, immunofluorescence, and flow cytometry. Our data showed that iSMS improved PAX7 expression in vitro, while MYOD1, MYOG, MYF5, and MYH3 expression were significantly reduced. These findings suggest that, at three weeks of myogenic differentiation, iSMS cultures retained satellite-like cells in a less activated, progenitor-like state. Accordingly, we identified higher expression of canonical Notch signaling genes such as JAG1 and NOTCH1 in iSMS compared to 2D. We also characterized the response of 2D and iSMS to terminal differentiation medium, providing a valuable comparison with muscle fibers derived from human adult myoblasts. Additionally, we showed that DMD iSMS-derived progenitors proliferated at reduced levels compared with WT, a characteristic not observed in progenitors derived from 2D cultures. Finally, we performed iSMS and 2D myogenic differentiation of iPSC lines from three patients with DMD. Our results highlight important advantages of using the iSMS differentiation platform over 2D for DMD in vitro modeling. Exploring these 3D systems may help to gain a deeper understanding of SCs behavior to advance in novel treatments for DMD, which might be applicable to other forms of muscular disorders.
The professional relationship between general practitioners (GPs) and endodontists is essential for high-quality patient care. The purpose of this study was to provide a dual-perspective evaluation of the referral patterns and professional perceptions held by both referring dentists (RDs) and endodontists (EDs) to identify modern barriers to effective collaboration. An anonymous 22-item online survey was distributed to EDs and RDs through professional networks and social media. The questionnaire addressed demographics, clinical workflows, and professional perceptions. Data were analyzed using Pearson chi-squared tests and binary logistic regression (p < 0.05). A total of 1,352 responses were analyzed (793 EDs, 559 RDs). Clinical procedural problems were the primary driver for referral for both RDs (47.2%) and EDs (50.7%). However, significant perceptual gaps were identified: 30% of RDs believed restorability assessment was primarily the endodontist's responsibility, compared to 20.6% of EDs (p < 0.05). Although RDs reported high satisfaction with specialist reports, 44.2% of EDs found referral letters inadequate more than 30% of the time. While both groups prioritized phone communication for relationship maintenance (RD: 51.4%; ED: 25.7%), EDs placed a significantly higher value on personal office visits (18.2%) than RDs (7.4%). Relationship termination also differed, with RDs most commonly citing patient dissatisfaction (30.7%) and EDs citing divergent treatment philosophy (40.0%) as the primary reasons for discontinuing referral. The RD-ED referral pathway is characterized by shared clinical goals but significant discrepancies in documentation expectations and responsibility for restorability. Implementing standardized referral templates and improving bidirectional communication of restorative intent are essential for reducing professional friction and enhancing the continuity of patient care.
PSD95, a member of the membrane-associated guanylate kinase family, plays a key role in synaptic transmission. In this multidomain protein, the third PDZ domain has a complex regulatory mechanism that modulates its binding of carboxyl-terminal sequences. Phosphorylation of Tyr397, located in the additional α3 helix of this PDZ domain, has been shown to affect the domain's binding affinity. To explore the molecular basis of these changes in affinity, the crystal structure of the mutant Tyr397Glu, a point mutation intended to mimic phosphorylated tyrosine, has been determined. The crystal structure of this mutant reveals conformational changes induced by the introduction of a negative charge into the extra-domain α3 helix, suggesting communication between distant secondary-structure elements that may affect the binding affinity of this domain. Additionally, DSC folding studies show a noticeable decrease in the mutant's stability, indicating significant conformational changes. Altogether, the experimental results included in this work demonstrate that α3 is part of an electrostatic network that regulates stability and conformational changes at distant sites, including the β-hairpin at the binding site.
Domestic cat hepatitis B virus (DCHBV) is a member of the Hepadnaviridae family and has been associated with hepatocellular carcinoma (HCC) in cats. This study aimed to determine the prevalence of DCHBV and associations with feline immunodeficiency virus (FIV), feline leukaemia virus (FeLV) and feline coronavirus (FCoV) infections in cats in Serbia, and to characterise the detected DCHBV genomes. Whole blood, serum and liver samples from 308 animals were screened by real-time (RT-)PCR for DCHBV, FIV, FeLV, and FCoV. The prevalence of DCHBV was 2.60%, with no significant associations observed between DCHBV infection and age, sex, or coinfection status. Three whole genome sequences were obtained, and phylogenetic analysis demonstrated that the Serbian strains belong to genotype A. Molecular analysis revealed three unique nonsynonymous substitutions in the S ORF. Within the C ORF, a 28-amino acid N-terminal precore region with conserved cysteine residues critical for protein maturation was identified, along with the C-terminal arginine-rich domain. A putative core promoter region was detected, containing two motifs analogous to the pgRNA and pcRNA initiator elements described in hepatitis B virus (HBV). DCHBV sequences contained two 11-bp direct repeats with DR2 located in X ORF and DR1 positioned in the C ORF. This study represents the first report of DCHBV in Serbia, providing new insights into its epidemiology and genomic features. The findings expand current knowledge of its molecular diversity and underscore the importance of genomic characterisation for understanding its role in liver disease development.
In ratiometric sensors, a conventional strategy for target detection is to modulate one signal via resonance energy transfer (RET), while keeping the other signal constant despite fluctuations in the target concentration. To avoid the drawback of low quenching efficiency caused by long-distance interaction in RET, the selection of functional material can eliminate the adverse effects of long distance through direct contact with the luminophore, thus improving the quenching efficiency. In this work, a U-shaped chain conjugated to the second antibodies (Ab2) at both terminals was hybridized with ethylenediaminetetraacetic acid (EDTA)-modified signal probe chain capable of inducing signal variation to assemble an antigen-responsive DNA clamp, which responded to the target concentration. When Ab2 on an antigen-responsive DNA clamp specifically recognized the target antigen, the signal probe chain was released, thereby enabling the coordination of Cu2+ on the surface of CdTe: Cu+ quantum dots (QDs) with EDTA. Since Cu2+ acted as a coreaction accelerator to enhance the response of CdTe: Cu+ QDs, the coordination compound locked Cu2+, thereby precluding valence state conversions of Cu+/Cu2+. With the reference signal of CeEu-MOF, the signal of the CdTe: Cu+ QDs decreased with an increase in target concentration. The ratiometric sensor constructed on this basis exhibited a wide detection range of 10-4 - 103 U/mL and a low limit of detection of 3.21 × 10-5 U/mL (IUPAC standard), enabling the sensitive and accurate detection and providing a positive reference for the clinical diagnosis of pancreatic cancer.
Myrosinase (β-thioglucoside glucohydrolase, EC 3.2.1.147) catalyzes the conversion of glucosinolates into bioactive isothiocyanates such as sulforaphane, a compound of considerable interest for food and nutraceutical applications. However, the limited availability and variable stability of plant-derived myrosinase constrain its industrial use, underscoring the need for alternative production platforms. Here, we report the functional heterologous expression of broccoli myrosinase in Bacillus subtilis, a Generally Recognized As Safe (GRAS) microorganism widely employed for industrial enzyme production. A codon-optimized myrosinase cDNA was expressed under the constitutive P43 promoter using the pTTB2 system, generating constructs with and without an N-terminal His tag. Two competence-based transformation strategies were evaluated, showing that induction in SM1/SM2 minimal media significantly enhanced transformation efficiency compared with a conventional HS/LS protocol. Recombinant B. subtilis clones exhibited measurable myrosinase activity in crude protein extracts, whereas no activity was detected in the non-transformed control strain. Specific activities ranged from 0.316 to 2.614 U mg⁻¹ depending on the construct and clone, with noticeable variability between independent measurements. SDS-PAGE analysis revealed a protein band consistent with the expected molecular mass of myrosinase (∼64.5 kDa), and affinity-based enrichment of the His-tagged enzyme confirmed retention of catalytic activity. Although the enzyme was not purified to homogeneity, the observed activity demonstrates the feasibility of B. subtilis as a food-grade host for myrosinase production. This study establishes a proof-of-concept microbial platform for further optimization through strain engineering, secretion strategies, and downstream process development for food and biotechnological applications.
Skin photoaging is predominantly induced by ultraviolet (UV) irradiation. Intense pulsed light (IPL) is a commonly employed non-ablative treatment for photoaging. However, the effects and mechanisms of IPL on UV-induced skin photoaging remain insufficiently understood. In this study, we aimed to examine the anti-photoaging effects of IPL and elucidate the underlying mechanisms. This study revealed that UV triggered extracellular signal-regulated kinases (ERK) together with c-jun NH2-terminal kinase (JNK), while selectively suppressed UV-induced ERK phosphorylation while activating JNK in human skin keratinocytes. The different ERK/JNK expression patterns induced by UV and IPL resulted in distinct c-fos/c-jun (activator protein 1) phosphorylation, cyclin D1 expression, and matrix metalloproteinase (MMP) secretion. In vivo, IPL inhibited MMP expression in guinea pig skin and promoted c-fos/c-jun phosphorylation, epidermal proliferation, and collagen remodeling. These findings indicated that ERK was involved in IPL rejuvenation by regulating c-fos, c-jun, cyclin D1, and MMPs, providing a potential target for skin rejuvenation.
To analyse the short-term effectiveness of soft bracing in the treatment of adolescent idiopathic scoliosis (AIS) patients in terms of the correction success rate, daily wear time and comfort levels and explore the sources of heterogeneity. A literature search was performed using PubMed, EMBASE, Web Of Science, and Cochrane Library from the establishment of the literature database to April 2023. According to the evaluation criteria for the effectiveness of bracing from the International Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT) and the evaluation indicators of the success rate in previous studies, the success rate was defined as a Cobb angle ≤ 5° curve progression at maturity and a terminal follow-up angle < 45°. The success rate of soft bracing was compared with that of observation and rigid bracing. The daily wear time and comfort levels of soft bracing were compared with those of rigid bracing. The data were analyzed using RevMan 5.4, Stata 15.0 and IBM SPSS 25.0. Twelve studies involving 510 patients were included in the meta-analysis. In the single-arm analysis of 12 studies, the success rate of soft braces was 70% [OR = 0.70, 95% CI (0.61, 0.77), P < 0.0001]. In the double-arm analysis, 4 studies reported that the success rate of soft bracing was lower than that of rigid bracing [RR = 0.66, 95% CI (0.53, 0.81), P < 0.0001]. Three studies reported that the success rate of soft bracing was higher than that of observation [RR = 2.02, 95% CI (1.41, 2.89), P = 0.0001]. According to the subgroup analysis, the success rate of the Cobb angle < 30° was 71% [OR = 0.71, 95% CI (0.63, 0.78), P < 0.00001], and the success rate of the prospective studies was 75% [OR = 0.75, 95% CI (0.70, 0.79), P < 0.00001]. The study types were heterogeneous source and the subgroup with a Cobb angle < 30° had a higher success rate and less heterogeneity. The wear time every day of the brace was 20.83 ± 2.08 h for the soft braces and 12.85 ± 2.08 h for the rigid braces, and there was a significant difference between the two groups (t = 10.39, p < 0.001). Soft braces had short-term effectiveness for mild to moderate AIS patients compared with observation groups, and they had a lower success rate and higher daily wear time and comfort levels than rigid bracing. The subgroup of patients with a Cobb angle < 30° had a higher success rate and less heterogeneity in terms of soft bracing.
The intrinsic programmability of nucleic acids has positioned them as versatile molecular building blocks for constructing nanodevices with significant diagnostic and therapeutic potential. However, the clinical translation of these constructs is severely hindered by major pharmacokinetic (PK) and biophysical limitations, including susceptibility to enzymatic degradation, short circulation half-life, and inefficient cellular uptake. Chemical modification, encompassing nucleobase engineering, backbone and sugar-ring alterations, terminal conjugation, and higher-order structural reinforcement, provides a powerful strategy to overcome these barriers by enhancing in vivo stability, prolonging circulation, improving cellular internalization, and enabling stimulus-responsive cargo release. In this review, we summarize recent advances in chemically modified nucleic acid nanodevices, focusing on how specific chemical designs modulate physicochemical properties, improve pharmacokinetics, enable organ- or cell-selective targeting, and enable spatiotemporally controlled molecular release. We further highlight their emerging applications in precision drug delivery, high-sensitivity biosensing, and integrated theranostics. Finally, we critically discuss persistent translational challenges, including batch-to-batch scalability, immunogenicity, and long-term nanotoxicity, and propose forward-looking solutions, such as AI-assisted design, to pave the way for industrial adoption and clinical implementation.
This study aimed to investigate the quality of dying and death in an end-stage intensive care unit (ICU). We surveyed the quality of death of 99 end-stage ICU patients at a tertiary hospital in Suzhou using the Chinese nurse version of the ICU Quality of Death Questionnaire and a self-developed family version of the Patient Quality of Death Questionnaire. The patients' mean total quality of dying and death score was 44.72 ± 8.20. Moreover, 43.8% of the surveyed family members believed that the patients were peaceful at the end of their life, whereas 34.4% did not, and 21.9% were unsure. Health insurance status showed a significant negative correlation with both the total patient quality of death score (r = -0.205) and the end-of-life care score (r = -0.352). Based on the observational data and limited family interview sample from this study, the overall quality of death for end-stage ICU patients was relatively low. Scores on the quality of dying and death were correlated with patient age and health insurance status; however, these findings require further validation through multi-center, large-sample studies.
Free-space optical communication (FSOC) terminals require rapid and accurate beam alignment. Conventional alignment schemes typically rely on beam splitting and dedicated sensing paths, which increase optical loss and system complexity. In this paper, we propose a common-path FSOC terminal enabled by a terraced multi-core fiber (MCF) and a gradient-descent laser nutation (GDLN) algorithm for fine alignment. The performance and operational field of view (FOV) of the proposed system were experimentally validated on a collimated-light tunnel platform, achieving a fine-alignment FOV of up to ±3.33 mrad. An outdoor experiment was further conducted between two buildings separated by 860 m. A six-axis motion platform applied external disturbances with an amplitude of 3° to the terminal at 4-hour intervals over a duration of 24 h. The system automatically realigned to restore the link within 4 s. Furthermore, real-time single-wavelength 10 Gbps IMDD transmission was demonstrated with a BER of 1.242×10-11.
Phosphatidylcholine (PC), the predominant phospholipid in eukaryotic membranes, also plays a crucial role in certain bacterial species, often mediating interactions with eukaryotic hosts. In bacteria, a major pathway for PC biosynthesis involves the three-step methylation of phosphatidylethanolamine, catalyzed by phospholipid N-methyltransferases (Pmts). While the binding site for the methyl donor S-adenosyl-l-methionine is well characterized in Pmt enzymes, the detailed mechanism of methyl group transfer remains poorly understood. In this study, we combined computational and biochemical approaches to identify the amino acid residues critical for the catalytic activity of two distinct Pmt classes: the Rhodobacter (R)-type enzyme from Rubellimicrobium thermophilum (RtPmtA) and the Sinorhizobium (S)-type enzyme from Agrobacterium tumefaciens (AtPmtA). Despite low sequence identity, both enzyme types share similar reaction mechanisms, with tyrosine residues playing key roles in methyl group transfer. In RtPmtA, two highly conserved tyrosines located within the substrate-binding pocket on the N-terminal αA-helix are critical for enzymatic function. In contrast, AtPmtA depends on a single tyrosine buried in the protein core for catalysis. These findings reveal distinct active site architectures and suggest that R-type and S-type enzymes have evolved class-specific structural strategies for tyrosine activation. This divergence highlights the evolutionary flexibility of Pmt enzymes, despite their shared catalytic function.