Temperature-Driven Stopped-Flow Experiments for Investigating the Initial Aggregation of the α-Synuclein Amyloid Protein, Focusing on Active and Inactive Phases.

The primary objective of this research is to further examine the events occurring during the active or burst phase by focusing on the aggregation of the Syn amyloid protein. Regarding this aspect, it was initially conducted rapid temperature variations using stopped-flow spectrometry and tyrosyl group fluorescence emission detection, within the initial 500 milliseconds in buffered Syn solutions at pH 7, exploring various temperature ranges to investigate protein aggregation. The results obtained were contrasted with results obtained for the Nα-acetyl-L-tyrosinamide (NAYA) parent compound in the same conditions. The utilization of the NAYA compound is suitable as it mimics the peptide bonds in proteins and contains a tyrosyl group resembling the four tyrosyl groups found in the Syn protein structure (the protein has no tryptophan residues). Furthermore, the NAYA compound adopts an intramolecularly hydrogen-bonded structure even in an aqueous solution, similar to the interactions seen in the hydrophilic face of ß-sheets. Additionally, the Syn protein system can exhibit the presence of ß-sheets as a result of the existence of very low abundant Syn amyloid precursor forms or nuclei during the initial stages of the protein aggregation. Thus, a relationship is present between the molecular processes in the NAYA and Syn protein systems, making the NAYA's application crucial in this research. Moreover, to aid in understanding the results, it was also compared the events during the quiescent or inactive phase (30-500 milliseconds) with those in the burst phase (up to 10 milliseconds) using stopped-flow spectrometry conditions. Steady-state measurements were beneficial in comprehending the occurrences in both the quiescent and burst phases examined. Although protein aggregation and disaggregation were observed during the quiescent phase, determining these processes in the burst phase was more challenging. In the latter case, the aggregation of the Syn protein is actually initiated by the interaction of the intrinsically disordered Syn monomers. In the quiescent phase, first-order rate constants were measured and analysis showed that Syn protein aggregation and disaggregation occur simultaneously. At lower temperatures, early protein disaggregation outweighs protein aggregation whereas at higher temperatures protein disaggregation and aggregation are rather similar. It is also need to highlight that the burst phase, while distinct from the quiescent phase, can be considered as a possible structural phase for obtaining details about the aggregation of this specific disordered protein in solution on a very short timescale.

Influence of Screw Length and Cement Position within the Injured Vertebra on Fixation Strength in Short-Segment Fixation of Osteoporotic Thoracolumbar Burst Fractures.

OBJECTIVE: The prevalence of osteoporotic vertebral fractures has increased with aging populations, necessitating effective treatments such as percutaneous kyphoplasty combined with posterior screw fixation. However, biomechanical research on the effects of using short screws on fixation stability and bone stress or on the impact of bone cement bonding to screws on structural strength is lacking. This study aimed to optimize short-segment fixation strategies for osteoporotic thoracolumbar burst fractures by analyzing the biomechanical effects of pedicle screw length and bone-cement augmentation. METHODS: Four models of the thoracolumbar spine were established using computed tomography data of a female volunteer: (1) short screws in the injured vertebra without contact with the bone cement, (2) long screws without contact with the bone cement, (3) long screws in contact with the bone cement; and (4) long screws without the bone cement. The four fixation models were simulated under physiological loads. The range of motion, implant stress, and segmental stability were assessed. RESULTS: The three groups containing the bone cement exhibited similar performances in terms of stability and stress distribution, whereas the group without the bone cement exhibited a poorer biomechanical performance. Incorporation of the bone cement enhanced the biomechanical properties of the structure, and short screws in the injured vertebra without contact with the bone cement did not significantly compromise the biomechanical performance. CONCLUSION: Short screws in injured vertebrae without contact with the bone cement can achieve satisfactory stability and stress distribution. It is feasible to implant short screws in the injured vertebrae, reduce the number of bilaterally injured vertebrae, and inject bone cement through the non-pedicle approach during the surgical procedure, which simplifies the surgical process.

Continuous theta burst stimulation ameliorates cognitive deficits in microinfarcts mice via inhibiting glial activation and promoting paravascular CSF-ISF exchange.

Microinfarcts are widespread in the elderly, accompanied by varying degrees of cognitive decline. Continuous theta burst stimulation (cTBS) has been demonstrated to be neuroprotective on cognitive dysfunction, but the underlying cellular mechanism has been still not clear. In the present study, we evaluated the effects of cTBS on cognitive function and brain pathological changes in mice model of microinfarcts. The spatial learning and memory was assessed by Morris water maze (MWM), Glymphatic clearance efficiency was evaluated using in vivo two-photon imaging. The loss of neurons, activation of astrocytes and microglia, the expression and polarity distribution of the astrocytic aquaporin-4 (AQP4) were assessed by immunofluorescence staining. Our results showed that cTBS treatment significantly improved the spatial learning and memory, accelerated the efficiency of glymphatic clearance, up-regulated the AQP4 expression and improved the polarity distribution of AQP4 in microinfarcts mice. Besides, cTBS treatment increased the number of surviving neurons, whereas decreased the activated astrocytes and microglia. Our study suggested that cTBS accelerated glymphatic clearance and inhibited the excessive gliogenesis, which ultimately exerted neuroprotective effects on microinfarcts mice.

Decoding burst swimming performance: a scaling perspective on time-to-fatigue.

Fatigue curves quantify fish swimming performance, providing information about the time ([Formula: see text]) fish can swim against a steady flow velocity (Uf) before fatiguing. Such curves represent a key tool for many applications in ecological engineering, especially for fish pass design and management. Despite years of research, though, our current ability to model fatigue curves still lacks theoretical foundations and relies primarily on fitting empirical data, as obtained from time-consuming and costly experiments. In the present article, we address this shortcoming by proposing a theoretical analysis that builds upon concepts of fish hydrodynamics to derive scaling laws linking statistical properties of [Formula: see text] to velocities Uf, pertaining to the so-called burst range. Theoretical arguments, in the present study, suggest that the proposed scaling laws may hold true for all fish species and sizes. A new experimental database obtained from over 800 trials and five small-sized Cypriniformes support theoretical predictions satisfactorily and calls for further experiments on more fish species and sizes to confirm their general validity.

Continuous Theta Burst Stimulation Inhibits Oxidative Stress-Induced Inflammation and Autophagy in Hippocampal Neurons by Activating Glutathione Synthesis Pathway, Improving Cognitive Impairment in Sleep-Deprived Mice.

Sleep deprivation (SD) has been reported to have a negative impact on cognitive function. Continuous theta burst stimulation (cTBS) shows certain effects in improving sleep and neurological diseases, and its molecular or cellular role in SD-induced cognition impairment still need further exploration. In this study, C57BL/6 mice were subjected to 48 h of SD and cTBS treatment, and cTBS treatment significantly improved SD-triggered impairment of spatial learning and memory abilities in mice. Additionally, cTBS reduced malondialdehyde levels, increased superoxide dismutase activities, and inhibited the production of inflammatory cytokines, alleviating oxidative stress and inflammation levels in hippocampal tissues of SD model mice. cTBS decreased LC3II/LC3I ratio, Beclin1 protein levels, and LC3B puncta intensity, and elevated p62 protein levels to suppress excessive autophagy in hippocampal tissues of SD-stimulated mice. Then, we proved that inhibiting oxidative stress alleviated inflammation, autophagy, and death of hippocampal neuron cells through an in vitro cellular model for oxidative stress, and cTBS treatment promoted the production of glutathione (GSH), the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and the mRNA expression of GSH synthesis-related genes to enhance antioxidant capacity in hippocampal tissues of SD mice. An Nrf2 inhibitor ML385 or a GSH synthesis inhibitor BSO reversed the alleviating effects of cTBS treatment on oxidative stress-associated damage of hippocampal tissues and cognitive impairment in SD model mice. Altogether, our study demonstrated that cTBS mitigates oxidative stress-associated inflammation and autophagy through activating the Nrf2-mediated GSH synthesis pathway, improving cognitive impairment in SD mice.

Suppressive effects of toll-like receptor 2, toll-like receptor 4, and toll-like receptor 7 on protective responses to Mycobacterium bovis BCG from epithelial cells.

Mycobacteria have several mechanisms for evasion of protective responses mounted by the host. In this study, we unravel yet another mechanism that is mediated by Toll-Like Receptors TLR2, TLR4, and TLR7 in epithelial cells. We show that mycobacterial infection of epithelial cells increases the expression of TLR2, TLR4, and TLR7. Stimulation of either TLR along with mycobacterial infection results in an inhibition of oxidative burst resulting in increased survival of mycobacteria inside epithelial cells. TLR stimulation along with mycobacterial infection also inhibits activation of epithelial cells for T cell responses by differentially regulating the activation of ERK-MAPK and p38-MAPK along with inhibition of co-stimulatory molecule CD86 expression. Furthermore, stimulation of either TLR inhibits the induction of apoptosis and autophagy. Knockdown of either TLR by specific siRNAs reverses the inhibition by ROS and apoptosis by mycobacteria and results in reduced intracellular survival of mycobacteria in a MyD88-dependent manner. These results point towards a negative role for TLR2, TLR4, and TLR7 in regulating protective responses to M. bovis BCG infection in epithelial cells.

Intermittent theta burst stimulation in adolescents and young adults with depressive disorders: protocol of a randomized, sham-controlled study with a sequential Bayesian design for adaptive trials.

Intermittent theta burst stimulation (iTBS), a variant of repetitive transcranial magnetic stimulation (rTMS), is an established treatment for adults with major depressive disorder (MDD). Due to its favorable safety profile, iTBS is also a promising early intervention in the transition phase from adolescence to early adulthood, but this has not been systematically investigated to date. Thus, the EARLY-BURST trial investigates the efficacy and safety of iTBS over the left dorsolateral prefrontal cortex (lDLPFC) in treatment-seeking young patients (age 16-26 years) with depressive disorders (i.e. major depressive disorder, persistent depressive disorder, bipolar depression), allowing for relevant co-morbidities. Participants have not received antidepressant or antipsychotic medication during the last 12 months except for short-term (< 2 weeks) on-demand medication. The trial will employ a novel sequential Bayesian, randomized, double-blind, parallel-group, sham-controlled design. Up to 90 patients at two clinical sites (Munich, Augsburg) will be randomized 1:1 to the treatment groups, with sequential analyses starting after 26 patients in each group completed the treatment. The primary outcome will be the difference in depression severity at week 6 (post-treatment visit) between active iTBS and sham iTBS, assessed with the Montgomery-Åsberg Depression Rating Scale (MADRS). The trial is planned to be expanded towards a three-arm leapfrog design, contingent on securing additional funding. Thus, in addition to potentially providing evidence of iTBS's efficacy in adolescents and young adults with depressive disorders, the EARLY-BURST trial aims at setting the stage for subsequent platform trials in this dynamic research field, where novel adaptive study designs are required to meet the need for rapidly testing promising new vs established rTMS protocols.Trial registration: DRKS00033313.

Mitigating adverse effects of Cu-containing intrauterine devices using a highly biocompatible Cu5Fe alloy.

Copper-containing intrauterine devices (Cu-IUD) are adopted by worldwide women for contraception with the advantages of long-term effectiveness, reversibility and affordability. However, adverse effects occur in the initial implantation stage of Cu-IUD in uterine because of the burst release of Cu2+. To minimize the burst release, in this study, we designed a series of Cu-Fe alloys with 0.5 wt%, 1 wt% and 5 wt% Fe and also further produced ultrafine grained (UFG) structure for these alloys via equal-channel angular pressing. The microstructures and properties of the coarse grained (CG) Cu, CG Cu-Fe alloys and UFG Cu-Fe alloys were systematically investigated, including grain structure and phase compositions, metallic ions release behavior, electrochemical corrosion performance, and in vitro cytotoxicity. With careful comparison and selection, we chose the CG Cu-5Fe and UFG Cu-5Fe for in vivo tests using rat model, including tissue biocompatibility, in vivo corrosion behavior, and contraceptive effectiveness. Moreover, the corrosion mechanism of the Cu-5Fe alloy and its improved biocompatibility was discussed. Both CG and UFG Cu-5Fe alloys exhibited dramatic suppression of Cu2+ release in simulated uterine fluid for the long-term immersion process. The in vivo tissue compatibility was significantly improved with both CG and UFG Cu-5Fe alloys implanted in the rats' uterine while the high contraceptive efficacy was well maintained. Due to the superior biocompatibility, the CG and UFG Cu-5Fe alloys can be the promising candidate material for Cu-IUD. STATEMENT OF SIGNIFICANCE: A highly biocompatible Cu-Fe alloy was designed and fabricated for Cu-containing intrauterine devices (Cu-IUD). With 5 wt% Fe, the burst release of Cu2+ is inhibited due to the formed galvanic cell of Cu and Fe, resulting in earlier release of Fe3+. As Fe is the most abundant essential trace element of human body, it can mitigate the toxic effects of Cu2+, thus significantly improving both in vitro cell compatibility and in vivo tissue compatibility. More importantly, the Cu-5Fe alloy exhibits 100 % contraceptive efficiency as the CG Cu, but with greatly reduced adverse effects to the uterus tissues. An advanced Cu-IUD can be developed using Cu-Fe alloys.

Evaluating the Efficacy of Orthoses in the Conservative Treatment of Thoracolumbar Fractures: A Systematic Review.

Background: Thoracolumbar fractures are common traumatic injuries that can be treated conservatively or by surgery, depending on the type and severity of the injury. This study aimed to determine the efficiency of various orthoses used for these fractures based on the available literature. Methods: Between 1950 and 2023, a search was conducted in some databases, including PubMed Central and MEDLINE, ISI Web of Knowledge, Cochrane-centered Register of Controlled Trial (CCTR), Embase, and Scopus. Some keywords-such as conservative treatment, orthoses, brace, and cast-were used in combination with thoracolumbar fracture, burst fracture, and compressive fracture. The quality of the studies was evaluated using the PEDro scale. Two researchers independently reviewed the studies. Results: Based on the results of the included studies, orthosis is not necessary for stable burst and compression fractures. Based on the inclusion criteria, 20 papers were selected for the final analysis, 12 of which were on the use of spinal braces and casting (with quality between 1 and 6), 2 on the no-treatment approach, and 6 on comparing the outputs of treatment with spinal braces with no braces. Conclusion: Although the use of orthosis and cast is one of the conservative treatments recommended for patients with thoracolumbar fractures, it seems that for stable burst fractures and compression fractures, the use of a brace does not provide any benefits. However, the use of a brace or cast is recommended for burst fractures with more than 1 column fracture.

Burst abdomen: a preventable risk of severe maternal morbidity in a developing country (a case-control study at a university teaching hospital in Tanzania).

Introduction: burst abdomen is a preventable complication of caesarean section that carries an increased risk of maternal death, especially in developing countries including Tanzania. The study aimed to identify the risk factors and high-risk patients for burst abdomen at Muhimbili National Hospital in Tanzania. Methods: a case-control study was performed at Muhimbili National Hospital in Dar es Salaam from 2nd April to 27th December 2019. Characteristics of interest of one case of burst abdomen were compared to three randomly selected controls that consisted of caesarean deliveries either 24 hours before or after the time of delivery of cases. The chi-square test, Fischer´s exact test, and multivariate analysis were used. The level of significance was p < 0.05. Results: a total of 524 women that met the inclusion criteria, comprising 131 cases and 393 controls, delivered by caesarean section in the most recent pregnancy at Muhimbili National Hospital. Cases were independently associated with perioperative illness, including cough (OR 3.8, 95%CI 1.9-7.6), chorioamnionitis (OR 4.5, 95% CI 1.3-14.7), and surgical site infection (OR 3.2, 95% CI 1.7-6.4), and a vertical midline incision wound (OR 1.9, 95% CI 1.2-3.1) compared to control group. Most cases (70%) had intact sutures and loose surgical knots. Conclusion: burst abdomen remains a cause of unnecessary severe maternal morbidity and is independently associated with perioperative illnesses such as cough, chorioamnionitis surgical site infection, and a vertical midline abdominal incision. Thus, there is a need for modifying abdominal fascia closure techniques for patients at risk.

Increasing mind wandering with accelerated intermittent theta burst stimulation over the left dorsolateral prefrontal cortex.

Mind wandering (MW) is the intentional or unintentional experience of attending to internal task-unrelated thoughts while being occupied with an external task. Even though maintaining task focus is assumed to require executive functions (EF), it is not clear how and to what extent MW and EF interact. Research has found that activity in the dorsolateral prefrontal cortex (DLPFC) is associated with EF and MW. To understand the causal role of the DLPFC in relation to MW and EF, researchers have turned to non-invasive brain stimulation. Thus far, most studies have used transcranial direct current stimulation, but the results have been inconclusive. To further elucidate the relationship between the DLPFC, EF and MW, we conducted a pre-registered, sham-controlled, triple-blinded within-subject experiment by combining intermittent theta burst stimulation (iTBS) interleaved with a recently developed MW-EF task. In contrast to our expectations, participants reported significantly more MW following real iTBS as compared to sham stimulation. However, at the same time, psychomotor precision and EF improved, indicating that participants were able to engage in resource-intensive MW while simultaneously performing well on the task. We argue that iTBS enhanced the underlying executive resources that could be used to increase both MW and task performance in line with the resource-control view of MW. This finding opens exciting avenues for studying the complex interplay between MW and EF and provides empirical support for the utility of iTBS in improving executive performance during a demanding cognitive task.

Gastric Rupture Secondary to a Heimlich Maneuver: A Case Report.

A gastric rupture resulting from abdominal trauma is a rare occurrence with a frequency of less than 2% of blunt abdominal injuries. Furthermore, gastric perforation secondary to the Heimlich maneuver is even rarer, with only a handful of cases reported in the literature. Here, we present a case of isolated gastric rupture following a successful Heimlich maneuver. Laparotomy revealed a large perforation along the lesser curvature of the stomach. The perforation was repaired by primary closure and reinforced with omental patching.

Repetitive Transcranial Magnetic Stimulation (rTMS) in Major Depression.

Major depressive disorder (MDD) is a psychiatric disorder with several effective therapeutic approaches, being antidepressants and psychotherapies the first-line treatments. Nonetheless, due to side effects, limited efficacy, and contraindications for these treatments, alternative treatment options are required. Neurostimulation is a non-pharmacological and non-psychotherapeutic approach that has been under study for diverse neuropsychiatric conditions in the form of electrical or magnetic stimulation of the brain. Repetitive transcranial magnetic stimulation (rTMS) is a neurostimulation method designed to generate magnetic fields and deliver magnetic pulses to stimulate the brain cortex. The magnetic pulses produce electrical currents in the brain which are not intense enough to provoke seizures, differentiating this method from other forms of neurostimulation that produce seizures. Although the exact rTMS mechanisms of action are not completely understood, rTMS seems to cause its beneficial effects through changes in neuroplasticity. Devices and protocols for rTMS are still evolving, becoming more efficient over time. There are still some challenges to be addressed, including further refinement of parameters (coil/device type, location, intensity, frequency, number of sessions, and duration of treatment); treatment cost and burden for patients; and treatment resistance. However, the efficacy, tolerability, and safety of some rTMS protocols have been demonstrated in different double-blind sham-controlled randomized controlled trials and meta-analyses for treatment-resistant depression.

Dihydrorhodamine-123 flow cytometry method: time for substantial revision in technical procedure.

The dihydrorhodamine 123 assay is generally applied to measure the production of intracellular reactive oxygen species in neutrophils using flow cytometry and is considered a diagnostic evaluation for chronic granulomatous disease. In fact, there is a broad range of variables that can directly or indirectly affect test results, either individually or collectively. It is therefore crucial to identify the ideal requirements to achieve reliable results as well as using these requirements to provide standard operating procedures that should be taken into account. Therefore, we focus on aligning optimum results by comparing preanalytical and analytical phases that influence test results, such as the effect of various anticoagulants, transport and maintaining temperature (24°C or 4°C) of samples, test prime run time, appropriate solution concentrations, and effect of incubation temperature (24°C or 37°C) during the test run.

Outcomes of Thoracolumbar Burst Fractures Treated With Open Versus Minimally Invasive Percutaneous Posterior Spinal Stabilization: A Retrospective Study at a Rural Teaching Hospital in South India.

Background Thoracolumbar spine fractures are the most prevalent type of axial skeleton fractures, with approximately two-thirds occurring between T11 and L2. Percutaneous pedicle screw fixation has been reported to be an effective treatment for thoracolumbar fractures. Minimally invasive percutaneous pedicle screw fixation yields outcomes comparable to those of the standard open procedure and has the advantages of less stress, bleeding, and pain, as well as rapid postoperative recovery. The main objective of this research was to compare the clinical and radiological outcomes of two surgical approaches (open and percutaneous posterior spinal stabilization), concentrating on nonosteoporotic AO Spine Type A3 thoracolumbar burst fractures between T11 and L2. Materials and methods We conducted a retrospective study in our hospital, where cases of thoracolumbar burst fractures meeting the inclusion criteria were chosen retrospectively from April 2022 to March 2023. A total of 54 patients (aged 18-60 years) who underwent spinal stabilization were included in this investigation. The population was divided into two cohorts, with 27 patients in each: Group A underwent open posterior spinal stabilization, and Group B underwent percutaneous posterior spinal stabilization. Data retrieved from medical records were analyzed with at least a six-month follow-up, mainly assessing the demographic data, intraoperative parameters, duration of hospitalization, clinical outcomes (Visual Analog Scale, Oswestry Disability Index, and McGill Pain Questionnaire scores), and radiological outcomes (vertebral wedge angle and correction loss). Results Both groups had a male preponderance. There were statistically meaningful distinctions between both groups regarding intraoperative parameters (blood loss and surgical duration) and primary clinical outcome parameters (Visual Analog Scale, Oswestry Disability Index, and McGill Pain Questionnaire scores) in the early phase of the study. However, there were no statistically significant differences concerning radiological parameters (vertebral wedge angle and correction loss) or primary clinical outcome parameters at the last follow-up. Conclusion The treatment modalities (open and percutaneous posterior spinal stabilization surgery) were equally safe and effective. However, the percutaneous group demonstrated significant reductions in the length of the surgical procedure, blood loss during surgery, duration of hospital stay, and immediate postoperative pain scores, all of which could potentially benefit patients.

Substantiating the Short Burst Duration in Cortical Myoclonus.

BACKGROUND: Myoclonus is characterized by involuntary, shock-like movements, of which cortical (CM) and non-cortical myoclonus (NCM) are most common. Electrophysiology can help differentiate between these subtypes; however, the diagnostic value of several features is largely unknown. OBJECTIVE: This study aims to determine the diagnostic value of the burst duration in distinguishing CM and NCM. METHODS: We manually identified the burst duration of 8 patients with CM, confirmed by electromyography-electroencephalography registration or somatosensory-evoked potentials, and 19 patients with NCM, suspected due to a myoclonus-dystonia phenotype (MYC/DYT-SGCE positive and negative). RESULTS: The sensitivity and specificity were calculated to assess the diagnostic value. The burst duration of CM (31.1 ms) was significantly shorter than that of NCM (56.7 ms), with a sensitivity of 100% and a specificity of 89.5% at a threshold of 45.0 ms. A minimum of 10 randomly selected bursts were sufficient for reliable diagnostic accuracy. CONCLUSION: The burst duration seems a valuable supportive diagnostic criterion for distinguishing CM and NCM. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

A review of research on tire burst and vehicle stability control.

Tire burst is an accidental occurrence that poses a serious threat to the driving stability and road safety of vehicles. Therefore, it is of great practical significance to investigate early warning systems for tire burst and develop stability and safety control measures after burst incidents. The development of an accurate model that can effectively represent the impact of tire burst on vehicle dynamics is crucial for the design of control systems and the development of stability control strategies. Most of the existing research on tire burst models is based on static tire tests, the effectiveness of these models still needs to be further verified. The main approach to studying the impact of burst tires on vehicle performance is to embed a burst tire model into a vehicle dynamics model. Understanding the impact of tire burst on vehicle performance is essential for identifying burst incidents and developing stability control strategies. The research on burst identification primarily focuses on early warning systems and estimating vehicle state parameters after burst incidents, while the current research on stability control strategies focuses on enabling vehicles to continue running safely after burst incidents through braking, active steering, and collaborative control. Currently, there is no comprehensive review of research on vehicle tire burst stability control. Therefore, this paper primarily reviews five aspects: (a) the causes and prevention of tire burst, (b) the impact of tire burst on vehicle performance, (c) burst identification, (d) stability control strategies for burst incidents, and (e) future prospects for tire burst research.

Identification and functional analysis of lysophosphatidic acid phosphatase type 6 (ACP6) gene in golden pompano (Trachinotusovatus).

Golden pompano (Trachinotus ovatus), a marine farmed fish, is economically valuable in China. Lysophosphatidic acid phosphatase type 6 (ACP6) is a type of histidine acid phosphatase and plays an important role in regulating host inflammatory responses and anti-cancer effects in mammals. However, its function in teleost remains unknown. The present study aimed to investigate ACP6 function in golden pompano. ACP6 from golden pompano was identified, cloned, and named TroACP6. The open reading frame of TroACP6 was 1275 bp in length, encoding 424 amino acids. The TroACP6 protein shared high sequence identity (43.32%-90.57 %) with the ACP6 of other species. It contained a histidine phosphatase domain with the active site motif "RHGART" and the catalytic dipeptide HD (histidine and aspartate). Meanwhile, TroACP6 mRNA was widely distributed in the various tissues of healthy golden pompano, with the maximum expression in the head kidney. The function of TroACP6 was analyzed both in vitro and in vivo, and the results revealed that the purified recombinant TroACP6 protein exhibited optimum phosphatase activity at pH 6.0 and 50 °C in vitro. Meanwhile, upon Edwardsiella tarda challenge, TroACP6 expression in tissues increased significantly in vivo. In addition, TroACP6 overexpression enhanced the respiratory burst activity and superoxide dismutase activity of head kidney macrophages in vivo. Furthermore, the overexpression and knockdown of TroACP6 in vivo had a significant effect on bacterial infection. In summary, the study findings indicate that TroACP6 in golden pompano is involved in host defense against bacterial infection.

HOCl forms lipid N-chloramines in cell membranes of bacteria and immune cells.

Neutrophils orchestrate a coordinated attack on bacteria, combining phagocytosis with a potent cocktail of oxidants, including the highly toxic hypochlorous acid (HOCl), renowned for its deleterious effects on proteins. Here, we examined the occurrence of lipid N-chloramines in vivo, their biological activity, and their neutralization. Using a chemical probe for N-chloramines, we demonstrate their formation in the membranes of bacteria and monocytic cells exposed to physiologically relevant concentrations of HOCl. N-chlorinated model membranes composed of phosphatidylethanolamine, the major membrane lipid in Escherichia coli and an important component of eukaryotic membranes, exhibited oxidative activity towards the redox-sensitive protein roGFP2, suggesting a role for lipid N-chloramines in protein oxidation. Conversely, glutathione a cellular antioxidant neutralized lipid N-chloramines by removing the chlorine moiety. In line with that, N-chloramine stability was drastically decreased in bacterial cells compared to model membranes. We propose that lipid N-chloramines, like protein N-chloramines, are involved in inflammation and accelerate the host immune response.