N4BP1 mediates RAM domain-dependent notch signaling turnover during neocortical development.

Notch signaling pathway activity, particularly fluctuations in the biologically active effector fragment NICD, is required for rapid and efficient dynamic regulation of proper fate decisions in stem cells. In this study, we identified NEDD4-binding protein 1 (N4BP1), which is highly expressed in the developing mouse cerebral cortex, as a negative modulator of Notch signaling dynamics in neural progenitor cells. Intriguingly, N4BP1 regulated NICD stability specifically after Notch1 S3 cleavage through ubiquitin-mediated degradation that depended on its RAM domain, not its PEST domain, as had been extensively and previously described. The CoCUN domain in N4BP1, particularly the "Phe-Pro" motif (862/863 amino acid), was indispensable for mediating NICD degradation. The Ring family E3 ligase Trim21 was, in contrast to other NEDD4 family members, required for N4BP1-regulated NICD degradation. Overexpression of N4BP1 in cortical neural progenitors promoted neural stem cell differentiation, whereas neural progenitor cells lacking N4BP1 were sensitized to Notch signaling, resulting in the maintenance of stem-like properties in neural progenitor cells and lower production of cortical neurons.

A meet-up of acetyl phosphate and c-di-GMP modulates BldD activity for development and antibiotic production.

Actinobacteria are ubiquitous bacteria undergoing complex developmental transitions coinciding with antibiotic production in response to stress or nutrient starvation. This transition is mainly controlled by the interaction between the second messenger c-di-GMP and the master repressor BldD. To date, the upstream factors and the global signal networks that regulate these intriguing cell biological processes remain unknown. In Saccharopolyspora erythraea, we found that acetyl phosphate (AcP) accumulation resulting from environmental nitrogen stress participated in the regulation of BldD activity through cooperation with c-di-GMP. AcP-induced acetylation of BldD at K11 caused the BldD dimer to fall apart and dissociate from the target DNA and disrupted the signal transduction of c-di-GMP, thus governing both developmental transition and antibiotic production. Additionally, practical mutation of BldDK11R bypassing acetylation regulation could enhance the positive effect of BldD on antibiotic production. The study of AcP-dependent acetylation is usually confined to the control of enzyme activity. Our finding represents an entirely different role of the covalent modification caused by AcP, which integrated with c-di-GMP signal in modulating the activity of BldD for development and antibiotic production, coping with environmental stress. This coherent regulatory network might be widespread across actinobacteria, thus has broad implications.

An Orthogonal CRISPR/dCas12a System for RNA Imaging in Live Cells.

CRISPR/Cas technology has made great progress in the field of live-cell imaging beyond genome editing. However, effective and easy-to-use CRISPR systems for labeling multiple RNAs of interest are still needed. Here, we engineered a CRISPR/dCas12a system that enables the specific recognition of the target RNA under the guidance of a PAM-presenting oligonucleotide (PAMmer) to mimic the PAM recognition mechanism for DNA substrates. We demonstrated the feasibility and specificity of this system for specifically visualizing endogenous mRNA. By leveraging dCas12a-mediated precursor CRISPR RNA (pre-crRNA) processing and the orthogonality of dCas12a from different bacteria, we further demonstrated the proposed system as a simple and versatile molecular toolkit for multiplexed imaging of different types of RNA transcripts in live cells with high specificity. This programmable dCas12a system not only broadens the RNA imaging toolbox but also facilitates diverse applications for RNA manipulation.

The oncogenic role and regulatory mechanism of ACAA2 in human ovarian cancer.

Acetyl-CoAacyltransferase2 (ACAA2) is a key enzyme in the fatty acid oxidation pathway that catalyzes the final step of mitochondrial ß oxidation, which plays an important role in fatty acid metabolism. The expression of ACAA2 is closely related to the occurrence and malignant progression of tumors. However, the function of ACAA2 in ovarian cancer is unclear. The expression level and prognostic value of ACAA2 were analyzed by databases. Gain and loss of function were carried out to explore the function of ACAA2 in ovarian cancer. RNA-seq and bioinformatics methods were applied to illustrate the regulatory mechanism of ACAA2. ACAA2 overexpression promoted the growth, proliferation, migration, and invasion of ovarian cancer, and ACAA2 knockdown inhibited the malignant progression of ovarian cancer as well as the ability of subcutaneous tumor formation in nude mice. At the same time, we found that OGT can induce glycosylation modification of ACAA2 and regulate the karyoplasmic distribution of ACAA2. OGT plays a vital role in ovarian cancer as a function of oncogenes. In addition, through RNA-seq sequencing, we found that ACAA2 regulates the expression of DIXDC1. ACAA2 regulated the malignant progression of ovarian cancer through the WNT/ß-Catenin signaling pathway probably. ACAA2 is an oncogene in ovarian cancer and has the potential to be a target for ovarian cancer therapy.

Tunable single frequency Hz-magnitude narrow linewidth Brillouin fiber laser based on parity-time symmetry.

An Hz-magnitude ultra-narrow linewidth single-frequency Brillouin fiber laser (BFL) is proposed and experimentally demonstrated. The single frequency of the laser is selected by parity-time (PT) symmetry, which consists of a stimulated Brillouin scatter (SBS) gain path excited by a 24 km single-mode fiber (SMF) and an approximately equal length loss path tuned with a variable optical attenuator (VOA). These paths are coupled through a fiber Bragg grating (FBG) into a wavelength space. Accomplishing single-frequency oscillation involves the precise adjustment of polarization control (PC) and VOA to attain the PT broken phase. In the experiment, the linewidth of the proposed BFL is 9.58 Hz. The optical signal-to-noise ratio (OSNR) reached 78.89 dB, with wavelength and power fluctuations of less than 1pm and 0.02 dB within one hour. Furthermore, the wavelength can be tuned from 1549.9321 nm to 1550.2575 nm, with a linewidth fluctuation of 1.81 Hz. The relative intensity noise (RIN) is below -74 dB/Hz. The proposed ultra-narrow single-frequency BFL offers advantages such as cost-effectiveness, ease of control, high stability and excellent output characteristics, making it highly promising for the applications in the coherent detection.

High resolution and large measurement range voltage sensing based on an optoelectronic oscillator utilizing an unbalanced Mach-Zehnder interferometer.

A voltage sensor with high resolution and large measurement range based on an optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The key component in the cavity to select the oscillating signal is a finite impulse response (FIR)-microwave photonic filter (MPF) which consists of a sinusoidal broadband optical signal, an unbalanced Mach-Zehnder interferometer (MZI), a section of dispersion compensating fiber, and a photodetector. The center frequency of the FIR-MPF is mainly determined by the free spectral range (FSR) of the FIR-MPF. In the lower arm of the MZI, a cylindrical piezoelectric ceramic (PZT) wrapped with a section of optical fiber acts as voltage sensing head. Due to the inverse piezoelectric effect of PZT, the variation of the voltage will cause radial deformation of the cylindrical PZT and then lead to the change of the FSR of the MZI, determining the shift of center frequency of FIR-MPF as well as the frequency of the oscillating signal of the OEO. Thus, by monitoring the shift of the oscillation frequency of the OEO using an electric spectrum analyzer or a digital signal processor, a high-speed interrogation and high-resolution voltage measurement can be realized. Additionally, in the proposed scheme, an infinite impulse response (IIR)-MPF consisting of a fiber ring resonator is cascaded with the FIR-MPF to ensure the single-mode oscillation of the OEO. The experimental results show that a total range of 1700 V voltage sensing from - 200 V to 1500 V is accomplished with the voltage sensitivity of 0.25 GHz/100 V and the resolution of 0.3 V. By adjusting the proportion of the length of single mode fiber between two branches of MZI, the impact of temperature can be greatly reduced. The proposed sensor offers advantages such as a large measurement range, high resolution, high-speed interrogation, and stability to temperature disturbances, making it highly suitable for sensing applications in smart grids.

Indispensable role of Nectin-like 4 in regulating synapse-related molecules, synaptic structure, and individual behavior.

Nectin-like family members (Necls) are involved in synaptic organization. In contrast to that of Necl-2/CADM1/SynCAM1, which is critical in synaptic events, investigation of Necl-4/CADM4/SynCAM4 in synapses has largely lagged behind given the particularity of homophilic self-interactions compared to interactions with other Necls. We sought to further understand the role of Necl-4 in synapses and found that knockout of Necl-4 led to aberrant expression levels of proteins mediating synaptic function in cortex homogenates and augmented accumulation of ionotropic glutamate receptor in postsynaptic density fractions, although a compensatory effect of Necl-1 on the expression levels existed. Concurrently, we also found increased synaptic clefts in the cortex and simplified dendritic morphology of primary cultured cortical neurons. Experiments on individual behaviors suggested that compared to their wild-type littermates, Necl-4-KO mice exhibited impaired acquisition of spatial memory and working memory and enhanced behavioral despair and anxiety-like behavior. These findings suggest that Necl-4 mediates synaptic function and related behaviors through an indispensable role and offer a new perspective about collaboration and specialization among Necls.

Intestine bacterial community affects the growth of the Pacific white shrimp (Litopenaeus vannamei).

Increasing evidence suggests that intestine microorganisms are closely related to shrimp growth, but there is no existing experiment to prove this hypothesis. Here, we compared the intestine bacterial community of fast- and slow-growing shrimp at the same developmental stage with a marked difference in body size. Our results showed that the intestine bacterial communities of slow-growing shrimp exhibited less diversity but were more heterogeneous than those of fast-growing shrimp. Uncultured_bacterium_g_Candidatus Bacilloplasma, Tamlana agarivorans, Donghicola tyrosinivorans, and uncultured_bacterium_f_Flavobacteriaceae were overrepresented in the intestines of fast-growing shrimp, while Shimia marina, Vibrio sp., and Vibrio campbellii showed the opposite trends. We further found that the bacterial community composition was significantly correlated with shrimp length, and some bacterial species abundances were found to be significantly correlated with shrimp weight and length, including T. agarivorans and V. campbellii, which were chosen as indicators for a reverse gavage experiment. Finally, T. agarivorans was found to significantly promote shrimp growth after the experiment. Collectively, these results suggest that intestine bacterial community could be important factors in determining the growth of shrimp, indicating that specific bacteria could be tested in further studies against shrimp growth retardation. KEY POINTS: • A close relationship between intestine bacterial community and shrimp growth was proven by controllable experiments. • The bacterial signatures of the intestine were markedly different between slow- and fast-growing shrimp, and the relative abundances of some intestine bacterial species were correlated significantly with shrimp body size. • Reverse gavage by Tamlana agarivorans significantly promoted shrimp growth.

Epidemiologic features and therapeutic strategies of kerion: A nationwide multicentre study.

BACKGROUND: Kerion is a severe type of tinea capitis that is difficult to treat and remains a public health problem. OBJECTIVES: To evaluate the epidemiologic features and efficacy of different treatment schemes from real-world experience. METHODS: From 2019 to 2021, 316 patients diagnosed with kerion at 32 tertiary Chinese hospitals were enrolled. We analysed the data of each patient, including clinical characteristics, causative pathogens, treatments and outcomes. RESULTS: Preschool children were predominantly affected and were more likely to have zoophilic infection. The most common pathogen in China was Microsporum canis. Atopic dermatitis (AD), animal contact, endothrix infection and geophilic pathogens were linked with kerion occurrence. In terms of treatment, itraconazole was the most applied antifungal agent and reduced the time to mycological cure. A total of 22.5% of patients received systemic glucocorticoids simultaneously, which reduced the time to complete symptom relief. Furthermore, glucocorticoids combined with itraconazole had better treatment efficacy, with a higher rate and shorter time to achieving mycological cure. CONCLUSIONS: Kerion often affects preschoolers and leads to serious sequelae, with AD, animal contact, and endothrix infection as potential risk factors. Glucocorticoids, especially those combined with itraconazole, had better treatment efficacy.

Universal DNA-Based Sensing Toolbox for Programming Cell Functions.

By recombining natural cell signaling systems and further reprogramming cell functions, use of genetically engineered cells and bacteria as therapies is an innovative emerging concept. However, the inherent properties and structures of the natural signal sensing and response pathways constrain further development. We present a universal DNA-based sensing toolbox on the cell surface to endow new signal sensing abilities for cells, control cell states, and reprogram multiple cell functions. The sensing toolbox contains a triangular-prismatic-shaped DNA origami framework and a sensing core anchored inside the internal confined space to enhance the specificity and efficacy of the toolbox. As a proof of principle, the sensing toolbox uses the customizable sensing core with signal sensing switches and converters to recognize unconventional signal inputs, deliver functional components to cells, and then control cell responses, including specific tumor cell death, immune cell disinhibition and adhesion, and bacterial expression. This work expands the diversity of cell sensing signals and reprograms biological functions by constructing nanomechanical-natural hybrid cells, providing new strategies for engineering cells and bacteria in diagnosis and treatment applications.

Water Extract of Portulaca Oleracea Inhibits PEDV Infection-Induced Pyrolysis by Caspase-1/GSDMD.

Porcine epidemic diarrhea virus (PEDV) belongs to the coronavirus family and the coronavirus genus, causing contact enteric infection in pigs. It is one of the most serious diseases that threatens the pig industry. However, there is currently no specific drug to prevent and treat the disease, indicating that we need to be vigilant about the spread of the disease and the development of anti-PEDV drugs. The dried aerial parts of the plant Portulaca oleracea in the family Portulacaceous, whose decoction can be used to treat acute enteritis, dysentery, diarrhea, and other diseases. This study explored the potential mechanism of water extract of Portulaca oleracea (WEPO) in PEDV-induced pyroptosis in Vero cells. PEDV decreased the viability of Vero cells in a dose- and time-dependent manner, causing cell damage, upregulating the level of intracellular Nlrp3, and inhibiting the level of Gasdermin D (GSDMD) and the activation of Caspase-1. WEPO can inhibit PEDV-induced pyroptosis, reduce the elevation of inflammatory factors caused by infection, and exhibit a dose-dependent effect. Knockdown of Caspase-1 and GSDMD separately can induce the production of the inflammatory factor IL-1ß to significantly decrease and increase, respectively. These results suggest that WEPO can inhibit cell pyroptosis caused by PEDV and that the Caspase-1 and GSDMD pathways play an important role in this process.

RNase H-Driven crRNA Switch Circuits for Rapid and Sensitive Detection of Various Analytical Targets.

The clustered regularly interspaced short palindromic repeats (CRISPR/Cas12a) system has exhibited great promise in the rapid and sensitive molecular diagnostics for its trans-cleavage property. However, most CRISPR/Cas system-based detection methods are designed for nucleic acids and require target preamplification to improve sensitivity and detection limits. Here, we propose a generic crRNA switch circuit-regulated CRISPR/Cas sensor for the sensitive detection of various targets. The crRNA switch is engineered and designed in a blocked state but can be activated in the presence of triggers, which are target-induced association DNA to initiate the trans-cleavage activity of Cas12a for signal reporting. Additionally, RNase H is introduced to specifically hydrolyze RNA duplexed with the DNA trigger, resulting in the regeneration of the trigger to activate more crRNA switches. Such a combination provides a generic and sensitive strategy for the effective sensing of the p53 sequence, thrombin, and adenosine triphosphate. The design is incorporated with nucleic acid nanotechnology and extensively broadens the application scope of the CRISPR technology in biosensing.

A DNA Nanodevice-Based Platform with Diverse Capabilities.

Social biotic colonies often perform intricate tasks by interindividual communication and cooperation. Inspired by these biotic behaviors, a DNA nanodevice community is proposed as a universal and scalable platform. The modular nanodevice as the infrastructure of platform contains a DNA origami triangular prism framework and a hairpin-swing arm machinery core. By coding and decoding a signal domain on the shuttled output strand in different nanodevices, an orthogonal inter-nanodevice communication network is established to connect multi-nanodevices into a functional platform. The nanodevice platform enables implementation of diverse tasks, including signal cascading and feedback, molecular input recording, distributed logic computing, and modeling of simulation for virus transmission. The nanodevice platform with powerful compatibility and programmability presents an elegant example of the combination of the distributed operation of multiple devices and the complicated interdevice communication network, and may become a new generation of intelligent DNA nanosystems.

NECL2 regulates blood-testis barrier dynamics in mouse testes.

The adhesion protein nectin-like molecule 2 (NECL2) is involved in spermatogenesis and participates in the connections between Sertoli cells and germ cells. Necl2 deficiency leads to infertility in male mice. We found that NECL2 is relatively highly expressed on the cell membranes of preleptotene spermatocytes. It is known that preleptotene spermatocytes pass through the blood-testis barrier (BTB) from the base of the seminiferous tubules to the lumen to complete meiosis. We hypothesized that the NECL2 protein on the surfaces of preleptotene spermatocytes has an effect on the BTB when crossing the barrier. Our results showed that Necl2 deficiency caused the levels of proteins in the BTB to be abnormal, such as those of Claudin 3, claudin 11, and Connexin43. NECL2 interacted and colocalized with adhesion proteins forming the BTB, such as Connexin43, Occludin, and N-cadherin. NECL2 regulated BTB dynamics when preleptotene spermatocytes passed through the barrier, and Necl2 deficiency caused BTB damage. Necl2 deletion significantly affected the testicular transcriptome, especially the expression of spermatogenesis-related genes. These results suggest that before meiosis and spermatid development occur, BTB dynamics regulated by NECL2 are necessary for spermatogenesis.

Dual wavelength laser Doppler anemometer for simultaneous velocity and particulate size distribution measurements in submarine environments.

An in-situ laser Doppler current probe (LDCP) for the simultaneous measurements of the micro-scale subsurface current speed and the characterizations of micron particles is dedicated in this paper. The LDCP performs as an extension sensor for the state-of-the-art laser Doppler anemometry (LDA). The all-fiber LDCP utilized a compact dual wavelength (491 nm and 532 nm) diode pumped solid state laser as the light source to achieve the simultaneous measurements of the two components of the current speed. Besides its ability for the measurements of the current speed, the LDCP is also capable of obtaining the equivalent spherical size distribution of the suspended particles within small size range. The micro-scale measurement volume formed by two intersecting coherent laser beams makes it possible to accurately estimate the size distribution of the micron suspended particles with high temporal and spatial resolution. With its deployment during the field campaign at Yellow Sea, the LDCP has been experimentally demonstrated as an effective instrument to capture the micro-scale subsurface ocean current speed. The algorithm for retrieving the size distribution of the small suspended particles (2∼7.5µm) has been developed and validated. The combined LDCP system could be applied to the continuous long-term observations of plankton community structure, ocean water optical parameter over a wide range, and useful to elucidate the processes and interactions of the carbon cycles in the upper ocean.

Simultaneous magnetic field and temperature measurement with high resolution based on cascaded microwave photonic filters.

A simultaneous magnetic field and temperature sensing scheme based on cascaded microwave photonic filters (MPFs) with high resolution is proposed and experimentally demonstrated. A polarization maintaining fiber bonded with a giant magnetostrictive material acts both as a magnetic field sensing probe and an important unit of a dispersion-induced MPF. A 500 m single mode fiber in a two-tap MPF is used to perform temperature compensation. The power fading frequency of the dispersion-induced MPF and the dip frequency of the two-tap MPF are selected to monitor the magnetic field and temperature changes. When temperature changes, both power fading frequency and dip frequency will change. While only power fading frequency shifts as magnetic field changes. Consequently, dual parameter sensing can be achieved by monitoring the characteristic microwave frequencies of the two MPFs. The temperature cross-sensitivity is well resolved in this way. In the experiment, the microwave frequency changes 5.84 MHz as external magnetic field increases by 1 mT. The corresponded theoretical resolution can reach 0.17 nT, which is only limited by the minimum resolution of vector network analyzer.

Theoretical investigation of pure-state single-photon and large-bandwidth-correlation biphoton generation from micro/nanofiber.

Pure-state single photons and large-bandwidth-correlation biphotons are fundamental resources for quantum information processing. The dispersion properties of micro/nanofiber (MNF) can be tailored by carefully choosing its diameter, resulting in a flexibly tailored biphoton spectrum. We theoretically investigate pure-state single photons and large-bandwidth-correlation biphotons produced by degenerate spontaneous four-wave mixing in MNF. In our simulation, a single-photon state with a purity of 99% will be theoretically attained by choosing the appropriate pump bandwidth and center wavelength with respect to the diameter and length of the MNF. Further, when an appropriate diameter with a negligible curvature at the zero dispersion wavelength is chosen, even a narrow pump bandwidth is capable of motivating remarkably broadband correlation biphotons, e.g., for a MNF diameter of 0.7 µm, the theoretical full width at half maximum is 473 nm. In practice, the application of a MNF-based quantum light source is dependent on the technologies that precisely control and measure the diameter. Our theoretical investigation will guide the experimental realization of high-quality quantum light sources based on MNF.

Femtosecond laser printing-assisted etching tailored hard and brittle micro-convex surface.

We report a femtosecond laser print-assisted dry etching technology for high-efficiency, high-quality, and tailored fabricating of a micro-convex surface (MCS) on hard and brittle materials. Liquid ultraviolet curing adhesive (UVCA) was transferred from a donor substrate to a receiving substrate by femtosecond laser-induced forward transfer, and the transferred microdroplet spontaneously has a smooth surface under the action of surface tension. And then an MCS with a high-quality surface was formed on hard and brittle materials by UV curing and dry etching. The effects of laser parameters and receiving substrate surface free energy on MCS morphology were investigated. According to the variation of the numerical aperture, the two methods to change the morphology of the MCS were divided into independent/joint regulation of diameter and height. We showed that a hexagonal array containing a variety of MCS morphologies can be fabricated on a fused silica by setting the appropriate parameters. And the fabrication time of an MCS in a large-area array was only 1.1 s.

The effects of sodium butyrate (NaB) combination with soy saponin dietary supplementation on the growth parameters, intestinal performance and immune-related genes expression of hybrid grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂).

Soy saponins are generally known to have negative effects on growth and the intestines of aquatic animals, and appropriate levels of sodium butyrate (NaB) may provide some mitigating effects. We investigated the effects of low and high levels of soy saponin and the protective effects of NaB (based on high level of soy saponin) on growth, serum cytokines, distal intestinal histopathology, and inflammation in hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂). The experiment included four groups: fishmeal group (FM, 0.00% saponin and 0.00% NaB), low saponin group (SL, 0.30% saponin and 0.00% NaB), high saponin group (SH, 1.50% saponin and 0.00% NaB) and high saponin with NaB group (SH-NaB, 1.50% saponin and 0.13% NaB). The results showed compared to FM, the final body weight (FBW) and weight gain (WG) were significantly higher and lower in SL and SH, respectively (P < 0.05). Compared to SH, the FBW and WG were significant higher in SH-NaB (P < 0.05). In the serum, compared to FM, the interferon γ (IFN-γ) and interleukin-1ß (IL-1ß) levels in SH were significantly increased (P < 0.05). Compared to SH, the IFN-γ level was significantly decreased in SH-NaB (P < 0.05). In the distal intestine, based on Alcian Blue-Periodic Acid-Schiff (AB-PAS) observation, the goblet cell/µm was significantly increased and decreased in the SL and SH, respectively, compared to FM. The intestinal diameter/plica height ratio in the SH was significantly higher than those in the FM, SL and SH-NaB (P < 0.05). The NO and ONOO- levels in the SH were significantly higher than that in FM and SL (P < 0.05). At the transcriptional level in the distal intestine, compared to FM, the mRNA levels of tumor necrosis factor (tnfα), il1ß, interleukin-8 (il8) and ifnγ were significantly up-regulated in the SH (P < 0.05). Compared to the SH, tnfα, il8 and ifnγ were significantly down-regulated in the SH-NaB (P < 0.05). Compared to the FM, the mRNA levels of claudin3, claudin15, zo2 and zo3 were significantly up-regulated in the SL (P < 0.05). The mRNA levels of occludin, claudin3, claudin12, claudin15, zo1, zo2 and zo3 were significantly down-regulated in the SH compared to the FM (P < 0.05). Additionally, compared to the SH, the mRNA levels of occludin, claudin3, claudin12, claudin15, zo1, zo2 and zo3 were significantly up-regulated in the SH-NaB (P < 0.05). After the 7-day Vibrio parahaemolyticus challenge test, the survival was significantly higher and lower in the SL and SH, respectively, compared to FM (P < 0.05). Overall, low and high levels of soy saponins had positive and negative effects on growth, disease resistance, serum cytokines, and distal intestinal development and anti-inflammation, respectively, in hybrid grouper. NaB effectively increased disease resistance and improved distal intestinal inflammation in hybrid grouper, but the effects of NaB were mainly observed in improving distal intestinal tight junctions.

Antibiotic resistance and drug modification: Synthesis, characterization and bioactivity of newly modified potent pleuromutilin derivatives with a substituted piperazine moiety.

Antibiotic-resistant bacteria pose a major global public health concern, owing to the lack of effective antibacterial drugs. Consequently, the discovery and development of innovative antibacterial drug classes with unique mechanisms of action are urgently needed. In this study, we designed, synthesised, and tested a series of novel pleuromutilin derivatives with piperazine linker substituted by amino acids moieties to determine their antibacterial properties. Most synthesized compounds exhibited potent activities against Staphylococcus aureus (S. aureus), methicillin-resistant S. aureus (MRSA), and methicillin-resistant Staphylococcus epidermidis. Compound 6l, the most potent antibacterial agent created in this study, displayed a rapid bactericidal activity against MRSA, Klebsiella pneumoniae and S. aureus cfr N12. Moreover, pharmacokinetics study of compound 6l exhibited good PK performance with a low in vivo clearance (CL = 1965 mL/h/kg) and a suitable half-life (T1/2 = 11.614 ± 5.123 h). Molecular docking experiments revealed the binding model of compound 6l to the unmethylated A2503 of peptidyl transferase centre of 23S rRNA. Interaction pattern of 6l with cfr-mediated ribosomes revealed by molecular dynamics. Moreover in vivo mouse systemic infection experiments with compound 6l revealed its effectiveness against MRSA and S. aureus cfr N12 with the ED50 of 11.08 mg/kg and 14.63 mg/kg body weight, respectively.