Author Correction: STEEP mediates STING ER exit and activation of signaling.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

STEEP mediates STING ER exit and activation of signaling.

STING is essential for control of infections and for tumor immunosurveillance, but it can also drive pathological inflammation. STING resides on the endoplasmic reticulum (ER) and traffics following stimulation to the ERGIC/Golgi, where signaling occurs. Although STING ER exit is the rate-limiting step in STING signaling, the mechanism that drives this process is not understood. Here we identify STEEP as a positive regulator of STING signaling. STEEP was associated with STING and promoted trafficking from the ER. This was mediated through stimulation of phosphatidylinositol-3-phosphate (PtdIns(3)P) production and ER membrane curvature formation, thus inducing COPII-mediated ER-to-Golgi trafficking of STING. Depletion of STEEP impaired STING-driven gene expression in response to virus infection in brain tissue and in cells from patients with STING-associated diseases. Interestingly, STING gain-of-function mutants from patients interacted strongly with STEEP, leading to increased ER PtdIns(3)P levels and membrane curvature. Thus, STEEP enables STING signaling by promoting ER exit.

Innovative ochre processing and tool use in China 40,000 years ago.

Homo sapiens was present in northern Asia by around 40,000 years ago, having replaced archaic populations across Eurasia after episodes of earlier population expansions and interbreeding1-4. Cultural adaptations of the last Neanderthals, the Denisovans and the incoming populations of H. sapiens into Asia remain unknown1,5-7. Here we describe Xiamabei, a well-preserved, approximately 40,000-year-old archaeological site in northern China, which includes the earliest known ochre-processing feature in east Asia, a distinctive miniaturized lithic assemblage with bladelet-like tools bearing traces of hafting, and a bone tool. The cultural assembly of traits at Xiamabei is unique for Eastern Asia and does not correspond with those found at other archaeological site assemblages inhabited by archaic populations or those generally associated with the expansion of H. sapiens, such as the Initial Upper Palaeolithic8-10. The record of northern Asia supports a process of technological innovations and cultural diversification emerging in a period of hominin hybridization and admixture2,3,6,11.

Hypothetical chloroplast reading frame 51 encodes a photosystem I assembly factor in cyanobacteria.

Hypothetical chloroplast open reading frames (ycfs) are putative genes in the plastid genomes of photosynthetic eukaryotes. Many ycfs are also conserved in the genomes of cyanobacteria, the presumptive ancestors of present-day chloroplasts. The functions of many ycfs are still unknown. Here, we generated knock-out mutants for ycf51 (sll1702) in the cyanobacterium Synechocystis sp. PCC 6803. The mutants showed reduced photoautotrophic growth due to impaired electron transport between photosystem II (PSII) and PSI. This phenotype results from greatly reduced PSI content in the ycf51 mutant. The ycf51 disruption had little effect on the transcription of genes encoding photosynthetic complex components and the stabilization of the PSI complex. In vitro and in vivo analyses demonstrated that Ycf51 cooperates with PSI assembly factor Ycf3 to mediate PSI assembly. Furthermore, Ycf51 interacts with the PSI subunit PsaC. Together with its specific localization in the thylakoid membrane and the stromal exposure of its hydrophilic region, our data suggest that Ycf51 is involved in PSI complex assembly. Ycf51 is conserved in all sequenced cyanobacteria, including the earliest branching cyanobacteria of the Gloeobacter genus, and is also present in the plastid genomes of glaucophytes. However, Ycf51 has been lost from other photosynthetic eukaryotic lineages. Thus, Ycf51 is a PSI assembly factor that has been functionally replaced during the evolution of oxygenic photosynthetic eukaryotes.

Coevolution of tandemly repeated hlips and RpaB-like transcriptional factor confers desiccation tolerance to subaerial Nostoc species.

Desert-inhabiting cyanobacteria can tolerate extreme desiccation and quickly revive after rehydration. The regulatory mechanisms that enable their vegetative cells to resurrect upon rehydration are poorly understood. In this study, we identified a single gene family of high light-inducible proteins (Hlips) with dramatic expansion in the Nostoc flagelliforme genome and found an intriguingly special convergence formed through four tandem gene duplication. The emerged four independent hlip genes form a gene cluster (hlips-cluster) and respond to dehydration positively. The gene mutants in N. flagelliforme were successfully generated by using gene-editing technology. Phenotypic analysis showed that the desiccation tolerance of hlips-cluster-deleted mutant decreased significantly due to impaired photosystem II repair, whereas heterologous expression of hlips-cluster from N. flagelliforme enhanced desiccation tolerance in Nostoc sp. PCC 7120. Furthermore, a transcription factor Hrf1 (hlips-cluster repressor factor 1) was identified and shown to coordinately regulate the expression of hlips-cluster and desiccation-induced psbAs. Hrf1 acts as a negative regulator for the adaptation of N. flagelliforme to the harsh desert environment. Phylogenetic analysis revealed that most species in the Nostoc genus possess both tandemly repeated Hlips and Hrf1. Our results suggest convergent evolution of desiccation tolerance through the coevolution of tandem Hlips duplication and Hrf1 in subaerial Nostoc species, providing insights into the mechanism of desiccation tolerance in photosynthetic organisms.

Age-related decline in melatonin contributes to enhanced osteoclastogenesis via disruption of redox homeostasis.

BACKGROUND: Increased oxidative stress contributes to enhanced osteoclastogenesis and age-related bone loss. Melatonin (MT) is an endogenous antioxidant and declines with aging. However, it was unclear whether the decline of MT was involved in the enhanced osteoclastogenesis during the aging process. METHODS: The plasma level of MT, oxidative stress status, bone mass, the number of bone marrow-derived monocytes (BMMs) and its osteoclastogenesis were analyzed in young (3-month old) and old (18-month old) mice (n = 6 per group). In vitro, BMMs isolated from aged mice were treated with or without MT, followed by detecting the change of osteoclastogenesis and intracellular reactive oxygen species (ROS) level. Furthermore, old mice were treated with MT for 2 months to investigate the therapeutic effect. RESULTS: The plasma level of MT was markedly lower in aged mice compared with young mice. Age-related decline in MT was accompanied by enhanced oxidative stress, osteoclastogenic potential and bone loss. MT intervention significantly suppressed the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis, decreased intracellular ROS and enhanced antioxidant capacity of BMMs from aged mice. MT supplementation significantly attenuated oxidative stress, osteoclastogenesis, bone loss and deterioration of bone microstructure in aged mice. CONCLUSIONS: These results suggest that age-related decline of MT enhanced osteoclastogenesis via disruption of redox homeostasis. MT may serve as a key regulator in osteoclastogenesis and bone homeostasis, thereby highlighting its potential as a preventive agent for age-related bone loss.

De-Pinning Fermi Level and Accelerating Surface Kinetics with an ALD Finish Boost the Fill Factor of BiVO4 Photoanodes to 44.

With the rapid development of performance and long-term stability, bismuth vanadate (BiVO4 ) has emerged as the preferred photoanode in photoelectrochemical tandem devices. Although state-of-the-art BiVO4 photoanodes realize a saturated photocurrent density approaching the theoretical maximum, the fill factor (FF) is still inferior, pulling down the half-cell applied bias photon-to-current efficiency (HC-ABPE). Among the major fundamental limitations are the Fermi level pinning and sluggish surface kinetics at the low applied potentials. This work demonstrates that the plasma-assisted atomic layer deposition technique is capable of addressing these issues by seamlessly installing an angstrom-scale FeNi-layer between BiVO4 and electrolyte. Not only this ultrathin FeNi layer serves as an efficient OER cocatalyst, more importantly, it also effectively passivates the surface states of BiVO4 , de-pins the surface Fermi level, and enlarges the built-in voltage, allowing the photoanode to make optimal use of the photogenerated holes for achieving high FF up to 44% and HC-ABPE to 2.2%. This study offers a new approach for enhancing the FF of photoanodes and provides guidelines for designing efficient unassisted solar fuel devices.

Epidural administration of large dose of opioid µ receptor agonist may impair cardiac functions and myocardial viability via desensitizing transient receptor potential vanilloid 1.

The incidence of postoperative myocardial injury remains high as the underlying pathogenesis is still unknown. The dorsal root ganglion (DRG) neurons express transient receptor potential vanilloid 1 (TRPV1) and its downstream effector, calcitonin gene-related peptide (CGRP) participating in transmitting pain signals and cardiac protection. Opioids remain a mainstay therapeutic option for moderate-to-severe pain relief clinically, as a critical component of multimodal postoperative analgesia via intravenous and epidural delivery. Evidence indicates the interaction of opioids and TRPV1 activities in DRG neurons. Here, we verify the potential impairment of myocardial viability by epidural usage of opioids in postoperative analgesia. We found that large dose of epidural morphine (50 µg) significantly worsened the cardiac performance (+dP/dtmax reduction by 11% and -dP/dtmax elevation by 24%, all P < 0.001), the myocardial infarct size (morphine vs Control, 0.54 ± 0.09 IS/AAR vs. 0.23 ± 0.06 IS/AAR, P < 0.001) and reduced CGRP in the myocardium (morphine vs. Control, 9.34 ± 2.24 pg/mg vs. 21.23 ± 4.32 pg/mg, P < 0.001), while induced definite suppression of nociception in the postoperative animals. It was demonstrated that activation of µ-opioid receptor (µ-OPR) induced desensitization of TRPV1 by attenuating phosphorylation of the channel in the dorsal root ganglion neurons, via inhibiting the accumulation of cAMP. CGRP may attenuated the buildup of ROS and the reduction of mitochondrial membrane potential in cardiomyocytes induced by hypoxia/reoxygenation. The findings of this study indicate that epidurally giving large dose of µ-OPR agonist may aggravate myocardial injury by inhibiting the activity of TRPV1/CGRP pathway.

Stacked Covalent Organic Ribbons Perpendicular to Graphene Oxide Sheets; a 1D-p-2D Design for Photocatalytic Tandem Reactions.

Development of one dimensional covalent organic frameworks (1D-COFs) with potential in light absorption and catalysis is still challenging, due to their rapid interpenetration to form 2D and 3D porous structures. Here we report a successful synthesis of imine-linked 1D covalent organic ribbons (COR), using two simple linear building blocks 1,4-Benzenediamine (Bda) and [2,2'-Bipyridine]-5,5'-dicarbaldehyde (Bpy). The obtained 1D structure with nanorod morphology could keep its physicochemical characteristic properties when it is perpendicular to the surface of graphene oxide (GO) sheets (1D-p-2D structure). Due to an AB π- π stacking and efficient charge transfer between perpendicular 1D COR and GO sheets, the obtained nanocomposite showed strong visible light absorbance (400-700 nm) with coefficient of 4.400 M-1 cm-1 and decreased recombination rate of photogenerated reactive species by 92 %. The strategy of 1D-p-2D light driven system greatly enhanced the photocatalytic activity in practical applications such as both oxidation and hydrogenation tandem reactions to a rate constant of higher than 0.02 min-1 . This study presents the first case of 1D covalent organic polymers grown perpendicularly on a carbon-based layer for boosting electron mobility through the junction between the two components.

Tanshinone IIA attenuates osteoarthritis via inhibiting aberrant angiogenesis in subchondral bone.

Excessive angiogenesis in subchondral bone is a pathological feature of osteoarthritis (OA). Tanshinone IIA (TIIA), an active compound found in Salvia miltiorrhiza, demonstrates significant anti-angiogenic properties. However, the effect of TIIA on abnormal subchondral angiogenesis in OA is still unclear. This study aims to investigate the mechanism of TIIA in modulating subchondral bone angiogenesis during OA and assess its therapeutic potential in OA. Our findings demonstrate that TIIA attenuated articular cartilage degeneration, normalized subchondral bone remodeling, and effectively suppressed aberrant angiogenesis within subchondral bone in monosodium iodoacetate (MIA)-induced OA mice. Additionally, the angiogenesis capacity of primary CD31hiEmcnhi endothelial cells was observed to be significantly reduced after treatment with TIIA in vitro. Mechanically, TIIA diminished the proportion of hypertrophic chondrocytes, ultimately leading to a substantial reduction in the secretion of vascular endothelial growth factor A (VEGFA). The supernatant of hypertrophic chondrocytes promoted the tube formation of CD31hiEMCNhi endothelial cells, whereas TIIA inhibited this process. Furthermore, TIIA effectively suppressed the expression of vascular endothelial growth factor receptor 2 (VEGFR2) along with its downstream MAPK pathway in CD31hiEmcnhi endothelial cells. In conclusion, our data indicated that TIIA could effectively inhibit the abnormal angiogenesis in subchondral bone during the progression of OA by suppressing the VEGFA/VEFGR2/MAPK pathway. These findings significantly contribute to our understanding of the abnormal angiogenesis in OA and offer a promising therapeutic target for OA treatment.

A Chemo-Enzymatic Cascade Strategy for the Synthesis of Phosphatidylcholine Incorporated with Structurally Diverse FAHFAs.

Fatty acid esters of hydroxy fatty acids (FAHFAs), a newly discovered class of human endogenous complex lipids showing great promise for treating diabetes and inflammatory diseases, exist naturally in extremely low concentrations. This work reports a chemo-enzymatic approach for the comprehensive synthesis of phospholipids containing FAHFAs via sequential steps: hydratase-catalyzed hydration of unsaturated fatty acids to generate structurally diverse hydroxy fatty acids (HFAs), followed by the selective esterification of these HFAs with fatty acids mediated by secondary alcohol-specific Candida antarctica lipase A (CALA), resulting in the formation of a series of diverse FAHFA analogs. The final synthesis is completed through carbodiimide-based coupling of FAHFAs with glycerophosphatidylcholine. Optimal reaction conditions are identified for each step, and the substrate affinity of CALA, responsible for the catalytic mechanisms during FAHFA production, is evaluated through molecular docking. Compared to multistep lab-tedious chemical synthesis, this route, relying on natural building blocks and natural biocatalysts, is significantly facile, scalable, and highly selective, affording high yields (74-98 mol %) in each step for the construction of higher FAHFA-PC series (10/12/13-FAHFAs). The developed strategy aims to increase the availability of naturally occurring FAHFA species and provide the tools for the construction of versatile and novel analogs of FAHFA conjugates.

Theoretical Validation of Non-Noble Cu Sites Integrated on SnO2 Nanoflowers for Enhanced Gas Sensing of Ethanethiol at Room Temperature.

Ethanethiol (EtSH), being highly toxic, flammable, and explosive, poses significant risks to human health and safety and is capable of causing fires and explosions. Room-temperature detection using chemiresistive gas sensors is essential for managing these risks. However, the gas-sensing performance of conventional metal-oxide sensing materials may be limited by their weak interaction with EtSH at room temperature. Herein, SnO2 nanoflowers assembled with non-noble Cu-site-enriched porous nanosheets were designed and prepared by an in situ self-template pyrolysis synthesis strategy to enable highly sensitive and selective room-temperature detection of EtSH. By regulating the number of non-noble Cu sites, these nanoflowers achieved efficient EtSH sensing with a Ra/Rg value of 11.0 at 50 ppb, ensuring high selectivity, reproducibility, and stability at room temperature. Moreover, a comparative analysis of the room-temperature gas-sensing performance of SnO2 nanoflowers with non-noble Fe- or Ni-site-enriched nanosheets highlights the benefits of non-noble Cu sites for EtSH detection. Density functional theory (DFT) analysis reveals that non-noble Cu sites have a unique affinity for EtSH, offering preferential binding over other gases and explaining the outstanding sensing performance of non-noble Cu-site-enriched nanosheet-assembled SnO2 nanoflowers. The structural and interface engineering of the sensing materials presented in this work provides a promising approach for offering efficient and durable gas sensors operable at room temperature.

A Novel Dinuclear Complex-PLC Composite Material as Fluorescent Switch in Treatment on Osteoarthritis.

In this study, we synthesized a novel Co(II)-containing coordination compound (CP) [Co2(MMBA)2(HPT)2(H2O)2]·2H2O (1) through a solvothermal reaction of Co(NO3)6·6H2O with 3-(pyridin-2-yl)-1 H-1,2,4-triazole (HPT) and 2-(4-methylbenzoyl)benzoic acid (HMMBA). Fluorescence spectroscopy confirmed that this compound exhibited superior blue fluorescence properties compared to the original ligands. Further, aspirin (ASA) was loaded onto this CP via physical adsorption to create CP-ASA. Interestingly, the fluorescence properties of the CP decreased with the loading of the drug but were restored upon drug release. Leveraging the unique optical properties and biocompatibility of Polymer Liquid Crystal (PLC), we further encapsulated CP-ASA, forming the CP-PLC@ASA composite. The target product was confirmed through various characterization techniques including Elemental Analysis (EA), Fourier-Transform Infrared Spectroscopy (FT-IR), Powder X-Ray Diffraction (PXRD), and Thermogravimetric Analysis (TGA). Moreover, the biological activity of this composite was evaluated in vitro for osteoarthritis, and its potential mechanisms were explored.

The role of the cGAS-STING signaling pathway in viral infections, inflammatory and autoimmune diseases.

Pattern recognition receptors are an essential part of the immune system, which detect pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) and help shape both innate and adaptive immune responses. When dsDNA is present, cyclic GMP-AMP Synthase (cGAS) produces a second messenger called cyclic GMP-AMP (cGAMP), which then triggers an adaptor protein called STING, and eventually activates the expression of type I interferon (IFN) and pro-inflammatory cytokines in immune cells. The cGAS-STING signaling pathway has been receiving a lot of attention lately as a key immune-surveillance mediator. In this review, we summarize the present circumstances of the cGAS-STING signaling pathway in viral infections and inflammatory diseases, as well as autoimmune diseases. Modulation of the cGAS-STING signaling pathway provides potential strategies for treating viral infections, inflammatory diseases, and autoimmune diseases.

Evaluation of disease severity and prediction of severe cases in children hospitalized with influenza A (H1N1) infection during the post-COVID-19 era: a multicenter retrospective study.

BACKGROUND: The rebound of influenza A (H1N1) infection in post-COVID-19 era recently attracted enormous attention due the rapidly increased number of pediatric hospitalizations and the changed characteristics compared to classical H1N1 infection in pre-COVID-19 era. This study aimed to evaluate the clinical characteristics and severity of children hospitalized with H1N1 infection during post-COVID-19 period, and to construct a novel prediction model for severe H1N1 infection. METHODS: A total of 757 pediatric H1N1 inpatients from nine tertiary public hospitals in Yunnan and Shanghai, China, were retrospectively included, of which 431 patients diagnosed between February 2023 and July 2023 were divided into post-COVID-19 group, while the remaining 326 patients diagnosed between November 2018 and April 2019 were divided into pre-COVID-19 group. A 1:1 propensity-score matching (PSM) was adopted to balance demographic differences between pre- and post-COVID-19 groups, and then compared the severity across these two groups based on clinical and laboratory indicators. Additionally, a subgroup analysis in the original post-COVID-19 group (without PSM) was performed to investigate the independent risk factors for severe H1N1 infection in post-COIVD-19 era. Specifically, Least Absolute Shrinkage and Selection Operator (LASSO) regression was applied to select candidate predictors, and logistic regression was used to further identify independent risk factors, thus establishing a prediction model. Receiver operating characteristic (ROC) curve and calibration curve were utilized to assess discriminative capability and accuracy of the model, while decision curve analysis (DCA) was used to determine the clinical usefulness of the model. RESULTS: After PSM, the post-COVID-19 group showed longer fever duration, higher fever peak, more frequent cough and seizures, as well as higher levels of C-reactive protein (CRP), interleukin 6 (IL-6), IL-10, creatine kinase-MB (CK-MB) and fibrinogen, higher mechanical ventilation rate, longer length of hospital stay (LOS), as well as higher proportion of severe H1N1 infection (all P < 0.05), compared to the pre-COVID-19 group. Moreover, age, BMI, fever duration, leucocyte count, lymphocyte proportion, proportion of CD3+ T cells, tumor necrosis factor α (TNF-α), and IL-10 were confirmed to be independently associated with severe H1N1 infection in post-COVID-19 era. A prediction model integrating these above eight variables was established, and this model had good discrimination, accuracy, and clinical practicability. CONCLUSIONS: Pediatric H1N1 infection during post-COVID-19 era showed a higher overall disease severity than the classical H1N1 infection in pre-COVID-19 period. Meanwhile, cough and seizures were more prominent in children with H1N1 infection during post-COVID-19 era. Clinicians should be aware of these changes in such patients in clinical work. Furthermore, a simple and practical prediction model was constructed and internally validated here, which showed a good performance for predicting severe H1N1 infection in post-COVID-19 era.

Leachate derived humic-like substances drive the variation in microbial communities in landfill-affected groundwater.

Landfills are commonly used for waste disposal in many countries, and pose a significant threat of groundwater contamination. Dissolved organic matter (DOM) plays a crucial role as a carbon and energy source, supporting the growth and activity of microorganisms. However, the changes in the DOM signature and microbial community composition in landfill-affected groundwater and their bidirectional relationships remain inadequately explored. Herein, we showed that DOM originating from more recent landfills mainly comprises microbially produced substances resembling tryptophan and tyrosine. Conversely, DOM originating from older landfills predominantly comprises fulvic-like and humic-like compounds. Leachate leakage increases microbial diversity and richness and facilitates the transfer of foreign bacteria from landfills to groundwater, thereby increasing the vulnerability of the microbial ecosystem in groundwater. Deterministic processes dominated the assembly of the groundwater microbial community, while stochastic processes accounted for an increased proportion of the microbial community in the old landfills. The dominant phyla observed in groundwater were Proteobacteria, Bacteroidota, and Actinobacteriota, and humic-like substances play a crucial role in driving the variation in microbial communities in landfill-affected groundwater. Predictions using PICRUSt2 suggested significant associations between various metabolic pathways and microbial communities, with the Kyoto Encyclopedia of Genes and Genomes pathway "Metabolism" being the most predominant. The findings contribute to advancing our understanding of the transformation of DOM and its interplay with microbial communities and can serve as a scientific reference for decision-making regarding groundwater pollution monitoring and remediation.

[Research on automatic generation of multimodal medical image reports based on memory driven].

The task of automatic generation of medical image reports faces various challenges, such as diverse types of diseases and a lack of professionalism and fluency in report descriptions. To address these issues, this paper proposes a multimodal medical imaging report based on memory drive method (mMIRmd). Firstly, a hierarchical vision transformer using shifted windows (Swin-Transformer) is utilized to extract multi-perspective visual features of patient medical images, and semantic features of textual medical history information are extracted using bidirectional encoder representations from transformers (BERT). Subsequently, the visual and semantic features are integrated to enhance the model's ability to recognize different disease types. Furthermore, a medical text pre-trained word vector dictionary is employed to encode labels of visual features, thereby enhancing the professionalism of the generated reports. Finally, a memory driven module is introduced in the decoder, addressing long-distance dependencies in medical image data. This study is validated on the chest X-ray dataset collected at Indiana University (IU X-Ray) and the medical information mart for intensive care chest x-ray (MIMIC-CXR) released by the Massachusetts Institute of Technology and Massachusetts General Hospital. Experimental results indicate that the proposed method can better focus on the affected areas, improve the accuracy and fluency of report generation, and assist radiologists in quickly completing medical image report writing.

Platelet-rich plasma promotes skeletal muscle regeneration and neuromuscular functional reconstitution in a concentration-dependent manner in a rat laceration model.

Abnormal function of injured muscle with innervation loss is a challenge in sports medicine. The difficulty of rehabilitation is regenerating and reconstructing the skeletal muscle tissue and the neuromuscular junction (NMJ). Platelet-rich plasma (PRP) releases various growth factors that may provide an appropriate niche for tissue regeneration. However, the specific mechanism of the PRP's efficacy on muscle healing remains unknown. In this study, we injected PRP with different concentration gradients (800, 1200, 1600 × 109 pl/L) or saline into a rat gastrocnemius laceration model. The results of histopathology and neuromyography show that PRP improved myofibers regeneration, facilitated electrophysiological recovery, and reduced fibrosis in a concentration-dependent manner. Furthermore, we found that PRP promotes the activity of satellite cells by upregulating the expression of the myogenic regulatory factor (MyoD, myogenin). Meanwhile, PRP promotes the regeneration and maturation of acetylcholine receptor (AChR) clusters of the Neuromuscular junction (NMJ) on the regenerative myofibers. Finally, we found that the expression of the Agrin, LRP4, and MuSK was upregulated in the PRP-treated groups, which may contribute to AChR cluster regeneration and functional recovery. The conclusions proposed a hypothesis for PRP treatment's efficacy and mechanism in muscle injuries, indicating promising application prospects.

Mycoplasma infection of cancer cells enhances anti-tumor effect of oxidized methylcytidines.

Oxidized methylcytidines 5-hydroxymethyl-2'deoxycytidine (5hmdC) and 5-formy-2'deoxycytidine (5fdC) are deaminated by cytidine deaminase (CDA) into genome-toxic variants of uridine, triggering DNA damage and cell death. These compounds are promising chemotherapeutic agents for cancer cells that are resistant to pyrimidine derivative drugs, such as decitabine and cytarabine, which are inactivated by CDA. In our study, we found that cancer cells infected with mycoplasma exhibited a markedly increased sensitivity to 5hmdC and 5fdC, which was independent of CDA expression of cancer cells. In vitro biochemical assay showed that the homologous CDA protein from mycoplasma was capable of deaminating 5hmdC and 5fdC into their uridine form. Moreover, mycoplasma infection increased the sensitivity of cancer cells to 5hmdC and 5fdC, whereas administration of Tetrahydrouridine (THU) attenuated this effect, suggesting that mycoplasma CDA confers a similar effect as human CDA. As mycoplasma infection occurs in many primary tumors, our findings suggest that intratumoral microbes could enhance the tumor-killing effect and expand the utility of oxidized methylcytidines in cancer treatment.

Selective and Sustainable Production of Sub-terminal Hydroxy Fatty Acids by a Self-Sufficient CYP102 Enzyme from Bacillus Amyloliquefaciens.

Enzymatic hydroxylation of fatty acids by Cytochrome P450s (CYPs) offers an eco-friendly route to hydroxy fatty acids (HFAs), high-value oleochemicals with various applications in materials industry and with potential as bioactive compounds. However, instability and poor regioselectivity of CYPs are their main drawbacks. A newly discovered self-sufficient CYP102 enzyme, BAMF0695 from Bacillus amyloliquefaciens DSM 7, exhibits preference for hydroxylation of sub-terminal positions (ω-1, ω-2, and ω-3) of fatty acids. Our studies show that BAMF0695 has a broad temperature optimum (over 70 % of maximal enzymatic activity retained between 20 to 50 °C) and is highly thermostable (T50 >50 °C), affording excellent adaptive compatibility for bioprocesses. We further demonstrate that BAMF0695 can utilize renewable microalgae lipid as a substrate feedstock for HFA production. Moreover, through extensive site-directed and site-saturation mutagenesis, we isolated variants with high regioselectivity, a rare property for CYPs that usually generate complex regioisomer mixtures. BAMF0695 mutants were able to generate a single HFA regiosiomer (ω-1 or ω-2) with selectivities from 75 % up to 91 %, using C12 to C18 fatty acids. Overall, our results demonstrate the potential of a recent CYP and its variants for sustainable and green production of high-value HFAs.