Arabidopsis cryptochromes interact with SOG1 to promote the repair of DNA double-strand breaks.

Cryptochromes (CRYs) are blue light (BL) photoreceptors to regulate a variety of physiological processes including DNA double-strand break (DSB) repair. SUPPRESSOR OF GAMMA RADIATION 1 (SOG1) acts as the central transcription factor of DNA damage response (DDR) to induce the transcription of downstream genes, including DSB repair-related genes BRCA1 and RAD51. Whether CRYs regulate DSB repair by directly modulating SOG1 is unknown. Here, we demonstrate that CRYs physically interact with SOG1. Disruption of CRYs and SOG1 leads to increased sensitivity to DSBs and reduced DSB repair-related genes' expression under BL. Moreover, we found that CRY1 enhances SOG1's transcription activation of DSB repair-related gene BRCA1. These results suggest that the mechanism by which CRYs promote DSB repair involves positive regulation of SOG1's transcription of its target genes, which is likely mediated by CRYs-SOG1 interaction.

"Point by point" source: The Chinese pine plantations in North China by evidence from mtDNA.

The geographical variation and domestication of tree species are an important part of the theory of forest introduction, and the tracing of the germplasm is the theoretical basis for the establishment of high-quality plantations. Chinese pine (Pinus tabuliformis Carr.) is an important native timber tree species widely distributed in northern China, but it is unclear exactly where germplasm of the main Chinese pine plantation populations originated. Here, using two mtDNA markers, we analyzed 796 individuals representing 35 populations (matR marker), and 873 individuals representing 38 populations (nad5-1 marker) of the major natural and artificial populations in northern China, respectively (Shanxi, Hebei and Liaoning provinces). The results confirmed that the core position of natural SX* populations ("*" means natural population) in the Chinese pine populations of northern China, the genetic diversity of HB and LN plantations was higher than that of natural SX* populations, and there was a large difference in genetic background within the groups of SX* and LN, HB showed the opposite. More importantly, we completed the "point by point" tracing of the HB and LN plantings. The results indicated that almost all HB populations originated from SX* (GDS*, ZTS*, GCS*, and THS*), which resulted in homogeneity of the genetic background of HB populations. Most of germplasm of the LN plantations originated from LN* (ZJS* and WF*), and the other part originated from GDS* (SX*), resulting in the large differences in the genetic background within the LN group. Our results provided a reliable theoretical basis for the scientific allocation, management, and utilization of Chinese pine populations in northern China, and for promoting the high-quality establishment of Chinese pine plantations.

How does the ion concentration affect the functions of kinesin BimC.

BimC family proteins are bipolar motor proteins belonging to the kinesin superfamily which promote mitosis by crosslinking and sliding apart antiparallel microtubules. Understanding the binding mechanism between the kinesin and the microtubule is crucial for researchers to make advances in the treatment of cancer and other malignancies. Experimental research has shown that the ion concentration affects the function of BimC significantly. But the insights of the ion-dependent function of BimC remain unclear. By combining molecular dynamics (MD) simulations with a series of computational approaches, we studied the electrostatic interactions at the binding interfaces of BimC and the microtubule under different KCl concentrations. We found the electrostatic interaction between BimC and microtubule is stronger at 0 mM KCl compared to 150 mM KCl, which is consistent with experimental conclusions. Furthermore, important salt bridges and residues at the binding interfaces of the complex were identified, which illustrates the details of the BimC-microtubule interactions. Molecular dynamics analyses of salt bridges identified that the important residues on the binding interface of BimC are positively charged, while those residues on the binding interface of the tubulin heterodimer are negatively charged. The finding in this work reveals some important mechanisms of kinesin-microtubule binding, which helps the future drug design for cancer therapy.

News Coverage of the COVID-19 Pandemic on Social Media and the Public's Negative Emotions: Computational Study.

BACKGROUND: Social media has become an increasingly popular and critical tool for users to digest diverse information and express their perceptions and attitudes. While most studies endeavor to delineate the emotional responses of social media users, there is limited research exploring the factors associated with the emergence of emotions, particularly negative ones, during news consumption. OBJECTIVE: We aim to first depict the web coverage by news organizations on social media and then explore the crucial elements of news coverage that trigger the public's negative emotions. Our findings can act as a reference for responsible parties and news organizations in times of crisis. METHODS: We collected 23,705 Facebook posts with 1,019,317 comments from the public pages of representative news organizations in Hong Kong. We used text mining techniques, such as topic models and Bidirectional Encoder Representations from Transformers, to analyze news components and public reactions. Beyond descriptive analysis, we used regression models to shed light on how news coverage on social media is associated with the public's negative emotional responses. RESULTS: Our results suggest that occurrences of issues regarding pandemic situations, antipandemic measures, and supportive actions are likely to reduce the public's negative emotions, while comments on the posts mentioning the central government and the Government of Hong Kong reveal more negativeness. Negative and neutral media tones can alleviate the rage and interact with the subjects and issues in the news to affect users' negative emotions. Post length is found to have a curvilinear relationship with users' negative emotions. CONCLUSIONS: This study sheds light on the impacts of various components of news coverage (issues, subjects, media tone, and length) on social media on the public's negative emotions (anger, fear, and sadness). Our comprehensive analysis provides a reference framework for efficient crisis communication for similar pandemics at present or in the future. This research, although first extending the analysis between the components of news coverage and negative user emotions to the scenario of social media, echoes previous studies drawn from traditional media and its derivatives, such as web newspapers. Although the era of COVID-19 pandemic gradually brings down the curtain, the commonality of this research and previous studies also contributes to establishing a clearer territory in the field of health crises.

A 5' UTR Language Model for Decoding Untranslated Regions of mRNA and Function Predictions.

The 5' UTR, a regulatory region at the beginning of an mRNA molecule, plays a crucial role in regulating the translation process and impacts the protein expression level. Language models have showcased their effectiveness in decoding the functions of protein and genome sequences. Here, we introduced a language model for 5' UTR, which we refer to as the UTR-LM. The UTR-LM is pre-trained on endogenous 5' UTRs from multiple species and is further augmented with supervised information including secondary structure and minimum free energy. We fine-tuned the UTR-LM in a variety of downstream tasks. The model outperformed the best known benchmark by up to 5% for predicting the Mean Ribosome Loading, and by up to 8% for predicting the Translation Efficiency and the mRNA Expression Level. The model also applies to identifying unannotated Internal Ribosome Entry Sites within the untranslated region and improves the AUPR from 0.37 to 0.52 compared to the best baseline. Further, we designed a library of 211 novel 5' UTRs with high predicted values of translation efficiency and evaluated them via a wet-lab assay. Experiment results confirmed that our top designs achieved a 32.5% increase in protein production level relative to well-established 5' UTR optimized for therapeutics.

ADA2b acts to positively regulate blue light-mediated photomorphogenesis in Arabidopsis.

Cryptochromes (CRYs) act as blue light photoreceptors to regulate various plant physiological processes including photomorphogenesis and repair of DNA double strand breaks (DSBs). ADA2b is a conserved transcription co-activator that is involved in multiple plant developmental processes. It is known that ADA2b interacts with CRYs to mediate blue light-promoted DSBs repair. Whether ADA2b may participate in CRYs-mediated photomorphogenesis is unknown. Here we show that ADA2b acts to inhibit hypocotyl elongation and hypocotyl cell elongation in blue light. We found that the SWIRM domain-containing C-terminus mediates the blue light-dependent interaction of ADA2b with CRYs in blue light. Moreover, ADA2b and CRYs act to co-regulate the expression of hypocotyl elongation-related genes in blue light. Based on previous studies and these results, we propose that ADA2b plays dual functions in blue light-mediated DNA damage repair and photomorphogenesis.

Patient-specific ascending aortic intervention criteria.

OBJECTIVES: Ascending aortic aneurysms pose a different risk to each patient. We aim to provide personalized risk stratification for such patients based on sex, age, body surface area and aneurysm location (root versus ascending). METHODS: Root and ascending diameters, and adverse aortic events (dissection, rupture, death) of ascending thoracic aortic aneurysm patients were analysed. Aortic diameter was placed in context vis-a-vis the normal distribution in the general population with similar sex, age and body surface area, by conversion to z scores. These were correlated of major adverse aortic events, producing risk curves with 'hinge points' of steep risk, constructed separately for the aortic root and mid-ascending aorta. RESULTS: A total of 1162 patients were included. Risk curves unveiled generalized thresholds of z = 4 for the aortic root and z = 5 for the mid-ascending aorta. These correspond to individualized thresholds of less than the standard criterion of 5.5 cm in the vast majority of patients. Indicative results include a 75-year-old typical male with 2.1 m2 body surface area, who was found to be at increased risk of adverse events if root diameter exceeds 5.15 cm, or mid ascending exceeds 5.27 cm. An automated calculator is presented, which identifies patients at high risk of adverse events based on sex, age, height, weight, and root and ascending size. CONCLUSIONS: This analysis exploits a large sample of aneurysmal patients, demographic features of the general population, pre-dissection diameter, discrimination of root and supracoronary segments, and statistical tools to extract thresholds of increased risk tailor-made for each patient.

Mid-Term Outcome after Extracorporeal Life Support in Postcardiotomy Cardiogenic Shock: Recovery and Quality of Life.

Background: Extracorporeal life support (ECLS) therapy for refractory postcardiotomy cardiogenic shock (rPCS) is associated with high early mortality rates. This study aimed to identify negative predictors of mid-term survival and to assess health-related quality of life (HRQoL) and recovery of the survivors. Methods: Between 2017 and 2020, 142 consecutive patients received ECLS therapy following cardiac surgery. The median age was 66.0 [57.0-73.0] years, 67.6% were male and the median EuroSCORE II was 10.5% [4.2-21.3]. In 48 patients, HRQoL was examined using the 36-Item Short Form Survey (SF-36) and the modified Rankin-Scale (mRS) at a median follow-up time of 2.2 [1.9-3.2] years. Results: Estimated survival rates at 3, 12, 24 and 36 months were 47%, 46%, 43% and 43% (SE: 4%). Multivariable Cox Proportional Hazard regression analysis revealed preoperative EuroSCORE II (p = 0.013), impaired renal function (p = 0.010), cardiopulmonary bypass duration (p = 0.015) and pre-ECLS lactate levels (p = 0.004) as independent predictors of mid-term mortality. At the time of follow-up, 83.3% of the survivors were free of moderate to severe disability (mRS < 3). SF-36 analysis showed a physical component summary of 45.5 ± 10.2 and a mental component summary of 50.6 ± 12.5. Conclusions: Considering the disease to be treated, ECLS for rPCS is associated with acceptable mid-term survival, health-related quality of life and functional status. Preoperative EuroSCORE II, impaired renal function, cardiopulmonary bypass duration and lactate levels prior to ECLS implantation were identified as negative predictors and should be included in the decision-making process.

Assessing Interferon Regulatory Factor 4 Complex Formation: Differential Behavior of Homocomplexes Versus Heterocomplexes Induced by Mutations.

Interferon regulatory factor 4 (IRF4) is a crucial transcription factor that plays a vital role in lymphocyte development, including in the fate-determining steps in terminal differentiation. It is also implicated in the development of lymphoid tumors such as multiple myeloma and adult T-cell leukemia. IRF4 can form a homodimer and multiple heterocomplexes with other transcription factors such as purine-rich box1 and activator protein 1. Each protein complex binds to specific DNA sequences to regulate a distinct set of genes. However, the precise relationship among these complex formations remains unclear. Herein, we investigated the abilities of IRF4 proteins with functional mutations in the IRF-association domain and autoinhibitory region to form complexes using luciferase reporter assays. The assays allowed us to selectively assess the activity of each complex. Our results revealed that certain IRF-association domain mutants, previously known to have impaired heterocomplex formation, maintained or even enhanced homodimer activity. This discrepancy suggests that the mutated amino acid residues selectively influence homodimer activity. Conversely, a phosphomimetic serine mutation in the autoinhibitory region displayed strong activating effects in all complexes. Furthermore, we observed that partner proteins involved in heterocomplex formation could disrupt the activity of the homodimer, suggesting a potential competition between homocomplexes and heterocomplexes. Our findings provide new insights into the mechanistic function of IRF4.

DNA Adducts in Cancer Chemotherapy.

DNA adducting drugs, including alkylating agents and platinum-containing drugs, are prominent in cancer chemotherapy. Their mechanisms of action involve direct interaction with DNA, resulting in the formation of DNA addition products known as DNA adducts. While these adducts are well-accepted to induce cancer cell death, understanding of their specific chemotypes and their role in drug therapy response remain limited. This perspective aims to address this gap by investigating the metabolic activation and chemical characterization of DNA adducts formed by the U.S. FDA-approved drugs. Moreover, clinical studies on DNA adducts as potential biomarkers for predicting patient responses to drug efficacy are examined. The overarching goal is to engage the interest of medicinal chemists and stimulate further research into the use of DNA adducts as biomarkers for guiding personalized cancer treatment.

Inhibiting autophagy enhanced mitotic catastrophe-mediated anticancer immune responses by regulating the cGAS-STING pathway.

Given the limitations of the response rate and efficacy of immune checkpoint inhibitors (ICIs) in clinical applications, exploring new therapeutic strategies for cancer immunotherapy is necessary. We found that 5-(3,4,5-trimethoxybenzoyl)-4-methyl-2-(p-tolyl)imidazole (BZML), a microtubule-targeting agent, exhibited potent anticancer activity by inducing mitotic catastrophe in A549/Taxol and L929 cells. Nuclear membrane disruption and nuclease reduction provided favorable conditions for cGAS-STING pathway activation in cells with mitotic catastrophe. Similar results were obtained in paclitaxel-, docetaxel- and doxorubicin-induced mitotic catastrophe in various cancer cells. Notably, the surface localization of CALR and MHC-I and the release of HMGB1 were also significantly increased in cells with mitotic catastrophe, but not in apoptotic cells, suggesting that mitotic catastrophe is an immunogenic cell death. Furthermore, activated CD8+T cells enhanced the anticancer effects originating from mitotic catastrophe induced by BZML. Inhibiting the cGAS-STING pathway failed to affect BZML-induced mitotic catastrophe but could inhibit mitotic catastrophe-mediated anticancer immune effects. Interestingly, the expression of p-TBK1 first increased and then declined; however, autophagy inhibition reversed the decrease in p-TBK1 expression and enhanced mitotic catastrophe-mediated anticancer immune effects. Collectively, the inhibition of autophagy can potentiate mitotic catastrophe-mediated anticancer immune effects by regulating the cGAS-STING pathway, which explains why the anticancer immune effects induced by chemotherapeutics have not fully exerted their therapeutic efficacy in some patients and opens a new area of research in cancer immunotherapy.

Diterpenoids from Euphorbia peplus possessing cytotoxic and anti-inflammatory activities.

Phytochemical investigation into the medium polar fraction of the ethanol extract of Euphorbia peplus led to the identification of 32 diterpenoids with five structural types. Compounds 1-5 and 7-11 are reported for the first time, while the configuration of 6,7-epoxy group of 6 was revised to be ß-oriented. Compounds 1-5 feature a rare structural variation of the double bond at Δ1 migrating to Δ1(10) in the tigliane-type diterpenoid family. Biologically, compound 21 was found to be the only one to show moderate cytotoxic activity, associated with the presence of a benzoyloxy residue at C-16. Besides, compounds 4, 8, 12, 13, 16, and 19 show significant inhibitory activities against NO production induced by LPS in RAW264.7 macrophage cells, with IC50 values within 2-5 µM. Structure-activity relationship (SAR) analysis revealed that the ingenane-type diterpenoids have the best anti-inflammatory activity, and the esterification at 3-OH or 5-OH is crucial. Further biological researches demonstrated that 13, the predominant metabolite in this plant, exerts anti-inflammatory effects by blocking the activation of NF-κB and MAPK signaling pathways.

Rare flavanone-diarylheptanoid hybrids from Typha angustifolia shows anti breast cancer activity via activating TGF-ß1/Smad signaling pathway.

Four new flavanone-diarylheptanoid hetero dimers, typhatifolins A-D (1-4), were separated from the pollen of a widely distributed medicinal plant Typha angustifolia. Structures of these rare hybrids were elucidated by detailed interpretation of spectroscopic data, and their absolute configurations were determined on the basis of Mosher's method and ECD analyses. All the four compounds showed moderate to significant cytotoxicities against a panel of tumor cell lines with IC50 values ranging from 0.67 to 12.48 µM. Further in vitro antitumor evaluation for typhatifolin B (TTB, 2) on two breast cancer cells (4T1 and MDA-MB231) revealed that it could remarkably induce cell apoptosis and G0/G1 cycle arrest, as well as block cell migration and invasion. Mechanistically, TTB could exert its antitumor effect via activating the TGF-ß1 (transforming growth factor beta 1) signaling pathway as evidenced by RNA-seq analysis and immunoblotting experiments, which was further corroborated by treating cancer cells with a TGF-ß signaling inhibitor. Lastly, the in vivo anti breast cancer activity was demonstrated by applying the mixture of typhatifolins A-D to a preclinical animal model.

Decreasing trends of mean and extreme snowfall in High Mountain Asia.

Intense warming profoundly alters precipitation phase patterns and intensity in High Mountain Asia (HMA). While snowfall climatology and precipitation extremes have been studied, there is a lack of understanding of snowfall extremes within HMA. Here, we investigate the spatial and temporal variability of non-extreme and extreme snowfall in hydrological years 1979-2020 using multi-source meteorological data, compare weather systems during extreme and non-extreme snowfall events, and identify key circulation factors that influence fluctuations in mean annual snowfall and extreme snowfall. The snowfall amount (-0.13 d/mm), days (-0.56 d/a), and fraction (-0.0012) were significantly reduced in HMA, with a shorter snowfall season (-0.52 d/a). Some extreme snowfall metrics (maximum 1-day snowfall and maximum 3-day snowfall) were insensitive to climate change, whereas the maximum consecutive snowfall days (-0.007 d/a), snowfall amount (-0.0023 mm/a), heavy snowfall days (S95pD; 0.0087 d/a), and extremely heavy snowfall days (S99pD; -0.1019 d/a) showed significant decreases. Synthetic analyses show that extreme snowfall events were more likely to occur within a narrow temperature range (-5 °C to 3 °C) with higher relative humidity and precipitation compared to non-extreme events. A stepwise regression method was used to determine that the fluctuation in the average annual snowfall was closely related to the Atlantic Multidecadal Oscillation, whereas the variation in extreme snowfall was mainly influenced by the Southern Oscillation Index. Our research provides a reference for assessing the potential impacts of climate change on a regional scale for risk management and disaster adaptation.

Asymptomatic Females Are at Higher Risk for Perioperative TIA/Stroke and Males Are at Higher Risk for Long-Term Mortality after Carotid Artery Stenting: A Vascular Quality Initiative Analysis.

The study aims to review the sex differences with respect to transient ischemic attack (TIA)/stroke and death in the perioperative period and on long-term follow-up among asymptomatic patients treated with carotid stenting (CAS) in the vascular quality initiative (VQI). All cases reported to VQI of asymptomatic CAS (ACAS) patients were reviewed. The primary end point was risk of TIA/stroke and death in the in-hospital perioperative period and in the long-term follow-up. The secondary end point was to evaluate predictors of in-hospital perioperative TIA/stroke and mortality on long-term follow-up after CAS. There were 22,079 CAS procedures captured from January 2005 to April 2019. There were 5,785 (62.7%) patients in the ACAS group. The rate of in-hospital TIA/stroke was higher in female patients (2.7 vs. 1.87%, p = 0.005) and the rate of death was not significant (0.03 vs. 0.07%, p = 0.66). On multivariable logistic regression analysis, prior/current smoking history (odds ratio = 0.58 [95% confidence interval or CI = 0.39-0.87]; p = 0.008) is a predictor of in-hospital TIA/stroke in females. The long-term all-cause mortality is significantly higher in male patients (26.9 vs. 15.7%, p < 0.001). On multivariable Cox-regression analysis, prior/current smoking history (hazard ratio or HR = 1.17 [95% CI = 1.01-1.34]; p = 0.03), coronary artery disease or CAD (HR = 1.15 [95% CI = 1.03-1.28]; p = 0.009), chronic obstructive pulmonary disease or COPD (HR = 1.73 [95% CI = 1.55-1.93]; p < 0.001), threat to life American Society of Anesthesiologists (ASA) class (HR = 2.3 [95% CI = 1.43-3.70]; p = 0.0006), moribund ASA class (HR = 5.66 [95% CI = 2.24-14.29]; p = 0.0003), and low hemoglobin levels (HR = 0.84 [95% CI = 0.82-0.86]; p < 0.001) are the predictors of long-term mortality. In asymptomatic carotid disease patients, women had higher rates of in-hospital perioperative TIA/stroke and a predictor of TIA/stroke is a prior/current history of smoking. Meanwhile, long-term all-cause mortality is higher for male patients compared with their female counterparts. Predictors of long-term mortality are prior/current smoking history, CAD, COPD, higher ASA classification of physical status, and low hemoglobin level. These data should be considered prior to offering CAS to asymptomatic female and male patients and careful risks versus benefits discussion should be offered to each individual patient.

Diagnosis and treatment experience of atypical hepatic cystic echinococcosis type 1 at a tertiary center in China.

BACKGROUND: Some hydatid cysts of cystic echinococcosis type 1 (CE1) lack well-defined cyst walls or distinctive endocysts, making them difficult to differentiate from simple hepatic cysts. AIM: To investigate the diagnostic methods for atypical hepatic CE1 and the clinical efficacy of laparoscopic surgeries. METHODS: The clinical data of 93 patients who had a history of visiting endemic areas of CE and were diagnosed with cystic liver lesions for the first time at the People's Hospital of Xinjiang Uygur Autonomous Region (China) from January 2018 to September 2023 were retrospectively analyzed. Clinical diagnoses were made based on findings from serum immunoglobulin tests for echinococcosis, routine abdominal ultrasound, high-frequency ultrasound, abdominal computed tomography (CT) scan, and laparoscopy. Subsequent to the treatments, these patients underwent reexaminations at the outpatient clinic until October 2023. The evaluations included the diagnostic precision of diverse examinations, the efficacy of surgical approaches, and the incidence of CE recurrence. RESULTS: All 93 patients were diagnosed with simple hepatic cysts by conventional abdominal ultrasound and abdominal CT scan. Among them, 16 patients were preoperatively diagnosed with atypical CE1, and 77 were diagnosed with simple hepatic cysts by high-frequency ultrasound. All the 16 patients preoperatively diagnosed with atypical CE1 underwent laparoscopy, of whom 14 patients were intraoperatively confirmed to have CE1, which was consistent with the postoperative pathological diagnosis, one patient was diagnosed with a mesothelial cyst of the liver, and the other was diagnosed with a hepatic cyst combined with local infection. Among the 77 patients who were preoperatively diagnosed with simple hepatic cysts, 4 received aspiration sclerotherapy of hepatic cysts, and 19 received laparoscopic fenestration. These patients were intraoperatively diagnosed with simple hepatic cysts. During the follow-up period, none of the 14 patients with CE1 experienced recurrence or implantation of hydatid scolices. One of the 77 patients was finally confirmed to have CE complicated with implantation to the right intercostal space. CONCLUSION: Abdominal high-frequency ultrasound can detect CE1 hydatid cysts. The laparoscopic technique serves as a more effective diagnostic and therapeutic tool for CE.

Design, Synthesis, and Biological Evaluation of Potent and Selective PROTAC Degraders of Oncogenic KRASG12D.

KRASG12D, the most frequent KRAS oncogenic mutation, is a promising target for cancer therapy. Herein, we report the design, synthesis, and biological evaluation of a series of KRASG12D PROTACs by connecting the analogues of MRTX1133 and the VHL ligand. Structural modifications of the linker moiety and KRAS inhibitor part suggested a critical role of membrane permeability in the degradation activity of the KRASG12D PROTACs. Mechanism studies with the representative compound 8o demonstrated that the potent, rapid, and selective degradation of KRASG12D induced by 8o was via a VHL- and proteasome-dependent manner. This compound selectively and potently suppressed the growth of multiple KRASG12D mutant cancer cells, displayed favorable pharmacokinetic and pharmacodynamic properties in mice, and showed significant antitumor efficacy in the AsPC-1 xenograft mouse model. Further optimization of 8o appears to be promising for the development of a new chemotherapy for KRASG12D-driven cancers as the complementary therapeutic strategy to KRAS inhibition.

A Water-Soluble Chitosan Derivative for the Release of Bioactive Deferoxamine.

Deferoxamine (DFO) is a water-soluble iron chelator used pharmacologically for the management of patients with transfusional iron overload. However, DFO is not cell-permeable and has a short plasma half-life, which necessitates lengthy parenteral administration with an infusion pump. We previously reported the synthesis of chitosan (CS) nanoparticles for sustained slow release of DFO. In the present study, we developed solid dispersions and nanoparticles of a carboxymethyl water-soluble chitosan derivative (CMCS) for improved DFO encapsulation and release. CS dispersions and nanoparticles with DFO have been prepared by ironical gelation using sodium triphosphate (TPP) and were examined for comparison purposes. The successful presence of DFO in CMCS polymeric dispersions and nanoparticles was confirmed through FTIR measurements. Furthermore, the formation of CMCS nanoparticles led to inclusion of DFO in an amorphous state, while dispersion of DFO in the polymeric matrix led to a decrease in its crystallinity according to X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results. An in vitro release assay indicated sustained release of DFO from CS and CMCS nanoparticles over 48 h and 24 h, respectively. Application of CMCS-DFO dispersions to murine RAW 264.7 macrophages or human HeLa cervical carcinoma cells triggered cellular responses to iron deficiency. These were exemplified in the induction of the mRNA encoding transferrin receptor 1, the major iron uptake protein, and the suppression of ferritin, the iron storage protein. Our data indicate that CMCS-DFO nanoparticles release bioactive DFO that causes effective iron chelation in cultured cells.

CDRIME-MTIS: An enhanced rime optimization-driven multi-threshold segmentation for COVID-19 X-ray images.

To improve the detection of COVID-19, this paper researches and proposes an effective swarm intelligence algorithm-driven multi-threshold image segmentation (MTIS) method. First, this paper proposes a novel RIME structure integrating the Co-adaptive hunting and dispersed foraging strategies, called CDRIME. Specifically, the Co-adaptive hunting strategy works in coordination with the basic search rules of RIME at the individual level, which not only facilitates the algorithm to explore the global optimal solution but also enriches the population diversity to a certain extent. The dispersed foraging strategy further enriches the population diversity to help the algorithm break the limitation of local search and thus obtain better convergence. Then, on this basis, a new multi-threshold image segmentation method is proposed by combining the 2D non-local histogram with 2D Kapur entropy, called CDRIME-MTIS. Finally, the results of experiments based on IEEE CEC2017, IEEE CEC2019, and IEEE CEC2022 demonstrate that CDRIME has superior performance than some other basic, advanced, and state-of-the-art algorithms in terms of global search, convergence performance, and escape from local optimality. Meanwhile, the segmentation experiments on COVID-19 X-ray images demonstrate that CDRIME is more advantageous than RIME and other peers in terms of segmentation effect and adaptability to different threshold levels. In conclusion, the proposed CDRIME significantly enhances the global optimization performance and image segmentation of RIME and has great potential to improve COVID-19 diagnosis.

The carboxy terminus causes interfacial assembly of oleate hydratase on a membrane bilayer.

The soluble flavoprotein oleate hydratase (OhyA) hydrates the 9-cis double bond of unsaturated fatty acids. OhyA substrates are embedded in membrane bilayers; OhyA must remove the fatty acid from the bilayer and enclose it in the active site. Here, we show that the positively charged helix-turn-helix motif in the carboxy terminus (CTD) is responsible for interacting with the negatively charged phosphatidylglycerol (PG) bilayer. Super-resolution microscopy of Staphylococcus aureus cells expressing green fluorescent protein fused to OhyA or the CTD sequence shows subcellular localization along the cellular boundary, indicating OhyA is membrane-associated and the CTD sequence is sufficient for membrane recruitment. Using cryo-electron microscopy, we solved the OhyA dimer structure and conducted 3D variability analysis of the reconstructions to assess CTD flexibility. Our surface plasmon resonance experiments corroborated that OhyA binds the PG bilayer with nanomolar affinity and we found the CTD sequence has intrinsic PG binding properties. We determined that the nuclear magnetic resonance structure of a peptide containing the CTD sequence resembles the OhyA crystal structure. We observed intermolecular NOE from PG liposome protons next to the phosphate group to the CTD peptide. The addition of paramagnetic MnCl2 indicated the CTD peptide binds the PG surface but does not insert into the bilayer. Molecular dynamics simulations, supported by site-directed mutagenesis experiments, identify key residues in the helix-turn-helix that drive membrane association. The data show that the OhyA CTD binds the phosphate layer of the PG surface to obtain bilayer-embedded unsaturated fatty acids.