PI3Kγ maintains the self-renewal of acute myeloid leukemia stem cells by regulating the pentose phosphate pathway.

ABSTRACT: Acute myeloid leukemia (AML) is an aggressive hematological malignancy originating from transformed hematopoietic stem or progenitor cells. AML prognosis remains poor owing to resistance and relapse driven by leukemia stem cells (LSCs). Targeting molecules essential for LSC function is a promising therapeutic approach. The phosphatidylinositol 3-kinase (PI3K)/AKT pathway is often dysregulated in AML. We found that although PI3Kγ is highly enriched in LSCs and critical for self-renewal, it was dispensable for normal hematopoietic stem cells. Mechanistically, PI3Kγ-AKT signaling promotes nuclear factor erythroid 2-related factor 2 (NRF2) nuclear accumulation, which induces 6-phosphogluconate dehydrogenase (PGD) and the pentose phosphate pathway, thereby maintaining LSC stemness. Importantly, genetic or pharmacological inhibition of PI3Kγ impaired expansion and stemness of murine and human AML cells in vitro and in vivo. Together, our findings reveal a key role for PI3Kγ in selectively maintaining LSC function by regulating AKT-NRF2-PGD metabolic pathway. Targeting the PI3Kγ pathway may, therefore, eliminate LSCs without damaging normal hematopoiesis, providing a promising therapeutic strategy for AML.

Identification of two novel heterodimeric ABC transporters in melanoma: ABCB5ß/B6 and ABCB5ß/B9.

ABCB5 is a member of the ABC transporter superfamily composed of 48 transporters, which have been extensively studied for their role in cancer multidrug resistance and, more recently, in tumorigenesis. ABCB5 has been identified as a marker of skin progenitor cells, melanoma, and limbal stem cells. It has also been associated with multidrug resistance in several cancers. The unique feature of ABCB5 is that it exists as both a full transporter (ABCB5FL) and a half transporter (ABCB5ß). Several studies have shown that the ABCB5ß homodimer does not confer multidrug resistance, in contrast to ABCB5FL. In this study, using three complementary techniques, (1) nanoluciferase-based bioluminescence resonance energy transfer, (2) coimmunoprecipitation, and (3) proximity ligation assay, we identified two novel heterodimers in melanoma: ABCB5ß/B6 and ABCB5ß/B9. Both heterodimers could be expressed in High-Five insect cells and ATPase assays revealed that both functional nucleotide-binding domains of homodimers and heterodimers are required for their basal ATPase activity. These results are an important step toward elucidating the functional role of ABCB5ß in melanocytes and melanoma.

Highly active CAR T cells that bind to a juxtamembrane region of mesothelin and are not blocked by shed mesothelin.

SignificanceMesothelin (MSLN) is a cell-surface protein that is a popular target for antibody-based therapies. We have identified shed MSLN as a major obstacle to successful antibody therapies and prepared a monoclonal antibody that inhibits shedding and makes very active CAR T cells whose activity is not blocked by shed MSLN and merits further preclinical development.

Structure of complex III with bound antimalarial agent CK-2-68 provides insights into selective inhibition of Plasmodium cytochrome bc1 complexes.

Among the various components of the protozoan Plasmodium mitochondrial respiratory chain, only Complex III is a validated cellular target for antimalarial drugs. The compound CK-2-68 was developed to specifically target the alternate NADH dehydrogenase of the malaria parasite respiratory chain, but the true target for its antimalarial activity has been controversial. Here, we report the cryo-EM structure of mammalian mitochondrial Complex III bound with CK-2-68 and examine the structure-function relationships of the inhibitor's selective action on Plasmodium. We show that CK-2-68 binds specifically to the quinol oxidation site of Complex III, arresting the motion of the iron-sulfur protein subunit, which suggests an inhibition mechanism similar to that of Pf-type Complex III inhibitors such as atovaquone, stigmatellin, and UHDBT. Our results shed light on the mechanisms of observed resistance conferred by mutations, elucidate the molecular basis of the wide therapeutic window of CK-2-68 for selective action of Plasmodium vs. host cytochrome bc1, and provide guidance for future development of antimalarials targeting Complex III.

Hypoxia-induced P4HA1 overexpression promotes post-ischemic angiogenesis by enhancing endothelial glycolysis through downregulating FBP1.

BACKGROUND: Angiogenesis is essential for tissue repair in ischemic diseases, relying on glycolysis as its primary energy source. Prolyl 4-hydroxylase subunit alpha 1 (P4HA1), the catalytic subunit of collagen prolyl 4-hydroxylase, is a glycolysis-related gene in cancers. However, its role in glycolysis-induced angiogenesis remains unclear. METHODS: P4HA1 expression was modulated using adenoviruses. Endothelial angiogenesis was evaluated through 5-ethynyl-2'-deoxyuridine incorporation, transwell migration, and tube formation assays in vitro. In vivo experiments measured blood flow and capillary density in the hindlimb ischemia (HLI) model. Glycolytic stress assays, glucose uptake, lactate production, and quantitative reverse transcription-polymerase chain reaction (RT-PCR) were employed to assess glycolytic capacity. Transcriptome sequencing, validated by western blotting and RT-PCR, was utilized to determine underlying mechanisms. RESULTS: P4HA1 was upregulated in endothelial cells under hypoxia and in the HLI model. P4HA1 overexpression promoted angiogenesis in vitro and in vivo, while its knockdown had the opposite effect. P4HA1 overexpression reduced cellular α-ketoglutarate (α-KG) levels by consuming α-KG during collagen hydroxylation. Downregulation of α-KG reduced the protein level of a DNA dioxygenase, ten-eleven translocation 2 (TET2), and its recruitment to the fructose-1,6-biphosphatase (FBP1) promoter, resulting in decreased FBP1 expression. The decrease in FBP1 enhanced glycolytic metabolism, thereby promoting endothelial angiogenesis. CONCLUSIONS: Hypoxia-induced endothelial P4HA1 overexpression enhanced angiogenesis by promoting glycolytic metabolism reprogramming through the P4HA1/α-KG/TET2/FBP1 pathway. The study's findings underscore the significance of P4HA1 in post-ischemic angiogenesis, suggesting its therapeutic potential for post-ischemic tissue repair.

Application of Nontarget High-Resolution Mass Spectrometry Fingerprints for Qualitative and Quantitative Source Apportionment: A Real Case Study.

High-resolution mass spectrometry (HRMS) provides extensive chemical data, facilitating the differentiation and quantification of contaminants of emerging concerns (CECs) in aquatic environments. This study utilizes liquid chromatography-HRMS for source apportionment in Chebei Stream, an urban water stream in Guangzhou, South China. Initially, 254 features were identified as potential CECs by the nontarget screening (NTS) method. We then established 1689, 1317, and 15,759 source-specific HRMS fingerprints for three distinct sources, the mainstream (C3), the tributary (T2), and the rain runoff (R1), qualitatively assessing the contribution from each source downstream. Subsequently, 32, 55, and 3142 quantitative fingerprints were isolated for sites C3, T2, and R1, respectively, employing dilution curve screening for source attribution. The final contribution estimates downstream from sites C3, T2, and R1 span 32-96, 12-23, and 8-23%, respectively. Cumulative contributions from these sources accurately mirrored actual conditions, fluctuating between 103 and 114% across C6 to C8 sites. Yet, with further tributary integration, the overall source contribution dipped to 52%. The findings from this research present a pioneering instance of applying HRMS fingerprints for qualitative and quantitative source tracking in real-world scenarios, which empowers the development of more effective strategies for environmental protection.

Isoimperatorin Inhibits Angiogenesis by Suppressing VEGFR2 Signaling Pathway.

PURPOSE: Angiogenesis involves in many pathological processes, including tumor metastasis, diabetic retinopathy, and rheumatoid arthritis. Therefore, identifying therapeutic drugs that target angiogenesis may be a promising strategy for disease treatment. Isoimperatorin is a furanocoumarin with anti-inflammatory and anti-microbial effects. However, the impacts of isoimperatorin on angiogenesis and its underlying mechanisms remain unclear. This study aimed to verify its effects on vascular endothelial growth factor (VEGF)-induced endothelial angiogenesis. METHODS: We employed various assays including 5-ethynyl-2'-deoxyuridine incorporation assay, transwell migration assay, wound healing assay, tube formation assay, and Western blot to evaluate the effects of isoimperatorin on angiogenesis in vitro. Additionally, we utilized Western blot and immunofluorescence analysis to examine the activation of vascular endothelial growth factor receptor (VEGFR) 2 and its downstream signaling pathways following isoimperatorin treatment. To further validate the anti-angiogenic effects of isoimperatorin in vivo, we conducted a matrigel plug assay and established an orthotopic tumor model. RESULTS: We demonstrated that pretreatment with isoimperatorin inhibited VEGF-induced endothelial cell proliferation, migration, and tube formation. Isoimperatorin also suppressed angiogenesis in vivo in a matrigel plug assay and in an orthotopic tumor model. Our results revealed that isoimperatorin exhibited anti-angiogenic effects via inhibiting VEGFR2 and its downstream signaling pathways activation. CONCLUSIONS: Our study showed that isoimperatorin suppressed angiogenesis by targeting the VEGFR2 signaling pathway and could be a potential therapeutic agent for targeting angiogenesis.

Differences between resident self-assessments and faculty- assessments on Anesthesiology Milestones and associated factors: a cross-sectional study.

BACKGROUND: Accurate self-assessment is crucial for the professional development of physicians. There has been sparse data on the accuracy of self-assessments on Anesthesiology Milestones. The aim of this study was to investigate the differences between resident self-assessments and faculty-assessments on Anesthesiology Milestones and the associated factors. METHODS: This was a cross-sectional study conducted in a general tertiary university-affiliated hospital. We included anesthesia residents who were enrolled in the standardized residency training program in postgraduate year two and three at the time of the Milestone evaluation. We requested evaluations of competencies from both the Clinical Competency Committee faculty and the anesthesia residents themselves, utilizing the Chinese version of Anesthesiology Milestones in January 2023 and January 2024. The primary outcome was the differences between self- and faculty-assessments, calculated by subtracting the faculty-rated score from the self-rated score on each subcompetency. RESULTS: A total of 46 and 42 residents were evaluated in year 2023 and 2024, respectively. The self-rated sum score was significantly higher than that rated by faculty [mean (standardized deviation): 120.39 (32.41) vs. 114.44 (23.71), P = 0.008 in paired t test] with an intraclass correlation coefficient of 0.55 [95% confidence interval (CI): 0.31 to 0.70]. The Bland-Altman plots revealed significant overestimation in patient care (bias 0.32, 95% CI: 0.05 to 0.60), practice-based learning and improvement (bias 0.45, 95% CI: 0.07 to 0.84), and professionalism (bias 0.37, 95% CI: 0.02 to 0.72). Ratings from residents with master's degrees (mean difference: -1.06, 95% CI: -1.80 to -0.32, P = 0.005) and doctorate degrees (mean difference: -1.14, 95% CI: -1.91 to -0.38, P = 0.003) were closer to the faculty-assessments than residents with bachelor's degrees. Compared with patient care, the differences between self- and faculty- rated scores were smaller in medical knowledge (mean difference: -0.18, 95% CI: -0.35 to -0.02, P = 0.031) and interpersonal and communication skills (mean difference: -0.41, 95% CI: -0.64 to -0.19, P < 0.001) in the generalized estimating equation logistic regression model. CONCLUSIONS: This study revealed that residents tended to overestimate themselves, emphasizing the need to improve the accuracy of Milestones self-assessment. The differences between self- and faculty-assessments were associated with residents' degrees and domains of competency.

Integrated Reconfigurable Photon-Pair Source Based on High-Q Nonlinear Chalcogenide Glass Microring Resonators.

Chalcogenide glasses (ChGs) have recently emerged as enabling materials for building reconfigurable nanophotonic devices by employing their refractive index changes associated with photosensitive effects. In particular, the availability of low-loss thin-film ChGs and the realization of high-Q microresonators provide exciting opportunities for integrated photonics. So far, the ChG photonic devices are predominately operated in the classical optics regime. In this work, we present the realization on-chip bright photon-pair quantum light sources via spontaneous four-wave mixing in a high-Q microring resonator fabricated on the newly developed ChG Ge25Sb10S65 platform. The emission wavelength of the photon-pair source can be continuously tuned across a double-free spectral range in a reconfigurable manner. Our work serves as a starting point to fully unleash the potential of exploiting ChGs for developing reconfigurable integrated quantum photonic devices.

Upregulation of SLITRK5 in patients with epilepsy and in a rat model.

SLIT and NTRK-like protein-5 (SLITRK5) is one of the six members of SLITRK protein family, which is widely expressed in central nervous system (CNS). In brain, SLITRK5 plays important roles in neurite outgrowth, dendritic branching, neuron differentiation, synaptogenesis, and signal transmission of neurons. Epilepsy is a common, chronic neurological disorder characterized by recurrent spontaneous seizures. The pathophysiological mechanism of epilepsy remains unclear. Neuronal apoptosis, abnormal nerve excitatory transmission, and synaptic remodeling are thought to be involved in the development of epilepsy. To explore whether there is a potential relationship between SLITRK5 and epilepsy, we investigated the expression and distribution of SLITRK5 in patients with temporal lobe epilepsy (TLE) and a rat model of epilepsy. We collected cerebral cortex samples from patients with drug-refractory temporal lobe epilepsy, and a rat model of epilepsy induced by lithium chloride/pilocarpine was established. The ways of immunohistochemistry, double-immunofluorescence labeling and western blot have been used in our study to research the expression and distribution of SLITRK5 in the temporal lobe epilepsy patients and epilepsy animal model. All of the results have shown that SLITRK5 is mainly localized in the cell cytoplasm of neurons both in patients with TLE and in epilepsy model. In addition, compared with nonepileptic controls, the expression of SLITRK5 was upregulated in the temporal neocortex of TLE patients. And both in the temporal neocortex and hippocampus of pilocarpine-induced epilepsy rats, the expression of SLITRK5 was increased at 24 h after status epilepticus (SE), with a relatively high level within 30 days, and reached the peak on the 7th day after SE. Our preliminary results revealed that SLITRK5 may have a potential relationship with epilepsy, which may be a foundation for the further study of the underlying mechanism between SLITRK5 and epilepsy and the therapeutic targets of antiepileptic drugs.

Genome-wide DNA methylation profiling of gastric cardia cancer.

BACKGROUND AND AIM: Aberrant DNA methylation has been found in various cancer types including gastric cancer, yet the genome-wide DNA methylation profile of gastric cardia cancer (GCC) remains unclear. Therefore, we aimed to profile the DNA methylation pattern of GCC and identify promising diagnostic epigenetic biomarkers. METHODS: We investigated the genome-wide DNA methylation pattern in eight pairs of GCC and adjacent normal tissues using Illumina 850K microarrays. Subsequently, bisulfite-pyrosequencing and quantitative real-time PCR were performed on eight pairs of GCC-adjacent normal tissues for validation. Finally, we performed immunohistochemistry to examine ADHFE1 expression on 126 pairs of GCC-adjacent normal samples. RESULTS: DNA methylome analysis showed global hypomethylation and local hypermethylation of promoter cytosine-phosphate-guanine (CpG) islands (CGIs) in GCC tissues compared with gastric cardia normal mucosa (P < 2.2 × 10-16 ). Differential methylation analysis identified a total of 91 723 differentially-methylated probes (DMPs), and the candidate gene with the largest average DNA methylation difference mapped to ADHFE1 (mean Δß = 0.53). Subsequently, three DMPs in the ADHFE1 promoter were validated by pyrosequencing. Notably, the mean methylation level of the three candidate DMPs (ADHFE1_cg08090772, ADHFE1_cg19283840, and ADHFE1_cg20295442) was negatively associated with ADHFE1 mRNA expression level (Spearman rho = -0.64, P = 0.01). Moreover, both mRNA (P = 0.0213) and protein (P < 0.0001) expression of ADHFE1 were significantly decreased in GCCs compared with the adjacent normal tissues. CONCLUSIONS: Our results reveal DNA methylation aberrations in GCC and that ADHFE1 gene DNA methylation contributes to the risk of GCC, thus providing novel mechanistic insights into gastric cardia cancer carcinogenesis.

Estrogen promotes the proliferation and migration of endometrial cancer cells by upregulating the expression of lncRNA HOTAIR.

OBJECTIVE: Estrogen (E2) is the main contributor to the progression of endometrial cancer (EC). The long noncoding RNA HOX antisense intergenic RNA (HOTAIR) is emerging as a new regulator in several cancer types. This study aimed to investigate the role of HOTAIR in EC development and identify the underlying molecular mechanisms. METHODS: HOTAIR expression levels in human EC tissues and the corresponding adjacent tissues and human EC Ishikawa cells were determined by quantitative PCR. Ishikawa cells were treated with E2 or estrogen receptor (ER) inhibitor ICI182780, transfected with siHOTAIR oligo, or infected with lentivirus expressing shHOTAIR/shNC, alone or in combinations. The protein expression of polycomb repressive complex 2 (PRC2) was evaluated by western blotting, and cell migration was measured by transwell assays. A xenograft tumorigenic model was established by inoculating control or stable shHOTAIR-infected Ishikawa cells into nude mice and implanting 17ß-estradiol release pellets. RESULTS: HOTAIR expression was significantly elevated in human EC tissues. E2 exposure markedly increased HOTAIR levels in Ishikawa cells. Notably, E2 increased the protein expression of PRC2 and promoted EC cell migration, which were dependent on HOTAIR expression, as HOTAIR knockdown abolished these effects of E2. Similarly, E2 promoted the in vivo proliferation of grafted Ishikawa cells via upregulated HOTAIR expression in nude mice. CONCLUSIONS: Human EC tissues highly express HOTAIR, and E2-induced EC progression depends on HOTAIR expression. This work suggests that the E2-HOTAIR axis is a potential therapeutic target in EC therapy.

Structures of synthetic nanobody-SARS-CoV-2 receptor-binding domain complexes reveal distinct sites of interaction.

Combating the worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the emergence of new variants demands understanding of the structural basis of the interaction of antibodies with the SARS-CoV-2 receptor-binding domain (RBD). Here, we report five X-ray crystal structures of sybodies (synthetic nanobodies) including those of binary and ternary complexes of Sb16-RBD, Sb45-RBD, Sb14-RBD-Sb68, and Sb45-RBD-Sb68, as well as unliganded Sb16. These structures reveal that Sb14, Sb16, and Sb45 bind the RBD at the angiotensin-converting enzyme 2 interface and that the Sb16 interaction is accompanied by a large conformational adjustment of complementarity-determining region 2. In contrast, Sb68 interacts at the periphery of the SARS-CoV-2 RBD-angiotensin-converting enzyme 2 interface. We also determined cryo-EM structures of Sb45 bound to the SARS-CoV-2 spike protein. Superposition of the X-ray structures of sybodies onto the trimeric spike protein cryo-EM map indicates that some sybodies may bind in both "up" and "down" configurations, but others may not. Differences in sybody recognition of several recently identified RBD variants are explained by these structures.

Therapeutic Inhibition of Acid-Sensing Ion Channel 1a Recovers Heart Function After Ischemia-Reperfusion Injury.

BACKGROUND: Ischemia-reperfusion injury (IRI) is one of the major risk factors implicated in morbidity and mortality associated with cardiovascular disease. During cardiac ischemia, the buildup of acidic metabolites results in decreased intracellular and extracellular pH, which can reach as low as 6.0 to 6.5. The resulting tissue acidosis exacerbates ischemic injury and significantly affects cardiac function. METHODS: We used genetic and pharmacologic methods to investigate the role of acid-sensing ion channel 1a (ASIC1a) in cardiac IRI at the cellular and whole-organ level. Human induced pluripotent stem cell-derived cardiomyocytes as well as ex vivo and in vivo models of IRI were used to test the efficacy of ASIC1a inhibitors as pre- and postconditioning therapeutic agents. RESULTS: Analysis of human complex trait genetics indicates that variants in the ASIC1 genetic locus are significantly associated with cardiac and cerebrovascular ischemic injuries. Using human induced pluripotent stem cell-derived cardiomyocytes in vitro and murine ex vivo heart models, we demonstrate that genetic ablation of ASIC1a improves cardiomyocyte viability after acute IRI. Therapeutic blockade of ASIC1a using specific and potent pharmacologic inhibitors recapitulates this cardioprotective effect. We used an in vivo model of myocardial infarction and 2 models of ex vivo donor heart procurement and storage as clinical models to show that ASIC1a inhibition improves post-IRI cardiac viability. Use of ASIC1a inhibitors as preconditioning or postconditioning agents provided equivalent cardioprotection to benchmark drugs, including the sodium-hydrogen exchange inhibitor zoniporide. At the cellular and whole organ level, we show that acute exposure to ASIC1a inhibitors has no effect on cardiac ion channels regulating baseline electromechanical coupling and physiologic performance. CONCLUSIONS: Our data provide compelling evidence for a novel pharmacologic strategy involving ASIC1a blockade as a cardioprotective therapy to improve the viability of hearts subjected to IRI.

Chaperone-tip adhesin complex is vital for synergistic activation of CFA/I fimbriae biogenesis.

Colonization factor CFA/I defines the major adhesive fimbriae of enterotoxigenic Escherichia coli and mediates bacterial attachment to host intestinal epithelial cells. The CFA/I fimbria consists of a tip-localized minor adhesive subunit, CfaE, and thousands of copies of the major subunit CfaB polymerized into an ordered helical rod. Biosynthesis of CFA/I fimbriae requires the assistance of the periplasmic chaperone CfaA and outer membrane usher CfaC. Although the CfaE subunit is proposed to initiate the assembly of CFA/I fimbriae, how it performs this function remains elusive. Here, we report the establishment of an in vitro assay for CFA/I fimbria assembly and show that stabilized CfaA-CfaB and CfaA-CfaE binary complexes together with CfaC are sufficient to drive fimbria formation. The presence of both CfaA-CfaE and CfaC accelerates fimbria formation, while the absence of either component leads to linearized CfaB polymers in vitro. We further report the crystal structure of the stabilized CfaA-CfaE complex, revealing features unique for biogenesis of Class 5 fimbriae.

Faster Deep Inertial Pose Estimation with Six Inertial Sensors.

We propose a novel pose estimation method that can predict the full-body pose from six inertial sensors worn by the user. This method solves problems encountered in vision, such as occlusion or expensive deployment. We address several complex challenges. First, we use the SRU network structure instead of the bidirectional RNN structure used in previous work to reduce the computational effort of the model without losing its accuracy. Second, our model does not require joint position supervision to achieve the best results of the previous work. Finally, since sensor data tend to be noisy, we use SmoothLoss to reduce the impact of inertial sensors on pose estimation. The faster deep inertial poser model proposed in this paper can perform online inference at 90 FPS on the CPU. We reduce the impact of each error by more than 10% and increased the inference speed by 250% compared to the previous state of the art.

Loss-induced switching between electromagnetically induced transparency and critical coupling in a chalcogenide waveguide.

Optical loss is generally perceived to be an adverse effect in integrated optics. Herein, in contrast, we propose a mechanism to harness the loss in a coupled ${\rm {high-}}{\! Q}$ resonators system to realize on-chip electromagnetically induced transparency (EIT). The increasing loss of one of the coupled resonators results in a difference in ${Q}$ factor, leading to EIT generation. This optical loss-induced EIT is studied analytically using the coupled-mode theory and demonstrated experimentally in chalcogenide coupled microring resonators. By taking advantage of the chalcogenide phase change materials that feature exceptional optical property contrasts, we further demonstrate the loss-induced mechanism to realize fast and nonvolatile responses between the EIT state and the critical coupling state in a monolithically integrated chip. Our results provide a new perspective to harvest the negative loss effect of coupled resonators for tunable photonic devices, which might shed new light on the design ideology for on-chip slow-light optical components.

Crystal structure of bacterial cytochrome bc1 in complex with azoxystrobin reveals a conformational switch of the Rieske iron-sulfur protein subunit.

Cytochrome bc1 complexes (cyt bc1), also known as complex III in mitochondria, are components of the cellular respiratory chain and of the photosynthetic apparatus of non-oxygenic photosynthetic bacteria. They catalyze electron transfer (ET) from ubiquinol to cytochrome c and concomitantly translocate protons across the membrane, contributing to the cross-membrane potential essential for a myriad of cellular activities. This ET-coupled proton translocation reaction requires a gating mechanism that ensures bifurcated electron flow. Here, we report the observation of the Rieske iron-sulfur protein (ISP) in a mobile state, as revealed by the crystal structure of cyt bc1 from the photosynthetic bacterium Rhodobacter sphaeroides in complex with the fungicide azoxystrobin. Unlike cyt bc1 inhibitors stigmatellin and famoxadone that immobilize the ISP, azoxystrobin causes the ISP-ED to separate from the cyt b subunit and to remain in a mobile state. Analysis of anomalous scattering signals from the iron-sulfur cluster of the ISP suggests the existence of a trajectory for electron delivery. This work supports and solidifies the hypothesis that the bimodal conformation switch of the ISP provides a gating mechanism for bifurcated ET, which is essential to the Q-cycle mechanism of cyt bc1 function.

Yellow nutsedge WRI4-like gene improves drought tolerance in Arabidopsis thaliana by promoting cuticular wax biosynthesis.

BACKGROUND: Cuticular wax plays important role in protecting plants from drought stress. In Arabidopsis WRI4 improves drought tolerance by regulating the biosynthesis of fatty acids and cuticular wax. Cyperus esculentus (yellow nutsedge) is a tough weed found in tropical and temperate zones as well as in cooler regions. In the current study, we report the molecular cloning of a WRI4-like gene from Cyperus esculentus and its functional characterization in Arabidopsis. RESULTS: Using RACE PCR, full-length WRI-like gene was amplified from yellow nutsedge. Phylogenetic analyses and amino acid comparison suggested it to be a WRI4-like gene. According to the tissue-specific expression data, the highest expression of WRI4-like gene was found in leaves, followed by roots and tuber. Transgenic Arabidopsis plants expressing nutsedge WRI4-like gene manifested improved drought stress tolerance. Transgenic lines showed significantly reduced stomatal conductance, transpiration rate, chlorophyll leaching, water loss and improved water use efficiency (WUE). In the absence of drought stress, expression of key genes for fatty acid biosynthesis was not significantly different between transgenic lines and WT while that of cuticular wax biosynthesis genes was significantly higher in transgenic lines than WT. The PEG-simulated drought stress significantly increased expression of key genes for fatty acid as well as wax biosynthesis in transgenic Arabidopsis lines but not in WT plants. Consistent with the gene expression data, cuticular wax load and deposition was significantly higher in stem and leaves of transgenic lines compared with WT under control as well as drought stress conditions. CONCLUSIONS: WRI4-like gene from Cyperus esculentus improves drought tolerance in Arabidopsis probably by promoting cuticular wax biosynthesis and deposition. This in turn lowers chlorophyll leaching, stomatal conductance, transpiration rate, water loss and improves water use efficiency under drought stress conditions. Therefore, CeWRI4-like gene could be a good candidate for improving drought tolerance in crops.

Association of TLR3 (rs3775291) and IL-10 (rs1800871) gene polymorphisms with susceptibility to Hepatitis B infection: A meta-analysis.

TLR3 and IL-10 play a crucial role in antiviral defence. However, there is a controversy between TLR3 rs3775291 and IL-10 rs1800871 polymorphisms and the risk of hepatitis B virus (HBV) infection. The purpose of this study is to explore the relationship between the two single nucleotide mutations and the risk of HBV infection by meta-analysis. Medline, EMBASE, Web of Science, CNKI, China Wanfang database were searched for the case-control studies on the relationship between TLR3 rs3775291 and IL-10 rs1800871 polymorphism and susceptibility to HBV, updated to June 2020. The data were analysed by Stata 15.0 software. A total of 22 articles were included. The results showed that in the analysis of IL10 rs1800871 polymorphism and the risk of HBV infection, the pooled OR was 1.21 (95% CI 1.06-1.37), 1.28 (95% CI 1.04-1.56) and 1.20 (95% CI 1.06-1.37) and 1.40 (95% CI 1.07-1.83) in the allele model (C vs. T), dominant model (CC+CT vs. TT), recessive model (CC vs. CT+TT) and homozygous model (CC vs. TT), respectively. There was no statistical significance in the heterozygote model. A subgroup analysis of the Asian population showed similar results. The analysis of TLR3 rs3775291 polymorphism and the risk of HBV showed that in the allele model (T vs. C), the pooled OR was 1.30 (95% CI 1.05-1.61). Except for the recessive model, no significances were found in other genetic models. In conclusion, TLR3 rs3775291 and IL-10 rs1800871 polymorphisms are associated with the risk of HBV. Allele C and genotype CC at IL10 rs1800871 loci, as well as allele T and genotype TT at TLR rs3775291 loci, may increase susceptibility to Hepatitis B infection.