368 research outputs found

    The Toxoplasma gondii Cyst Wall Protein CST1 Is Critical for Cyst Wall Integrity and Promotes Bradyzoite Persistence

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    Toxoplasma gondii infects up to one third of the world\u27s population. A key to the success of T. gondii as a parasite is its ability to persist for the life of its host as bradyzoites within tissue cysts. The glycosylated cyst wall is the key structural feature that facilitates persistence and oral transmission of this parasite. Because most of the antibodies and reagents that recognize the cyst wall recognize carbohydrates, identification of the components of the cyst wall has been technically challenging. We have identified CST1 (TGME49_064660) as a 250 kDa SRS (SAG1 related sequence) domain protein with a large mucin-like domain. CST1 is responsible for the Dolichos biflorus Agglutinin (DBA) lectin binding characteristic of T. gondii cysts. Deletion of CST1 results in reduced cyst number and a fragile brain cyst phenotype characterized by a thinning and disruption of the underlying region of the cyst wall. These defects are reversed by complementation of CST1. Additional complementation experiments demonstrate that the CST1-mucin domain is necessary for the formation of a normal cyst wall structure, the ability of the cyst to resist mechanical stress, and binding of DBA to the cyst wall. RNA-seq transcriptome analysis demonstrated dysregulation of bradyzoite genes within the various cst1 mutants. These results indicate that CST1 functions as a key structural component that confers essential sturdiness to the T. gondii tissue cyst critical for persistence of bradyzoite forms

    Polysulfide Catalytic Materials for Fast-Kinetic Metal–Sulfur Batteries: Principles and Active Centers

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    Benefiting from the merits of low cost, ultrahigh-energy densities, and environmentally friendliness, metal–sulfur batteries (M–S batteries) have drawn massive attention recently. However, their practical utilization is impeded by the shuttle effect and slow redox process of polysulfide. To solve these problems, enormous creative approaches have been employed to engineer new electrocatalytic materials to relieve the shuttle effect and promote the catalytic kinetics of polysulfides. In this review, recent advances on designing principles and active centers for polysulfide catalytic materials are systematically summarized. At first, the currently reported chemistries and mechanisms for the catalytic conversion of polysulfides are presented in detail. Subsequently, the rational design of polysulfide catalytic materials from catalytic polymers and frameworks to active sites loaded carbons for polysulfide catalysis to accelerate the reaction kinetics is comprehensively discussed. Current breakthroughs are highlighted and directions to guide future primary challenges, perspectives, and innovations are identified. Computational methods serve an ever-increasing part in pushing forward the active center design. In summary, a cutting-edge understanding to engineer different polysulfide catalysts is provided, and both experimental and theoretical guidance for optimizing future M–S batteries and many related battery systems are offered

    Alcohol Consumption and Ankle-to-Brachial Index: Results from the Cardiovascular Risk Survey

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    BACKGROUND AND METHODOLOGY: A low ankle-to-brachial index (ABI) is a strong correlate of cardiovascular disease and subsequent mortality. The relationship between ABI and alcohol consumption remains unclear. Data are from the Cardiovascular Risk Survey (CRS), a multiple-ethnic, community-based, cross-sectional study of 14,618 Chinese people (5757 Hans, 4767 Uygurs, and 4094 Kazakhs) aged 35 years and over at baseline from Oct. 2007 to March 2010. The relationship between alcohol intake and ABI was determined by use of analysis of covariance and multivariable regressions. PRINCIPAL FINDINGS: In men, alcohol consumption was significantly associated with ABI (P<0.001). After adjusted for the confounding factors, such as age, sex, ethnicity, body mass index, smoking, work stress, diabetes, and fasting blood glucose, the difference remained significant (P<0.001); either the unadjusted or multivariate-adjusted odds ratio (OR) for peripheral artery disease (PAD) was significantly higher in men who consumed >60.0 g/d [OR = 3.857, (95% CI: 2.555-5.824); OR = 2.797, (95% CI: 1.106-3.129); OR = 2.878, (95% CI: 1.215-4.018); respectively] and was significantly lower in men who consumed 20.1-40.0 g/d [OR= 0.330, (95% CI: 0.181-0.599); OR = 0.484, (95% CI: 0.065-0.894); OR = 0.478, (95% CI: 0.243-1.534); respectively] and 40.1-60.0 g/d [OR= 0.306, (95% CI: 0.096-0.969); OR = 0.267, (95% CI: 0.087-0.886); OR = 0.203, (95% CI: 0.113-0.754); respectively] compared with never drinking, respectively (all P<0.01). Neither in unadjusted nor in multivariate-adjusted model was the association between ABI and alcohol consumption significant (all P>0.05) in women. Similarly, PAD was not correlated with alcohol intake in women (all P>0.05). CONCLUSIONS/SIGNIFICANCE: Our results indicated that in Chinese men, alcohol consumption was associated with peripheral artery disease, and consumption of less than 60 g/d had an inverse association with peripheral atherosclerosis whereas consumption of 60 g/d or more had a positive association

    Gibberellin A4 monohydrate

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    The title compond, C19H24O5·H2O, has two gibberellin A4 mol­ecules and two water mol­ecules in the asymmetric unit. The A and B rings have chair conformations, whereas the C and D rings have envelope conformations; the two rings which contain the lactone and carbonyl bridge adopt chair and envelope conformations. The crystal structure is established by O—H⋯O hydrogen bonds and supported by C—H⋯O hydrogen bonds

    Subacute Combined Degeneration, Pernicious Anemia and Gastric Neuroendocrine Tumor Occured Simultaneously Caused by Autoimmune Gastritis

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    Subacute combined degeneration (SCD) is a relatively rare myelopathy mainly caused by vitamin B12 (VitB12) deficiency. There are many causes contributing to VitB12 deficiency. Autoimmune gastritis might lead to severe VitB12 malabsorption and in its advanced stage pernicious anemia (PA) may occur. Besides, long-term hypergastrinemia arising from achlorhydria in autoimmune gastritis is associated with neuroendocrine tumors (NETs). Patients diagnosed with SCD coexistent with PA and NET are seldomly reported. We describe a 34-year-old woman with an initial complaint of progressive fatigue, weakness and numbness in her limbs and disturbed gait. Physical examination revealed appearance of anemia, ataxia, decrease of superficial and deep sense, and positive Babinski’s sign. Laboratory tests disclosed macrocytic anemia, elevated intrinsic factor antibody and spinal MRI showed extensive T2-weighted hyperintensity in the dorsal columns. A gastric polyp was revealed by gastroscopy and histology showed an NET in the background of severe atrophic gastritis. Symptoms of the patient were relieved by a multidisciplinary therapy. In patients with SCD, PA should be suspected and prompt further investigations to elucidate causes and direct treatment

    Polysulfide Catalytic Materials for Fast‐Kinetic Metal–Sulfur Batteries: Principles and Active Centers

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    Benefiting from the merits of low cost, ultrahigh‐energy densities, and environmentally friendliness, metal–sulfur batteries (M–S batteries) have drawn massive attention recently. However, their practical utilization is impeded by the shuttle effect and slow redox process of polysulfide. To solve these problems, enormous creative approaches have been employed to engineer new electrocatalytic materials to relieve the shuttle effect and promote the catalytic kinetics of polysulfides. In this review, recent advances on designing principles and active centers for polysulfide catalytic materials are systematically summarized. At first, the currently reported chemistries and mechanisms for the catalytic conversion of polysulfides are presented in detail. Subsequently, the rational design of polysulfide catalytic materials from catalytic polymers and frameworks to active sites loaded carbons for polysulfide catalysis to accelerate the reaction kinetics is comprehensively discussed. Current breakthroughs are highlighted and directions to guide future primary challenges, perspectives, and innovations are identified. Computational methods serve an ever‐increasing part in pushing forward the active center design. In summary, a cutting‐edge understanding to engineer different polysulfide catalysts is provided, and both experimental and theoretical guidance for optimizing future M–S batteries and many related battery systems are offered.DFG, 449814841, Organisch-Polyoxometallat-Co-Kristall-abgeleitete mesoporöse Metallcarbide/-nitride für die Wasserstofferzeugung aus Meerwasse

    Neuropeptide Y-mediated sex- and afferent-specific neurotransmissions contribute to sexual dimorphism of baroreflex afferent function

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    BACKGROUND: Molecular and cellular mechanisms of neuropeptide-Y (NPY)-mediated gender-difference in blood pressure (BP) regulation are largely unknown. METHODS: Baroreceptor sensitivity (BRS) was evaluated by measuring the response of BP to phenylephrine/nitroprusside. Serum NPY concentration was determined using ELISA. The mRNA and protein expression of NPY receptors were assessed in tissue and single-cell by RT-PCR, immunoblot, and immunohistochemistry. NPY was injected into the nodose while arterial pressure was monitored. Electrophysiological recordings were performed on nodose neurons from rats by patch-clamp technique. RESULTS: The BRS was higher in female than male and ovariectomized rats, while serum NPY concentration was similar among groups. The sex-difference was detected in Y1R, not Y2R protein expression, however, both were upregulated upon ovariectomy and canceled by estrogen replacement. Immunostaining confirmed Y1R and Y2R expression in myelinated and unmyelinated afferents. Single-cell PCR demonstrated that Y1R expression/distribution was identical between A- and C-types, whereas, expressed level of Y2R was ~15 and ~7 folds higher in Ah- and C-types than A-types despite similar distribution. Activation of Y1R in nodose elevated BP, while activation of Y2R did the opposite. Activation of Y1R did not alter action potential duration (APD) of A-types, but activation of Y2R- and Y1R/Y2R in Ah- and C-types frequency-dependently prolonged APD. N-type ICa was reduced in A-, Ah- and C-types when either Y1R, Y2R, or both were activated. The sex-difference in Y1R expression was also observed in NTS. CONCLUSIONS: Sex- and afferent-specific expression of Neuropeptide-Y receptors in baroreflex afferent pathway may contribute to sexual-dimorphic neurocontrol of BP regulation

    Ultrasound measurement of vastus lateralis and vastus medialis muscle parameters to identify chronic thyrotoxic myopathy

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    Introduction: Chronic thyrotoxic myopathy (CTM) is a common, easily neglected complication of hyperthyroidism. There are currently no standard diagnostic criteria for CTM, and the ultrasonic characteristics of CTM-affected skeletal muscle remain unclear. Herein, we aimed to evaluate hyperthyroid patients for CTM by ultrasound and identify ultrasonic muscle parameter cutoffs for CTM diagnosis. Materials and methods: Each participant underwent ultrasonography. The original (muscle thickness (MT), pennation angle (PA), and cross-sectional area (CSA)) and corrected (MT/height (HT), MT/body mass index (BMI), CSA/HT, and CSA/BMI) parameters of the vastus lateralis and vastus medialis (VM) were evaluated. The diagnostic effectiveness of ultrasound for predicting CTM was determined using receiver operating characteristic (ROC) curve analysis. Our study included 203 participants: 67 CTM patients (18 males, 49 females), 67 non-CTM patients (28 males, 39 females) and 69 healthy controls (20 males, 49 females). Results: The CTM group had lower muscular ultrasonic and anthropometric parameters, higher thyroid hormone and thyroid-stimulating hormone receptor antibody (TRAb) levels, and a longer duration of hyperthyroidism than the non-CTM group (P < 0.05). The VM-PA, VM-CSA, VM-CSA/HT, and VM-CSA/BMI were lower in females than in males (P < 0.05). Free thyroxine (FT4) and TRAb both showed significant negative correlations with VM-MT, VM-MT/HT, VM-CSA, and VM-CSA/HT (P < 0.05). VM-MT/BMI and VM-CSA/HT, respectively, best predicted male and female CTM (AUC = 0.84, 0.85; cutoff ≤ 0.07, < 4.01). Conclusion: Ultrasound measurement of muscular parameters, especially in the VM, is a valid and feasible way of diagnosing and characterizing possible CTM in hyperthyroidism
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