31 research outputs found
Dependence of resting-state-based cerebrovascular reactivity (CVR) mapping on spatial resolution
Cerebrovascular reactivity (CVR) is typically assessed with a carbon dioxide (CO2) stimulus combined with BOLD fMRI. Recently, resting-state (RS) BOLD fMRI has been shown capable of generating CVR maps, providing a potential for broader CVR applications in neuroimaging studies. However, prior RS-CVR studies have primarily been performed at a spatial resolution of 3–4 mm voxel sizes. It remains unknown whether RS-CVR can also be obtained at high-resolution without major degradation in image quality. In this study, we investigated RS-CVR mapping based on resting-state BOLD MRI across a range of spatial resolutions in a group of healthy subjects, in an effort to examine the feasibility of RS-CVR measurement at high resolution. Comparing the results of RS-CVR with the maps obtained by the conventional CO2-inhalation method, our results suggested that good CVR map quality can be obtained at a voxel size as small as 2 mm isotropic. Our results also showed that, RS-CVR maps revealed resolution-dependent sensitivity. However, even at a high resolution of 2 mm isotropic voxel size, the voxel-wise sensitivity is still greater than that of typical task-evoked fMRI. Scan duration affected the sensitivity of RS-CVR mapping, but had no significant effect on its accuracy. These findings suggest that RS-CVR mapping can be applied at a similar resolution as state-of-the-art fMRI studies, which will broaden the use of CVR mapping in basic science and clinical applications including retrospective analysis of previously collected fMRI data
Translationally controlled tumor protein, a dual functional protein involved in the immune response of the silkworm, Bombyx mori.
Insect gut immunity is the first line of defense against oral infection. Although a few immune-related molecules in insect intestine has been identified by genomics or proteomics approach with comparison to well-studied tissues, such as hemolymph or fat body, our knowledge about the molecular mechanism underlying the gut immunity which would involve a variety of unidentified molecules is still limited. To uncover additional molecules that might take part in pathogen recognition, signal transduction or immune regulation in insect intestine, a T7 phage display cDNA library of the silkworm midgut is constructed. By use of different ligands for biopanning, Translationally Controlled Tumor Protein (TCTP) has been selected. BmTCTP is produced in intestinal epithelial cells and released into the gut lumen. The protein level of BmTCTP increases at the early time points during oral microbial infection and declines afterwards. In vitro binding assay confirms its activity as a multi-ligand binding molecule and it can further function as an opsonin that promotes the phagocytosis of microorganisms. Moreover, it can induce the production of anti-microbial peptide via a signaling pathway in which ERK is required and a dynamic tyrosine phosphorylation of certain cytoplasmic membrane protein. Taken together, our results characterize BmTCTP as a dual-functional protein involved in both the cellular and the humoral immune response of the silkworm, Bombyx mori
Evaluation of Synergetic Development of Water and Land Resources Based on a Coupling Coordination Degree Model
The interaction between water and land resources (WALRs) has been further enhanced with the development of human production activities. Evaluating the synergetic development (SD) level of WALRs is conducive to discovering the weakness of comprehensive utilization of resources and promoting sustainable development. However, previous studies did not clearly elucidate the effects of the synergetic development between WALRs (SD-WALRs). For evaluation methods, the impact of various subsystem development levels on the whole system is often ignored due to its unclear definition. Therefore, in this research, the concept of the SD-WALRs was defined based on synergetic theory. By using the “Driving Force–Pressure–State–Impact–Response” (DPSIR) model, comprehensive evaluation index systems of WALR development were established. The index systems were regarded as efficacy functions of the coupling coordination degree (CCD) model, and the evaluation model of the SD-WALR level was constructed based on it. Taking Luoyang City as an example, using the latest 10 years (2010–2019) with available data as the study period, the results showed that the value of the SD degree increased from 0.609 to 0.789 during the study period, which reached the level of intermediate synergetic development. In general, the development of WALRs showed a positive trend from “high coupling but low synergetic development” to “high synergetic development”
Correction: Yang et al. A Kinesin Vdkin2 Required for Vacuole Formation, Mycelium Growth, and Penetration Structure Formation of Verticillium dahliae. J. Fungi 2022, 8, 391
In the original publication [...
A Kinesin Vdkin2 Required for Vacuole Formation, Mycelium Growth, and Penetration Structure Formation of <em>Verticillium dahliae</em>
The soil-borne vascular fungus Verticillium dahliae infects hundreds of dicotyledonous plants, causing severe wilt diseases. During the initial colonization, V. dahliae develops a penetration peg to enable infection of cotton roots. In some phytopathogenic fungi, vacuoles play a critical role in normal formation of the infection structure. Kinesin 2 protein is associated with vacuole formation in Ustilago maydis. To identify the function of vacuoles in the V. dahliae infection structure, we identified VdKin2, an ortholog of kinesin 2, in V. dahliae and investigated its function through gene knockout. VdKin2 mutants showed severe defects in virulence and were suppressed during initial infection and root colonization based on observation of green fluorescent protein-labeled V. dahliae. We also found that deletion of VdKin2 compromised penetration peg formation and the derived septin neck. Disruption strains were viable and showed normal microsclerotia formation, whereas mycelium growth and conidial production were reduced, with shorter and more branched hyphae. Furthermore, the VdKin2 mutant, unlike wild-type V. dahliae, lacked a large basal vacuole, accompanied by a failure to generate concentrated lipid droplets. Taken together, VdKin2 regulates vacuole formation by V. dahliae, which is required for conidiation, mycelium growth, and penetration structure formation during initial plant root infection
Induction of anti-microbial peptides mRNA expression and activation of ERK signaling by BmTCTP.
<p>qRT-PCR analysis of the mRNA levels of <i>CecropinA1</i> and <i>Attacin</i> (A), <i>Tube</i>, <i>Pelle</i>, <i>FADD</i> and <i>Dredd</i> (B) in BmNs cells under BmTCTP or BSA treatment. In the presence of MEK inhibitor U0126 or PD098059, the mRNA levels of <i>CecropinA1</i> and <i>Attacin</i> after BmTCTP treatment were examined at different time points (C) or at different concentrations of inhibitors (D) by qRT-PCR. E. qRT-PCR analysis of the mRNA levels of <i>ERK</i>, <i>CecropinA1</i> and <i>Attacin</i> under BmTCTP treatment at indicated time points in dsRNA-transfected cells. F. ERK phosphorylation was examined at indicated time points after BmTCTP treatment, the phosphorylation intensity was normalized to the protein level of Tubulin and annotated as mean fold increase (± S.D.) over the normalized phosphorylation intensity at the 0 min. G. Membrane protein extracted from BmNs cells under BmTCTP treatment at indicated time points was immunoblotted with anti-phosphotyrosine antibody 4G10. The mRNA levels of all target molecules measured by qRT-PCR were normalized to the internal control and represented as mean ± S.D.</p
Partial list of in-frame hits identified from the silkworm midgut using phage display.
<p>Translationally Controlled Tumor Protein in bold. LPS, Lipopolysaccharide; Bb, <i>Bacillus bombyseptieus</i>; Sm, <i>Serratia marcescens</i>. âś“ indicates the protein was recovered in the biopans when corresponding bait was used.</p
BmTCTP-mediated phagocytosis by silkworm hemoctyes.
<p>Internalized red fluorescence-labeled latex beads (A) and FITC-labeled bacteria (B, C) pre-coated by BmTCTP or BSA in hemocytes which were stained with DAPI for nucleus in blue or DiO for cytoplasmic membrane in green (A) were subjected to analysis by fluorescence microscopy. Experiment was repeated three times and representative image were shown here. The percentage of engulfed targets was obtained by multiplying the % of phagocytosing cells with the mean number of internalized beads/bacteria. Each histogram corresponds to the mean value of samples from 5–8 larvae (± S.D.). Significant differences between BmTCTP and BSA treatment are marked by asterisks (*<i>p</i><0.05, **<i>p</i><0.01).</p
Expression and localization of BmTCTP in the silkworm midgut.
<p>A. The existence of BmTCTP in midgut lumen, peritrophic membrane, gut juice and hemolymph of the silkworm was analyzed by Western blotting. Equal amount of protein (20 µg) extracted from each tissue was subjected to SDS-PAGE analysis followed with immunoblotting analysis. B. The expression of BmTCTP in midgut epithelial cells was analyzed by immunohistochemistry. The nucleus was stained with DAPI, and BmTCTP was stained with anti-BmTCTP polyclonal antibody followed with FITC-conjugated secondary antibody, rabbit pre-immune serum was used as negative control. Gu, gut lumen; Ep, epithelia. C. The expression level of BmTCTP in midgut lumen after oral infection of <i>B. bombyseptieus</i> or <i>S. marcescens</i> at indicated time point was examined by Western blotting, then normalized to the amount of BmTCTP level at 0 h and annotated as mean fold increase (± S.D.). Experiment was repeated three times and representative images were shown here.</p
X-Band GaN Power HEMTs with Power Density of 2.23W/mm Grown on Sapphire by MOCVD
The growth,fabrication,and characterization of 0.2μm gate-length AlGaN/GaN HEMTs,with a high mobility GaN thin layer as a channel,grown on (0001) sapphire substrates by MOCVD,are described.The unintentionally doped 2.5μm thick GaN epilayers grown with the same conditions as the GaN channel have a room temperature electron mobility of 741cm2/(V·s) at an electron concentration of 1.52×1016 cm-3.The resistivity of the thick GaN buffer layer is greater than 108Ω·cm at room temperature.The 50mm HEMT wafers grown on sapphire substrates show an average sheet resistance of 440.9Ω/□ with uniformity better than 96%.Devices of 0.2μm×40μm gate periphery exhibit a maximum extrinsic transconductance of 250mS/mm and a current gain cutoff frequency of77GHz.The AlGaN/GaN HEMTs with 0.8mm gate width display a total output power of 1.78W (2.23W/mm) and a linear gain of 13.3dB at 8GHz.The power devices also show a saturated current density as high as 1.07A/mm at a gate bias of 0.5V