301 research outputs found

    First complete mitochondrial genome of the tribe Coccini (Hemiptera, Coccomorpha, Coccidae) and its phylogenetic implications

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    Soft scale insects (Hemiptera, Coccidae) are important pests of various agricultural and horticultural crops and ornamental plants. They have negative impacts on agriculture and forestry. The tribe Coccini represents one of the most ancient evolutionary lineages of soft scale insects. However, no complete Coccini mitochondrial genome (mitogenome) is available in public databases. Here, we described the complete mitogenome of Coccus hesperidum L., 1758. The 15,566 bp mitogenome of C. hesperidum had a high A+T content (83.4%) and contained a typical set of 37 genes, with 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs) and two ribosomal RNA genes (rRNAs). Only seven tRNAs had the typical clover-leaf secondary structure and the remaining tRNAs lacked the DHU arm, TψC arm or both. Moreover, a comparative analysis of all reported scale insect mitogenomes from GenBank database was performed. The mitogenomes of scale insects showed high similarities in base composition and A+T content. Additionally, our phylogenetic analysis confirmed the monophyly of Coccomorpha and revealed that the archaeococcoids were the most basal lineage within Coccomorpha, while Ericerus pela and Didesmococcus koreanus, belonging to Coccidae, were often mixed with Aclerdidae, making Coccidae a paraphyletic group. These findings expand the mitogenome database of scale insects and provide new insights on mitogenome evolution for future studies across different insect groups

    Nanotube ferroelectric tunnel junctions with giant tunneling electroresistance ratio

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    Low-dimensional ferroelectric tunnel junctions are appealing for the realization of nanoscale nonvolatile memory devices due to their inherent advantage of device miniaturization. Those based on current mechanisms still have restrictions including low tunneling electroresistance (TER) effects and complex heterostructures. Here, we introduce an entirely new TER mechanism to construct the nanotube ferroelectric tunnel junction with ferroelectric nanotubes as the tunneling region. When rolling a ferroelectric monolayer into a nanotube, due to the coexistence of its intrinsic ferroelectric polarization with the flexoelectric polarization induced by bending, there occurs metal-insulator transition depending on radiative polarization states. For the pristine monolayer, its out-of-plane polarization is tunable by an in-plane electric field, the conducting states of the ferroelectric nanotube can thus be tuned between metallic and insulating via axial electric means. Using {\alpha}-In2Se3 as an example, our first-principles density functional theory calculations and nonequilibrium Green's function formalism confirm the feasibility of the TER mechanism and indicate an ultrahigh TER ratio exceeding 9.9*10^10% of the proposed nanotube ferroelectric tunnel junctions. Our findings provide a promising approach based on simple homogeneous structures for high density ferroelectric microelectronic devices with excellent ON/OFF performance.Comment: 15 pages, 5 figure

    Development and characterization of a core set of SSR markers for fingerprinting analysis of Chinese maize varieties

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    A core set of 60 SSRs was selected and modified using 231 Chinese and USA maize (Zea mays L.) inbred lines from more than 2000 SSRs for DNA fingerprinting analysis. All 60 SSR markers met the following criteria: (1) amplification of a single locus; (2) distinct amplification products; (3) adequate intervals between adjacent alleles; (4) suitable PCR fragment size; (5) reasonable discrimination power (DP); and (6) even distribution across the maize genome. Furthermore, the 60 SSR primers were re-designed to adjust the PCR product size. Together with the application of four different fluorescent dyes, a high-throughput 10-plex capillary electrophoresis platform was explored. The 60 core SSR markers were further divided into three groups (20 SSRs per group) according to peak morphology and DP value. Groups I, II and III were used in DNA fingerprinting analysis as a basic core, an expanded core and a candidate core set respectively. The allele number per locus varied from three to 22 with an average of 8.95; the average number of alleles per group I, II and III was a respective 7.35, 7.8 and 11.4. The DP values ranged from 0.366 to 0.913, with an average of 0.718 among all loci; the average group DP values were 0.697, 0.718 and 0.737 for groups I, II and III respectively; and the cumulative values of discrimination power (CDP) approached 1 for all groups. Cluster analysis results using 60 selected loci divided the Chinese inbred lines into six groups, including Luda Red Cob, P, Improved Reid, Tang-si-ping-tou, Waxy and Lancaster. The USA inbred lines were segregated into four groups, including SSS, Lancaster, Iodent and Oh43/Oh07Mid mixed

    A Classification Method Based on Principal Components of SELDI Spectra to Diagnose of Lung Adenocarcinoma

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    Lung cancer is the leading cause of cancer death worldwide, but techniques for effective early diagnosis are still lacking. Proteomics technology has been applied extensively to the study of the proteins involved in carcinogenesis. In this paper, a classification method was developed based on principal components of surface-enhanced laser desorption/ionization (SELDI) spectral data. This method was applied to SELDI spectral data from 71 lung adenocarcinoma patients and 24 healthy individuals. Unlike other peak-selection-based methods, this method takes each spectrum as a unity. The aim of this paper was to demonstrate that this unity-based classification method is more robust and powerful as a method of diagnosis than peak-selection-based methods.The results showed that this classification method, which is based on principal components, has outstanding performance with respect to distinguishing lung adenocarcinoma patients from normal individuals. Through leaving-one-out, 19-fold, 5-fold and 2-fold cross-validation studies, we found that this classification method based on principal components completely outperforms peak-selection-based methods, such as decision tree, classification and regression tree, support vector machine, and linear discriminant analysis.The classification method based on principal components of SELDI spectral data is a robust and powerful means of diagnosing lung adenocarcinoma. We assert that the high efficiency of this classification method renders it feasible for large-scale clinical use

    Cardiac manifestations in a Chinese cohort of fetuses from mothers with anti-Ro and anti-La antibodies

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    ObjectivesTo analyze the clinical characteristics, echocardiographic features, and prognosis of fetuses based on three groups of cardiac manifestations associated with maternal anti-Ro and anti-La antibodies in China. This study included three groups: the isolated-arrhythmia, isolated-endocardial fibroelastosis (EFE), and mixed groups.MethodsWe prospectively evaluated 36 fetuses with cardiac manifestations due to maternal anti-Ro and anti-La antibodies from our center between 2016 and 2020 in China. Clinical and echocardiographic data were collected.ResultsThere were 13 patients (36%) in the isolated-arrhythmia group, eight (22%) in the isolated-EFE group, and 15 (42%) in the mixed group. All patients in the isolated-EFE group presented with mild EFE. Severe EFE was identified in four patients (27%) in the mixed group. Atrioventricular block (AVB) was more common in the isolated-arrhythmia group (13, 100%) than in the mixed group (6, 40%; p = 0.001). Moderate-severe mitral regurgitation (p = 0.006), dilated cardiomyopathy (DCM, p = 0.017), and low cardiovascular profile scores (p = 0.013) were more common in the mixed group than in the other two groups. Twenty-one mothers decided to terminate the pregnancy and 15 fetuses were born with regular perinatal treatment. They all survived at 1 year of age. One patient in the isolated-arrhythmia group and two in the mixed group required a pacemaker due to third-degree AVB or atrioventricular junctional rhythm. Five patients in the isolated-EFE group and five in the mixed group had no DCM or heart failure and the location of mild EFE was significantly reduced.ConclusionFetal cardiac manifestations due to maternal anti-Ro and anti-La antibodies can be divided into three groups, i.e., the isolated-arrhythmia, isolated-EFE, and mixed groups. AVB usually occurs in the isolated-arrhythmia group. Severe EFE, moderate-severe mitral regurgitation, and DCM mainly appear in the mixed group. Location of mild EFE significantly reduces after birth and the outcome of fetuses with mild EFE depends on the presence of arrhythmia and its subtypes

    Effects of Astragalus Polysaccharide on Immune Responses of Porcine PBMC Stimulated with PRRSV or CSFV

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    BACKGROUND: Astragalus polysaccharide (APS) has been used as an immunomodulator that can enhance immune responses, whereas the immunomodulatory effects of APS on porcine peripheral blood mononuclear cells (PBMCs) exposed to porcine reproductive and respiratory syndrome virus (PRRSV) and classical swine fever virus (CSFV) have not been investigated. METHODOLOGY/PRINCIPAL FINDINGS: Porcine PBMCs were cultured in complete RPMI media in the presence of the R98-strain of PRRSV (5×10(4) TCID(50)/ml) or C-strain of CSFV (10(3) TCID(50)/ml) with or without APS. The expression of mRNA for CD28, cytotoxic T-lymphocyte antigen 4 (CTLA-4), transforming growth factor-β (TGF-β), interleukin 2 (IL-2) and IL-10 was assayed by TaqMan real-time RT-PCR. The expression of mRNA for CD28 and CTLA-4 increased at 24 h after stimulation of PBMCs with CSFV and the increased production of CTLA-4 was confirmed by western blot analysis, whereas the increases were inhibited by the addition of APS. In addition, APS alone upregulated IL-2 and TGF-β mRNA expression in PBMCs and the addition of APS had the capacity to prevent a further increase in IL-2 mRNA expression in PBMCs during CSFV or PRRSV infection, but had no effect on TGF-β mRNA expression. The production of tumor necrosis factor-alpha (TNF-α) increased at 12 h after stimulation with PRRSV or CSFV, but not with PRRSV plus APS or CSFV plus APS, whereas the addition of APS to PBMCs infected with PRRSV or CSFV promoted IL-10 mRNA expression. CONCLUSIONS: We suggested that APS had immunomodulatory effects on cells exposed to PRRSV or CSFV. It might be that APS via different mechanisms affects the activities of immune cells during either PRRSV or CSFV infection. This possibility warrants further studies to evaluate whether APS would be an effective adjuvant in vaccines against PRRSV or CSFV

    The violent youth of bright and massive cluster galaxies and their maturation over 7 billion years

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    In this study, we investigate the formation and evolution mechanisms of the brightest cluster galaxies (BCGs) over cosmic time. At high redshift (z ∼ 0.9), we selected BCGs and most massive cluster galaxies (MMCGs) from the Cl1604 supercluster and compared them to low-redshift (z ∼ 0.1) counterparts drawn from the MCXC meta-catalogue, supplemented by Sloan Digital Sky Survey imaging and spectroscopy. We observed striking differences in the morphological, colour, spectral, and stellar mass properties of the BCGs/MMCGs in the two samples. High-redshift BCGs/MMCGs were, in many cases, star-forming, late-type galaxies, with blue broad-band colours, properties largely absent amongst the low-redshift BCGs/MMCGs. The stellar mass of BCGs was found to increase by an average factor of 2.51 ± 0.71 from z ∼ 0.9 to z ∼ 0.1. Through this and other comparisons, we conclude that a combination of major merging (mainly wet or mixed) and in situ star formation are the main mechanisms which build stellar mass in BCGs/MMCGs. The stellar mass growth of the BCGs/MMCGs also appears to grow in lockstep with both the stellar baryonic and total mass of the cluster. Additionally, BCGs/MMCGs were found to grow in size, on average, a factor of ∼3, while their average Sérsic index increased by ∼0.45 from z ∼ 0.9 to z ∼ 0.1, also supporting a scenario involving major merging, though some adiabatic expansion is required. These observational results are compared to both models and simulations to further explore the implications on processes which shape and evolve BCGs/MMCGs over the past ∼7 Gyr
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