669 research outputs found
Design, Synthesis, and In vitro Antitumor Activity Evaluation of Novel 4‐pyrrylamino Quinazoline Derivatives
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88050/1/j.1747-0285.2011.01234.x.pd
Generating axial magnetic fields via two plasmon decay driven by a twisted laser
We propose a new way of axial magnetic fields generation in a
non-relativistic laser intensity regime by using a twisted light carrying
orbital angular momentum (OAM) to stimulate two-plasmon decay (TPD) in a
plasma. The growth of TPD driven by an OAM light in a Laguerre-Gauss (LG) mode
is investigated through three dimensional fluid simulations and theory. A
theory based on the assumption that the electron plasma waves (EPWs) are
locally driven by a number of local plane-wave lasers predicts the maximum
growth rate proportional to the peak amplitude of the pump laser field and is
verified by the simulations. The OAM conservation during its transportation
from the laser to the TPD daughter EWPs is shown by both the theory and the
simulations. The theory predicts generation of ~40T axial magnetic fields
through the OAM absorption via TPD, which has perspective applications in the
field of high energy density physics.Comment: 6 pages, 3 figures
Inhibition of TRF2 Accelerates Telomere Attrition and DNA Damage in Naïve CD4 T Cells During HCV Infection
T cells play a crucial role in viral clearance and vaccine responses; however, the mechanisms that regulate their homeostasis during viral infections remain unclear. In this study, we investigated the machineries of T-cell homeostasis and telomeric DNA damage using a human model of hepatitis C virus (HCV) infection. We found that naïve CD4 T cells in chronically HCV-infected patients (HCV T cells) were significantly reduced due to apoptosis compared with age-matched healthy subjects (HSs). These HCV T cells were not only senescent, as demonstrated by overexpression of aging markers and particularly shortened telomeres; but also DNA damaged, as evidenced by increased dysfunctional telomere-induced foci (TIF). Mechanistically, the telomere shelterin protein, in particular telomeric repeat binding factor 2 (TRF2) that functions to protect telomeres from DNA damage, was significantly inhibited posttranscriptionally via the p53-dependent Siah-1a ubiquitination. Importantly, knockdown of TRF2 in healthy T cells resulted in increases in telomeric DNA damage and T-cell apoptosis, whereas overexpression of TRF2 in HCV T cells alleviated telomeric DNA damage and T-cell apoptosis. To the best of our knowledge, this is the first report revealing that inhibition of TRF2 promotes T-cell telomere attrition and telomeric DNA damage that accelerates T-cell senescent and apoptotic programs, which contribute to naïve T-cell loss during viral infection. Thus, restoring the impaired T-cell telomeric shelterin machinery may offer a new strategy to improve immunotherapy and vaccine response against human viral diseases
Genetic map of Triticum turgidum based on a hexaploid wheat population without genetic recombination for D genome
BACKGROUND: A synthetic doubled-haploid hexaploid wheat population, SynDH1, derived from the spontaneous chromosome doubling of triploid F(1) hybrid plants obtained from the cross of hybrids Triticum turgidum ssp. durum line Langdon (LDN) and ssp. turgidum line AS313, with Aegilops tauschii ssp. tauschii accession AS60, was previously constructed. SynDH1 is a tetraploidization-hexaploid doubled haploid (DH) population because it contains recombinant A and B chromosomes from two different T. turgidum genotypes, while all the D chromosomes from Ae. tauschii are homogenous across the whole population. This paper reports the construction of a genetic map using this population. RESULTS: Of the 606 markers used to assemble the genetic map, 588 (97%) were assigned to linkage groups. These included 513 Diversity Arrays Technology (DArT) markers, 72 simple sequence repeat (SSR), one insertion site-based polymorphism (ISBP), and two high-molecular-weight glutenin subunit (HMW-GS) markers. These markers were assigned to the 14 chromosomes, covering 2048.79 cM, with a mean distance of 3.48 cM between adjacent markers. This map showed good coverage of the A and B genome chromosomes, apart from 3A, 5A, 6A, and 4B. Compared with previously reported maps, most shared markers showed highly consistent orders. This map was successfully used to identify five quantitative trait loci (QTL), including two for spikelet number on chromosomes 7A and 5B, two for spike length on 7A and 3B, and one for 1000-grain weight on 4B. However, differences in crossability QTL between the two T. turgidum parents may explain the segregation distortion regions on chromosomes 1A, 3B, and 6B. CONCLUSIONS: A genetic map of T. turgidum including 588 markers was constructed using a synthetic doubled haploid (SynDH) hexaploid wheat population. Five QTLs for three agronomic traits were identified from this population. However, more markers are needed to increase the density and resolution of this map in the future study
Hydrogen Sulfide Alleviates Postharvest Senescence of Grape by Modulating the Antioxidant Defenses
Hydrogen sulfide (H2S) has been identified as an important gaseous signal in plants. Here, we investigated the mechanism of H2S in alleviating postharvest senescence and rotting of Kyoho grape. Exogenous application of H2S released from 1.0 mM NaHS remarkably decreased the rotting and threshing rate of grape berries. H2S application also prevented the weight loss in grape clusters and inhibited the decreases in firmness, soluble solids, and titratable acidity in grape pulp during postharvest storage. The data of chlorophyll and carotenoid content suggested the role of H2S in preventing chlorophyll breakdown and carotenoid accumulation in both grape rachis and pulp. In comparison to water control, exogenous H2S application maintained significantly higher levels of ascorbic acid and flavonoid and total phenolics and reducing sugar and soluble protein in grape pulp. Meanwhile, H2S significantly reduced the accumulation of malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anion (O2∙-) in grape pulp. Further investigations showed that H2S enhanced the activities of antioxidant enzymes ascorbate peroxidase (APX) and catalase (CAT) and decreased those of lipoxygenase (LOX) in both grape peels and pulp. In all, we provided strong evidence that H2S effectively alleviated postharvest senescence and rotting of Kyoho grape by modulating antioxidant enzymes and attenuating lipid peroxidation
Evolutionary trajectories of snake genes and genomes revealed by comparative analyses of five-pacer viper
Snakes have numerous features distinctive from other tetrapods and a rich history of genome evolution that is still obscure. Here, we report the high-quality genome of the five-pacer viper, Deinagkistrodon acutus, and comparative analyses with other representative snake and lizard genomes. We map the evolutionary trajectories of transposable elements (TEs), developmental genes and sex chromosomes onto the snake phylogeny. TEs exhibit dynamic lineage-specific expansion, and many viper TEs show brain-specific gene expression along with their nearby genes. We detect signatures of adaptive evolution in olfactory, venom and thermal-sensing genes and also functional degeneration of genes associated with vision and hearing. Lineage-specific relaxation of functional constraints on respective Hox and Tbx limb-patterning genes supports fossil evidence for a successive loss of forelimbs then hindlimbs during snake evolution. Finally, we infer that the ZW sex chromosome pair had undergone at least three recombination suppression events in the ancestor of advanced snakes. These results altogether forge a framework for our deep understanding into snakes' history of molecular evolution
Intravenous Injections of Human Mesenchymal Stromal Cells Modulated the Redox State in a Rat Model of Radiation Myelopathy
The main aim of the present study was to assess the antioxidative effects of human umbilical cord-derived mesenchymal stromal cells (UC-MSCs) in a rat model of radiation myelopathy. UC-MSCs were isolated from Wharton’s jelly (WJ) of umbilical cords. An irradiated cervical spinal cord rat model (C2-T2 segment) was generated using a 60Co irradiator to deliver 30 Gy of radiation. UC-MSCs were injected through the tail vein at 90 days, 97 days, 104 days, and 111 days after-irradiation. Histological damage was examined by cresyl violet/Nissl staining. The activities of two antioxidant enzymes catalase (CAT) and glutathione peroxidase (GPX) in the spinal cord were measured by the biomedical assay. In addition, the levels of vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang-2) in the spinal cord were determined by ELISA methods. Multiple injections of UC-MSCs through the tail vein ameliorated neuronal damage in the spinal cord, increased the activities of the antioxidant enzymes CAT and GPX, and increased the levels of VEGF and Ang-2 in the spinal cord. Our results suggest that multiple injections of UC-MSCs via the tail vein in the rat model of radiation myelopathy could significantly improve the antioxidative microenvironment in vivo
Expression of p53, inducible nitric oxide synthase and vascular endothelial growth factor in gastric precancerous and cancerous lesions: correlation with clinical features
BACKGROUND: The growth and metastasis of tumors depend on the development of an adequate blood supply via angiogenesis. Recent studies indicate that the inducible nitric oxide synthase (iNOS), vascular endothelial growth factor (VEGF) and the tumor suppressor p53 are fundamental play-markers of the angiogenic process. Overexpression of iNOS and VEGF has been shown to induce angiogenesis in tumors. P53 suppresses angiogenesis by down-regulating VEGF and iNOS. The correlation of expression of p53, VEGF and iNOS and clinical features in gastric carcinogenesis, however, has not been well characterized. METHODS: The expression of p53, iNOS and VEGF in gastric precancerous and cancerous lesions and its relation with the clinical features was determined with immunohistochemistry (avidin-biotin-peroxidase complex method) on 55 randomly selected GC patients and 60 symptom-free subjects from the mass survey in the high-incidence area for GC in Henan, northern China. RESULTS: The positive immunostainig rates for p53, iNOS and VEGF in gastric carcinomas were 51%, 44% and 51%, respectively, and correlated well with TNM stages, but did not show significant difference among the groups with different degrees of gastric wall invasion depth by GC. A positive immunostaining reaction for the iNOS protein was significantly correlated with lymph node metastasis (p = 0.019; Spearman correlation coefficient). P53 protein accumulation was higher in the poorly-differentiated gastric carcinoma than in well-differentiated one. In gastric biopsies, no positive immunosatining was observed for p53, iNOS and VEGF in the histologically normal tissue and chronic superficial gastritis (CSG). However, p53, iNOS and VEGF positive immunostaining was observed in the tissues with different severities of lesions of chronic atrophic gastritis (CAG), intestinal metaplasia (IM) and dysplasia (DYS), and the positive rates increased with the lesion progression from CAG to IM to DYS. A high coincidental positive and negative immunostaining rate for p53, iNOS and VEGF was observed both in biopsy samples with CAG, IM and DYS from the symptom-free subjects and in gastric cancer tissue from the GC patients. CONCLUSIONS: The present results indicated that p53 protein accumulation and increased expression of iNOS and VEGF might be responsible for gastric carcinogenesis and tumor aggressiveness of gastric cancer
Prevalence of bovine viral diarrhea virus in cattle between 2010 and 2021: A global systematic review and meta-analysis
BackgroundBovine viral diarrhea is one of the diseases that cause huge economic losses in animal husbandry. Many countries or regions have successively introduced eradication plans, but BVDV still has a high prevalence in the world. This meta-analysis aims to investigate the prevalence and risk factors of BVDV in the world in recent 10 years, and is expected to provide some reference and theoretical basis for BVDV control plans in different regions.MethodRelevant articles published from 2010 to 2021 were mainly retrieved from NCBI, ScienceDirect, Chongqing VIP, Chinese web of knowledge (CNKI), web of science and Wanfang databases.Results128 data were used to analyze the prevalence of BVDV from 2010 to 2021. BVDV antigen prevalence rate is 15.74% (95% CI: 11.35–20.68), antibody prevalence rate is 42.77% (95% CI: 37.01–48.63). In the two databases of antigen and antibody, regions, sampling time, samples, detection methods, species, health status, age, sex, breeding mode, and seasonal subgroups were discussed and analyzed, respectively. In the antigen database, the prevalence of dairy cows in the breed subgroup, ELISA in the detection method subgroup, ear tissue in the sample subgroup, and extensive breeding in the breeding mode were the lowest, with significant differences. In the antibody database, the prevalence rate of dairy cows in the breed subgroup and intensive farming was the highest, with a significant difference. The subgroups in the remaining two databases were not significantly different.ConclusionThis meta-analysis determined the prevalence of BVDV in global cattle herds from 2010 to 2021. The prevalence of BVDV varies from region to region, and the situation is still not optimistic. In daily feeding, we should pay attention to the rigorous and comprehensive management to minimize the spread of virus. The government should enforce BVDV prevention and control, implement control or eradication policies according to local conditions, and adjust the policies in time
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