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排序方式: 共有165条查询结果,搜索用时 15 毫秒
1.
Somayeh Shokri Shahab Mahmoudvand Reza Taherkhani Fatemeh Farshadpour 《Journal of cellular physiology》2019,234(3):2143-2151
Coronavirus (CoV) infections are commonly associated with respiratory and enteric disease in humans and animals. In 2012, a new human disease called Middle East respiratory syndrome (MERS) emerged in the Middle East. MERS was caused by a virus that was originally called human coronavirus-Erasmus Medical Center/2012 but was later renamed as Middle East respiratory syndrome coronavirus (MERS-CoV). MERS-CoV causes high fever, cough, acute respiratory tract infection, and multiorgan dysfunction that may eventually lead to the death of the infected individuals. The exact origin of MERS-CoV remains unknown, but the transmission pattern and evidence from virological studies suggest that dromedary camels are the major reservoir host, from which human infections may sporadically occur through the zoonotic transmission. Human to human transmission also occurs in healthcare facilities and communities. Recent studies on Middle Eastern respiratory continue to highlight the need for further understanding the virus-host interactions that govern disease severity and infection outcome. In this review, we have highlighted the major mechanisms of immune evasion strategies of MERS-CoV. We have demonstrated that M, 4a, 4b proteins and Plppro of MERS-CoV inhibit the type I interferon (IFN) and nuclear factor-κB signaling pathways and therefore facilitate innate immune evasion. In addition, nonstructural protein 4a (NSP4a), NSP4b, and NSP15 inhibit double-stranded RNA sensors. Therefore, the mentioned proteins limit early induction of IFN and cause rapid apoptosis of macrophages. MERS-CoV strongly inhibits the activation of T cells with downregulation of antigen presentation. In addition, uncontrolled secretion of interferon ɣ-induced protein 10 and monocyte chemoattractant protein-1 can suppress proliferation of human myeloid progenitor cells. 相似文献
2.
Neelam Shahab Kamarulzaman Kamaruddin Jacqueline Platt Philip R Butler Stephen G Oliver Glyn Hobbs 《Biotechnology letters》1994,16(10):1015-1020
Summary In order to examine the physiology ofStreptomyces coelicolor when growing on solid media, we have employed a membrane overlay technique and used a new approach to extract substrate and product compounds from the agar. Comparisons made with liquid grown cultures indicate a change from non-growth associated productivity of actinorhodin in liquid culture, to growth associated production on agar plates. In contrast, the temporal control of methylenomycin production was virtually identical under both culture conditions. Considerable extracellular protein production was observed during growth on agar. 相似文献
3.
Fast classification and compositional analysis of cornstover fractions using Fourier transform near-infrared techniques 总被引:2,自引:0,他引:2
The objectives of this research were to determine the variation of chemical composition across botanical fractions of cornstover, and to probe the potential of Fourier transform near-infrared (FT-NIR) techniques in qualitatively classifying separated cornstover fractions and in quantitatively analyzing chemical compositions of cornstover by developing calibration models to predict chemical compositions of cornstover based on FT-NIR spectra. Large variations of cornstover chemical composition for wide calibration ranges, which is required by a reliable calibration model, were achieved by manually separating the cornstover samples into six botanical fractions, and their chemical compositions were determined by conventional wet chemical analyses, which proved that chemical composition varies significantly among different botanical fractions of cornstover. Different botanic fractions, having total saccharide content in descending order, are husk, sheath, pith, rind, leaf, and node. Based on FT-NIR spectra acquired on the biomass, classification by Soft Independent Modeling of Class Analogy (SIMCA) was employed to conduct qualitative classification of cornstover fractions, and partial least square (PLS) regression was used for quantitative chemical composition analysis. SIMCA was successfully demonstrated in classifying botanical fractions of cornstover. The developed PLS model yielded root mean square error of prediction (RMSEP %w/w) of 0.92, 1.03, 0.17, 0.27, 0.21, 1.12, and 0.57 for glucan, xylan, galactan, arabinan, mannan, lignin, and ash, respectively. The results showed the potential of FT-NIR techniques in combination with multivariate analysis to be utilized by biomass feedstock suppliers, bioethanol manufacturers, and bio-power producers in order to better manage bioenergy feedstocks and enhance bioconversion. 相似文献
4.
Ann Pa Jill S. Craven Xiaotao T. Bi Staffan Melin Shahab Sokhansanj 《The International Journal of Life Cycle Assessment》2012,17(2):220-231
Purpose
Environmental footprints of wood pellets produced in British Columbia (BC) of Canada are to be estimated based on industry surveys and published emission factor data. 相似文献5.
Pegah Rahimizadeh Tohid Rezaei Topraggaleh Mohammad Hossein Nasr‐Esfahani Niloofar Ziarati Shahab Mirshahvaladi Vahid Esmaeili Soroush Seifi Poopak Eftekhari‐Yazdi Abdolhossein Shahverdi 《Molecular reproduction and development》2020,87(1):115-123
Failed oocyte activation has been observed in unexplained infertile (UI) and asthenoteratozoospermic (AT) men. The deficiency of phospholipase C‐zeta (PLCζ) could be a possible reason for such failures and has not been studied yet. We investigated the expression and localization of PLCζ protein in the sperms of patients with UI and AT conditions. The relationships between PLCζ‐related parameters with male age, sperm characteristics, DNA integrity, and cellular maturity were assessed. Semen samples were collected from fertile (n = 40), UI (n = 40), and AT (n = 40) men. Subsequently, semen analysis, DNA fragmentation, hyaluronic acid‐binding ability, and PLCζ level along with its distribution were evaluated using computer‐assisted sperm analyzer, sperm chromatin structure assay (SCSA), hyaluronic acid‐binding assay (HBA), western blot analysis and immunofluorescence microscopy, respectively. Unlike SCSA, the values of HBA, and PLCζ expression were significantly reduced in UI and AT patients compared to fertile men, whereas no significant differences were observed among the experimental groups in terms of PLCζ localization patterns. The regression analysis also showed that HBA is the only variable associated with PLCζ levels. Furthermore, the correlation of male age with PLCζ localization in postacrosomal, equatorial, and acrosomal+postacrosomal+equatorial (A+PA+E) patterns, as well as the relation of normal morphology, with the (A+PA+E) pattern, remained in the regression model. Our findings indicated that reduced PLCζ level along with the increased DNA fragmentation and impaired maturation may be possible etiologies of decreased fertilization in the studied subjects. 相似文献
6.
This paper looks at the series solutions of three dimensional boundary layer flow. An Oldroyd-B fluid with variable thermal conductivity is considered. The flow is induced due to stretching of a surface. Analysis has been carried out in the presence of heat generation/absorption. Homotopy analysis is implemented in developing the series solutions to the governing flow and energy equations. Graphs are presented and discussed for various parameters of interest. Comparison of present study with the existing limiting solution is shown and examined. 相似文献
7.
Yibing Xu Jianping Sun Michael A. Sheard Hung C. Tran Zesheng Wan Wei Yao Liu Shahab Asgharzadeh Richard Sposto Hong Wei Wu Robert C. Seeger 《Cancer immunology, immunotherapy : CII》2013,62(10):1637-1648
Background
Treatment for children with high-risk neuroblastoma with anti-disialoganglioside mAb ch14.18, IL-2, and GM-CSF plus 13-cis-retinoic acid after myeloablative chemotherapy improves survival, but 40 % of patients still relapse during or after this therapy. The microenvironment of high-risk neuroblastoma tumors includes macrophages, IL-6, and TGFβ1. We hypothesized that this microenvironment suppresses anti-tumor functions of natural killer (NK) cells and that lenalidomide, an immune-modulating drug, could overcome suppression.Methods
Purified NK cells were cultured with IL-2, neuroblastoma/monocyte-conditioned culture medium (CM), IL-6, TGFβ1, and lenalidomide in various combinations and then characterized using cytotoxicity (direct and antibody-dependent cell-mediated cytotoxicity), cytokine, flow cytometry, and Western blotting assays. Anti-tumor activity of NK cells with lenalidomide, ch14.18, or both was evaluated with a xenograft model of neuroblastoma.Results
CM from neuroblastoma/monocyte co-cultures contains IL-6 and TGFβ1 that suppress IL-2 activation of NK cell cytotoxicity and IFNγ secretion. IL-6 and TGFβ1 activate the STAT3 and SMAD2/3 pathways in NK cells and suppress IL-2 induction of cytotoxicity, granzymes A and B release, perforin expression, and IFNγ secretion. Lenalidomide blocks IL-6 and TGFβ1 activation of these signaling pathways and inhibits their suppression of NK cells. Neuroblastoma cells in NOD/SCID mice exhibit activated STAT3 and SMAD2/3 pathways. Their growth is most effectively inhibited by co-injected peripheral blood mononuclear cells (PBMC) containing NK cells when mice are treated with both ch14.18 and lenalidomide.Conclusion
Immunotherapy with anti-tumor cell antibodies may be improved by lenalidomide, which enhances activation of NK cells and inhibits their suppression by IL-6 and TGFβ1. 相似文献8.
Mohammad Bahram Urmas Kõljalg Petr Kohout Shahab Mirshahvaladi Leho Tedersoo 《Mycorrhiza》2013,23(1):11-19
Introduction of exotic plants change soil microbial communities which may have detrimental ecological consequences for ecosystems. In this study, we examined the community structure and species richness of ectomycorrhizal (EcM) fungi associated with exotic pine plantations in relation to adjacent native ectomycorrhizal trees in Iran to elucidate the symbiont exchange between distantly related hosts, i.e. Fagales (Fagaceae and Betulaceae) and Pinaceae. The combination of morphological and molecular identification approaches revealed that 84.6 % of species with more than one occurrence (at least once on pines) were shared with native trees and only 5.9 % were found exclusively on pine root tips. The community diversity of ectomycorrhizal fungi in the pine plantations adjacent to native EcM trees was comparable to their adjacent native trees, but the isolated plantations hosted relatively a species-poor community. Specific mycobionts of conifers were dominant in the isolated plantation while rarely found in the plantations adjacent to native EcM trees. These data demonstrate the importance of habitat isolation and dispersal limitation of EcM fungi in their potential of host range expansion. The great number of shared and possibly compatible symbiotic species between exotic Pinaceae and local Fagales (Fagaceae and Betulaceae) may reflect their evolutionary adaptations and/or ancestral compatibility with one another. 相似文献
9.
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