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Jing Yang Chenghang Yang Jiahui Qian Facai Li Junlong Zhao Rui Fang 《Microbial biotechnology》2020,13(6):2057-2069
Individuals with inhibited immunity may develop lethal toxoplasmosis; thus, a safe and effective vaccine is urged to be developed. Toxoplasma gondii (T. gondii) α-amylase (α-AMY) is one of the enzymes responsible for starch digestion. In the present study, we first generated a ME49Δα-amy mutant and discovered that loss of α-AMY robustly grew in vitro but contributed to significant virulence attenuation in vivo. Therefore, we established a mouse model to explore the protective immunity of Δα-amy mutant against acute and chronic toxoplasmosis. The results indicated that the survival rates of short-term or long-term immunized mice re-infected with the tachyzoites of multiple T. gondii strains were nearly 100%. ME49Δα-amy not only could provide protective immunity against tachyzoites infection but also could resist the infection of tissue cysts. Furthermore, we detected that ME49Δα-amy vaccination could effectively eliminate the proliferation of parasites in mice and prevent the formation of cysts. The significant increases of Th1-type cytokines, Th2-type cytokines and specific total IgG and IgG subclasses (IgG2a and IgG1) confirmed efficiency of a combination of cellular and humoral immunity against infection. In conclusion, ME49Δα-amy attenuated strain can produce strong immune responses to provide efficient protection against toxoplasmosis, which signifies that ME49Δα-amy mutant may be a potential vaccine candidate. 相似文献
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Junlong Liu Guiquan Guan Zhijie Liu Aihong Liu Miling Ma Qi Bai Hong Yin Jianxun Luo 《Experimental parasitology》2013,133(2):217-221
Theileria sinensis was recently isolated and named as an independent Theileria species that infects cattle in China. To date, this parasite has been described based on its morphology, transmission and molecular studies, indicating that it should be classified as a distinct species. To test the validity of this taxon, the two internal transcribed spacers (ITS1 and ITS2) and the 5.8S rRNA gene were cloned and sequenced from three T. sinensis isolates. The complete ITS sequences were compared with those of other Theileria sp. available in GenBank. Phylogenetic analyses based on sequence data for the complete ITS sequences indicate that T. sinensis lies in a distinct clade that is separate from that of T. buffeli/orientalis and T. annulata. Sequence comparisons indicate that different T. sinensis isolates possess unique sizes of ITS1 and ITS2 as well as species-specific nucleotide sequences. This analysis provides new molecular data to support the classification of T. sinensis as a distinct species from other known Theileria spp. based on ITS sequences. 相似文献
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Gao J Luo J Li Y Fan R Zhao H Guan G Liu J Wiske B Sugimoto C Yin H 《Experimental & applied acarology》2007,41(4):289-303
A primary cDNA library with a size of 1.34 × 106 PFU was constructed from Haemaphysalis qinghaiensis eggs and was immunoscreened with rabbit anti-H. qinghaiensis serum. One clone (Hq22, named following those clones obtained from adult Haemaphysalis qinghaiensis cDNA library which we constructed before) screened from the cDNA library was selected randomly for sequencing. The entire
sequence of the clone was subsequently obtained using rapid amplification of the cDNA ends (RACE). A search of the cloned
sequence against GenBank revealed that it related to ribosomal protein L23a (Rpl23a) and had a high percentage similarity
to this protein from different species. Conserved domains for Rpl23a were also identified in the cloned sequence. Expression
analysis by RT-PCR showed that this gene is expressed in salivary glands, midguts, other tissues and different developmental
stages of H. qinghaiensis. Based on the H. qinghaiensis Rpl23a sequence, open reading frames (ORF) of Rpl23a of Heamaphysalis longicornis and Boophilus microplus were also cloned and were performed for comparison with Rpl23a of H. qinghaiensis and other organisms as well. Vaccine based on Rpl23a recombinant protein cannot protect sheep against H. qinghaiensis. 相似文献
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Adipocyte differentiation induced using nonspecific siRNA controls in cultured human mesenchymal stem cells
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RNA interference (RNAi) is gene silencing induced by double-stranded RNA of 21-23 nucleotides in length, termed small interfering RNA, or siRNA. RNAi-based techniques have been widely applied to elucidate gene function, identify drug targets, and used in trials as a promising adjunct to silence disease-causing genes. However, emerging evidence suggests unexpected changes in expression of untargeted genes as a consequence of an off-target effect by RNAi in mammalian cells. To date, our understanding of such effects on stem cells is limited. We transfected human fetal femur-derived mesenchymal stem cells using commercially available nonspecific siRNA controls and examined adipocyte differentiation in the cells using morphology, histochemistry, and quantitative real-time PCR to examine the expression of key genes for adipogenic or osteogenic differentiation. We report here the induction of adipocyte differentiation in human mesenchymal stem cells using nonspecific siRNAs raising concerns as to the specificity of RNAi in stem cells and, critically, a need to understand and delineate the rules governing the specificity of RNAi. 相似文献
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Zou J Zhou L Du XX Ji Y Xu J Tian J Jiang W Zou Y Yu S Gan L Luo M Yang Q Cui Y Yang W Xia X Chen M Zhao X Shen Y Chen PY Worley PF Xiao B 《Developmental cell》2011,20(1):97-108
mTor kinase is involved in cell growth, proliferation, and differentiation. The roles of mTor activators, Rheb1 and Rheb2, have not been established in?vivo. Here, we report that Rheb1, but not Rheb2, is critical for embryonic survival and mTORC1 signaling. Embryonic deletion of Rheb1 in neural progenitor cells?abolishes mTORC1 signaling in developing brain and increases mTORC2 signaling. Remarkably, embryonic and early postnatal brain development appears grossly normal in these Rheb1f/f,Nes-cre mice with the notable exception of deficits of myelination. Conditional expression of Rheb1 transgene in neural progenitors increases mTORC1 activity and promotes myelination in the brain. In addition the Rheb1 transgene rescues mTORC1 signaling and hypomyelination in the Rheb1f/f,Nes-cre mice. Our study demonstrates that Rheb1 is essential for mTORC1 signaling and myelination in the brain, and suggests that mTORC1 signaling plays a role in selective cellular adaptations, rather than general cellular viability. 相似文献
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Wang J Zhao B Wang X Yao J Zhang J 《International journal of biological macromolecules》2012,50(5):1201-1206
It was essential to understand the chemical structure of polysaccharides for further research and biochemical or medical application of this natural biopolymer. In the present study, sulfated derivatives of guar gum with high degree of sulfation (DS) were synthesized using 4-dimethylaminopyridine (DMAP)/dimethylcyclohexylcarbodiimide (DCC) as catalyst in homogeneous conditions. The effects of the ratio of chlorosulfuric acid to pyridine, the content of catalyst and reaction temperature were investigated. Results of FT-IR, (1)H and (13)C NMR indicated that C-6 substitution was predominant in sulfated polysaccharide. In the sulfation reaction, a sharp decrease in M(W) was observed. The enhanced antioxidant activities of sulfated polysaccharides were not a function of a single factor but a combination of high DS and low molecule weight. 相似文献
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J Xiong W Zhang J Su J Shangguan Y Lin Y Yang R Zhang L Xie H Wang 《World journal of microbiology & biotechnology》2012,28(2):721-727
Nucleoside analogues are used widely for the treatment of viral diseases and cancer, however the preparation of some important
intermediates of these nucleoside analogues, including 2′-deoxyadenosine (dAR) and 5-methyluridine (5-MU), remains inconvenient.
To optimize the synthesis of dAR and 5-MU, recombinant strains and auto-induction medium were employed in this study. E. coli
BL21(DE3) strains overexpressing purine nucleoside phosphorylase (PNP), uridine phosphorylase (UP) and thymidine phosphorylase
(TP) were constructed and cultured in auto-induction ZYM-Fe-5052 medium for 8 h. The cultures of these strains were then used
directly to synthesize dAR and 5-MU. Under optimized conditions, 30 mM adenine was converted to 29 mM dAR in 1 h, and 32 mM
5-MU was obtained from 60 mM thymine, using 6% (v/v) cell solutions as biocatalysts. These results indicate that our convenient
and efficient method is ideal for the preparation of dAR and 5-MU, and has potential for the preparation of other nucleoside
analogue intermediates. 相似文献
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Jiang Peipei Wang Huimin Fu Xiaoli Dai Xiaoqin Kou Liang Wang Junlong 《Plant and Soil》2018,425(1-2):433-440
Plant and Soil - Leaf-litter decomposition rate (k L ) regulates nutrient dynamics and is affected at microsite level by species traits, soil biota and microclimate conditions. Fallen fruits form... 相似文献