Emiliania huxleyi is the most prominent modern coccolithophore,a group of marine unicellular eukaryotes that play a critical role in ocean biogeochemistry.Coccolithoviruses are large double stranded DNA viruses,which ...Emiliania huxleyi is the most prominent modern coccolithophore,a group of marine unicellular eukaryotes that play a critical role in ocean biogeochemistry.Coccolithoviruses are large double stranded DNA viruses,which is responsible for the demise of large oceanic blooms formed by E.huxleyi.E.huxleyi virus(EhVs)acquired a series of enzyme-coding genes predicted to be involved in the sphingolipid biosynthesis by horizontal gene transfer between virus-host.Currently,there is limited experimental validation identifying the functions of these genes in EhV.Genetic transformation of eukaryotic cells is a powerful tool to get an insight into gene functions of the studied organisms.Serine palmitoyltransferase(SPT)catalyzes the first committed step in de novo sphingolipid biosynthetic pathway.Here,a novel vector system for the transformation of E.huxleyi was designed.It contained fragments of promoter and terminator sequences of E.huxleyi endogenic fucoxanthin chlorophyll a/c-binding protein gene“fcp”and harbored EhV-99B1 spt gene.The resultant recombinant transformation vectors pEhux-I-spt and pEhux-II were co-transferred into E.huxleyi BOF92 by electroporation.Transformants were obtained upon glufosinate-ammonium selection,and confirmed by Southern hybridization,genome PCR,qRT-PCR and Western blot screening of spt gene,which indicated that spt gene was integrated into the nuclear genome and was expressed at the mRNA and protein levels.The expression of the viral spt gene led to differences in lipid compositions analyzed using thin-layer chromatography(TLC).The results present the genetic transformation system for E.huxleyi,providing additional genetic resource with potential for exploring basic biological questions such as the virus-host interactions.展开更多
Composition and electron concentration dependence of transformation temperature in Ni2＋x＋y Mn1-xGa1-y, Ni2＋x Mn1-x Ga alloys with first order magnetic transition were studied. For Ni2 ＋ x ＋ y Mn1- x Ga1-y alloys,...Composition and electron concentration dependence of transformation temperature in Ni2＋x＋y Mn1-xGa1-y, Ni2＋x Mn1-x Ga alloys with first order magnetic transition were studied. For Ni2 ＋ x ＋ y Mn1- x Ga1-y alloys, martensitic transformation temperature TM increases and Curie temperature Tc decreases with the increase of electron concentration e/a, they intercept at e/a = 7.68. TM and Tc decrease when continue to increase electron concentration. While for Ni2＋x Mn1-xGa alloys, they cross at e/a = 7. 635. Before their crossing, the change tendency with e/a is the same as Ni2＋x＋yMn1-xGa1-y alloys;, after their crossing, both TM and Tc increase slowly. The different relations between TM and Tc and e/a within two NiMnGa alloys show that TM and Tc depend not only on e/a, but also on composition.展开更多
A new mutant human papillomavirus type 16 E7 gene, termed HPV16 HBE7, was isolated from cervical carcinoma biopsy samples from patients in an area with high incidence of cervical cancer (Hubei province, China). A prev...A new mutant human papillomavirus type 16 E7 gene, termed HPV16 HBE7, was isolated from cervical carcinoma biopsy samples from patients in an area with high incidence of cervical cancer (Hubei province, China). A previous study showed that the HPV16 HBE7 protein was primarily cytoplasmic while wild-type HPV16 E7 protein, termed HPV16 WE7, was concentrated in the nucleus. With the aim of studying the biological functions of HPV16 HBE7, the transforming potential of HPV16 HBE7 in NIH/3T3 cells was detected through observation of cell morphology, cell proliferation assay and anchorage-independent growth assay. The effect of HPV16 HBE7 on cell cycle was examined by flow cytometry. Dual-luciferase reporter assay and RT-PCR were used to investigate the influence of HPV16 HBE7 protein on the expression of regulation factors associated with G1/S checkpoint. The results showed that HPV16 HBE7 protein, as well as HPV16 WE7 protein, held transformation activity. NIH/3T3 cells expressing HPV16 HBE7 could easily transition from G1 phase into S phase and expressed high level of cyclin A and cdc25A. These results indicated HPV16 mutant E7 protein, located in the cytoplasm, induces oncogenic transformation of NIH/3T3 cells via up-regulation of cyclin A and cdc25A.展开更多
A 0.06%C low carbon steel was deformed in torsion over the temperature range 877-917℃in a 2% H_2 - Ar gas atmosphere.Strains of 0.25 -5.0 were applied at strain rates ofε= 0.04 s^(-1) andε= 0.4 s^(-1) to study the ...A 0.06%C low carbon steel was deformed in torsion over the temperature range 877-917℃in a 2% H_2 - Ar gas atmosphere.Strains of 0.25 -5.0 were applied at strain rates ofε= 0.04 s^(-1) andε= 0.4 s^(-1) to study the formation of ferrite by dynamic transformation(DT) at temperatures above the A_(e3).The critical strain for ferrite formation by DT was aboutε= 0.2 and its volume fraction increased with strain and decreased with temperature above the A_(e3).Average ferrite grain sizes of 1.5μm to 5μm were produced,which decreased with strain rate.At the lower strain rate(ε= 0.04 s^(-1)) reverse transformation(RT) took place during deformation once an incubation time of about 40 s,was exceeded.An increase in strain rate fromε= 0.04 s^(-1) toε= 0.4 s^(-1) arrested RT during testing at all temperatures as the total test times did not exceed 13 s.The present work shows that DT is favored at higher strain rates by increasing the driving force(i.e.stored energy ) and by suppressing RT.展开更多
An optimized recombinant HPV16 E6E7 fusion gene (HPV16 ofE6E7) was constructed according to codon usage for mammalian cell expression, and a mutant of HPV16 ofE6E7 fusion gene (HPV16 omfE6E7) was generated by site-dir...An optimized recombinant HPV16 E6E7 fusion gene (HPV16 ofE6E7) was constructed according to codon usage for mammalian cell expression, and a mutant of HPV16 ofE6E7 fusion gene (HPV16 omfE6E7) was generated by site-directed mutagenesis at L57G, C113R for the E6 protein and C24G, E26G for the E7 protein for HPV16 ofE6E7 [patent pending (CN 101100672)]. The HPV16 omfE6E7 gene constructed in this work not only lost the transformation capability to NIH 3T3 cells and tumorigenicity in SCID mice, but also maintained very good stability and antigenicity. These results suggests that the HPV16 omfE6E7 gene should undergo further study for application as a safe antigen-specific therapeutic vaccine for HPV16-associated tumors.展开更多
This paper is to extend the Poincar’e Lemma for differential forms in a bounded, convex domain [1] in Rn to a more general domain that, we call, is deformable to every point in itself. Then we extend the homotopy ope...This paper is to extend the Poincar’e Lemma for differential forms in a bounded, convex domain [1] in Rn to a more general domain that, we call, is deformable to every point in itself. Then we extend the homotopy operator T in [1] to the domain defromed to every point of itself.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.41576166,21707042,31771972)the Fujian Province Natural Science Foundation of China(Nos.2019J01696,2017J01447,2017J01636)。
文摘Emiliania huxleyi is the most prominent modern coccolithophore,a group of marine unicellular eukaryotes that play a critical role in ocean biogeochemistry.Coccolithoviruses are large double stranded DNA viruses,which is responsible for the demise of large oceanic blooms formed by E.huxleyi.E.huxleyi virus(EhVs)acquired a series of enzyme-coding genes predicted to be involved in the sphingolipid biosynthesis by horizontal gene transfer between virus-host.Currently,there is limited experimental validation identifying the functions of these genes in EhV.Genetic transformation of eukaryotic cells is a powerful tool to get an insight into gene functions of the studied organisms.Serine palmitoyltransferase(SPT)catalyzes the first committed step in de novo sphingolipid biosynthetic pathway.Here,a novel vector system for the transformation of E.huxleyi was designed.It contained fragments of promoter and terminator sequences of E.huxleyi endogenic fucoxanthin chlorophyll a/c-binding protein gene“fcp”and harbored EhV-99B1 spt gene.The resultant recombinant transformation vectors pEhux-I-spt and pEhux-II were co-transferred into E.huxleyi BOF92 by electroporation.Transformants were obtained upon glufosinate-ammonium selection,and confirmed by Southern hybridization,genome PCR,qRT-PCR and Western blot screening of spt gene,which indicated that spt gene was integrated into the nuclear genome and was expressed at the mRNA and protein levels.The expression of the viral spt gene led to differences in lipid compositions analyzed using thin-layer chromatography(TLC).The results present the genetic transformation system for E.huxleyi,providing additional genetic resource with potential for exploring basic biological questions such as the virus-host interactions.
文摘Composition and electron concentration dependence of transformation temperature in Ni2＋x＋y Mn1-xGa1-y, Ni2＋x Mn1-x Ga alloys with first order magnetic transition were studied. For Ni2 ＋ x ＋ y Mn1- x Ga1-y alloys, martensitic transformation temperature TM increases and Curie temperature Tc decreases with the increase of electron concentration e/a, they intercept at e/a = 7.68. TM and Tc decrease when continue to increase electron concentration. While for Ni2＋x Mn1-xGa alloys, they cross at e/a = 7. 635. Before their crossing, the change tendency with e/a is the same as Ni2＋x＋yMn1-xGa1-y alloys;, after their crossing, both TM and Tc increase slowly. The different relations between TM and Tc and e/a within two NiMnGa alloys show that TM and Tc depend not only on e/a, but also on composition.
基金National Natural Science Foundation of China (Grant No.30571955 and 30772308)
文摘A new mutant human papillomavirus type 16 E7 gene, termed HPV16 HBE7, was isolated from cervical carcinoma biopsy samples from patients in an area with high incidence of cervical cancer (Hubei province, China). A previous study showed that the HPV16 HBE7 protein was primarily cytoplasmic while wild-type HPV16 E7 protein, termed HPV16 WE7, was concentrated in the nucleus. With the aim of studying the biological functions of HPV16 HBE7, the transforming potential of HPV16 HBE7 in NIH/3T3 cells was detected through observation of cell morphology, cell proliferation assay and anchorage-independent growth assay. The effect of HPV16 HBE7 on cell cycle was examined by flow cytometry. Dual-luciferase reporter assay and RT-PCR were used to investigate the influence of HPV16 HBE7 protein on the expression of regulation factors associated with G1/S checkpoint. The results showed that HPV16 HBE7 protein, as well as HPV16 WE7 protein, held transformation activity. NIH/3T3 cells expressing HPV16 HBE7 could easily transition from G1 phase into S phase and expressed high level of cyclin A and cdc25A. These results indicated HPV16 mutant E7 protein, located in the cytoplasm, induces oncogenic transformation of NIH/3T3 cells via up-regulation of cyclin A and cdc25A.
文摘A 0.06%C low carbon steel was deformed in torsion over the temperature range 877-917℃in a 2% H_2 - Ar gas atmosphere.Strains of 0.25 -5.0 were applied at strain rates ofε= 0.04 s^(-1) andε= 0.4 s^(-1) to study the formation of ferrite by dynamic transformation(DT) at temperatures above the A_(e3).The critical strain for ferrite formation by DT was aboutε= 0.2 and its volume fraction increased with strain and decreased with temperature above the A_(e3).Average ferrite grain sizes of 1.5μm to 5μm were produced,which decreased with strain rate.At the lower strain rate(ε= 0.04 s^(-1)) reverse transformation(RT) took place during deformation once an incubation time of about 40 s,was exceeded.An increase in strain rate fromε= 0.04 s^(-1) toε= 0.4 s^(-1) arrested RT during testing at all temperatures as the total test times did not exceed 13 s.The present work shows that DT is favored at higher strain rates by increasing the driving force(i.e.stored energy ) and by suppressing RT.
基金National 863 Program(2007AA021107)Beijing Municipal Commission of Education Research Projects(KM201010005008)Doctoral Start-up Foundation of Beijing University of Technology
文摘An optimized recombinant HPV16 E6E7 fusion gene (HPV16 ofE6E7) was constructed according to codon usage for mammalian cell expression, and a mutant of HPV16 ofE6E7 fusion gene (HPV16 omfE6E7) was generated by site-directed mutagenesis at L57G, C113R for the E6 protein and C24G, E26G for the E7 protein for HPV16 ofE6E7 [patent pending (CN 101100672)]. The HPV16 omfE6E7 gene constructed in this work not only lost the transformation capability to NIH 3T3 cells and tumorigenicity in SCID mice, but also maintained very good stability and antigenicity. These results suggests that the HPV16 omfE6E7 gene should undergo further study for application as a safe antigen-specific therapeutic vaccine for HPV16-associated tumors.
文摘This paper is to extend the Poincar’e Lemma for differential forms in a bounded, convex domain [1] in Rn to a more general domain that, we call, is deformable to every point in itself. Then we extend the homotopy operator T in [1] to the domain defromed to every point of itself.
基金Supported by the National Natural Science Foundation of China(1146103211401267)+2 种基金the Foundation of Jiangxi University of Science and Technology(NSFJ2015-G25)the Youth Foundation of Jiangxi Provincial Education Department of China(GJJ150646GJJ151356)
