The actin nucleator actin-related protein complex(Arp2/3) is composed of seven subunits: Arp2,Arp3, p40/ARPC1(P40), p34/ARPC2(P34), p21/ARPC3(P21), p20/ARPC4(P20), and p16/ARPC5(P16). Arp2/3 plays crucial roles in a v...The actin nucleator actin-related protein complex(Arp2/3) is composed of seven subunits: Arp2,Arp3, p40/ARPC1(P40), p34/ARPC2(P34), p21/ARPC3(P21), p20/ARPC4(P20), and p16/ARPC5(P16). Arp2/3 plays crucial roles in a variety of cellular activities through regulation of actin polymerization. Autographa californica multiple nucleopolyhedrovirus(Ac MNPV), one of the beststudied alphabaculoviruses, induces Arp2/3 nuclear relocation and mediates nuclear actin polymerization to assist in virus replication. We have demonstrated that Ac34, a viral late-gene product, induces translocation of the P40 subunit of Arp2/3 to the nucleus during Ac MNPV infection. However, it remains unknown whether Ac34 could relocate other Arp2/3 subunits to the nucleus. In this study, the effects of the viral protein Ac34 on the distribution of these subunits were studied by an immunofluorescence assay. Arp2, P34, P21, and P20 cloned from Spodoptera frugiperda(Sf9) cells showed mainly cytoplasmic localization and were relocated to the nucleus in the presence of Ac34. In addition, Arp3 was localized in the cytoplasm in both the presence and absence of Ac34, and P16 showed whole-cell localization. In contrast to Sf9 cells, all subunits of mammalian Arp2/3 showed no nuclear relocation in the presence of Ac34. Co-immunoprecipitation analysis of the interaction between Ac34 and Arp2/3 subunits revealed that Ac34 bound to P40,P34, and P20 of Sf9 cells. However, none of the subunits of mammalian Arp2/3 interacted with Ac34, indicating that protein-protein interaction is essential for Ac34 to relocate Arp2/3 subunits to the nucleus.展开更多
This work aims at enhancing the workability of Al2 O3-Mg O castables. Al2 O3-Mg O castables were prepared using tabular alumina particles（ 5-3,3-1,≤1 mm）,tabular alumina fines（ ≤0. 088 mm）,fused magnesia（ ≤1 m...This work aims at enhancing the workability of Al2 O3-Mg O castables. Al2 O3-Mg O castables were prepared using tabular alumina particles（ 5-3,3-1,≤1 mm）,tabular alumina fines（ ≤0. 088 mm）,fused magnesia（ ≤1 mm）,reactive alumina micropowder（ PFR40,PBR,and CL） and calcined alumina micropowder（ AC34 B5 and CT） as the main starting materials,calcium aluminate cement（ Secar71） as the binder,and polycarboxylic acid water reducer WS,FS,and AD as the dispersive agent,respectively. Effects of three dispersive agents addition（ 0. 4 mass% WS,0. 2 mass% FS and 1 mass% AD）,two kinds of reactive alumina micropowder addition（ PFR40 and PBR）,composite alumina micropowder addition（ PFR40-AC34 B5 and CL-CT,the mass ratio from 9/0 to 3/6）on the flow value,apparent porosity,bulk density,cold crushing strength and cold modulus of rupture of Al2 O3-MgO castables were investigated. The results show that：（ 1） with PBR or PFR40,the castables with0. 4 mass% WS own better performance than those with0. 2 mass% FS or 1 mass% AD;（ 2） compared with the castables with CL-CT composite powder, the castables with PFR40-AC34 B5 composite powder have slightly higher flow value; with the decreasing ratio of PFR40 and AC34 B5,or the decreasing ratio of CL andCT,the castables have declined flow value and the dried castable specimens have decreased density but the mildly changed strength; in consideration of the high price of reactive alumina,a proper compositing ratio shall be selected.展开更多
基金supported by grants from National Natural Science Foundation of China (31030027, 31470261, 31321001, and 31270191)The Royal Dutch Academy of Science and Arts (08-PSABD-01) is acknowledged for financing part of this research
文摘The actin nucleator actin-related protein complex(Arp2/3) is composed of seven subunits: Arp2,Arp3, p40/ARPC1(P40), p34/ARPC2(P34), p21/ARPC3(P21), p20/ARPC4(P20), and p16/ARPC5(P16). Arp2/3 plays crucial roles in a variety of cellular activities through regulation of actin polymerization. Autographa californica multiple nucleopolyhedrovirus(Ac MNPV), one of the beststudied alphabaculoviruses, induces Arp2/3 nuclear relocation and mediates nuclear actin polymerization to assist in virus replication. We have demonstrated that Ac34, a viral late-gene product, induces translocation of the P40 subunit of Arp2/3 to the nucleus during Ac MNPV infection. However, it remains unknown whether Ac34 could relocate other Arp2/3 subunits to the nucleus. In this study, the effects of the viral protein Ac34 on the distribution of these subunits were studied by an immunofluorescence assay. Arp2, P34, P21, and P20 cloned from Spodoptera frugiperda(Sf9) cells showed mainly cytoplasmic localization and were relocated to the nucleus in the presence of Ac34. In addition, Arp3 was localized in the cytoplasm in both the presence and absence of Ac34, and P16 showed whole-cell localization. In contrast to Sf9 cells, all subunits of mammalian Arp2/3 showed no nuclear relocation in the presence of Ac34. Co-immunoprecipitation analysis of the interaction between Ac34 and Arp2/3 subunits revealed that Ac34 bound to P40,P34, and P20 of Sf9 cells. However, none of the subunits of mammalian Arp2/3 interacted with Ac34, indicating that protein-protein interaction is essential for Ac34 to relocate Arp2/3 subunits to the nucleus.
文摘This work aims at enhancing the workability of Al2 O3-Mg O castables. Al2 O3-Mg O castables were prepared using tabular alumina particles（ 5-3,3-1,≤1 mm）,tabular alumina fines（ ≤0. 088 mm）,fused magnesia（ ≤1 mm）,reactive alumina micropowder（ PFR40,PBR,and CL） and calcined alumina micropowder（ AC34 B5 and CT） as the main starting materials,calcium aluminate cement（ Secar71） as the binder,and polycarboxylic acid water reducer WS,FS,and AD as the dispersive agent,respectively. Effects of three dispersive agents addition（ 0. 4 mass% WS,0. 2 mass% FS and 1 mass% AD）,two kinds of reactive alumina micropowder addition（ PFR40 and PBR）,composite alumina micropowder addition（ PFR40-AC34 B5 and CL-CT,the mass ratio from 9/0 to 3/6）on the flow value,apparent porosity,bulk density,cold crushing strength and cold modulus of rupture of Al2 O3-MgO castables were investigated. The results show that：（ 1） with PBR or PFR40,the castables with0. 4 mass% WS own better performance than those with0. 2 mass% FS or 1 mass% AD;（ 2） compared with the castables with CL-CT composite powder, the castables with PFR40-AC34 B5 composite powder have slightly higher flow value; with the decreasing ratio of PFR40 and AC34 B5,or the decreasing ratio of CL andCT,the castables have declined flow value and the dried castable specimens have decreased density but the mildly changed strength; in consideration of the high price of reactive alumina,a proper compositing ratio shall be selected.
