scholarly journals A Structure−Permeability Relationship of Ultrathin Nanoporous Silicon Membrane:  A Comparison with the Nuclear Envelope

2008 ◽  
Vol 130 (13) ◽  
pp. 4230-4231 ◽  
Author(s):  
Eunkyoung Kim ◽  
Hui Xiong ◽  
Christopher C. Striemer ◽  
David Z. Fang ◽  
Philippe M. Fauchet ◽  
...  
1988 ◽  
Vol 90 (2) ◽  
pp. 237-245
Author(s):  
J.M. Lord ◽  
J.A. Thick ◽  
C.M. Bunce ◽  
A.M. Taylor ◽  
P.H. Gallimore ◽  
...  

The monoclonal antibody AGF2.3 identifies a nuclear envelope protein that is restricted to certain cell types. In particular, this antigen shows a reduced level of expression during haemopoietic cell maturation. In this study, we have examined the relationship of this protein to known nuclear envelope proteins that have a similar molecular mass. Antigen extraction and immunoelectron microscope studies revealed that the AGF2.3 protein is an integral membrane protein present at both the inner and outer aspects of the nuclear envelope. The protein is not associated with nuclear pores and therefore is distinct from pore complex proteins. The AGF2.3 protein does not have ATPase activity. Therefore, this protein is also distinct from a myosin heavy chain-like ATPase that is associated with the nuclear envelope. The AGF2.3 antibody identifies a novel nuclear envelope protein. Further studies of the biochemical nature of the AGF2.3 protein should provide insight into novel cellular processes at the nuclear envelope relating to the lineage or maturation status of cells.


1990 ◽  
Vol 110 (2) ◽  
pp. 255-261 ◽  
Author(s):  
G Ching ◽  
E Wang

Statin has previously been identified to be a 57-kD protein present in the nuclei of quiescent and senescent human fibroblasts, but not in their replicating counterparts (Wang, E. 1985. J. Cell Biol. 100: 545-551). In the present report we demonstrate by immunoprecipitation analysis of fractionated cellular extracts the existence of two populations of statin. The Triton X-100-soluble statin is found in replicating sparse cultures as well as in quiescent confluent cultures and quiescent serum-starved cultures of young human fibroblasts, but the Triton X-100-insoluble, nuclear envelope-localized statin is present only in the quiescent cultures. Two-dimensional gel analysis of the immunoprecipitated cellular fractions reveals that both populations of statin have an isoelectric point of 5.3. Pulse-chase experiments show that statin is synthesized as a 57-kD polypeptide and is not processed from a precursor of different molecular mass. Experiments on serum stimulation of quiescent cells show that synthesis of the Triton X-100-insoluble statin decreases rapidly during the transition from the G0 to S phase, and that this decrease is accompanied by a slower reduction in synthesis of the Triton X-100-soluble statin. These results suggest that the cellular expression of the two populations of statin may be associated with the mechanisms controlling the transition between the growing state and the quiescent state and confirm the previous finding that the Triton X-100-insoluble, nuclear envelope-localized statin could be used as a marker for cells arrested at the G0 phase of the cell cycle.


2012 ◽  
Vol 258 (15) ◽  
pp. 5654-5658 ◽  
Author(s):  
M. Jaouadi ◽  
W. Dimassi ◽  
M. Gaidi ◽  
R. Chtourou ◽  
H. Ezzaouia

2006 ◽  
Vol 15 (3) ◽  
pp. 671-677 ◽  
Author(s):  
K.-L. Chu ◽  
S. Gold ◽  
V. Subramanian ◽  
C. Lu ◽  
M.A. Shannon ◽  
...  

2011 ◽  
Vol 10 (04n05) ◽  
pp. 793-796 ◽  
Author(s):  
H. V. BALACHANDRA ACHAR ◽  
ENAKSHI BHATTACHARYA

Separation of biomolecules based on their size and charge is an important procedure employed in biomolecular analysis. Nanosieve comprising of a semi-permeable membrane with nanometer-sized pores is used for this purpose. Described here is the fabrication of ultra thin nanoporous silicon membrane, which can be used as nanosieve, making use of standard microelectronics fabrication techniques. Lithography and bulk silicon etching is used to initially create a 10 μm thick sacrificial membrane in the center of a 200 μm thick silicon substrate. A three-layer stack of SiO2 , amorphous silicon ( a-Si ) and SiO2 is then deposited using chemical vapor deposition technique. The sample is subjected to rapid thermal annealing during which pores are formed in the a-Si layer. Finally, the 15 nm thick nanoporous silicon membrane is released using reactive ion etching of the sacrificial membrane. The formation of the pores is confirmed by transmission and scanning electron microscope images. At present the pore formation is random; our future work will focus on controlled nucleation of silicon nanocrystals so as to get pores at desired locations.


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