Electron microscopy and X-ray microanalysis as tools for fine localization of the ?-glucuronidase activity in transgenic plants harbouring the GUS reporter gene

PROTOPLASMA ◽  
1992 ◽  
Vol 170 (1-2) ◽  
pp. 68-76 ◽  
Author(s):  
J. -C. Caissard ◽  
J. Rembur ◽  
Dominique Chriqui
2001 ◽  
Vol 48 (3) ◽  
pp. 637-646 ◽  
Author(s):  
W Nowak ◽  
M Gawłowska ◽  
A Jarmołowski ◽  
J Augustyniak

Matrix attachment regions (MARs) are thought to participate in the organization and segregation of independent chromosomal loop domains. Although there are several reports on the action of natural MARs in the context of heterologous genes in transgenic plants, in our study we tested a synthetic MAR (sMAR) with the special property of unpairing when under superhelical strain, for its effect on reporter gene expression in tobacco plants. The synthetic MAR was a multimer of a short sequence from the MAR 3' end of the immunoglobulin heavy chain (IgH) enhancer. This sMAR sequence was used to flank the beta-glucuronidase (GUS) reporter gene within the T-DNA of the binary vector pBI121. Vectors with or without the sMARs were then used to transform tobacco plants by Agrobacterium tumefaciens. Transgenic plants containing the sMAR sequences flanking the GUS gene exhibited higher levels of transgene expression compared with transgenic plants which lacked the sMARs. This effect was observed independently of the position of the sMAR at the 5' side of the reporter gene. However, variation of the detected transgene expression was significant in all transformed plant populations, irrespective of the construct used.


Author(s):  
Richard S. Thomas ◽  
Mabel I. Corlett

Ash patterns produced by oxygen plasma microincineration(OPM) of thin-sectioned biological materials and examined with the transmission electron microscope (TEM) can show unambiguously the distribution of mineral substances in the specimen with resolutions down to 100 Å. The chemical nature of the mineral is not demonstrated, however. Electron-probe X-ray microanalysis (EXM), on the other hand, can determine precisely the nature of the mineral in ashgd or unashed sections but its spatial resolution is limited to 1000-10,000 A at best. Also its sensitivity of analysis on unashed specimens is limited by intolerance of the specimen to high beam intensities. Using both TEM and EXM together on ash patterns of suitable specimens can overcome their independent spatial and chemical limitations. Furthermore, use of OPM produces a highly stable mineral specimen for EXM, thereby improving sensitivity.


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