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Hemp I / Hemp II / Asplenium / Ferns / Xyloglucan / Xylan / Arabinan / Cell adhesion

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Xylans un-masked

The detection of xylan polysaccharides in both primary and secondary cell walls of tobacco stems has been studied with:

- two monoclonal antibodies: LM10 & LM11

and

- two carbohydrate-binding modules: CjCBM15 & CfCBM2b-1-2.

Right: Spatial mapping & quantification of molecular probe fluorescence in xylem cell walls.

For details see Hervé et al. 2009

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Bright-field image of a transverse section of a tobacco stem combined with the fluorescence detection of CfCBM2b-1-2 binding to xylans. Xylans are abundant in secondary cell walls of phloem fibres, xylem cells and fibres associated with internal phloem.


 
 

Pair of micrographs showing CjCBM15 binding to xylans in cortical regions of a transverse section of a tobacco stem.

Upper panel: untreated section.

Lower panel: equivalent section pre-treated with pectin-degrading enzyme to remove pectic homogalacturonan.

Xylan polysaccharides in the cell walls of the epidermis and regions of cortical parenchyma/collenchyma are unmasked by pectin removal allowing recognition by the CBM probe.

 
 

Micrograph showing epidermis and outer cortical tissue of tobacco stem section that has been pre-treated to remove pectic homogalacturonan. All cell walls are indicated by Calcofluor (blue) and the green fluorescence indicates the binding of monoclonal antibody LM11 to un-masked xylan epitopes at cell wall regions at the centre of thickenings at cell corners.

 
 

Equivalent combined micrograph as above showing epidermis and outer cortical tissue of tobacco stem showing all cell walls (blue) and monoclonal antibody LM10 binding (green) to xylan epitopes at inner cell wall regions that are peripheral to the cell wall thickenings at cell corners.

This pattern of occurrence of LM10 binding is in contrast to that observed for LM11 shown above indicating distinct spatial occurrence of the LM10 and LM11 xylan epitopes within the same cell walls.

 

 

 
       
     

 

 

 

 

   

 

   

Last modified 22/02/10