Gum arabic (powder)

树胶 gum

　　 亦称植物树胶，与弹性树胶不同，是植物的树皮、叶或根分泌的物质，为具有在水中膨润的凝胶或形成粘稠胶体溶液性的酸性物质的总称。与半纤维素也不同，是容易由弱水解除去的糖成分和难于分解部分所构成的高分子多糖，后者是含有六碳糖、五碳糖和糖醛酸的糖醛化合物。糖醛化合物的酸性基容易滴走，树胶可被调制成为游离酸或各种盐的形态。所熟知的有阿拉伯树胶（gum arabic；豆科金槐属的数种，尤其是阿拉伯胶树Acacia senegal的树皮），牧豆树树胶（mesquite gnm，豆科牧豆树

Silver Enhancement of Colloidal Gold

safe light conditions, as this delays self-nucleation of silver ions. The reaction is stopped by transfering the grids to bi-distilled water. Before staining with uranyl acetate and lead citrate, components like gum arabic have to be completely removed

Silver Enhancement Protocol

. The degree of staining may be monitored periodically under a bright-field microscope, adjusted to low light intensity. If a more intense staining is desired, place the slide back in the developer. For certain studies, addition of crude gum arabic to a final