Localization of glucuronoxylans in Japanese beech visualized by immunogold labelling

Summary An antiserum against glucuronoxylans (GXs) has been raised from a mouse. The dot-blot immunoassay and competitive inhibition test indicated that the antibodies could bind specifically to GXs. Therefore, the antiserum was used for immunogold labelling to investigate the localization of GXs in Japanese beech. Labelling of GXs was seen only in the secondary walls of xylem cells, but not in the primary walls or the middle lamella. GXs were evenly distributed in the secondary walls except for the outer part of the outer secondary-wall layer in which they were less abundant. The labelling density in each secondary-wall layer (S₁, S₂, and S₃) increased during cell wall formation. This result strongly suggests that the deposition of GXs occurs in a penetrative way.     

Immunogold labelling of serotonin-like and FMRFamide-like immunoreactive material in neurohaemal areas on abdominal nerves of Rhodnius prolixus

The ultrastructure of neurohaemal areas on abdominal nerves of the blood-sucking bug Rhodnius prolixus was investigated. Four types of axon terminals were found, distinguished by the morphology of their neurosecretory granules. By use of post-embedding immunogold labelling, granules in Type I axon terminals were shown to contain serotonin-like immunoreactive material, and granules in Type II axon terminals were shown to contain FMRFamide-like immunoreactive material. There was no colocalization of these materials. It is suggested that Type III terminals contain peptidergic diuretic hormone, which has previously been reported to be present in electron-dense neurosecretory granules in this neurohaemal area. The identity of material in Type IV terminals is unknown.