Goblet Guardians

What am I looking at?

This is a fluorescent image of the point where zebrafish gill filaments attach to the fish’s body. A single filament can be seen in the center of the image (1), and two partial filaments can be seen on either side (2 and 3). The light blue is the actin (4) contained in the cells. The magenta cells (5) express immune molecules called MHC-II, an important factor in the detection of infectious microbes by the immune system. The yellow/white cells at the base of the filaments, and scattered elsewhere, are cells that produce mucus for the gills (6).

Biology in the background

A fish’s gills extract oxygen from the water, allowing it to breathe. However, these structures are fragile and need protection from physical and microbial damage. The gills are covered with a bony plate called the operculum, which protects the gills from direct impact. However, as water runs over the gills, they are exposed to a significant amount of debris and microbes that could damage or infect them. This is where mucus comes in.

There are specialized cells called goblet cells concentrated at the bottom of each gill filament and spread throughout the filaments. These cells produce enough mucus to coat the gill filaments entirely. This coat of mucus traps debris and microorganisms, protecting the gills from damage.

These goblet cells are about 11 micrometers across, or roughly 7 times smaller than the width of a human hair.

Technique

This image was created using confocal microscopy.