Fluorescence Microscopy

The images in this gallery have been obtained with a confocal LSM (Laser Scanning Microscope) or by conventional fluorescent microscopy. In some cases, the usual "coding" of RGB (red, green, blue) for each channel has been changed to different colors.

 

Microglia

Microglia are a cell type, that is only found in the CNS (Central Nervous System; per human definition: brain and spinal cord). Usually microglial cells are in a so called ramified state, in which they are basically inactive. However they can be “activated” via various triggers (all caused by some kind of brain injury):

cytokines (a combination of lipopolysaccharide (LPS) and interferon-gamma is one of the most effective), degenerative diseases or physical injury.

Once activated, microglia assume an amoeboid (round, oval) morphology, and display a behavior similar to macrophages. They act as antigen-presenting, phagocytic, and cytotoxic cells, all three a hallmark of cells of the immune system.

The name microglia was first (1920) introduced by Pio del Rio-Hortega (1882 – 1945). Since the function and ontology of microglia was unknown at that time, and furthermore, the cells of the brain where divided into two types: neurons and “others”, which were termed by the generic expression “glia” (e.g. astroglia and oligodendroglia ), the term microglia was a reference 1. to their shape 2. to their obviously non-neuronal characteristics.

Hepatocyte

Hepatocyte is the terminus technicus for parenchymal liver cells, derived from the Greek word "hepar" which translates to liver (see also Hepatitis with the suffix "-itis", which, in medicine, has the general meaning "inflammation"). Hepatocytes are the major cell type of the liver (more than 80%), and they are responsible for a plethora of metabolic functions.

Fibroblasts

A cell type that is found in various so called "connective tissue"; the definition is rather difficult, since the term mainly refers to the ability of fibroblasts to synthesize and maintain the extracellular matrix of many organs. The term is a composition of "fibro-" from Latin "fibra" meaning fiber and "-blast" from Greek "blastos", meaning germ, bud.

Protein / Enzyme

The (confocal) fluorescence microscopy images in this gallery are mostly about connexin (which form gap junctions), nitric oxide synthase (iNOS, bNOS, eNOS), NF-KappaB (NFkB) and cytoskeleton (tubulin, neurofilament). Using a primary antibody (which binds to the protein) and a secondary antibody, labeled with a fluorochrome, which binds to the primary antibody, the images where obtained.

GFAP

Glial fibrillary acidic protein (GFAP) is a protein, first discovered in 1971. It belongs to a class of proteins called intermediate filaments (prominent members are tubulin (which forms microtubules), neurofilament, vimentin, ...), whose primary function is the formation of the cytoskeleton (the "skeleton" within the cytoplasm of all cells). The cytoskeleton is responsible for the shape, intracellular transport and cellular division (e.g. mitosis).
In the adult CNS, GFAP is almost exclusively expressed in astrocytes, and is thus regarded as a very reliable cellular marker.

Tubulin

The most common members of the tubulin family are alpha-tubulin and beta-tubulin, which, as dimers, make up microtubules. Microtubules have a diameter of 25 nm and a length between 200 nanometers and 25 micrometers (which is close to the diameter of the largest eukaryotic cells).
Besides their role as part of the cytoskeleton, they have the notable function of forming the mitotic spindle, used during cell divison to segregate the chromosomes