Silver stain
Encyclopedia
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
to selectively alter the appearance of the target.
Use in medicine
It is used to stain histologic sections. This kind of staining is important especially to show proteinProtein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s (for example type III collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
) and DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
. It is used to show both substances inside and outside cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
s. Silver staining is also used in temperature gradient gel electrophoresis
Temperature gradient gel electrophoresis
Temperature Gradient Gel Electrophoresis and Denaturing Gradient Gel Electrophoresis are forms of electrophoresis which use either a temperature or chemical gradient to denature the sample as it moves across an acrylamide gel. TGGE and DGGE can be applied to nucleic acids such as DNA and RNA,...
and in polyacrylamide gels.
Some cells are argentaffin. These reduce
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....
silver solution to metallic silver after formalin fixation
Fixation (histology)
In the fields of histology, pathology, and cell biology, fixation is a chemical process by which biological tissues are preserved from decay, thereby preventing autolysis or putrefaction...
. Other cells are argyrophilic. These reduce silver solution to metallic silver after being exposed to the stain that contains a reductant
Reducing agent
A reducing agent is the element or compound in a reduction-oxidation reaction that donates an electron to another species; however, since the reducer loses an electron we say it is "oxidized"...
, for example hydroquinone
Hydroquinone
Hydroquinone, also benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, having the chemical formula C6H42. Its chemical structure, shown in the table at right, has two hydroxyl groups bonded to a benzene ring in a para position. It is a white granular solid...
or formalin.
Silver nitrate forms insoluble silver phosphate
Silver phosphate
Silver phosphate or silver orthophosphate is a light sensitive, yellow, water insoluble chemical compound composed of silver and phosphate ions of formula Ag3PO4.- Synthesis, reactions and properties :...
with phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
ions; this method is known as the Von Kossa Stain. When subjected to a reducing agent, usually hydroquinone
Hydroquinone
Hydroquinone, also benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, having the chemical formula C6H42. Its chemical structure, shown in the table at right, has two hydroxyl groups bonded to a benzene ring in a para position. It is a white granular solid...
, it forms black elementary silver. This is used for study of formation of calcium phosphate
Calcium phosphate
Calcium phosphate is the name given to a family of minerals containing calcium ions together with orthophosphates , metaphosphates or pyrophosphates and occasionally hydrogen or hydroxide ions ....
particles during bone growth.
Silver staining is used in light microscopy. The metallic silver particles are deposited on sensitised reticulin fibres and are then easily seen in the microscopic preparations.
Silver stain aids in the perception of reticular fiber
Reticular fiber
Reticular fibers or reticulin is a histological term used to describe a type of fiber in connective tissue composed of type III collagen. Reticular fibers crosslink to form a fine meshwork...
s.
Karyotype analysis
Silver staining is also used in karyotypeKaryotype
A karyotype is the number and appearance of chromosomes in the nucleus of an eukaryotic cell. The term is also used for the complete set of chromosomes in a species, or an individual organism.p28...
analysis. Silver nitrate
Silver nitrate
Silver nitrate is an inorganic compound with chemical formula . This compound is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides...
stains the nucleolar organization region-associated protein. This yields a dark region where the silver is deposited, denoting the activity of rRNA
Ribosomal RNA
Ribosomal ribonucleic acid is the RNA component of the ribosome, the enzyme that is the site of protein synthesis in all living cells. Ribosomal RNA provides a mechanism for decoding mRNA into amino acids and interacts with tRNAs during translation by providing peptidyl transferase activity...
genes within the NOR. Chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
s 13, 14, 15, 21, and 22 have NORs.
Furthermore, NORs increase the silver stain activity from about 50 times. This protein was discovered by Watson and Crick.
Organisms highlighted
PseudomonasPseudomonas
Pseudomonas is a genus of gammaproteobacteria, belonging to the family Pseudomonadaceae containing 191 validly described species.Recently, 16S rRNA sequence analysis has redefined the taxonomy of many bacterial species. As a result, the genus Pseudomonas includes strains formerly classified in the...
,
Legionella
Legionella
Legionella is a pathogenic Gram negative bacterium, including species that cause legionellosis or Legionnaires' disease, most notably L. pneumophila. It may be readily visualized with a silver stain....
, Leptospira
Leptospira
Leptospira is a genus of spirochaete bacteria, including a small number of pathogenic and saprophytic species...
, H. pylori, and fungi like Pneumocystis and Candida.
Methenamine silver stains
There are several silver stains incorporating methenamine, including:- Grocott's methenamine silver stain, used widely as a screen for fungal organisms.
- Jones' stainJones' stainJones' stain, also Jones stain, is a methenamine silver-Periodic acid-Schiff stain used in pathology. It is also referred to as methenamine PAS which is commonly abbreviated MPAS....
, a methenamine silver-Periodic acid-SchiffPeriodic acid-SchiffPeriodic acid-Schiff is a staining method used to detect glycogen and other polysaccharides in tissues. The reaction of periodic acid oxidizes the diol functional groups in glucose and other sugars, creating aldehydes that react with the Schiff reagent to give a purple-magenta color...
that stains for basement membraneBasement membraneThe basement membrane is a thin sheet of fibers that underlies the epithelium, which lines the cavities and surfaces of organs including skin, or the endothelium, which lines the interior surface of blood vessels.- Composition :...
, availing to view the "spiked" GBMGBM-Medicine:* Glioblastoma multiforme, a type of brain tumor* Glomerular basement membrane, a part of the glomerulus which helps separate urine from blood-Other:* Game Boy Micro, a portable video game system from Nintendo...
associated with membranous glomerulonephritisMembranous glomerulonephritisMembranous glomerulonephritis is a slowly progressive disease of the kidney affecting mostly patients between ages of 30 and 50 years, usually Caucasian.It is one of the more common forms of nephrotic syndrome.-Terminology:...
.
Silver staining of SDS Polyacrylamide gels
Camillo GolgiCamillo Golgi
Camillo Golgi was an Italian physician, pathologist, scientist, and Nobel laureate.-Biography:Camillo Golgi was born in the village of Corteno, Lombardy, then part of the Austrian Empire. The village is now named Corteno Golgi in his honour. His father was a physician and district medical officer...
perfected the silver staining for the study of the nervous system
Nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...
. Golgi's method
Golgi's method
Golgi's method is a nervous tissue staining technique discovered by Italian physician and scientist Camillo Golgi in 1873. It was initially named the black reaction by Golgi, but it became better known as the Golgi stain or later, Golgi method.Golgi' staining was famously used by Spanish...
stains a limited number of cells at random in their entirety. The exact chemical mechanism by which this happens is still largely unknown. Silver staining was introduced by Kerenyi and Gallyas as a sensitive procedure to detect trace amounts of proteins in gel
Gel
A gel is a solid, jelly-like material that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state...
s. The technique has been extended to the study of other biological macromolecules that have been separated in a variety of supports. Classical Coomassie Brilliant Blue staining can usually detect a 50 ng protein band, Silver staining increases the sensitivity typically 50 times. Many variables can influence the colour
Color
Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...
intensity and every protein has its own staining characteristics; clean glassware, pure reagents and water of highest purity are the key points to successful staining.
Use in art
Silver staining is also a technique in traditional stained glassStained glass
The term stained glass can refer to coloured glass as a material or to works produced from it. Throughout its thousand-year history, the term has been applied almost exclusively to the windows of churches and other significant buildings...
to produce the yellow, brown or amber shading when painting on glass. It is a technique that is often used for realistic hair colors. It was discovered in the 14th Century but was not originally used very frequently.
External links
- http://www.biomalpar.org/updatedMethods_In_Malaria_Research_5thedition.pdf Hempelmann E. SDS-Protein PAGE and Proteindetection by Silverstaining and Immunoblotting of Plasmodium falciparum proteins. in: Moll K, Ljungström J, Perlmann H, Scherf A, Wahlgren M (eds) Methods in Malaria Research, 5th edition, 2008, 263-266