Glossary
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A
Adsorption
In the process of adsorption, an atom or molecule from a gas or liquid
settles on an interior surface of an adsorbent (e.g. active charcoal).
Absorption, on the other hand, describes the uptake of an atom or molecule within the free body/volume of a substance.
Aeroallergens
Inhalation allergens or aeroallergens are taken up during respiration. Typical examples are birch pollen allergens.
aerobic / anaerobic
Living organisms that require oxygen for life are designated as aerobic. Those requiring no oxygen are designated as anaerobic.
anoxic
describes a film/layer of water containing no dissolved oxygen. Certain microorganisms use nitrate, iron(III) or sulfate to decompose organic material in support of life.
Antibodies
Antibodies (also known as immunoglobulins) are proteins (albumin or egg white substances) classified as globulins. Vertebrates form antibodies in reaction to penetration by certain extraneous substances, the so-called antigens. Antibodies serve to ward off such extraneous substances (antigens). Antigens are almost exclusively macromolecular or molecules bound to or otherwise associated with (larger) particulate bodies. An example would be lipopolysaccharides located on the surface of bacteria. A particular antigen usually induces the generation of a particular matching antibody which only interacts with this specific antigen.
The specific binding of antibodies to antigens provides an essential component of defense against the invasion of extraneous substances. In opposition to substances that cause disease (pathogens), the formation of antibodies often leads to immunity. In other words, antibodies are central components of the immune systems of higher vertebrates. As indicated above, antibodies are also designated as immunoglobulins (Ig).
Aptamer
An aptamer (lat. aptus: fit) is a short single stranded DNA or RNA oligonucleotide, able to bind a target molecule specifically and with high affinity accordingly to its three dimensional structure. Aptamers are produced by means of SELEX procedures, an in vitro selection process. Aptamers are used for medical purposes (diagnosis and therapy), in basic research for the study of protein functions, as molecular recognition elements in analytical systems (including biosensors) as well as specific binding partners in enrichment and separation systems.
Aquifer
A geologic formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to springs and wells (definition by USGS; http://capp.water.usgs.gov/GIP/h2o_gloss).
Archaea
The archaea – formally also known as archaebacteria or primitive bacteria – form one of the three domains, alongside eubacteria and eukaryotes, in which all cellular organisms are distributed.
