Inoculation
When inoculation (colloquially seeding or inoculation ) is in the microbiology and cell biology adding a replicable object (for. Example, a cell culture or pathogens such as viruses or prions ) refers to a cell culture.
properties
The goal of inoculation is usually a maximum rate of cell division . In the case of an inoculation, a larger volume of a nutrient medium or culture medium is inoculated - usually proceeding from a starting culture . The number of particles in an inoculum is crucial for successful large-scale culture. Many bacteria require a certain cell density for bacterial growth in order to enter the exponential growth phase (also: logarithmic growth phase or log phase). If the inoculum is too small, the culture does not grow or grows only very slowly. In order to cultivate cells in large volumes, a series of ever larger precultures is used in biotechnology until the actual fermenter is inoculated. The cells are then in a continuous exponential growth phase from start to finish.
The inoculum of a microbial culture can come from all three phylogenetic domains of living beings : Archaebacteria ( Archaea ), bacteria ( Bacteria ) and eukaryotes ( Eukarya ). If the inoculum comes from the realm of multicellular eukaryotes ( fungi , plants and animals ), the microbial culture is called tissue or cell culture (an inoculum of protists and one- to few- celled animals, fungi and plants is often still called microbial culture ). They can be wild or cultured. The material that is transferred to a medium is called inoculum (also inoculate). The success of the inoculation depends on it and on the quality of the culture medium .
parameter
A good inoculum is fresh, sufficiently large (volume of inoculate / volume of culture) and has a good cell density (number of cells / volume).
A good culture is fresh, consists of a medium which fulfills all the conditions for the growth or multiplication of the microbial strain used, has an optimal environment for the growth or multiplication of the culture used, and is sufficient for the requirements of the nutrient medium and the inoculate disinfected.
The inoculum is sufficiently fresh if it has not been stored for too long under poor conditions (e.g. temperature, food supply, etc.). Exceptions are examinations of the survival stages . If the inoculum is too small, the culture will grow very slowly. Therefore, the size ratio of the inoculate to the culture is very important. In addition to the volume (size), the cell density of the inoculate is very important for a successful culture. Some large inoculates that contain only a few cells are not a sufficient starting medium for various microbial strains that require a certain cell density (cells per volume) in order to enter the exponential growth phase. In these cases precultures are used. As in biotechnology , they can be switched in ever larger series so that the starting medium is sufficiently large and dense. But they can also be set up again and again at certain inoculate-related time intervals so that the sufficient freshness of the inoculate can be maintained over longer periods of time.
A culture is fresh when the nutrients in the medium have not been used up and are still sufficiently available. The nutrient medium is selected depending on the microbial strain used. Some strains require special micro-components such as B. different ions, minerals, vitamins , some in turn narrow pH ranges. So that a culture can flourish, an environment must be created for it in which all necessary physical (temperature, humidity, air pressure etc.), chemical (composition of the medium, pH value etc.) and biological (nutrient supply, its access, possible symbionts etc.) parameters can be kept at an optimum for the strain or cell culture used. Sterility is also a prerequisite for the success of a culture. It is checked by the sterilization control and can be kept differently strict depending on the nutrient medium and inoculum. In general, however, the more sterile the culture conditions, the higher the chances of a successful culture. However, maintaining a high level of sterility is associated with high costs.
Other meanings
The purpose of vaccination today is to avoid disease through weakened pathogens. At the time of Robert Koch , on the other hand, one wanted to trigger the disease in question in animal experiments by vaccination with virulent pathogens ( etiological unicausalism of bacteriology ). In vaccination, there was a diametrical change in meaning from inoculation to vaccination , i.e. from inoculation to vaccination.
Vaccination with live vaccines was formerly known as inoculation. z. B. the variolation .
In social psychology, the inoculation theory describes a process with which psychological attitudes are made resistant to attempts at change. In marketing, an inoculation strategy stands for the concept of immunizing the target group against counter-arguments through active communication (in the sense of a vaccination).
literature
- Eckhard Bast: Microbiological Methods: An Introduction to Basic Working Techniques. 2nd edition 2001, spectrum. ISBN 978-3-8274-1072-6 .
Individual evidence
- ^ Christian Probst: Robert Koch , in: "About important doctors in history", Volume II, special edition, Droemersche Verlagsanstalt , Munich 1982, ISBN 3-426-03919-2 , pp. 69-99.