It deals and closes the types of bacterial culture

1. Reaacredited with B grade with a CGPA of 2.71 in the second cycle of NAAC
affiliated to manomanium sundaranar university, tirunelveli.
Post graduate & Research Centre – Department of microbiology
(government aided)
I SEM CORE: MICROBIAL PHYSIOLOGY AND METABOLISM (ZMBM13)
UNIT-5
TYPES OF CULTURES
S. INDHUMATHI
REG NO:20211232516110
I M.SC MICROBIOLOGY
ASSIGNED ON: 05/12/2021
TAKEN ON:10/01/2022
SUBMITTED TO,
GUIDE: DR.S.VISWANATHAN. PH.D.,
ASSISTANT PROFESSOR & HEAD
SPKC –ALWARKURICHI.

2. • Introduction.
• Axenic culture.
• Preparation of AXENIC culture
• Maintainance and Preservation.
• Experimental uses.
• Applications.

3. • AXENIC is derived from 2 Greek words.
A – without or free from.
XENOS – foreign particles.
• The term “AXENIC” was introduced by 2
American biologist James A Baker and
M.S.Ferguson in their article “Growth of
platyfish free from bacteria and other
microbes” in 1942.

4. It describes the state of culture , in which contain
only a single species, variety or strain of
particular organism is present.
It is otherwise called pure culture.
It is entirely free from contaminating organisms.
The earliest axenic culture were of bacteria and
unicellular eukaryotes.
Now-a-days axenic culture of many multicellular
organisms are also possible.

5. Uncontaminated colonies.
Pure culture
Contain only one micro organisms.
Free from pathogenic organisms and other Micro
Organisms.
Axenic culture achieved on plates.

6. CULTURE HEALTH ASSESSMENT
AXENIC CULTURE
ANTIBIOTIC TREATMENTS
ISOLATION

7. ISOLATION
1. The samples are serially diluted and gives rise to subsamples.
2. Plating techniques - pour plate Method, spread plate method
and streak plate method.
3. The platings are done to reduce the bacterial counts and to get
isolated colonies.
ANTIBIOTIC TREATMENT
1. There are a variety of antibiotics that can be added to
agar before it is poured into a plate and allowed to
solidify.
2. Some types of bacteria can only grow in the presence of
certain additives. This can also be used when creating
engineered strains of bacteria that contain an antibiotic-
resistance gene.

8. 3. When the selected antibiotic is added to the agar,
only bacterial cells containing the gene insert conferring
resistance will be able to grow.
4. These steps are repeated again to check the axenicity.

10. TIME INTERVAL
• The culture medium is checked periodically.
CONTAMINATION
• The subculture is checked for its contamination.
CHECKING
• The sample is kept on the enriched medium. If the culture
is pure, no organisms grow from the Agar plate.

11. • As axenic cultures are derived from very few
organisms, or even a single individual, they are useful
because the organisms present within them share a
relatively narrow gene pool.
• In the case of an asexual species derived
from a single individual, the resulting culture
should consist of identical organisms (though
processes such as mutation and horizontal
gene transfer may introduce a degree of
variability).

12. Important tool for study of symbiotic and
parasitic organisms in an controlled
environment.
It is used to observe lifestyle of entamoeba
and fungi increase in the lichens etc,.
It enables precise antigenic and biochemical
studies.
It is also used for Genome sequencing and
molecular studies of micro organisms.

14. • Synchronous culture.
• Methods.
• Applications.
• Asynchronous culture.

15. • Synchronous culture are composed of
populations of cells, that are at the same stage
of their life cycle.
• Synchronous growth of a bacterial population
are physiologically identical and in the same
stage in division of cycle at a given time.
• Thus the entire population is kept uniform
with respect to growth and division.

16. • There is no way to analyse a single bacterial
cell to obtain information about growth
behaviour (i.e.,) Organisation, differentiation
and macromolecular synthesis.
• Synchronous culture provides the entire cell
crop in the same stage of growth.

17. • In most of the bacterial cultures the stages of
growth and cell division cycle are completely
random.
• Thus it becomes difficult to understand the
properties during the cell division of cycle
using such cultures.
• Synchronous culture of bacteria can be
obtained by number of techniques.
1. Induction technique
2. Starvation technique
3. Filtration technique

18. • Induction technique - Temperature shocks of hot and
cold -combinations of heat and cold have been used to
induce synchrony.
• Starvation technique - allow the growth medium to
become depleated with respect to one of the nutrients
and transfer the organisms to fresh complete medium.
• In photosynthetic organisms, photosynthetic cells light
can be eliminated for several hours and re-introduce it.
• Drawback- It may interfere with normal metabolism of
the cell and data obtained from this of study must be
interpreted.

19. • The population of cells is fractionated on the basis of
size.
• The cells are filtered, so that smallest cells pass
through the filter.
• These small cells are the youngest, and must go
through their whole life cycle before dividing.
• Alternatively, the largest cells which are ready to divide
may be retained or retarted by a filter.
• These are collected separately and used to obtain a
synchronous culture.
• Instead of filtration, density gradient centrifugation is
also used to separate the cells.

20. 1. In this unsynchronized bacterial culture is filtered through
cellulose nitrate membrane filter.
2. The loosely bound bacterial cells are washed from the filter,
leaving some cells tightly associated with the filter.
3. The filter is now inverted and fresh medium is allowed to
flow through it.
4. New bacterial cells, that are produced by cell division and are
not tightly associated with the filter, are washed into the
effluent.
5. Hence, all cells in the effluent are newly formed, therefore at
the same stage of growth and division cycle. The effluent
thus represents a synchronous culture.

22. • It helps in the seperation of the smallest cells
from an exponential growing culture.
• It is used to study the cell cycle.
• It plays an important role in in the study of
genetics and metabolism.

23. • Asynchronous – occurring in different geologic
times.
• Asynchronous culture – In an actual culture
each cells divide sometime during the 20
minutes generation with about 1/20 of the
cells dividing each minute.
• It is a natural situation called asynchronous
growth.

26. Reference
• Microbiology (8th edition ) by Jacquelyn G.Black
• Prescott (7th edition) Harley and klein s Microbiology
• https://www.merriam-webster.com/dictionary/axenic#h1
• https://en.m.wikipedia.org/wiki/Axenic
• https://www.biologyonline.com/dictionary/axenic-culture
• https://www.vedantu.com/question-answer/axenic-culture-
is-a-pure-culture-without-any-class-11-biology-cbse-
602ff1711c2d714a4abf436d
• https://www.biologyonline.com/dictioaxenic-culturehttps
• https://www.slideshare.net/prdiphamal/parasite-culture