Types of microbial culture cultures)

It deals and closes the types of bacterial culture

1. SRI PARAMAKALYANI COLLEGE , Reaacredited with B grade with a CGPA of 2.71 in the second cycle of NAAC affiliated to manomanium sundaranar university, tirunelveli. ALWARKURICHI-627412. 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. AXENIC CULTURE synopsis Introduction. Axenic culture. Preparation of AXENIC culture Maintainance and Preservation. Experimental uses. Applications.

3. INTRODUCTION 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. AXENIC CULTURE 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. PREPARATION OF AXENIC CULTURE

7. procedure ISOLATION The samples are serially diluted and gives rise to subsamples. Plating techniques - pour plate Method, spread plate method and streak plate method. The platings are done to reduce the bacterial counts and to get isolated colonies. ANTIBIOTIC TREATMENT There are a variety of  antibiotics  that can be added to agar before it is poured into a plate and allowed to solidify. 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.

9. MAINTENANCE AND PRESERVATION

10. EXPERIMENTAL USES 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).

11. Applications of axenic culture Important tool for study of symbiotic and parasitic organisms in an controlled environment. I t 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.

12. A SYNCHRONOUS & SYNCHRONOUS GROWTH CULTURES Synopsis Synchronous culture. Methods. Applications. Asynchronous culture.

13. SYNCHRONOUS CULTURE 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.

14. 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.

15. Methods 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. Induction technique Starvation technique Filtration technique

16. Forced method 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.

17. Mechanical selection method (Filteration Technique) 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.

18. Helmstetter-cummings technique In this unsynchronized bacterial culture is filtered through cellulose nitrate membrane filter . The loosely bound bacterial cells are washed from the filter, leaving some cells tightly associated with the filter. The filter is now inverted and fresh medium is allowed to flow through it. New bacterial cells, that are produced by cell division and are not tightly associated with the filter, are washed into the effluent. 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.

19. Applications of synchronous culture 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.

20. ASYNCHRONOUS CULTURE 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.

21. Reference Microbiology (8 th edition ) by Jacquelyn G.Black Prescott (7 th 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/dictio axenic-culturehttps https://www.slideshare.net/prdiphamal/parasite-culture

22. THANK YOU The Chairman. The Secretary. Management Committee. The Principle,Sri Paramakalyani College. The Head - Department Of Microbiology. The staff Members - Department Of Microbiology.