For my internship which concerns the bone regeneration, I had the opportunity to be able to discover the cell culture. Some of you think maybe that the cell culture in microbiology is similar to the other types of cell cultures but they exist differences. We are going to begin by approaching the microbiology with a fast reminder of the characteristics of this domain because you already know it a lot about this subject then we will speak of other types of cell cultures and their differences with the microbiology. Microbiology The microbiology is the domain which studies microorganisms. We study bacteria, fungis, algaes or viruses. In this domain, we thus study as well procaryotes organisms as eucaryotes organisms (Fig 1). [1] Figure 1: Bacteria [2] and Yeast [3] representation Very often in microbiology, we study bacteria and yeasts because they are model organisms and easy to study thanks to different advantages. For example, their genomes is totally sequenced, their cycles of division is fast, they are easy to maintain in culture, etc. … Indeed, in microbiology, it is an advantage to study microorganisms because it simplifies the studies. In general, conditions to study microorganisms are not very complicated to be gathered. It is enough to realize rich media as LB media (lysogeny broth or media Luria-Bertani) which is a media used for the bacterial culture. [4] We can also quote the YPD media (Yeast extract Peptone Dextrose) which is a rich media for yeast culture. [5] However, we do not use only rich media in microbiology, we can also use poor media in order to create certains mutation in the studied colonies. We can make the cultures in liquid media in flasks or in solid media with petridish. Microorganisms are often also easy to study because they can possess various resistances on the conditions in which they live. There are for example bacteria living in very acid environment either in high temperatures. It is necessary to maintain regulary the colonies which we cultivate as by changing the media of culture but it is fast and does not necessarily ask to be made every day. The regulations for the culture of microorganisms depend in particular if we use it organisms modified genetically and if they are pathogenic or not. According to the degree of danger, it is going to be necessary to fit out the room of culture for example by putting an airlock of access, an independent system of aeration, etc… The material used in microbiology is petridishes which serve to cultivate microorganisms as bacteria, flasks are use also, biological hood (PSM), oeses, etc... (Fig 2). We always work in sterile conditions with a PSM or on a flame to avoid the contaminations of cultures. Figure 2: Petridishes [6] and oeses [7] The microbiology is a vast domain allowing many applications. We can very well used the microbiology to study the present mechanisms in microorganisms, we can also use microorganisms as bacteria to use them in genetic engineering for applications in biotechnologies. We can also study the viruses for applications in biomedical research. The subjects and thus the applications are really varied and we can use mircroorganisms in many different case of studies. Other type of cells culture The cell culture includes all the techniques allowing to cultivate in vitro cells, that is why we find inside the study of microorganisms as bacteria or yeasts. However, the cellular cuture also includes the culture of animal or human cells. [8] There are many types of cells. We can classify them according to their origin and according to the specificities. To start, we distinguish the animal cells of human cells. We are also going to separate according to if it is stem cells, primary cells or immortal lineages. A stem cell is a cell capable of differing in any type of tissues as muscular, osseous, neuronal or cardiac tissues. We can obtain stem cells by taking them directly from foeti, from blood of the umbilical cord or from embryos. We can also obtain stem cells by realizing genetic manipulations on adults cells which consist in undifferenciate adults cells to make become again stem cells and this cells are called induced pluripotent stem cells (iPSCs). There are several ethical problems about the use of stem cells in particular on the way of extracting them. [9] A primary cell is cell that we extracted directly on an organism. This type of cells have the particularity to undergo the senescence and thus die after a certain time. It is also necessary to take many precautions at the time of their extractions to avoid the contaminations by microorganisms. [10] The immortal cells are lineages which cannot age and thus not die in time. They can be obtained from various manners. For example, a lineage of cells can be immortal in the case of cancer cells, if they are infected by a virus making them immortal (ex: herpes virus, SV 40) or by genetic modifications. [11] We will use a type of cells according to the study which we realize. For example, in tissular engineering, we use very often stem cells because they are going to be interesting for the study on tissues regeneration. On the contrary, for other studies, for example it will be interesting to use immortal lineages because we can cultivate them infinitely without they die by apoptose. In the same way as the culture of microorganisms, we also use rich and poor media to cultivate the other types of cells. However, cultures are realized in liquid media in flask or in petridishes. The animal and human cells ask a particular maintenance. Indeed, it is necessary to begin by defrosting them then realizing passages. It corresponds simply to leave our cells in cultures to let them multiply. When we make a passage of our cells, it is made in a certain percentage of confluence according to the study which we realize. However, we are obliged to pass cells before having reached 100% of confluence to have better results. The number and the frequency of the passages depends on the density of cells which is present in the culture. [12] At the level of the material, it is a little bit different that for the culture of microorganisms on certain points. We also work under a PSM in sterile condition, we also use petridishes and incubators. On the other hand, we use special flasks or 96, 48, 24 or 6 well plates for the culture (Fig 3). Figure 3: Materials for cell culture [13]
The study of the animal and human cells show themselves very complex. Indeed, cells are sensitive and their resistance are very limited. It is always necessary to maintain them and to cultivate them in good conditions. Furthermore, their studies is complex because the size of their genome and the number of mechanisms which they possess is more raised than those of the microorganimes. At the level of the regulations, it is as the study of microorganisms. Certain rules must be respected and according to the type of cells whom we use, the room of culture must be adapted. It changes in particular if we cultivate stem cells or if we cultivate cells modified genetically. The applications with the human or animal cells and that they are primary, immortal cells or origins are really very vast. Indeed, we can realize many theoretical studies to try to understand many mechanisms but we can also make studies very applied for example to treat diseases as genetic diseases or cancers. Conclusion To conclude, the animal or human cell culture and microorganisms culture have common points but also differences. The principle is the same, we use rich or poor media in liquid or solid condition to cultivate cells. We have to pay attention in both cases on the contaminations. The used material is often the same except for some elements. In both cases, we have to make a strict regulations to cultivate cells. The main differences are situated at the level of the maintenance of the cultures, the complexity to study the organism. Indeed, the animal and human cells are more complex to study from part their biological properties as the size of their genomes but also by their sensibility and their resistances which is lower than microorganimes. Finally, that is with microorganisms as bacteria and yeasts or animal and human cells, their studies allow to answer numerous questions and applications on different subjects. Thank you for you reading and don't hesitate to make comments! See you! References [1] https://fr.wikipedia.org/wiki/Microbiologie [2] http://www.futura-sciences.com/sante/dossiers/biologie-bacteries-leur-monde-nous-1433/page/4/ [3] https://fr.wikipedia.org/wiki/Saccharomyces_cerevisiae [4] https://fr.wikipedia.org/wiki/LB_%28milieu_de_culture%29 [5] https://en.wikipedia.org/wiki/YEPD [6] http://www.usinenouvelle.com/expo/boites-de-petri-o1616.html [7] http://www.sawyoo.com/post_loop-clip-art_706829/ [8] https://fr.wikipedia.org/wiki/Culture_cellulaire [9] http://www.inserm.fr/dossiers-d-information/cellule-souche [10] https://fr.wikiversity.org/wiki/Culture_cellulaire/Culture_de_lign%C3%A9es [11] https://fr.wikiversity.org/wiki/Culture_cellulaire/Culture_primaire [12] https://fr.wikipedia.org/wiki/Passage_%28biologie%29 [13] http://www.dutscher.com/frontoffice/product?produitId=0A-30-08
0 Comments
Leave a Reply. |