Bacterial Conjugation - Hfr, f prime and f plasmid

[Music] welcome back guys welcome to another video tutorial from somos biology and in this video lecture we will be talking about the idea of F plus F minus H F R and F prime factors in bacterial conjugation you know bacterial conjugation is a method of exchanging genetic material from between two different bacteria in a same generation okay that is also known as horizontal gene transfer okay in the horizontal gene transfer it means the transfer of genetic element between the members of the same generation but in the parental gene transfer the usual method of gene transfer is from the father or mother to the daughter so this is from the parent to daughter but horizontal is between the siblings now in this case the bacterial conjugation is a process where two bacterial cell will involve in direct contact with each other to transfer the genetic materials okay now the genetic material they transfer most of the time with this bacterial conjugation process is via like mostly they are plasmids now extra chromosomal elements that are present in one bacteria they transfer dad to the next bacteria and why did do that because most of the cases whenever a bacterial cell occurs some sort of antibiotic resistance property or something in their gene that is usually presenting that extra chromosomal element or plasmids so all those genes that are present in the plasmids for example that plasmid contains a gene for antibiotic resistance or it might contain a gene for like producing a specific amino acid inside the cell so they want it to be transferred to the rest of the members so that they can also occur that for the same and this is one of the important methods by which bacteria transfer antibiotic resistance genes from one to other and all of those bacteria become antibiotic resistant so let us look at this whole process now in this whole process there are some terms known as if this is nothing but laws made all these things if plus if minus HFR if Prime all these things are part of plasmids which are extra chromosomal DNA element that can self-replicate now this plasmids are present in bacterial cell along with the bacterial chromosome so if I draw a bacteria and this is the bacterial chromosome plasmids are present in the bacterial cell this is the plasmid now this plus me there is some plasmid known as if plasmid if plasmid f stands for fertility okay now those bacteria containing F plasmid has a certain property of developing a pileus or pili structure which is an extension of the cytosol like this form a tube like thing this is known as six pillars because with the help of this pili this bacteria can interact with a nearby bacteria let me draw it with this blue color and so this blue bacteria here it carries its its own DNA let us say this is the own bacterial genome but it does not have any plasmids in there so this is called as f- plasmid or if if - cell actually not plasmid if - cell because they do not have F plus B they might have some other plasmid but they do not have this fertility plasmids present so they known as F - now those cells containing F plus made known as F plus cells because they have fertility plasmid present now what will happen here this fertility plasmid is going to be transferred to the donor bacteria so this whole process involved two things one is the sorry one is a donor bacteria another one is a recipient so donor bacteria provides or delivered that F plasmid to the recipient bacteria with the help of this tube that is also known as conjugation tube so let us look at the whole process this bacteria will interact directly physically with the recipient bacteria and they will engage in the formation of this structure will form a structure like this two different bacterias these are the bacterial chromosome element this is also the bacterial chromosome elements but the F plasmid that was present here will be transferred from this donor to the recipient okay through this chamber this chamber is known as conjugation - through this conjugation tube the donor transfers AF plasmid to the recipient that is the idea now when a donor which was a plus recipient was F - now once they transfer the plasmid to the F - f - cell become F plus because now they carry this a plasmid so they will again form this sex pillar so they become F plus okay so this is the first type of conjugation between a F plus and the F - I will write down here the conjugation type and result okay it starts with both one was F plus and the one is if - donor and recipient now the result becomes both of them becomes F Plus now the second type when this if plasmid is transferred let us say some part of this plasmid is transferred because let us say the plasmid is large and the bond if there is bacteria have to attach with a physical tube and they are present in solutions and environment with aqueous environment so there are a lot more Brownian motion and forces going on that sometimes can break this chamber or break this tube so conjugation tube can be disrupted and once the conjugation tube is disrupted it will disrupt the transfer of the genetic element transfer of F plasmid to the recipient cell so as it's broken down and the transport is halted then only some fragment of the F plasmid can reach to the F minus cell now that fragment have two different fit that fragment can either be destroyed or degraded with the help of nucleases or they can try to incorporate that fragment with the bacterial chromosome in the formation with the process of homologous recombination so with the help of homologous recombination they will try to incorporate the the fragment into the bacterial chromosome and now let us say they're incorporated that fragment so now if we look at this bacterial cell it will look something like this it carries fragment of the plasmid and rest of the bacterial chromosome now if you look at this bacteria this is not completely plasmid this is not purely bacterial DNA because it carries some part of the plasmid we call this type of strain as a h if our strain or HF our type of bacterial high frequency strain or high frequency for the recombination H F R why because this bacteria have higher tendency of transferring their genetic element to the fellow bacterias why and how let us look at that because as you see here as the bacterial chromosome is attached with some part of the F plasmid now they will try to get rid of this F plasmids in different time different time points so as they are going to change this in different time points in that case they will try to pinch out this part of the F plasmid so that they can form the plasmid entity separately during this production of out this pinching out so let me draw it here hope you can see during the process of say here you try to pinch it out by crossing or cross-linking these two areas during this process sometimes they might generate the F plasmid successfully but this process is not always perfect so some part of the bacterial chromosome remains there with the portion in that cell so when this thing happen with a checker formation we know now when we revert back from HFR to become a plus plasmid so on your way to if plus plasmid formation because if we successfully separate this fraction out we can form a plus plasmid but when try to form that some part of the bacterial chromosome can also be incorporated in the F prime if it plasmid so as a result of that this will not be termed as a F plus cell this type of cell carrying one pure bacterial chromosome and another F plus need linked with some part of the bacterial chromosome this type of cells are known as if prying cells or we write it down as a F prime so this one okay so now if I tell you about all those types let us say between I F + + F - another type of result is possible one deafplus will remain a plus well the F - will become H F R this is also another possibility now for the difference of H F R we can generate F 1 sorry F plus me F plus plus meat we can generate a plus from HFR strain during this generation sometimes we prepare if Prime cells if the process is not complete successfully or properly some part of the bacterial we'll remain and we end up with a F Prime okay so that is the idea of F plus F minus H F R and F Prime now the question that I asked you before why we call hf r as a high frequency of recombination because remember if you take a hf r cell and cross it with if - cell the future that we are going to get it could be hf r or sometimes it can also produce f + cells over there but the frequency of transferring this bacterial DNA with the help of hf r cell is very very high sorry not this one H of our cell this one it is very very high for the frequency of transferring the genetic content from HF our cell wave - cell or from HF or cell wave prime cell you take any other cell and use HF our cell as a donor the frequency of this transfer and the chances of recombination of this plasmid into the bacterial DNA of the other recipient is more high why it is I because remember in hf r it is already incorporated so if it's transferring the DNA the chances that the bacterial chromosome will also transfer with this process of hf r so what we can do we use hf r strains and we try to map the bacterial chromosome with the help of hf r in the process known as interrupted mating what it is exactly let us take a hf r stain if we take an HF our strain let me erase this part for now if I take an HF our strain let us say this is an H a first train I am growing it short in HF our strain we have few part of the if plasma the rest of them are the bacterial chromosome bacterial chromosome here is blue color now we use it to transform so as they carry more DNA to be transferred compared to the F plasmid because plasmid contains small part of the DNA compared to the bacterial chromosome so the transfer process between if plasmid F minus F + + F - is very fast but if you take H F R as it carries a lot of genetic content and whole of this DNA should be transferred the process take more time so conjugation tube is formed this is another bacteria and this bacteria have its own chromosomal DNA or element so now you see these are two bacteria of the same generation they have the same type of genes in those bacterial chromosome present so now it will start it will break this donor DNA some part and start not actually break but actually this they will start the rolling circle mechanism of replication and they'll use that to produce the DNA chain and start transferring so as they start transferring the DNA it will go and ultimately reach to the next cell so as we see both of them have a lot of the bacterial chromosome part common the chance of recombination is high now another answer is about interrupted mating now as we know that it carries more genetic content it will take more time to be transferred so we know that at different time points the chance that this tube is going to break is more so there is more chance that during some point of this whole process the conjugation - you will we will be degraded as a result of that the transfer process will be stopped so if the transfer process talked after let's say 10 minutes 10 minutes we allow them to be transferred and after that we we physically damage the tube to block the transfer we will see some part of some part of the DNA will be transformed if we allow 20 minutes to go and then stop we will see a larger amount of DNA will be transferred if we take 30 minutes again little more amount of DNA so by looking at that what we can tell is that which part of the DNA enters first which part of the DNA us later so now let us say we know about the position of the jeans like like let us say the Jean a/b c/d we know that when you block at ten minutes only a is transferred how do you know we can check the presence of this jeans by production of the products so you see the product of the a at the very early time then we will see the product of the B after 20 minute transmission so in that case we can tell a B both are transferred after 30 minutes ABC is transferred but B is still not transferred so by this fashion we can tell that the gene sequence will be a b c d and so on now think about this ABCD are different amino acid coding genes we can tell the tryptophan coding gene comes first then tyrosine coding gene comes in then you see encoding gene terms in so you can tell about this idea by interrupting the process of translation at different time points we can tell which part of the gene is present at which location and their relative placements so this is known as a bacterial chromosomal mapping that we can use the idea of this conjugation and we use HFR strains involved in this whole process so that in a sense is all about the bacterial conjugation involving F plus F minus H F R and F prime cells so if you liked this video please hit the like button share this video with your friends to get more videos like that and subscribe to my channel thank you

Channel: Shomu's Biology

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Keywords: suman bhattacharjee, shomus biology, Bacterial conjunction, Bacterial conjugation lecture, conjugation, horizontal gene transfer, gene transfer in bacteria, Bacterial genetic exchange, hfr conjunction, hfr strain, for plasmid, Bacterial plasmid, for prime plasmid, genetic recombination

Id: Hio0Hys_UaU

Length: 16min 52sec (1012 seconds)

Published: Sat Jul 23 2016