For some context, I have a Bachelors in Biology, and the pandemic forced me to pursue an online graduate program in another field, but I've wanted to get back into bio research for some time and gain some more experience. I've recently started working at a university microbiology research lab with a government grant. I've been working about a month, learning the protocols and shadowing the other associate present. Lately I've been struggling to get a satisfying yield out of purifying a plasmid from some E.coli cultures. I've communicated this throughout the process to both the other associate and the PI asking for potential ways to correct this, but recently, the PI brought up in conversation mentioning my other degree, as if to imply I wasn't qualified. He knew my background before hiring me and the way he phrased it made it seem like he was reconsidering that decision. I think this might foreshadow an upcoming termination if I fail to deliver results by the end of next week, and I want to ask how likely is that assessment.

I've done this protocol before with this lab with other plasmids, and I've managed to harvest a sufficient yield with those ones. I'm following the protocol as instructed and I've brought it up with both the other associate and the PI the difficulties I've been running into and asked what could be going on. The last we spoke, the PI has implied that I might be insufficiently trained or wasn't a good fit for benchwork, and to be honest I'm afraid that means I'm likely to be terminated soon. If that's the case, what can I expect from future job prospects, as I'm under the impression that it's somewhat of a career death sentence to have such an early termination in one's background. I really enjoy this job, I struggled to get a good job after receiving my Masters and I'm not entirely sure what to do with myself if I lose this one. The pandemic derailed my chances to do hands on research pre-baccaleaureate or as a grad-student, and I don't have think I have enough money, time, or references to try for another degree.

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    Your boss made one small comment, and now you're thinking that you will get terminated? That seems like a stretch. I think you and your PI need to have a conversation. Commented Jun 16, 2023 at 21:31
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    In any case, I don't think anyone here could do better than just provide pure speculation. Commented Jun 16, 2023 at 21:32
  • @WolfgangBangerth not quite true. In some countries, such casual termination might well be against the law. Commented Jun 19, 2023 at 8:40

2 Answers 2


In molecular biology, people talk about having "good lab hands", that is, that it is assumed that some people are just good getting results and other people are always behind and requiring help. Of course, this is all BS, since a plasmid prep is a plasmid prep and the bacteria do not care about your good hands: you either get an usable concentration of plasmids or you don't.

On the molecular biology side: on any multi-step protocol there are multiple points of failure, so you need to run positive controls alongside your regular prep. The easiest way to get a working control is to do the protocol side by side with someone who always gets it right, and I don't mean shadowing the person, but running the protocol side-by-side, you using your own pipettes, tubes, centrifuge, etc. You then keep your own culture to use as a positive control and run that along the bacteria from which you are having trouble isolating the plasmid, and you test the results after each step. You keep systematically testing until you can identify the point of failure. It could be that your pipettes need calibration, that you are setting the centrifuge to RCF vs RPM, that the enzymes they gave you were left on a tube by a window and are now denatured, etc.

Having said that, please note that plasmid preps are some of the most basic protocols in molecular biology, and that it should not take much time for an experienced bench biologist to figure out what's going wrong. The fact that you are not being given that type of assistance is concerning. Perhaps the people with the "good hands" are boycotting your progress. Again, plasmid preps are pretty basic stuff.

About the PI, a lot of these people treat lab techs as points in an assembly line. They just want results and don't want to be bothered with developing the skills of their techs. So, if a tech can't get results quickly, then they fire them and get another one who can do it.

Like others have said, you might be reading too much into this, but having worked in many biology labs, I can tell you that you might also be right in your assessment that they are looking to replace you. So ask for assistance running the positive control. If you are not given the assistance, and your PI fires you for something this small, it means that you don't really want to work there anyway. This definitely will not mean the end of your career as a bench scientist. You just get another job, just like you got this one, and with luck you'll find a lab that has a good support structure and someone takes the time to train you in the basic protocols.


Neither you nor me know what exactly is happening. Is the lack of good results your fault or is it part of the set-up? With other words, would someone else have gotten better results?

In a lab that is reasonably run, it is clear that newly hired lab assistants (?) without extensive experience need some time to get up to speed. This seems to have happened. You seemed to have done the correct thing by asking for help. Your PI probably experiences some frustration and made this frustration visible to you. This is also normal, just as helping someone when one has a lot of other things to do and then feeling frustrated is also normal.

You probably are over-reacting. Presumably, you were selected for the job because you were the best available within the budget. Presumably, your need for help is frustrating to others. That does not mean that you can be easily be replaced without someone else that can do a better job.

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