urgent help with microbial nicotine degradation needed

[enaa]

So.. I know I've posted on this forum before with a different subject, but I've decided that it would be better if I did something, well, ecomicrobiological. I should probably mention that I will be given acsses to a fully equipped microbiological lab.
Anyway, I've planned on isolating two of the nicotine degrading bacteria ( Pseudomonas putida and Arthrobacter nicotinovorans) from soil where tobacco was cultivated and comparing their activity. Maybe I could also try to optimise conditions. However, I wanted to add something a bit more challenging to the project, but I'm not sure what I could do. Can you please give me some hints, ideas...? I'd be very grateful!


Ena

[SciB]

Hi Ena,

Interesting. I had never heard of bacteria digesting nicotine, but they can metabolize just about anything so not surprising. There’s something I’m not getting, however. What is your hypothesis? Why would you want to culture bacteria that digest nicotine—to reduce nicotine levels in tobacco plants to make cigs less addictive?

Have you thought about studying the human ecomicrobiome? Humans are walking cultures of bacteria and fungi and I would bet tobacco smokers have a substantially different bacterial population from nonsmokers. Nicotine is toxic to many organisms so if there were bacteria around that degraded it, these bugs would be able to grow in the mouths of smokers. Here’s an article that talks about this (they even throw in coffee, too):

Can J Microbiol. 2008 Jun;54(6):501-8. doi: 10.1139/w08-032.
In vitro evaluation of the effect of nicotine, cotinine, and caffeine on oral microorganisms.
Cogo K, Montan MF, Bergamaschi Cde C, D Andrade E, Rosalen PL, Groppo FC.
Source
Department of Physiological Sciences, Area of Pharmacology, Anesthesiology and Therapeutics, Dentistry School of Piracicaba, State University of Campinas (UNICAMP), Piracicaba, SP, Brazil. [email protected]
Abstract
The aim of this in vitro study was to evaluate the effects of nicotine, cotinine, and caffeine on the viability of some oral bacterial species. It also evaluated the ability of these bacteria to metabolize those substances. Single-species biofilms of Streptococcus gordonii, Porphyromonas gingivalis, or Fusobacterium nucleatum and dual-species biofilms of S. gordonii -- F. nucleatum and F. nucleatum -- P. gingivalis were grown on hydroxyapatite discs. Seven species were studied as planktonic cells, including Streptococcus oralis, Streptococcus mitis, Propionibacterium acnes, Actinomyces naeslundii, and the species mentioned above. The viability of planktonic cells and biofilms was analyzed by susceptibility tests and time-kill assays, respectively, against different concentrations of nicotine, cotinine, and caffeine. High-performance liquid chromatography was performed to quantify nicotine, cotinine, and caffeine concentrations in the culture media after the assays. Susceptibility tests and viability assays showed that nicotine, cotinine, and caffeine cannot reduce or stimulate bacterial growth. High-performance liquid chromatography results showed that nicotine, cotinine, and caffeine concentrations were not altered after bacteria exposure. These findings indicate that nicotine, cotinine, and caffeine, in the concentrations used, cannot affect significantly the growth of these oral bacterial strains. Moreover, these species do not seem to metabolize these substances.

Repost to this same thread with more information on what kinds of experiments you were planning to do with nicotinobacteria and we will try to steer you into a winning project.

Best wishes,

Sybee

[deleted-132180]

Hi Ena,

Very interesting topic. Like Sybee had mentioned, I am also curious about what main question you're trying to address and what your hypothesis is. For example, why did you decide to study nicotine degrading bacteria and their activity, and why did you decide to isolate these particular species (Pseudomonas putida and Arthrobacter nicotinovorans) from the soil? Are these species known to degrade nicotine? Do they maintain a symbiotic relationship with tobacco plants, or is the relationship more antagonistic? If you let us know a little more background about your project, it would help us in helping you brainstorm for more ideas!

I really like Sybee's idea about looking at differences between the oral microbiota of non-smokers versus smokers and see whether nicotine-degrading bacteria are enriched in the mouth. It would also be cool to see the effects of nicotine on normal endogenous members of your oral microbiota--for example, is nicotine toxic to these bugs? If you can actually grow tobacco plants in the lab (and if these plants don't take super long to grow), it would also be cool to see if the presence or absence of these strains of bacteria will affect the growth or morphology of the plant in some way (if that is feasible at all). Furthermore, if you have an idea of the enzymes the bacteria use to break down nicotine, you can also generate mutant bacteria that are defective for these enzymes and then test how that will affect the growth or morphology of the plant. I'm not too familiar as to how this system works, so if you are working closely with a mentor who is an expert on this topic, it may be worth it to run it by him/her to see whether some of these ideas are worth testing and if the experiments to test them are feasible.

Let us know if you have anymore questions!

Connie