【Microbiology】Pseudomonas aeruginosa【Infectious Disease】

My major is organic chemistry, but recently I found myself interested in microbe. So today I'm gonna deal with one of the most famous microbe in the world.

Have you ever heard of Pseudomonas aeruginosa, that is shown in the above picture (this picture is cited from https://institute.yakult.co.jp/bacteria/4211/)? Maybe it is the most notorious bacterium due to its pathogenicity.

P.aeruginosa is a common Gram-negative, aerobic bacterium that can cause diseases in platns and animals. Human is also at the risk of it, but it usually does not have any effect on a person who has a non-compromised immune system. That is to say, a person whose immune system is less active than usual can be infected with it.

Some microbes including P.aeruginosa are known as opportunistic pathogens. An opportunistic infections is defined as an infection caused by pathogens that takes advantages of immunity not normally available (i.e. compromised immunity).

As I said before, a normal person is not infected with it. However, it does not mean its negative effect on human health is negligible. On the contrary, the health risk it causes is of great concern.

When it somehow penetrates into human blood, it can cause bactermea or septicemia (blood poisoning) and produce endotoxins. An endotoxin shock can bring about multiple organ failure, and eventually death.

To make matters worse, P.aeruginosa shows antibiotics resistence to some degree. First generation cephems (β-lactam antibiotics) such as penicillin and cefazolin are not effective against it, neither are tetracyclines and macrolide. Due to its infamous nature shown above, P.aeruginosa sometimes causes a nosocomial infection and is a serious nuisance for many doctors and patients.

This is a quick note about P.taeruginosa, but I would like to put an end to this entry. I'm currently planining to take a look at some other opportunistic pathogens such as Legionella pneumophila in the near furute.

Hope you enjoy this blog. Please do not hesitate to leave a comment or question :)

【Organic Chemistry】Wolff-Kishner Reduction

It's uneasy to decide which topic is suitable for the first entry of this blog, but as a chemistry student I think Organic Chemistry is the best.

Have you ever heard of Wolff-Kishner Reduction? This is probably the most famous reaction to reduce carbonyl funnctionalities to methylene groups.

The simplest scheme of this reaction is given as follows. Sorry for the poor quality :(

As this figure shows, a carbonyl functionality is firstly converted to an imine (aka Schiff Base), followed by the formation of a methylene group.

The mechanism of the first step in this scheme can be explained as a typical reaction between a carbonyl functionality and a hydrazine. A moderate acidic condition will be necessary in my opinion because this step begins with the protonation of the carbonyl functionality. On the other hand, adding too much acid also protonates hydrazine and the reaction does not proceed.

After that, the hydrazine moiety is further converted to a methylene group.Unlike the first step, base (e.g. KOH) will be required to complete this reaction. It deprotonates the hydrazine moiety, producing a carbanion.

It reacts with water and will be neutralized for the moment, but another deprotonation by the base produces a carbanion again. The hydrazine moiety is eliminated after this step.Finally, the carbanion reacts with water again, producing a methylene group.

This reaction is named after Ludwig Wolff, a German Chemist, and Nikolai Kischner, a Russian Chemist. (idk why "c" in "Kischner" was eliminated in the name of this reaction...)

Clemmensen reduction is another option to achieve the objective (conversion of a carbonyl functionality to a methylene group). I'm gonna review it in the near future.

Thank you for your attention!

About This Blog

This blog is mangaed by a Japanese Ph.D. student BiCyclo.

The main subject of this blog includes, but not limited to, various scientific subjects such as Math, Chemistry, Biology, Programming, and so on.

I'm also fond of studying English. This blog is fully written in English to improve my English skill and to share my opinion with as many people as possible. Please don't hesitate to notify me if you find any mistakes(grammartical, collocational, etc).

Hope you enjoy this blog.

BiCyclo