Microbial farming

We know the role of microbes in agriculture both beneficial and harmful. It is quite interesting to know fungi are reared as farms. Ants belonging to different genera use plant chewate as a substrate to grow fungi as farms and graze them. Same thing is practices by marsh snail Littoraria irrorata. 

Source and for further reading:

http://schaechter.asmblog.org/schaechter/2015/11/a-snippet-who-invented-agriculture-the-ants-or-the-bees.html

http://www.pnas.org/content/100/26/15643.full.pdf

Leaf cutting ants growing fungus. Image source: http://www.harunyahya.com/image/miracle_in_the_ant/atta1.jpg 

Littoraria irrorata Image source https://upload.wikimedia.org/wikipedia/commons/f/fc/Littoraria_irrorata.jpg

The history of penicillin

The history of Penicillin


We know the role of Noble laureate Sir Alexander Fleming in the discovery of Penicillin. But who is the first patient to receive Penicillin for treatment?

Sir Alexander Fleming

It was Albert Alexander who was a constable in the county of Oxford, London. He was accidentally injured with a rose thorn. The wound was infected with Staphylococci and Streptococci and his condition became very serious. His head was covered with abscess and his eye was removed. Still he faced the risk of death.

Howard Walter Florey

He was treated by Dr Howard Walter Florey. The clinical application of Penicillin was tested only in mice and they haven't tried a human volunteer. Due to the terminal illness of Albert Alexander, they decided to try Penicillin on him. 

Albert was given with 160mg of IV dose of Penicillin. He recovered well. But due to war time restrictions, they could not synthesis enough quantities of Penicillin. But the team successfully isolated Penicillin from the urine of Albert and given successfully for four consecutive days. But, they run out on the fifth day.Albert Alexander died on 15th March 1941.

Sources:
http://en.wikipedia.org/wiki/Albert_Alexander
https://www.youtube.com/watch?v=iWHq2m_Hwhw

TNPSC 21.12.2014 Group IV Results

Link to TNPSC Group IV solved questions. TNPSC official link

Radiant spider web like colonies

When we tried to assess the quality of air with settle plate technique we isolated some spider web like colonies. They might be Bacillus mycoides. It is quite amazing that this bacteria has two types of curvature ie., clockwise and counter clockwise. A strain can produce either curvature not both. The direction of curvature can be changed by altering NaCl concentration.



 

Further reading

Crystal Violet...

In a discussion, we were talking about the history of Gram staining.

Slowly talk shifted about the use of crystal violet MacConkey agar to inhibit  Gram positive bacteria. But how a simple dye inhibit a group of bacteria and become a selective agent?

Here comes the answer,

"The mode of action put forward by Steam & Stearn (1928) that the action of crystal violet is due to the formation of an unionized complex of bacteria with dye, is supported. Gram-negative organisms, such as E. coli, have high isoelectric points and contain less acidic components than Gram-positive bacteria which usually have lower isoelectric points, so the former combine with crystal violet less readily and are more resistant to the dye. "

Very happy to discuss science with youngsters...

 

Source: http://onlinelibrary.wiley.com/doi/10.1111/j.2042-7158.1967.tb09550.x/abstract

Image Courtesy: http://www.evidentcrimescene.com

[caption id="attachment_25" align="alignnone" width="288"] Crystal Violet[/caption]

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Life science December 2012 (Unofficial external link) 

Catalase

As a microbiologist we know some aerobic microorganisms produce catalase and we test it by adding hydrogen peroxide to the culture.

what do the catalase do in a microbial cell?

Hydrogen peoxide is produced in microbial cell during the exposure to Oxygen. The enzyme catalase breaks down hydrogen peroxide to water and oxygen.

2 H₂O₂ → 2 H₂O + O₂

Even anaerobic organisms like Methanosarcina barkeri produce catalase under oxidative stress.

In all animal cells and plant cells catalase is ubiquitously present. In humans the highest concentration of catalase is observed in Liver. Animals manage to survive even without catalase. Mouse with deleted catalase gene function normally. In humans deficiency of catalase may be linked with type II diabetes.The deficiency of catalase may lead to graying of hair due to the build up of hydrogen peroxide in body.

Some insects like Bombardier beetle uses catalase in another way. It has sac of catalase and sac of hydrogen peroxide and hydroquinones. For defence it squeezes the sacs. reaction of catalase with hydrogen peroxide cases release of oxygen which in turn causes oxidation of hydroquinones. It raises the temperature to boiling point. Vaporization and release of gases lead to the repellent spray and protects the insects from predators.