Isolating pure cultures

It was possible to see growth in the  water microbe cultures within 24 hours, although some were more slow growing.  It was important to monitor the cultures to check that there were no contaminants, and that only one bacteria was present.  Here are a few samples:

Colonies growing in marine agar, (MAR).  This has a high salt content and is
used to cultivate marine bacteria.

Colonies growing in MacConkey (MAC) Agar.  MAC provides essential 

nutrients and vitamins for the growth of micro-organisms.

Colonies growing in Yeast Nutrient Agar (YNA).  YNA supports the

growth of wide range of organisms, and is used to isolate rod bacteria.

There were two plates where I could observe two different colonies, so these had to be re-subbed carefully, streaking the two different strains on two different plates, and incubating them.

Once the cultures are established, I subbed the cultures again to more clearly define the nature of the bacteria.  They were plated on to Blood Heart Infusion (BHI) or YNA, as these media are both highly nutritious and are used to cultivate a wide range of bacteria.  

All environmental samples are incubated at 25oC.

It was amazing how many plates I had to manage!  First, the initial samples from three different collection sites were subbed on to eight different media; later, when the colonies grew, the isolated bacteria were re-subbed onto general purpose media to more clearly define their nature.  Finally, each colony was subbed again, this time on duplicate plates, one for the ICMP collection and one for DNA sequencing.

I devised  this spreadsheet to keep track of all the plates.  This seemed impossibly daunting at the beginning of my time in the lab when three Masters students were conducting a project related to kauri die-back.  However, I was able to methodically label, sort and manage the plates for this project.  It is a clear indication of my developing technical skills in the lab.