Microbes in the Spotlight: Achlya sp.

Welcome to learning thru research! This is the first in our ‘Microbes in the Spotlight’ series, where we get to learn more about certain microorganisms of focus. Today we are focusing on the Achlya sp. fungus! This fungus falls under the Oomycota class and hence is in the Eukaryota domain.

Latin Name: Achlya sp

Common name: Water mould

Appearance under the microscope: Under the light microscope filaments of varying lengths and widths were observed with hypha, which are the long, branching structures.

Preferred habitat: Water

Optimum Temperature: 20-25° C

Achlya sp. under a light microscope at 4.5x viewed using the AmScope software with a MU1000 camera

The interesting thing about Achlya sp is that is that it reproduces both sexually and asexually, by oospores and zoospores respectively. I'm sure the question that has popped into your mind is: What are oospores and zoospores? Well they are both units of reproduction - zoospores are motile, whilst oospores are able to survive in harsh environments.

As you can see from the gif above, this fungus arrived in a tube of lake water with split cucumber seed. This was done for easy manipulation in culture, however it may also be cultured in cornmeal agar.

What if there is no cornmeal agar available? Fear not! This fungus can be cultured in other media. YPD, is composed of yeast extract, peptone and glucose (and of course water); this as well as potato dextrose agar (PDA). Let's pause for the culture recipes

YPD(1000ml)	PDA at 25°C (Homemade)	PDA (Commercial)
Yeast Extract…...10g	Potato infusion…...200g	Potato starch…...4g
Peptone…...20g	Dextrose…...20g	Dextrose…...20g
Glucose…...20g	Agar…...20g	Agar…...15g
950ml of Distilled Water	1000ml of Distilled Water	1000ml of Distilled water
15g of Agar

To prepare the Homemade PDA:

1)To prepare potato infusion, boil 200 g sliced,  unpeeled potatoes in 1 liter distilled water for 30 min.

2) Filter through cheesecloth, saving effluent, which is potato infusion (or use commercial dehydrated form).

3) Mix with Dextrose, Agar and Water and boil to dissolve.

4) Autoclave 15 min at 121°C.

5) Final pH, 5.6 ± 0.2.

To prepare the Commercial PDA:

1) Add 39 g of the powder to 1 Litre of distilled water.
2) Boil while mixing to dissolve.
3) Autoclave 15 min at 121°C.

Now, initially there was no growth observed in either of the plates 😔

The literature did say it would take 4 days for the fungus to grow so I thought I would check in a few days time.

Later on that day…..

Surprise, surprise! There was some growth on the YPD plate but none on the PDA plate. It took 3 days for growth to occur on the PDA plate!

Whilst exploring the growth of this microorganism, I concluded from my observations that it grew better in YPD than in PDA maybe due to the peptone or/and yeast extract. However this conclusion was due to some unforeseen circumstances…..

The homemade potato dextrose agar used was contaminated!!!

Moral of the story: Ensure everything is done in sterile conditions!

Want to find out more?

Tsunehiro, Aki; Yukimasa, Matsumoto; Tsotomu, Morinaga; Seiji, Kawamoto; Seiko, Shigeta; Kazuhisa, Ono; Osamu, Suzuki (February 1999). "Lipid composition of a newly isolated polyunsaturated fatty acid producing fungus, Achyla sp. ma-2801". Journal of fermentation and bioengineering. 86 (5): 504–507. doi:10.1016/S0922-338X(98)80160-8. Retrieved 8 February 2015.
O'Brien, Megan A.; Misner, Ian; Lane, Christopher E. (March 2014). "Mitochondrial Genome Sequences and Comparative Genomics of Achlya hypogyna and Thraustotheca clavata". Eukaryotic Microbiology. 61 (2): 146–154. doi:10.1111/jeu.12092. PMID 24252096.