Microbes in the Spotlight: Sporosarcina Ureae

Welcome back! Second microorganism of focus in our ‘Microbes in the Spotlight’ series is (drumroll please)...... Sporosarcina ureae! This bacterium  falls under the Bacilli class and as it is a bacterium, you guessed it, falls under the Bacteria domain.

Latin Name: Sporosarcina ureae

Common name: None that I could find

Appearance under the microscope: Unfortunately, I did not get to view it under the microscope myself but the cells are 1–2.5 μm, spherical (coccoid) in shape with 0.5–1.5 μm endospores. As it is gram positive it would appear to be purple-coloured due to gram staining.

Preferred habitat: Soil. It can grow in high concentrations of urea, can sporulate and remain viable in unfavourable conditions

Optimum Temperature: 20–30°C

Optimum pH: 6.5–8

Sporosarcina ureae on day three of incubation at 30°C on LBA

Sporosarcina ureae is aerobic, motile, spore-forming (see the first in this series for a reminder of what spores are) and gram-positive. The gram-positive nature means the bacteria have a thick peptidoglycan wall. Sporosarcina ureae  are motile due to the presence of  flagella.

The optimum temperature and pH conditions are linked to the aerobic characteristic of Sporosarcina ureae , it metabolises via cellular respiration. Sporosarcina ureae  makes use of urea using the urease enzyme to convert urea into ammonia, hence why it can grow in soil with high concentrations of urea.

The opening gif shows this arrived in a tube of nutrient agar, with the instructions to culture at  25°C.  Although the nutrient agar recipe will be provided (we’re not pausing for the recipe just yet), what if there was no nutrient agar?

Well an alternative that could be used is Luria broth agar (LBA). Now, let's pause for the culture recipes

                            

LB(1000ml)	Nutrient Agar
Yeast Extract…...5g	Yeast/Beef extract…...3g
Trytone…...10g	Peptone…...5g
Sodium Chloride…...5g	Sodium Chloride…...5g
950ml of Distilled Water	1000ml of Distilled water
15g of Agar	Agar…...15g

To prepare the Nutrient Agar:

1)Dissolve 5g peptone in 850ml of distilled water
2) Dissolve 3g meat extract in the solution from step 1
3) Dissolve 15g of agar in the solution from step 2
4) Adjust pH to 7.0 at 25 °C
5) Bring to 1000ml with distilled water
6) Autoclave or filter sterilize

The LBA plates were incubated at 30 °C, which is the upper limit of the optimum temperature. Initially, there was no growth observed on the plate which I thought may have been due to the temperature. But after 3 days growth was observed on the plate

No contamination this time around and the microorganism grew in the LBA. Maybe next time you can explore alternative media?

Want to find out more?

Dworkin, Martin; Falkow, Stanley (2006). The Prokaryotes: Vol. 4: Bacteria: Firmicutes, Cyanobacteria. Springer. pp. 636–641.

McCoy, D.D.; Cetin, A.; Hausinger, R.P. (1992). "Characterization of urease from Sporosarcina ureae". Archives of microbiology. 157 (5): 411–416. doi:10.1007/bf00249097