Organizing co mmittee

DETERMINATION OF THE ACTIVITY OF BACTERIAL 
RIBONUCLEASES 
M.K. Narmukhamedova, T.S. Khusanov, G.H. Kadirova 
Institute of Microbiology of the Academy of Sciences of the Republic of Uzbekistan, 
Tashkent, 
e-mail: [e-mail]
 
 
Viruses cause various diseases in plants and reduce yield and quality of flour. The 
main part of plant damaging viruses are RNA viruses. Based on this, it can be 
considered that ribonuclease enzymes synthesized by some bacteria may have a 
negative effect on the spread of viruses in plant tissue. Currently, more than 20 
ribonucleases synthesized by bacteria: 
B. subtilis, B. amyloliquefaciens, B. intermedius, 
B. pumilus, B. licheniformis, B. circulates, B. thuringiensis
are known [1].
The toxicity of bacterial enzymes is less compared to chemical compounds, they are 
easily utilized by plants and decompose without accumulating harmful substances in the 
environment [2]. 
In this work, the ribonuclease activity of microorganisms: 
B. subtilis; B. cereus; B. 
licheniformis; B. pumilus; P. putida; P. aeruginosa; B. amyloliquefaciens; P. 
fluorescens; B. megaterium and P. syringae
has been determined. Microorganism 
strains were grown in LB medium with the addition of yeast RNA at 30
0
C. After 48 
hours, 5 ml of 1 M HCl was poured over the colony and waited for 5 minutes. White 
color if there is no RNase enzyme in cultured medium, if the enzyme is present, a clear 
halo is formed around the bacterial colony. We found the ribonuclease activity of 
bacteria by calculating the distance from the border of the colony to the halo end line. 
Table
 
Strains 
Halo, mm 
B. subtilis
4.5 
B. cereus
3.0 
B. licheniformis
2.3 
B. pumilus
3.0 
B. megaterium
2.5 
B. amyloliquefaciens
2.0 
P. fluorecens 
3.2 
P. aeruginosa 
4.5 
P. syringae 
3.5 
P. putida 
4.0 
According to the data presented in the table, strains of 
B. subtilis
and 
P. aeroginosa
produced halos of 4.5 mm and 
P. putida
of 4.0 mm and showed high ribonuclease 
activity.