CONTROL OF MOS BY CHEMICAL AGENTS CONTD..

D) HEAVY METALS & THEIR COMPOUNDS:


                                                                
                            Heavy metals have larger atomic weight & complex electronic configuration. The detrimental effect of small amount of heavy metals on microorganisms is called "Oligodynamic Effect".  This action can be seen when we place a coin or other clean piece of metal containing silver or copper on a culture media on an inoculated Petri Plate. The most effective metals are Hg,Ag, &  Cu.
           
                                   Fig: Oligodynamic Effect
  • Mercury(Hg):  It is in the form of mercuric chloride is very toxic & its efficacy decreases in the presence of organic compound. So, other components of mercury are used like Mercurochrome, Metaphein etc. 
  • Copper(Cu):  It is active against chlorophyll containing organisms & it is potent inhibitor of algae. Copper sulphate  is incorporated to algicide & used in swimming pool & water supply.
  • Silver(Ag): Silver is used in the form of silver nitrate as antiseptics & disinfectants. 1% silver nitrate is used in the eyes of new born to prevent Ophthalmia Neonatorum, which a gonococcal  infection of eyes.
USES:
Used in ointments as antiseptics, used as fungicide & algicidal , used for the treatment of Ophthalmia Neonatorum, used in swimming pool & water supplies. 

MODE OF ACTION: 


  • Heavy metals acts on cellular protein(Enzyme) & inactivate them.
  • Mercuric chloride acts on the enzyme that contains sulfhydryl group. 
  • High concentration of heavy metals salts coagulates cytoplasmic protein.
 Please visit this link to know more about mode of action; http://cmr.asm.org/content/12/1/147.full







               


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