In vitro Effects of Calcium, Magnesium, Mercury and Copper Ions on Neuraminidase of a Nigerian Newcastle Disease Virus Strains

Abstract

This study was carried out to determine the effects of cations on neuraminidase during NDV infections in poultry. A total of two hundred samples from dialyzed neuraminidase of NDV Kudu 113 strain were used for the experiment. Fifty samples each were used on four divalent cations, namely calcium (Ca²⁺), magnesium (Mg²⁺), mercury (Hg²⁺) and copper (Cu²⁺) ions. Neuraminidase activity of NDV Kudu 113 strain was determined in vitro in the presence of these cations, tested as their chloride form by periodate thiobarbituric acid assay method. Neuraminidase activity was also determined in the control samples that were without cations. Out of the four divalent cations examined, Hg²⁺ induced the highest neuraminidase activity of 75% at the concentration of 0.24M. Magnesium and Ca²⁺ ions also increased the activity of neuraminidase of NDV Kudu 113 strain in vitro. On the other hand, Cu²⁺ significantly inhibited the activity of this enzyme by 69.23% at the concentration of 0.47M. It was concluded that Ca²⁺, Mg²⁺ and Hg²⁺ induced increase in the activity of neuraminidase of NDV Kudu 113 strain, while Cu²⁺ inhibited its activity in vitro. Further studies should be carried out on the roles of these cations in Newcastle disease (ND) and the possible use of Cu²⁺ in the future as inhibitor of the activity of neuraminidase of NDV in vivo, so as to reduce the menance of ND in poultry.