Authors : S.B. Oladele , A.J. Nok , P. Abdu , H.M. Kazeem and K.A.N. Esievo
Abstract: Experiments were performed to determine some properties of neuraminidase of Newcastle Disease Virus (NDV) Kudu 113 strain, in order to deduce the possible effects of this enzyme on hosts cells during NDV infections in poultry; and to see how its properties are similar or different from neuraminidases of some viruses that have been previously characterized. The activity and properties of neuraminidase of NDV Kudu 113 strain were determined by periodate thiobarbituric acid assay method. Neuraminidase activity was detected in NDV Kudu 113 strain in vitro. The neuraminidase activity increased gradually from 24 h with the mean value of 101.4�2.8 �mol min 1 and attained its mean maximum activity of 167.2�5.4 �mol min 1 by 72 h post-inoculation into embryonated chicken�s eggs, after which the activity of the enzyme declined. The enzyme was precipitated at 55% by ammonium sulphate [(NH4)2SO4] saturation. The optimum pH and temperature of the enzyme were 5.5 and 40�C, respectively. The Michaelis constant (Km) and maximum velocity of reaction (Vmax) of this enzyme were 1.0�102 �mol L 1 and 3.03�10 4 �mol min 1, respectively. It was concluded that NDV Kudu 113 strain produced neuraminidase in vitro. The neuraminidase activity had a linear relationship with the dilution of the virus at higher serial dilutions. Neuraminidase of NDV Kudu 113 strain also cleaved sialic acid from fetuin (substrate) in vitro. It is likely that neuraminidase of this virus strain may cleave sialic acid from the surfaces of erythrocytes and other cells during in vivo NDV infections in poultry, thereby exposing the erythrocytes to destruction by reticulo-endothelial system.
S.B. Oladele , A.J. Nok , P. Abdu , H.M. Kazeem and K.A.N. Esievo , 2007. In vitro Production and Some Properties of Neuraminidase of a Nigerian Newcastle Disease Virus Strain . Journal of Animal and Veterinary Advances, 6: 712-717.