avian adenovirus was isolated from naturally infected birds during 1990 to 2003 in the vicinity ofkarachi, pakistan. the virus is known to cause hydro-pericardium syndrome (hps) in poultry. the mortalitywas recorded 20-50% in commercial broilers. fifty field samples were collected; however, six samples wereselected for molecular studies. these isolates were grown and characterized by cell cultu...

Structure/function relationship studies of proteins are greatly facilitated by recombinant DNA technology which allows specific amino acid mutations to be made at the DNA sequence level by site-specific mutagenesis employing synthetic oligonucleotides. This technique has been successfully used to alter one or two amino acids in a protein. Replacement of existing DNA sequence coding for several ...

Type I restriction enzymes bind to a specific DNA sequence and subsequently translocate DNA past the complex to reach a non-specific cleavage site. We have examined several potential blocks to DNA translocation, such as positive supercoiling or a Holliday junction, for their ability to trigger DNA cleavage by type I restriction enzymes. Introduction of positive supercoiling into plasmid DNA did...

It has been widely considered that DNA modification protects the chromosome of bacteria E. coli K-12 against their own restriction-modification systems. Chromosomal DNA is protected from degradation by methylation of target sequences. However, when unmethylated target sequences are generated in the host chromosome, the endonuclease activity of the EcoKI restriction-modification enzyme is inacti...

Stearoyl-CoA desaturase (SCD) is a rate-limiting enzyme in the biosynthesis of monounsaturated fatty acids (MUFA). A number of studies support the hypothesis that SCD gene regulation and polymorphism may affect fatty acid composition and fat quality in meat and milk. Single nucleotide polymorphisms in the coding region of the bovine stearoyl-CoA desaturase gene have been predicted to result in ...

In this study the restriction endonuclease analysis (REA) technique was used for the comparison of field isolates and vaccinal strain of Pasteurella multocida using Hha-I enzyme. On the basis of DNA finger prints, extent of homology among the field isolates and the vaccinal strain was observed. The study has provided the clear evidence that eight isolates of P. multocida used were serologically...

the µ (mu) opioid receptors, which mediate the effects of morphine, are widely distributed in brain. the purpose of this study was to design a simple expression system for rat µ-receptor in escherichia coli (bl21). in this laboratory study, rat µ-receptor cdna was isolated from pcdna3 vector using xba1 and hind3 restriction enzymes. pet-15b was digested by nco1 restriction enzyme. µ-receptor cd...

A specific endonuclease, Sau 3AI, has been partially purified from Staphylococcus aureus strain 3A by DEAE-cellulose chromatography. The enzyme cleaves adenovirus type 5 DNA many times, SV40 DNA eight times but does not cleave double-stranded phi X174 DNA. It recognizes the sequence (see article) and cleaves as indicated by the arrows. Evidence is presented that this enzyme plays a role in the ...