Three lytic actinophages specific for Streptomyces flavovirens were isolated from Egyptian soil and designated Sf1, Sf2 and Sf3. Phage isolates Sf1, Sf2 and Sf3 produced clear circular single plaques of 2, 1 and 3 mm in diameters, respectively. Thermal inactivation point, dilution end point and longevity in vitro of phages Sf1, Sf2 and Sf3 were found to be 86°C, 82°C and 76°C; 10-5, 10-3 and 10-5; 7, 6 and 7 days, respectively. The isolated phages were found to be stable at different pH levels ranging from 5 to 13. Particle size and morphology of each phage isolate were examined by transmission electron microscopy. The three isolated phages were of head and tail type. They varied in their head diameters and tail lengths. Using RAPD-PCR assay, only seven primers succeeded to generate polymorphic DNA products. Genetic distance value between phages Sf1 and Sf2 was 0.0, phages Sf1 and Sf3 was 1.0 and phages Sf2 and Sf3 was 0.89.

An improved method for purifying Chikungunya virus from cell culture supernatant of infected African Green Monkey Kidney cells is described. It employs a combination of polyethylene glycol precipitation and sucrose gradient ultracentrifugation. The infected cell culture supernatant was precipitated using polyethylene glycol and concentrated virus was banded at the interface of 20-60% (w/v) discontinuous sucrose gradient using rate zonal ultra centrifugation. Using a combination of SDS-PAGE and western blotting techniques, Chikungunya virus structural proteins were detected only in the fractions collected from the interface. The authenticity of the purified Chikungunya virions was further confirmed by reverse transcriptase polymerase chain reaction and transmission electron microscopic study. The developed method has immense application and is useful in making large quantity of purified Chikungunya virus for its characterization, virus morphological study and purification of Chikungunya virus like particles expressed from heterologous system.

Viral shedding in salivary secretions is a ubiquitous phenomenon in infected as well as carrier states. Transmission of different viruses via person-to-person can occur on a much large scale through parenteral routes. Prominent viruses that can be detected in saliva include- herpes simplex virus type 1, cytomegalovirus, human immunodeficiency virus, hepatitis C virus, Epstein barr virus. This paper reviews various viruses that can be detected in saliva either as whole or as RNA fragments.