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Listeria monocytogenes is a food borne pathogenic bacteria and caused a dangerous infection of humans. Six lytic bacteriophages specific to L. monocytogenes were isolated from irrigation and sewage waters and named ØLG, ØLA, ØLM, ØLD, ØLN and ØLP. The phages were propagated, and then purified by the ultracentrifugation. Morphological properties of Listeria phages showed that the phages were tailed phages, varied in their sizes and assigned to be a member of Siphoviridae (ØLG, ØLA, ØLM) and Myoviridae (ØLN, ØLD, ØLP) families. All Listeria phages were highly stable under different temperature conditions and its thermal inactivation point was reached to 80°C. The longevity in vitro of the phages was up to 60 days, as well as phages were active at pH values ranging from 4.0 to 12.0. Listeria phages did not lose their infectivity after exposure to UV for 90 min at 35 and 53 cm distances. Results of SDS-PAGE showed that phages had 5-6 protein fragments with molecular weights of 66, 45, 37, 35, 33 and 28 kDa distributed among the six phages.

Plant viruses cause serious disease of crop plants reducing both quality and quantity of final produce. Serological tests are used all over the world in laboratory and field based detection of plant viruses and they are of great indispensable importance in agricultural production; virus certification programs; agricultural quarantine and production of virus-free crops grown for processing or fresh market. Cross reaction between viruses and their strains antisera limits serological differentiation of viruses and their strains by enzyme-linked immunosorbent assay (ELISA). This study aims to characterize the antigenic property of Tomato mosaic virus ToMV coat protein by using some bioinformatic tools to analyze its gene. Therefore, new methods in antibody production could be used as equivalent to Mabs in its high specificity. ToMV isolate was confirmed by Transmission electron microscope and differential hosts and propagated on N. tabacum cv. Samson. Systemic infection was developed on N. tabacum cv. Samson and local infection on Datora metel; D. stramonium; N. glutinosa; Chenopodium amaranticolor; C. quinoa. ToMV was purified and used as immunizing agent for antiserum production. TEM showed rod shaped particles with 300 x 18 nm dimensions. The titer of produced antiserum was 1:1024 evaluated by microprecipitin test and indirect-ELISA. Coat protein gene was amplified by RT-PCR with expected size of (Approx. 500 bp). The PCR product was sequenced then the generated nucleotide sequence was translated into 160 amino acids. The amino acid sequence of Five B-cell epitopes, of 14 amino acid residues each, were predicted. Identifying Bcell epitopes play an important role in vaccine design, immunodiagnostic tests, and antibody production. Therefore, computational tools for reliably predicting B-cell epitopes are studied.

Rotavirus have been reported as the principal causal pathogen of acute gastroenteritis and one of the leading causes of child morbidity and mortality in Egypt .This study aimed to investigate biological , serological and molecular Rotavirus genotypes infection in Egypt . The blood and stool clinical specimens were collected randomly from 100 patients .They were analyzed for the presence of antigen and the antibody using enzyme-linked immunosorbent assay (ELISA). Rotavirus antigen in stool and antibodies in serum were detected by ELISA among Children (78.13); Female (12.5 ) and male (9.38%). Rotavirus titer was determinated as 5.5x10 7 ; 6.0x10 6 and 7.5x10 7 (PFU\ml) on vero cell of Female ; male and children respectively after 4 days Post infection. The cytopathic effects were granulation of cytoplasm , enlarged , swelling , rounded and multinucleated giant cells .The virus particles are non-enveloped with Icosahedral symmetry with about 70 nm in diameter .Rotavirus isolates showed homologous with RV isolates recorded in gene bank based on alignment and phylogenetic tree analysis. Six RV genotypes (G1P4, G1P6, G1P8 , G9P6 , G1P8, G3 P8) were detected in summer. Seven RV genotypes, (G1P4, G1P6, G1P8 , G3P4 , G3P6, G3P8 G9P8) were detected in in spring and five RV genotypes (G1P4, G1P8 , G3P4, G3P8 G9P8) were detected in winter seasons . SDS-PAGE showed seven structural and function of proteins were polymorphism variation among for Rotavirus isolates . RV genomic migration pattern of G1P4, G1P6, G1P8 , and G9P8 were varied in number , density and segmented to 12 , 9 , 10 , and 9 moved respectively .

The antiviral role of Moringaoleifera leaves extracts ((chloroform (CL), Ethyl acetate (E.A), methanol 80% (M) and n.butanol (n.b) to control Coxsackie B (COX-BV) viral infection was monitored in vitro compared with human interferon alpha (IFNᾰ-2a) in order to evaluate the antiviral activity of moringa leaves extracts. The phenolic compound was given higher conc. in E.A. extracts. Cytotoxicity was determined for Moringa leaves extracts on viability of HEP2 cell using MTT assay. The 98μg/ml concentrations for four extracts were considerably non-toxic for HEP2 cell line culture. Antiviral activity in Moringa extracts may be attributed to phenolic compounds and / or as a result of stimulation of COX-BV-sensitive HEP2 cells to express MX protein. Antiviral activity of Moringa leaves extracts compared with IFNᾰ-2a to cell lines against COX-BV viral infection was determined by assessment of the COX-BV virus infectivity titer declining rate and relative residual living cell count using End Point Assay, using three ways pretreatment, co-treatment and post-treatment cell line treated with Moringaextracts. It was found that the extract acetyl acetate was better as an MX gene expression level compared with its level in control cells. It was concluded that Moringaleaves extracts have antiviral activity against COX-BV.