The Complete Sequence of a Human Parainfluenzavirus 4 Genome

Although the human parainfluenza virus 4 (HPIV4) has been known for a long time, its genome, alone among the human paramyxoviruses, has not been completely sequenced to date. In this study we obtained the first complete genomic sequence of HPIV4 from a clinical isolate named SKPIV4 obtained at the Hospital for Sick Children in Toronto (Ontario, Canada). The coding regions for the N, P/V, M, F and HN proteins show very high identities (95% to 97%) with previously available partial sequences for HPIV4B. The sequence for the L protein and the non-coding regions represent new information. A surprising feature of the genome is its length, more than 17 kb, making it the longest genome within the genus Rubulavirus, although the length is well within the known range of 15 kb to 19 kb for the subfamily Paramyxovirinae. The availability of a complete genomic sequence will facilitate investigations on a respiratory virus that is still not completely characterized

Virus inactivation by ozone

grantor: University of TorontoOzone is a triatomic allotrope of oxygen. It is a desirable disinfectant because of its high oxidation potential. Its utilization has been primarily in water purification and sewage treatment industries to inactivate particular organic chemical pollutants and contaminating microorganisms. In this study, the parameters of inactivation of representative viruses by ozone were investigated. Ozone was produced in the 2-4 wt% range from oxygen, by corona discharge, using LifeTECH Corporation's Sterinetics™ generator. Ozone decay kinetics in aqueous solution were established at different pH, temperature and starting ozone concentrations. The inactivation of the enveloped virus, infectious bovine rhinotracheitis virus strain LA (IBRV) and the non-enveloped virus bovine adenovirus type 3 (BAd3) by defined ozone concentrations under defined conditions was explored. Virus infectivity was assessed by endpoint dilution [TCID50]. At ozone concentrations of 5 [mu]g/ml, BAd3 and IBRV titres were reduced by 3.0-3.1 and 3.3-4.3 logs, respectively. At lower ozone concentrations (0.25-0.5 [mu]g/ml), BAd3 titres were reduced 0.9-2.0 logs whereas IBRV titres were reduced 1.3-2.9 logs. These studies provide a detailed description of virus inactivation by ozone under defined conditions and can serve as a reference for applications of this technology to virus inactivation.M.Sc

Multiple Features of Advanced Melanoma Recapitulated in Tumorigenic Variants of Early Stage (Radial Growth Phase) Human Melanoma Cell Lines: Evidence For a Dominant Phenotype.

The vast majority of primary human cutaneous melanomas undergo a slow and gradual progression from a clinically indolent, curable radial growth phase (RGP) to a malignant vertical growth phase. We sought to develop a way of isolating genetically related malignant variants from a benign RGP human melanoma, called WM35. The parent and variants were then used as a model system to examine to what extent the expression of clinically and biologically relevant phenotypic features characteristic of advanced melanomas are associated with (and thus perhaps causative of) such a malignant conversion. Such a model system could also be used as a means of eventually identifying genetic alterations and cellular changes involved in the malignant switch in melanoma progression. To develop such a model, we subjected WM35 cells to retroviral insertional mutagenesis, which was followed by selection for progressive growth of solid tumors in nude mice. Highly aggressive and phenotypically stable tumorigenic variants were derived which contained at least four integrated proviruses. In contrast to the parental WM35 cells, these cell lines expressed several phenotypic features characteristic of naturally derived, advanced-stage malignant melanoma cells. Thus, in addition to tumor-forming ability in nude mice, the variants were growth factor and anchorage independent, overexpressed the MUC18 adhesion molecule, and lost responsiveness to the growth-inhibitory effect of several cytokines, including interleukin 6, transforming growth factor beta, interleukin 1beta, and tumor necrosis factor-alpha. Tumorigenicity and multicytokine resistance were dominant traits since in somatic cell hybrids between the parental cells and a tumorigenic subline no suppressive effect of the former cell population was observed. These findings suggest that one or more dominantly acting genetic alterations might be involved in this progression of RGP melanoma cells. The identity of such alterations remains to be determined