The non-structural protein 3 (NS3) of hepatitis C virus (HCV) is a highly promising target for anti-HCV therapy because of its multiple enzymatic activities, such as RNAstimulated nucleoside triphosphatase, RNA helicase and serine protease. The helicase domain of NS3 as well as domain 2 of the helicase were expressed in a baculovirus system to obtain in high yield active proteins for prospective studies of complexes of the helicase with its inhibitors. A novel direct fluorometric test of helicase activity with a quenched DNA substrate, 3 0 labeled with a Cy3 dye and 5 0 labeled with a Black Hole Quencher, was developed and optimal reaction conditions established. This test based on fluorescence resonance energy transfer is simple and fast. It allows for direct measurements of enzyme activity, circumventing laborious and complicated radioactive techniques that are poorly reproducible. The results obtained encourage us to propose this new fluorescent assay as a method enabling high throughput screening of anti-helicase compounds.

Supercoiled infectious DNA was isolated from nuclear polyhedrosis virus infecting great wax moth Galleria mellonella L.) Covalently closed DNA molecules constitute approximately 10--30 per cent in our preparations. These molecules dissappear during storage. Electron micrographs of supercoiled and open circular molecules are presented. Length of the open rings is about 50--52 micron. Infectivity of different DNA forms is discussed.

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A physical map of the M. neustria nuclear polyidrosis virus (ManeNPV) genome was constructed, the complete order of BamHJ, Kpnl and Pstl restriction enzyme sites was determined t a polyhedrin gene was localized on the map. The viral DNA size was calculated to be about 139 kbp. Restriction endonuclease profiles of the DNA of ManeNPV plaques isolate propagated in A. pernyi cells demonstrated ^persistent heterogeneity*, submolar bands were shown to appear in a digestion pattern of DNA of the first passage virus. These bands were proved to be due to the DNA molecules presence in the non-homogeneous virus DNA pool, their chains having been shown to carry a putative break in a definite site. Such a *break site» was localized on the physical, map of ManeNPV genome. The Baculoviridae contain double-stranded circular DNA viruses infecting a lot of species belonging mainly to the Lepidoptera> Diptera> and Hymenoptera orders. Baculoviruses with their large genomes and complex reproduction cycle accompanied by the cas cade gene expression regulation have become an interesting and well-made topic of molecular biology studies. The interest to the representatives of this family is also caused by three aspects of their practical use. First of them is an application of the baculoviruses as vectors for gene therapy, the problem being investigated during last decade [1, 2]. Two other aspects are more traditional: baculoviruses are considered as viral insecticides for pest insect control and are widely used as vectors for recombinant protein synthesis in both in vivo and in vitro cul tivated insect cells [3 J. M. neustria {Mane) larvae (Lepidoptera, Lasiocampidae) is a well known garden fruit pest insect, especially on apple trees. However, outbreaks of the pest mass reproduction occur often also in woods (first of all, in oak woods) of the forest-steppe zone.