Comparative population structure of Chinese sumac aphid Schlechtendalia chinensis and its primary host-plant Rhus chinensis.

Most of our current understanding of comparative population structure has been come from studies of parasite-host systems, whereas the genetic comparison of gallnut-aphids and their host-plants remain poorly documented. Here, we examined the population genetic structure of the Chinese sumac aphid Schlechtendalia chinensis and its unique primary host-plant Rhus chinensis in a mountainous province in western China using inter-simple sequence repeat (ISSR) markers. Despite being sampled from a mountainous geographic range, analysis of molecular variance (AMOVA) showed that the majority of genetic variation occurred among individuals within populations of both the aphid and its host.

Entry of Bombyx mori cypovirus 1 into midgut cells in vivo.

In vivo entry of Bombyx mori cypovirus 1 into the silkworm midgut was studied by electron microscopy of ultrathin sections of midguts from silkworm larvae that had been administered virus-contaminated leaves. In 3 h, virions were observed outside and inside midgut cells, including columnar cells, goblet cells and muscle cells. Virions were seen adhering to the plasma membrane of microvilli, embedding in the membrane and settling themselves intact inside the microvilli of the columnar cells.

Infection of wild-type Autographa californica multicapsid nucleopolyhedrovirus induces in vivo apoptosis of Spodoptera litura larvae.

Direct evidence of in vivo apoptosis of Spodoptera litura larvae was demonstrated by haemocoel inoculation with wild-type Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) budded virus (BV). In sharp contrast to natural infection, cadavers did not melt, liquefy and melanize. Typical morphological changes of apoptosis in insect haemocytes post-infection, including blebbing of the cell surface, chromatin margination and condensation, vacuolization of the cytoplasm and formation of apoptotic bodies, were observed by light and electron microscopy.

Apoptosis of Spodoptera litura cells induced by AcMNPV ie-1 gene.

Apoptosis was induced in Spodoptera litura Sl-zsu-1 cells transfected with plasmid pAcie-1 DNA containing ie-1 gene of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). Apoptotic bodies appeared 24 h post transfection and cell mortality peaked after 48 h. Electrophoresis of total DNA extract of Sl-zsu-1 cells showed a DNA ladder, indicating that transfection of ie-1 gene alone can trigger apoptosis directly or indirectly.

Cloning and Sequence Analysis of the Chitinase Gene of Spodoptera litura Nuclear Polyhedrosis Virus.

Using AcMNPV chiA-containing fragment as a probe, the chitinase gene of Spodoptera litura nuclear polyhedrosis virus (SpltNPV) was localized in two contiguous fragments, XbaI 5.1 kb and 2.1 kb, and the intact SpltNPV chiA gene was obtained by cloning and sequencing those two fragments.

Cloning and Expression of SpltMNPV Sl136 Gene and Functions of the Expressed Product.

By computer-assisted analysis, it was revealed that ORF136 gene product in SpltMNPV genome had the basic properties of membrane protein. A putative signal peptide was present at the N-terminal and a transmembrane region near the C-terminal of SL136 protein. In the N-terminal half region, there was a coiled-coil domain, which is a typical feature of a number of viral fusion proteins.