the population response of heliothis armigera larvae to nuclear polyhedrosis virus (npv) was investigated. the virus was introduced by permitting the larvae to feed on lettuce leaves. median lethal doses (ld50) were determined. the estimated ld50 values for the first, second, third, early, and late fourth larval instars were 5, 141, 1226, 5168 and 24553 polyhedra per larva respectively. in ...

Newborn mice of several inbred strains develop few or no tumors following inoculation with highly tumorigenic strains of polyomavirus. Here we show that such resistant strains can be divided into two groups based on the responses of adult mice to radiation followed by virus inoculation. Most strains show a radiation-sensitive form of resistance (Rr-s) and develop tumors following radiation and ...

Myxoma virus in European rabbits (Oryctolagus cuniculus) is one of the best documented examples of host-virus co-evolution. In the natural hosts (Sylvilagus brasiliensis or S. bachmani rabbits in the Americas), myxoma virus causes a benign cutaneous fibroma. In European rabbits, however, myxoma virus causes the fulminant disease, myxomatosis. When introduced into wild European rabbit population...

The replication-associated protein (Rep) of geminiviruses is involved in several biological processes brought about by the presence of distinct functional domains. Recently, we have exploited the multifunctional character of the Tomato yellow leaf curl Sardinia virus (TYLCSV) Rep to develop a molecular interference strategy to impair TYLCSV infection. We showed that transgenic expression of its...

(H1N1) became resistant to both oseltamivir and amantadine in a short span of 1 month. Oseltamivir-resistant A/Brisbane/59/2007-like clade 2B virus that had reassorted with A/Hong Kong/2652/2006-like clade 2C virus had apparently spread in the community and to other regions of the world. The possibility of reassortment with pandemic (H1N1) 2009 virus is a major concern. Resistance to oseltamivi...

Artificial microRNAs (amiRNAs) are the expression products of engineered microRNA (miRNA) genes that efficiently and specifically downregulate RNAs that contain complementary sequences. Transgenic plants expressing high levels of one or more amiRNAs targeting particular sequences in the genomes of some RNA viruses have shown specific resistance to the corresponding virus. This is the case of th...

The identification of molecular markers linked to leaf curl virus (CLCuV) disease resistance in cotton has the potential to improve both the efficiency and the efficacy of selection in cotton breeding programs. Genetic analysis suggested that CLCuV resistance is controlled by a single dominant gene. In this study, an interspecific F2 population derived from a cross of Gossypium barbadense and G...

Salicylhydroxamic acid (SHAM), an inhibitor of alternative oxidase (AOX), blocks salicylic acid-induced resistance to tobacco mosaic virus (TMV) but does not inhibit pathogenesis-related PR-1 protein synthesis or resistance to fungal and bacterial pathogens. We found that the synthetic resistance-inducing chemical 2, 6-dichloroisonicotinic acid also induced Aox transcript accumulation and SHAM-...

Potato virus Y (PVY) and Potato mop-top virus (PMTV) are viruses whose geographical distribution is expanding and economic losses are increasing, in contrast to most of other viruses infecting potato crops. Most potato cultivars lack broad-spectrum resistance to the new, genetically complex strains of PVY, and no efficient resistance to PMTV is known in potato. Control of the vectors of these v...