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Several genes have been identified to play important roles associated with sex selection in Drosophila melanogaster. An essential part is attributed to the sex-lethal gene that depends on the expression of the X:A (number of chromosomes to autosomes) ratio signal controlling both sex selection and dosage compensation processes in D. melanogaster. Interestingly, for sex selection in D. melanogaster there are no documented data addressing the role of the inhibitor of apoptosis (IAP) genes and their signaling influence on this biological process. In this study, we found that topical application of a 20-nucleotide-long antisense DNA fragment (oligoDIAP-2) from the death-associated inhibitor of apoptosis (DIAP)-2 gene interferes with D. melanogaster development and significantly decreases the number of female imagos and their biomass. We show that the applied antisense oligoDIAP-2 fragment downregulates the target DIAP-2 gene whose normal concentration is necessary for the development of female D. melanogaster. These data correspond to the results on downregulation of the target host IAP-Z gene of Lymantria dispar L. female imagos after topical treatment with an 18-nucleotide-long antisense DNA fragment from the L. dispar multicapsid nuclear polyhedrosis virus IAP-3 gene at the larval stage. The observed novel phenomenon linking the downregulation of insect IAP genes and the low rate of female imago development could have practical application, especially in insect pest control and molecular pathology.

The high efficiency of baculovirus infection is partially explained by the ability of the virus to suppress host defense machinery connected with the apoptosis pathway. Members of the baculovirus gene family, inhibitors of apoptosis (vIAPs), have been shown to inhibit apoptosis in baculovirus-infected cells. Here we showed that treatment of the LdMNPV-infected 1st instar gypsy moth (Lymantria dispar) caterpillars with sense (oligoBIR) and antisense (oligoRING) DNA oligonucleotides from the LdMNPV IAP3 gene induced elevated mortality of the insects. Apoptotic DNA ladder assay showed that the leading role in this phenomenon is played by the antisense oligoRING fragment of the vIAP3 gene. These results imply that the application of both antisense DNA oligonucleotides from vIAP genes and baculovirus preparations (one following the other) may be a potential method for plant protection against insect pests.

Currently, the use of insecticides is an acute problem. Due to rapid population growth, the primary task is to increase food production. Beyond abiotic factors (drought, soil salinity, etc.) that reduce crop yields, farmers face problems with insect pests that can decrease crop productivity up to 60%. Also, insects are carriers of severe viral and protozoan human diseases. The need for application of insecticides is not questioned but many of them cause resistance of insect pests to them. This, in turn, leads to the necessity to invent new insecticides that are safe and more effective for long-term use. Preparations based on conservative parts of nucleic acids, particularly contact DNA insecticides, could be used to solve insecticide resistance problem as control agents which are well-tailored to target insect pests. This mini review is devoted to these issues. [ABSTRACT FROM AUTHOR]

The high efficiency of baculovirus infection is partially explained by the ability of the virus to suppress host defense machinery connected with the apoptosis pathway. Members of the baculovirus gene family, inhibitors of apoptosis (vIAPs), have been shown to inhibit apoptosis in baculovirus-infected cells. Here we showed that treatment of the LdMNPV-infected 1st instar gypsy moth (Lymantria dispar) caterpillars with sense (oligoBIR) and antisense (oligoRING) DNA oligonucleotides from the LdMNPV IAP3 gene induced elevated mortality of the insects. Apoptotic DNA ladder assay showed that the leading role in this phenomenon is played by the antisense oligoRING fragment of the vIAP3 gene. These results imply that the application of both antisense DNA oligonucleotides from vIAP genes and baculovirus preparations (one following the other) may be a potential method for plant protection against insect pests. [ABSTRACT FROM AUTHOR]

The discovery of the post-transcriptional gene silencing (PTGS) mechanism, widely known as RNAi (RNA interference), has contributed towards the elucidation of the cellular machinery involved in the response against viral infections based on gene silencing, and in developmental regulation of translational suppression. The application of RNAi in insect pest management (IPM), and gene functional analysis, has been of enormous importance. Unfortunately, as RNAi has many times proven to be difficult to examine in Lepidoptera, focus has shifted to other potential post-genomic options in IPM. Special attention has afforded to novel DNA insecticides based on preparations of short single-stranded fragments of baculovirus anti-apoptosis genes, which represent a safe and relatively rapid alternative approach for IPM. This paper focuses on the drawbacks and advantages of DNA insecticides used in gypsy moth control and based on RNAi. [ABSTRACT FROM AUTHOR]

In this paper we evaluated the impact of the DNA oligonucleotides used as insecticides on the biochemical parameters of English oak (Quercus robur) and apple seedlings (Malus domestica). The assessment of the biochemical parameters of the plants was based on the measurement of the alkaline phosphatase activity and glucose concentration, important markers in plant cell, in the leaves of English oak and apple seedlings. We have found that the use of the RING domain fragment in a concentration of 5 pmol/cm2 of plant leaf, leads to a significant decrease in alkaline phosphatase activity in apple seedlings (p<0.05) and to a significant decrease in the concentration of glucose in the leaves of English oak (p<0.01) compared to the control, 24 hours after the treatment. However, the values of the parameters in the experimental groups were non-significant, compared to the control on the 7th day. These results suggest the absence of a long-term negative effect of the DNA oligonucleotides on apple seedlings and leaves of English oak. [ABSTRACT FROM AUTHOR]

This study investigates the mechanism of action of DNA insecticides, a novel preparation against gypsy moth (Lymantria dispar) based on the DNA fragments of the antiapoptotic gene of its nuclear polyhedrosis virus. In our experiments gypsy moth showed significant susceptibility to applied DNA insecticides on the basis of BIR and RING domains fragments of LdMNPV IAP-3, whereas common fruit fly and tobacco hornworm did not. PCR with the same fragments of BIR and RING domains of the LdMNPV IAP-3 gene as primers revealed parts of the genomes of gypsy moth, common fruit fly, and tobacco hornworm. Part of the gypsy moth genome cloned with the fragments of BIR and RING domains of the LdMNPV IAP-3 gene as primers has an overlap with the corresponding part of the LdMNPV IAP-3 gene and Lymantria dispar IAP-1 mRNA for an inhibitor of apoptosis protein with the high cover of the latter by query, which allows assuming that we cloned a part of a gypsy moth antiapoptosis gene. This finding suggests that DNA insecticides might act through the mechanisms characteristic for blocking of posttranscriptional expression of gypsy moth antiapoptosis genes. [ABSTRACT FROM AUTHOR]