A fast one-step reverse transcription and polymerase chain reaction (RT-PCR) amplification procedure providing highly specific complementary DNA from plant virus RNA

Molecular Detection of Canine Distemper Virus in Dogs in Baghdad Province, Iraq

Canine distemper (CD) is an infectious disease that affects dogs and is extremely contagious and lethal, with a high mortality and morbidity rates. It infects a broad variety of animals, including primates, cetaceans, and carnivores causing a multi-systemic pathological condition. This study aimed to detect canine distemper virus (CDV) in blood samples of dogs clinically suspected with distemper at the Baghdad Veterinary Hospital, Baghdad, Iraq. CDV nucleoprotein gene (N) was detected in the whole blood of 46 dogs using reverse transcription-PCR (RT-PCR). The partially amplified (591 bp) fragment of the N gene was detected in 12 of 46 (26%) blood samples of dogs examined. Based on the partial sequencing data of the N gene, three local isolates might be similar to the NCBI-BLAST reference CDV virus isolates FJ977579.1 China, AF378705.1 USA, and AF305419.1 UK, while other strains EU072200.1 Hungary, AF164967.1 Switzerland, KU578257.1 Germany, and AB474397.1 Japan were found to be rather distinct. The isolates displayed a higher level of similarity with the Snyder Hill CDV strain and Onderstepoort CDV strain. There was less homology with the CDV strain A75/17 of Switzerland and 007Lm CDV strain of Japan. In conclusion, this study confirmed that CDV infection is present in domestic dogs in Iraq. This may indicate a risk of the disease spreading to parts of the country that may be disease-free.

Metatranscriptomic Analysis of Larval Guts from Field-Collected and Laboratory-Reared Spodoptera frugiperda from the South American Subtropical Region

This is the first study to report a high-throughput approach integrating gene expression data from Spodoptera frugiperda guts and their associated metatranscriptomes. Our datasets provide information on the potential effects of environmental conditions on the expression profile of S. frugiperda larval guts, their associated metatranscriptome, and putative interactions between them.

Comparison of one-step RT-PCR and a nested PCR for the detection of canine distemper virus in clinical samples

OBJECTIVE

To develop a rapid and sensitive method for the detection of canine distemper virus (CDV) by nested PCR using clinical specimens.

DESIGN

A nested PCR was developed, compared to a one-step RT-PCR and validated.

PROCEDURE

Two sets of specific primers for a one-step RT-PCR and a nested PCR, targeting a 640 bp fragment and a 297 bp fragment, respectively, were selected from the highly conserved region of the nucleocapsid protein (NP) gene of CDV. The nested PCR and the one-step RT-PCR were used to amplify a part of the CDV NP gene of a CDV vaccinal strain and samples of urine, blood, nasal discharge and saliva from 29 dogs suspected of suffering CD.

RESULTS

Both the one-step RT-PCR and the nested PCR reacted with the CDV vaccinal strain, but not with canine parvovirus. The expected 640 bp fragment of the NP gene was detected in 11/22 (50.0%) blood, 10/20 (50.0%) urine, 5/25 (20.0%) saliva and 6/27 (22.2%) nasal swab samples by one-step RT-PCR, whereas the nested PCR amplified an expected 297 bp fragment of the NP gene in 18/22 (81.8%) blood, 15/20 (75.0%) urine, 14/25 (56%) saliva and 19/27 (70.3%) nasal swab samples.

CONCLUSION

The nested PCR detected CDV in blood, urine, nasal swab and saliva more frequently than did the one-step RT-PCR. Therefore, this assay should be a useful aid to antemortem diagnosis of CDV infections in dogs.

Simultaneous and co-operational amplification (Co-PCR): a new concept for detection of plant viruses

A new and highly sensitive method for the amplification of viral RNA targets from plant material has been developed and patented. This technique called Co-operational amplification (Co-PCR) can be carried out easily in a simple tetraprimer reaction based on the simultaneous action of four primers. The reaction process consists of the simultaneous reverse transcription of two different fragments from the same target, one containing the other; the production of four amplicons by the combination of the two pair of primers, one pair external to other; and the co-operational action of amplicons for the production of the largest fragment. The technique was used successfully, both in metal block and capillary air thermal cyclers for the detection of plant RNA viruses (Cherry leaf roll virus, Strawberry latent ringspot virus, Cucumber mosaic virus, Plum pox virus and Citrus tristeza virus). The sensitivity observed is at least 100 times higher than that achieved with RT-PCR and similar to nested RT-PCR. Colorimetric detection was coupled with this methodology facilitating its introduction for routine indexing programs and for phytosanitary selection of virus-free plant material.