Project description:Viromes of sour and sweet cherry trees in Hungarian germ line collections were surveyed using small RNA HTS as an unbiased method. RNA from leaf samples of different cultivars were purified and used to produce seven pools from which small RNA HTS libraries were prepared. The sequenced reads were analyzed using bioinformatic methods to revel the presence of viruses in the samples. Presence of the viruses were validated using RT-PCR.
Project description:During a proof-of-concept study, virome of millet, grown as weed was determined by small RNA HTS. As a result, from the pools of 20 randomly collected millet samples collected at two locations, we identified the presence of three viruses, two of them first time in Hungary. Based on our results we could only suspect that these viruses: wheat streak mosaic virus (WSMV), barley stripe mosaic virus (BYSMV) and barley virus G (BVG) could have been overwintered in millet or other monocotyledonous weeds growing at these fields. As a follow-up research, in the summer of 2021, we collected symptomatic leaves of several monocotyledonous plants at the same fields. This time the sampling was done in July. From the samples, small RNA HTS was carried out.
Project description:Pan-viral DNA array (PVDA) and high-throughput sequencing (HTS) are useful tools to identify novel virus of emerging diseases. However, both techniques have difficulties to identify viruses in clinical samples because of host genomic DNA (hgDNA) contamination. Both propidium monoazide (PMA) and ethidium bromide monoazide (EMA) have the capacity to bind free DNA but are cell membrane-impermeable and thus are unable to bind protected DNA and RNA such as viral genomic material. DNA modified by EMA or PMA is not amplifiable by polymerase. In order to assess the capacity of EMA or PMA to lower hgDNA, serum or lung tissue homogenates were spiked with porcine reproductive and respiratory virus (PRRSV) and were processed with different combination of treatment: with or without ultracentrifugation and incubation with or without different concentration of EMA or PMA. PVDA and HTS were used to evaluate the capacity of both techniques to detect the presence of PRRSV from each sample. Negative results were obtained by PVDA and low amount of PRRSV specific reads were obtained by HTS with untreated samples or samples treated only by ultracentrifugation. An increase capacity of PRRSV detection was observable by PVDA in EMA and PMA treated samples but PVDA best results were obtained following PMA treatment, with or without ultracentrifugation. HTS sensitivity was also improved by a treatment with EMA or PMA, but the number of reads was significantly higher in PMA treated samples. These results support the use of PMA as a treatment to increase sensitivity of PVDA and HTS.
Project description:Pan-viral DNA array (PVDA) and high-throughput sequencing (HTS) are useful tools to identify novel virus of emerging diseases. However, both techniques have difficulties to identify viruses in clinical samples because of host genomic DNA (hgDNA) contamination. Both propidium monoazide (PMA) and ethidium bromide monoazide (EMA) have the capacity to bind free DNA but are cell membrane-impermeable and thus are unable to bind protected DNA and RNA such as viral genomic material. DNA modified by EMA or PMA is not amplifiable by polymerase. In order to assess the capacity of EMA or PMA to lower hgDNA, serum or lung tissue homogenates were spiked with porcine reproductive and respiratory virus (PRRSV) and were processed with different combination of treatment: with or without ultracentrifugation and incubation with or without different concentration of EMA or PMA. PVDA and HTS were used to evaluate the capacity of both techniques to detect the presence of PRRSV from each sample. Negative results were obtained by PVDA and low amount of PRRSV specific reads were obtained by HTS with untreated samples or samples treated only by ultracentrifugation. An increase capacity of PRRSV detection was observable by PVDA in EMA and PMA treated samples but PVDA best results were obtained following PMA treatment, with or without ultracentrifugation. HTS sensitivity was also improved by a treatment with EMA or PMA, but the number of reads was significantly higher in PMA treated samples. These results support the use of PMA as a treatment to increase sensitivity of PVDA and HTS. A non specific DNA probe is used as a negative hybridization control. Also, specifics probes targeting pUC19 plasmid DNA is used as a DNA array positive control as well as a localization control. Finally, there are 34 probes of 70 nucleotides spotted in duplicate were selected to target PRRSV conserved regions. A total of 80 different tests were done by DNA array in order to evaluate different treatments conditions with EMA or PMA, with or without ultracentrifugation. A total of 58 samples were tested on specific lung tissue homogenates spiked with different concentration of PRRSV and 12 samples were serum samples spiked with one concentration of PRRSV. Finally. A total of six samples
Project description:High-throughput sequencing (HTS) has become a powerful tool for the detection of and sequence characterization of microRNAs (miRNA) and other small RNAs (sRNA). Unfortunately, the use of HTS data to determine the relative quantity of different miRNAs in a sample has been shown to be inconsistent with quantitative PCR and Northern Blot results. Several recent studies have concluded that the major contributor to this inconsistency is bias introduced during the construction of sRNA libraries for HTS and that the bias is primarily derived from the adaptor ligation steps; specifically where single stranded adaptors are sequentially ligated to the 3' and 5'-end of sRNAs using T4 RNA ligases. In this study we investigated the effects of ligation bias by using a pool of randomized ligation substrates, defined mixtures of miRNA sequences and several combinations of adaptors in HTS library construction. We show that like the 3' adaptor ligation step, the 5' adaptor ligation is also biased, not because of primary sequence, but instead due to secondary structures of the two ligation substrates. We find that multiple secondary structural factors influence final representation in HTS results. Our results provide insight about the nature of ligation bias and allowed us to design adaptors that reduce ligation bias and produce HTS results that more accurately reflect the actual concentrations of miRNAs in the defined starting material.
Project description:Viruses transmitted by small mammals and arthropods serve as global threats to humans. Most emergent and re-emergent viral agents are transmitted by these groups; therefore, the development of high-throughput screening methods for the detection and surveillance of such viruses is of great interest. In this study, we describe a DNA microarray platform that can be used for screening all viruses transmitted by small mammals and arthropods (SMAvirusChip) with nucleotide sequences that have been deposited in the GenBank. SMAvirusChip was designed with more than 15,000 oligonucleotide probes (60-mers), including viral and control probes. Two SMAvirusChip versions were designed: SMAvirusChip v1 contains 4209 viral probes for the detection of 409 viruses, while SMAvirusChip v2 contains 4943 probes for the detection of 416 viruses. SMAvirusChip was evaluated with 20 laboratory reference-strain viruses. These viruses could be specifically detected when alone in a sample or when artificially mixed within a single sample. The sensitivity of SMAvirusChip was evaluated using 10-fold serial dilutions of dengue virus (DENV). The results showed a detection limit as low as 2.6E3 RNA copies/mL. Additionally, the sensitivity was one log10 lower (2.6E2 RNA copies/mL) than quantitative real-time RT-PCR and sufficient to detect viral genomes in clinical samples. The detection of DENV in serum samples of DENV-infected patients (n= 6) and in a whole blood sample spiked with DENV confirmed the applicability of SMAvirusChip for the detection of viruses in clinical samples. In addition, in a pool of mosquito samples spiked with DENV, the virus was also detectable. SMAvirusChip was able to specifically detect viruses in cell cultures, serum samples, total blood samples and a pool of mosquitoes, confirming that cellular RNA/DNA did not interfere with the assay. Therefore, SMAvirusChip may represent an innovative surveillance method for the rapid identification of viruses transmitted by small mammals and arthropods. The SMAvirusChip v2 microarray includes more than 15,000 oligonucleotide probes (60-mers long) for the detection of viruses transmitted by small mammals and arthropods. The sequences of 4943 viral probes for the detection of 416 viruses (112 viruses transmitted by small mammals and 304 arboviruses) were included in this platform. Positive and negative control oligonucleotide probes were also included in the design.
Project description:Viruses transmitted by small mammals and arthropods serve as global threats to humans. Most emergent and re-emergent viral agents are transmitted by these groups; therefore, the development of high-throughput screening methods for the detection and surveillance of such viruses is of great interest. In this study, we describe a DNA microarray platform that can be used for screening all viruses transmitted by small mammals and arthropods (SMAvirusChip) with nucleotide sequences that have been deposited in the GenBank. SMAvirusChip was designed with more than 15,000 oligonucleotide probes (60-mers), including viral and control probes. Two SMAvirusChip versions were designed: SMAvirusChip v1 contains 4209 viral probes for the detection of 409 viruses, while SMAvirusChip v2 contains 4943 probes for the detection of 416 viruses. SMAvirusChip was evaluated with 20 laboratory reference-strain viruses. These viruses could be specifically detected when alone in a sample or when artificially mixed within a single sample. The sensitivity of SMAvirusChip was evaluated using 10-fold serial dilutions of dengue virus (DENV). The results showed a detection limit as low as 2.6E3 RNA copies/mL. Additionally, the sensitivity was one log10 lower (2.6E2 RNA copies/mL) than quantitative real-time RT-PCR and sufficient to detect viral genomes in clinical samples. The detection of DENV in serum samples of DENV-infected patients (n= 6) and in a whole blood sample spiked with DENV confirmed the applicability of SMAvirusChip for the detection of viruses in clinical samples. In addition, in a pool of mosquito samples spiked with DENV, the virus was also detectable. SMAvirusChip was able to specifically detect viruses in cell cultures, serum samples, total blood samples and a pool of mosquitoes, confirming that cellular RNA/DNA did not interfere with the assay. Therefore, SMAvirusChip may represent an innovative surveillance method for the rapid identification of viruses transmitted by small mammals and arthropods. The SMAvirusChip v1 microarray includes more than 15,000 oligonucleotide probes (60-mers long) for the detection of viruses transmitted by small mammals and arthropods. The sequences of 4209 viral probes for the detection of 409 viruses (109 viruses transmitted by small mammals and 300 arboviruses) were included in this platform. Positive and negative control oligonucleotide probes were also included in the design.
Project description:High-throughput sequencing (HTS) has become a powerful tool for the detection of and sequence characterization of microRNAs (miRNA) and other small RNAs (sRNA). Unfortunately, the use of HTS data to determine the relative quantity of different miRNAs in a sample has been shown to be inconsistent with quantitative PCR and Northern Blot results. Several recent studies have concluded that the major contributor to this inconsistency is bias introduced during the construction of sRNA libraries for HTS and that the bias is primarily derived from the adaptor ligation steps; specifically where single stranded adaptors are sequentially ligated to the 3' and 5'-end of sRNAs using T4 RNA ligases. In this study we investigated the effects of ligation bias by using a pool of randomized ligation substrates, defined mixtures of miRNA sequences and several combinations of adaptors in HTS library construction. We show that like the 3' adaptor ligation step, the 5' adaptor ligation is also biased, not because of primary sequence, but instead due to secondary structures of the two ligation substrates. We find that multiple secondary structural factors influence final representation in HTS results. Our results provide insight about the nature of ligation bias and allowed us to design adaptors that reduce ligation bias and produce HTS results that more accurately reflect the actual concentrations of miRNAs in the defined starting material. 28 samples were sequenced and the libraries were made using various synthetic oligo mixtures and adaptor combinations