Bibliografie tematiche / DsRNA

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Letteratura scientifica selezionata sul tema "DsRNA"

Autore: Grafiati
Pubblicato: 4 giugno 2021
Ultima modifica: 25 maggio 2024

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Articoli di riviste sul tema "DsRNA"

1

Han, Zhenhao, Jiwen Liu, Linghong Kong, Yunqiang He, Hongqu Wu e Wenxing Xu. "A special satellite-like RNA of a novel hypovirus from Pestalotiopsis fici broadens the definition of fungal satellite". PLOS Pathogens 19, n. 6 (7 giugno 2023): e1010889. http://dx.doi.org/10.1371/journal.ppat.1010889.

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Abstract (sommario):
Satellites associated with plant or animal viruses have been largely detected and characterized, while those from mycoviruses together with their roles remain far less determined. Three dsRNA segments (dsRNA 1 to 3 termed according to their decreasing sizes) were identified in a strain of phytopathogenic fungus Pestalotiopsis fici AH1-1 isolated from a tea leaf. The complete sequences of dsRNAs 1 to 3, with the sizes of 10316, 5511, and 631 bp, were determined by random cloning together with a RACE protocol. Sequence analyses support that dsRNA1 is a genome of a novel hypovirus belonging to genus Alphahypovirus of the family Hypoviridae, tentatively named Pestalotiopsis fici hypovirus 1 (PfHV1); dsRNA2 is a defective RNA (D-RNA) generating from dsRNA1 with septal deletions; and dsRNA3 is the satellite component of PfHV1 since it could be co-precipitated with other dsRNA components in the same sucrose fraction by ultra-centrifuge, suggesting that it is encapsulated together with PfHV1 genomic dsRNAs. Moreover, dsRNA3 shares an identical stretch (170 bp) with dsRNAs 1 and 2 at their 5′ termini and the remaining are heterogenous, which is distinct from a typical satellite that generally has very little or no sequence similarity with helper viruses. More importantly, dsRNA3 lacks a substantial open reading frame (ORF) and a poly (A) tail, which is unlike the known satellite RNAs of hypoviruses, as well as unlike those in association with Totiviridae and Partitiviridae since the latters are encapsidated in coat proteins. As up-regulated expression of RNA3, dsRNA1 was significantly down-regulated, suggesting that dsRNA3 negatively regulates the expression of dsRNA1, whereas dsRNAs 1 to 3 have no obvious impact on the biological traits of the host fungus including morphologies and virulence. This study indicates that PfHV1 dsRNA3 is a special type of satellite-like nucleic acid that has substantial sequence homology with the host viral genome without encapsidation in a coat protein, which broadens the definition of fungal satellite.
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2

Wen, Caiyi, Xinru Wan, Yuanyuan Zhang, Hongyan Du, Chenxing Wei, Rongrong Zhong, Han Zhang et al. "Molecular Characterization of the First Alternavirus Identified in Fusarium oxysporum". Viruses 13, n. 10 (8 ottobre 2021): 2026. http://dx.doi.org/10.3390/v13102026.

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Abstract (sommario):
A novel mycovirus named Fusarium oxysporum alternavirus 1(FoAV1) was identified as infecting Fusarium oxysporum strain BH19, which was isolated from a fusarium wilt diseased stem of Lilium brownii. The genome of FoAV1 contains four double-stranded RNA (dsRNA) segments (dsRNA1, dsRNA 2, dsRNA 3 and dsRNA 4, with lengths of 3.3, 2.6, 2.3 and 1.8 kbp, respectively). Additionally, dsRNA1 encodes RNA-dependent RNA polymerase (RdRp), and dsRNA2- dsRNA3- and dsRNA4-encoded hypothetical proteins (ORF2, ORF3 and ORF4), respectively. A homology BLAST search, along with multiple alignments based on RdRp, ORF2 and ORF3 sequences, identified FoAV1 as a novel member of the proposed family “Alternaviridae”. Evolutionary relation analyses indicated that FoAV1 may be related to alternaviruses, thus dividing the family “Alternaviridae” members into four clades. In addition, we determined that dsRNA4 was dispensable for replication and may be a satellite-like RNA of FoAV1—and could perhaps play a role in the evolution of alternaviruses. Our results provided evidence for potential genera establishment within the proposed family “Alternaviridae”. Additionally, FoAV1 exhibited biological control of Fusarium wilt. Our results also laid the foundations for the further study of mycoviruses within the family “Alternaviridae”, and provide a potential agent for the biocontrol of diseases caused by F. oxysporum.
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3

Jiang, Daohong, e Said A. Ghabrial. "Molecular characterization of Penicillium chrysogenum virus: reconsideration of the taxonomy of the genus Chrysovirus". Journal of General Virology 85, n. 7 (1 luglio 2004): 2111–21. http://dx.doi.org/10.1099/vir.0.79842-0.

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Abstract (sommario):
Molecular cloning and complete nucleotide sequencing of Penicillium chrysogenum virus (PcV) dsRNAs indicated that PcV virions contained four dsRNA segments with sizes of 3562, 3200, 2976 and 2902 bp. Each dsRNA segment had unique sequences and contained a single large open reading frame (ORF). In vitro translation of transcripts derived from full-length cDNA clones of PcV dsRNAs yielded single products of sizes similar to those predicted from the deduced amino acid sequences of the individual ORFs. Sequence similarity searches revealed that dsRNA1 encodes a putative RNA-dependent RNA polymerase. In this study, it was determined that dsRNA2 encodes the major capsid protein and that p4, encoded by dsRNA4, is virion-associated as a minor component. All four dsRNAs of PcV, like the genomic segments of viruses with multipartite genomes, were found to have extended regions of highly conserved terminal sequences at both ends. In addition to the strictly conserved 5′-terminal 10 nt, a second region consisting of reiteration of the sequence CAA was found immediately upstream of the AUG initiator codon. These (CAA) n repeats are reminiscent of the translational enhancer elements of tobamoviruses. The 3′-terminal 14 nt were also strictly conserved. As PcV and related viruses with four dsRNA segments (genus Chrysovirus) have not been previously characterized at the molecular level, they were provisionally classified in the family Partitiviridae, comprising viruses with bipartite genomes. This study represents the first report on molecular characterization of a chrysovirus and the results suggest the creation of a new family of mycoviruses with multipartite dsRNA genomes to accommodate PcV and related viruses.
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4

Wang, Yanfen, Hang Zhao, Jiayuan Cao, Xinming Yin, Yashuang Guo, Lihua Guo, Haiyan Wu e Meng Zhang. "Characterization of a Novel Mycovirus from the Phytopathogenic Fungus Botryosphaeria dothidea". Viruses 14, n. 2 (6 febbraio 2022): 331. http://dx.doi.org/10.3390/v14020331.

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Abstract (sommario):
Botryosphaeria dothidea is, globally, one of the most economically important phytopathogenic fungi worldwide, causing the canker and dieback of fruit trees. An increasing number of viruses infecting B. dothidea have lately been reported, several of which could confer hypovirulence. In this study, isolated from strain ZM170285-1 of B. dothidea, a novel double-stranded RNA (dsRNA) mycovirus, tentatively named Botryosphaeria dothidea partitivirus 2 (BdPV2), was identified well. The BdPV2 harbored three dsRNA segments (1–3) with lengths of 1751, 1568, and 1198 bp, which encoded an RNA-dependent RNA polymerase (RdRp), a capsid protein (CP), and a hypothetical protein of unknown function, respectively. BLASTp searches revealed that the predicted protein sequences of dsRNA1 and dsRNA2 had the highest identities (74.95% and 61.01%) with the corresponding dsRNAs of Penicillium stoloniferum virus S (PsV-S), whereas dsRNA3 shared the highest identity (32.95%) with the dsRNA3 of Aspergillus ochraceous virus 1 (AoV1). Phylogenetic analysis indicated that BdPV2 belonged to the Gammapartitivirus genus and Partitiviridae family. To our knowledge, this is the first report of a Gammapartitivirus in B. dothidea.
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5

Nameth, S. T., e S. L. Cheng. "Identification and Partial Characterization of Endogenous Double-stranded Ribonucleic Acid in Mulberry". Journal of the American Society for Horticultural Science 119, n. 4 (luglio 1994): 859–61. http://dx.doi.org/10.21273/jashs.119.4.859.

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Abstract (sommario):
Double-stranded ribonucleic acid (dsRNA) analysis of apparently healthy red mulberry (Morus rubra L.) yielded four distinct dsRNA banding profiles. dsRNA type 1 contained three dsRNA bands with approximate molecular weights (MWs) of 12.0, 1.0, and 0.9 × 106, respectively. dsRNA type 2 contained two dsRNA bands with MWs of 1.0 and 0.9 × 106. dsRNA type 3 contained four dsRNA bands with MWs of 1.0, 0.9, 0.89, and 0.88 × 106. dsRNA type 4 contained three dsRNA bands with MWs of 1.0, 0.88, and 0.87 × 106. No virus particles were associated with any of the samples analyzed. All four types of dsRNA were resistant to DNase I and RNase A in high salt and susceptible to RNase A in low salt. Mulberry dsRNAs were somewhat similar to endogenous dsRNAs (edsRNA) associated with other hosts. This is the first report of edsRNA associated with a deciduous tree.
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6

Zhai, Lifeng, Mengmeng Yang, Meixin Zhang, Ni Hong e Guoping Wang. "Characterization of a Botybirnavirus Conferring Hypovirulence in the Phytopathogenic Fungus Botryosphaeria dothidea". Viruses 11, n. 3 (17 marzo 2019): 266. http://dx.doi.org/10.3390/v11030266.

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Abstract (sommario):
A double-stranded RNA (dsRNA) virus was isolated and characterized from strain EW220 of the phytopathogenic fungus Botryosphaeria dothidea. The full-length cDNAs of the dsRNAs were 6434 bp and 5986 bp in size, respectively. The largest dsRNA encodes a cap-pol fusion protein that contains a coat protein gene and an RNA-dependent RNA polymerase (RdRp) domain, and the second dsRNA encodes a hypothetical protein. Genome sequence analysis revealed that the sequences of the dsRNA virus shared 99% identity with Bipolaris maydis botybirnavirus 1(BmBRV1) isolated from the causal agent of corn southern leaf blight, Bipolaris maydis. Hence, the dsRNA virus constitutes a new strain of BmBRV1 and was named Bipolaris maydis botybirnavirus 1 strain BdEW220 (BmBRV1-BdEW220). BmBRV1-BdEW220 contains spherical virions that are 37 nm in diameter and consist of two dsRNA segments. The structural proteins of the BmBRV1-BdEW220 virus particles were 110 kDa, 90 kDa, and 80 kDa and were encoded by dsRNA1 and 2-ORFs. Phylogenetic reconstruction indicated that BmBRV1 and BmBRV1-BdEW220 are phylogenetically related to the genus Botybirnavirus. Importantly, BmBRV1-BdEW220 influences the growth of B. dothidea and confers hypovirulence to the fungal host. To our knowledge, this is the first report of a botybirnavirus in B. dothidea.
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Peever, Tobin L., Yir-Chung Liu, Kerong Wang, Bradley I. Hillman, Robert Foglia e Michael G. Milgroom. "Incidence and Diversity of Double-Stranded RNAs Occurring in the Chestnut Blight Fungus, Cryphonectria parasitica, in China and Japan". Phytopathology® 88, n. 8 (agosto 1998): 811–17. http://dx.doi.org/10.1094/phyto.1998.88.8.811.

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Abstract (sommario):
Isolates of the chestnut blight fungus, Cryphonectria parasitica, were randomly sampled from 10 subpopulations in China and 8 subpopulations in Japan and screened for the presence of double-stranded (ds) RNA using an immunoblot procedure with a monoclonal antibody specific for dsRNA. The overall incidence of dsRNA in C. parasitica was 2 and 6% in China and Japan, respectively, much lower than the 28% found previously in North American populations. Genetic relatedness of dsRNAs within and among populations in China and Japan was examined using RNA-RNA hybridizations with labeled-dsRNA probes. The majority of Chinese and Japanese dsRNAs were members of a single hybridization group, related to Cryphonectria hypovirus 1 (CHV1) from Europe, and are referred to as CHV1-type dsRNAs. No evidence was obtained for genetic differentiation between CHV1-type dsRNAs sampled in China and Japan. Five Japanese isolates contained two genetically distinct dsRNAs. The larger segments (approximately 12 kilobases [kb]) were members of the CHV1 hybridization group, while the smaller segments (approximately 3 kb) did not hybridize with any known dsRNA from C. parasitica including the 2.7-kb dsRNA from isolate NB631 from New Jersey or dsRNA from isolate RC1 from Michigan. Two small dsRNA segments (approximately 1.8 and 2 kb) from one isolate sampled from Liaoning Province in northeastern China did not hybridize with any of the dsRNA probes tested including several described dsRNAs of similar size from C. parasitica in North America. Three dsRNAs from Anhui Province, China, hybridized to Cryphonectria hypovirus 2 (CHV2)-specific probes and are thus referred to as CHV2-type dsRNAs. Sequence analysis of 1,627 base pairs of these three CHV2-type dsRNAs from Anhui revealed that they were identical to each other in the region sequenced and very closely related to CHV2-NB58, isolated from New Jersey. We speculate that CHV2-NB58 may have been introduced into North America from this part of China. This is the first record of a North American C. parasitica dsRNA that is genetically related to a dsRNA from Asia.
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8

Valverde, Rodrigo A., e James F. Fontenot. "Variation in Double-stranded Ribonucleic Acid among Pepper Cultivars". Journal of the American Society for Horticultural Science 116, n. 5 (settembre 1991): 903–5. http://dx.doi.org/10.21273/jashs.116.5.903.

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Abstract (sommario):
Double-stranded ribonucleic acid (dsRNA) was found associated with 51 of 80 healthy pepper (Capsicum annuum L., C. frutescent L., C. chinense Jacq.) cultivars analyzed. In general, dsRNAs were consistent within particular cultivars. Twelve distinct dsRNA profiles that varied in the number and size of the dsRNA segments were obtained. All bell and pimento pepper cultivars analyzed had a similar dsRNA profile. Furthermore, all six cherry pepper cultivars tested were free of dsRNAs. However, an association between the dsRNA profile and the pepper group was not obtained with other cultivars. Selected dsRNAs were transmitted at a high rate through the seed of self-pollinated plants but were not transmitted through grafts to plants that lacked them.
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9

He, Wanwan, Wenbo Xu, Letian Xu, Kaiyun Fu, Wenchao Guo, Ralph Bock e Jiang Zhang. "Length-dependent accumulation of double-stranded RNAs in plastids affects RNA interference efficiency in the Colorado potato beetle". Journal of Experimental Botany 71, n. 9 (6 gennaio 2020): 2670–77. http://dx.doi.org/10.1093/jxb/eraa001.

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Abstract (sommario):
Abstract Transplastomic potato plants expressing double-stranded RNA (dsRNA) targeted against essential genes of the Colorado potato beetle (CPB) can be lethal to larvae by triggering an RNA interference (RNAi) response. High accumulation levels of dsRNAs in plastids are crucial to confer an efficient RNAi response in the insects. However, whether length and sequence of the dsRNA determine the efficacy of RNAi and/or influence the level of dsRNA accumulation in plastids is not known. We compared the RNAi efficacy of different lengths of dsRNA targeted against the CPB β-Actin gene (ACT) by feeding in vitro-synthesized dsRNAs to larvae. We showed that, while the 60 bp dsRNA induced only a relatively low RNAi response in CPB, dsRNAs of 200 bp and longer caused high mortality and similar larval growth retardation. When the dsRNAs were expressed from the plastid (chloroplast) genome of potato plants, we found that their accumulation were negatively correlated with length. The level of dsRNA accumulation was positively associated with the observed mortality, suppression of larval growth, and suppression of target gene expression. Importantly, transplastomic potato plants expressing the 200 bp dsRNA were better protected from CPB than plants expressing the 297 bp dsRNA, the best-performing line in our previous study. Our results suggest that the length of dsRNAs is an important factor that influences their accumulation in plastids and thus determines the strength of the insecticidal RNAi effect. Our findings will aid the design of optimized dsRNA expression constructs for plant protection by plastid-mediated RNAi.
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Ahn, II-Pyung, e Yong-Hwan Lee. "A Viral Double-Stranded RNA Up Regulates the Fungal Virulence of Nectria radicicola". Molecular Plant-Microbe Interactions® 14, n. 4 (aprile 2001): 496–507. http://dx.doi.org/10.1094/mpmi.2001.14.4.496.

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Abstract (sommario):
Double-stranded RNAs (dsRNAs) are widespread in plant pathogenic fungi, but their functions in fungal hosts remain mostly unclear, with a few exceptions. We analyzed dsRNAs from Nectria radicicola, the causal fungus of ginseng root rot. Four distinct sizes of dsRNAs, 6.0, 5.0, 2.5, and 1.5 kbp, were detected in 24 out of the 81 strains tested. Curing tests of individual dsRNAs suggested that the presence of 6.0-kbp dsRNA was associated with high levels of virulence, sporulation, laccase activity, and pigmentation in this fungus. The 6.0-kbp dsRNA-cured strains completely lost virulence-related phenotypes. This 6.0-kbp dsRNA was reintroduced by hyphal anastomosis to a dsRNA-cured strain marked with hygromycin resistance, which resulted in the restoration of virulence-related phenotypes. These results strongly suggest that 6.0-kbp dsRNA up regulates fungal virulence in N. radicicola. Sequencing of several cDNA clones derived from 6.0-kbp dsRNA revealed the presence of a RNA-dependent RNA polymerase (RDRP) gene. Phylogenetic analysis showed that this gene is closely related to those of plant cryptic viruses. Biochemical analyses suggested that the 6.0-kbp dsRNA may regulate fungal virulence through signal-transduction pathways involving cyclic AMP-dependent protein kinase and protein kinase C.
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Più fonti

Tesi sul tema "DsRNA"

1

Reddy, Vidita. "Role of dsRNA-induced DRAK1 in Apoptosis". University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1513349817056948.

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Lu, Lenette L. "dsRNA Signaling in Innate Immunity and Viral Inhibition". Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1220030971.

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3

Muccioli, Maria. "Characterizing dsRNA-induced inflammation in ovarian cancer cells". Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1405707670.

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4

Kilic, Ozlem III. "Effect of dsRNA-containing and dsRNA-free hypovirulent isolates of Fusarium oxysporum on severity of Fusarium seedling disease of Essex soybean". Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36965.

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Abstract (sommario):
Sixty-six isolates of F. oxysporum and F. solani were recovered from healthy and necrotic Essex soybean seedlings grown in naturally infested soil. These were tested for pathogenicity at 20 C and -0.01 MPa water potential in artificially infested, autoclaved field soil. Highly pathogenic, moderately pathogenic, and hypovirulent isolates of both species were identified. Fifty-seven F. oxysporum and nine F. solani isolates were tested for the presence of dsRNA. The presence of dsRNA was not associated with hypovirulence in F. oxysporum since some hypovirulent isolates contained dsRNA while other hypovirulent isolates did not. Furthermore, of six dsRNA-containing F. oxysporum isolates, three were hypovirulent, two were moderately pathogenic, and one isolate was highly pathogenic. Four segments of dsRNA, with sizes of 4.0, 3.1, 2.7, and 2.2 kb, were detected in extracts of all six F. oxysporum isolates. No morphological differences were found between dsRNA-containing and dsRNA-free F. oxysporum isolates. Attempts to cure dsRNA-containing hypovirulent F. oxysporum isolates, either by single-sporing of isolates or by using a range of concentrations of cycloheximide, were not successful. No dsRNA was found in any of the F. solani isolates tested. Pythium ultimum, an associate in Essex seedling disease, was isolated from water-soaked lesions and interfered with evaluations of disease caused by the Fusarium spp. Metalaxyl was used to control P. ultimum and had no apparent effect on symptoms associated with F. oxysporum and F. solani in field soil. Prior inoculation of Essex soybean seeds with conidia of dsRNA-free hypovirulent F. oxysporum isolates, plus metalaxyl seed treatment, significantly (p<0.05) reduced disease severity on both cotyledons and hypocotyls and increased the rate of seedling emergence in field soil, compared to the control plants treated with metalaxyl alone or not treated with metalaxyl. No significant (p>0.05) differences were found between dsRNA-containing and dsRNA-free hypovirulent F. oxysporum isolates in their effects on the reduction of disease severity. A mixture of two hypovirulent F. oxysporum isolates was significantly (p<0.05) more effective than single hypovirulent F. oxysporum isolates in increasing the rate of seedling emergence. Symptoms associated with P. ultimum were not affected by the prior inoculation of seeds with individual hypovirulent F. oxysporum isolates.
Master of Science
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5

Potgieter, Abraham Christiaan. "Cloning viral dsRNA genomes : analysis and application / A.C. Potgieter". Thesis, North-West University, 2004. http://hdl.handle.net/10394/334.

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Abstract (sommario):
Double-stranded RNA viruses occur in a large number of hosts in nature ranging from bacteria to mammals. Molecular studies of the double-stranded RNA viruses have greatly enhanced man's understanding of this large group of viruses as far as structure and function of their genes and epidemiology is concerned. However, one of the major prerequisites of obtaining this information is the ability to clone the genomes of these viruses for nucleotide sequencing and recombinant protein expression studies. In the dsRNA field, cloning viral genomes has historically been difficult and time consuming and created a bottleneck that hampered molecular studies. The main aim of this investigation was to optimise a method for cloning viral dsRNA genomes to the extent that it would be easy and fast as well as applicable to most dsRNA viruses. In this study a sequence-independent, oligo-ligation mediated dsRNA cloning procedure for large genes (up to 6.8 kb) was perfected and tailored for routine use to amplify and clone complete genome sets or individual genes. Complete genome sets could be amplified and cloned from as little as 1 ng dsRNA. The method was shown to be simple and efficient compared to other methods and is currently the only method that allows the amplification of complete genomes in a single PCR reaction. Complete gene sets of seven genomes from the Reovirus family, one from the Cystovirus family and one mycovirus, have been amplified and cloned. The full-length VP2 genes of all 9 AHSV and 24 BTV serotypes were also cloned. Phylogenetic analysis of VP2-genes revealed the same grouping of AHSVs and BTVs as serology. Several cloned genes of AHSV, rotavirus and EEV have been utilised for recombinant protein production establishing that the cloned cDNAs have full open reading frames. The nine AHSV VP2 genes have been developed as serotype-specific probes which allowed serotyping of AHSV isolates within 4 days compared to 2-4 weeks needed with the traditional serological serotyping. The new cloning procedure finally opens the bottleneck that hamstrung the development of complete repertoires of recombinant vaccines, molecular diagnostics and epidemiology to combat dsRNA viral diseases. It should now be possible to deliver on many of the expectations that were envisaged for dsRNA virus research and biotechnology since the advent of recombinant DNA technology.
Thesis (Ph.D. (Biochemistry))--North-West University, Potchefstroom Campus, 2004.
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Robinson, Helen Lynne. "Characterization of double-stranded RNA (dsRNA) from Rhizoctonia solani". Thesis, University of Edinburgh, 1999. http://webex.lib.ed.ac.uk/abstracts/robins01.pdf.

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Rodrigues, Paula. "Produção e caracterização de um antissoro policlonal para detecção de ds-RNA". Bachelor's thesis, UTAD, 1998. http://hdl.handle.net/10198/997.

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Abstract (sommario):
Os fitopatologistas têm feito um uso cada vez maior dos métodos serológicos na detecção e caracterização de fitopatogénios, por se tratar de técnicas rápidas, práticas e de elevada sensibilidade, que se podem adaptar às necessidades. De entre estes testes, as várias adaptações do ELISA (enzyme-linked immunosorbent assay) são, actualmente, os métodos mais divulgados, uma vez que permitem testar um elevado número de amostras num curto espaço de tempo e a preço moderado. A maioria dos vírus fitopatogénicos tem genoma de ss-RNA (ácido ribonucleico monocatenário) que, durante o processo replicativo, no interior das células do hospedeiro, dá origem a uma forma replicativa de ds-RNA (ácido ribonucleico bicatenário). Considerando que as plantas não infectadas não contêm quantidades detectáveis de ds-RNA, a sua presença em extractos vegetais é uma forte indicação de infecção viral. O presente trabalho desenvolveu-se no sentido de produzir um antissoro policlonal para um polinucleótido sintético bicatenário [poli(I):poli(C)] para detecção de ds-RNA. O antissoro foi caracterizado através de várias técnicas serológicas (ELISA-indirecto em placa de poliestireno, ELISA-indirecto em membrana de nitrocelulose e teste de difusão dupla em agar). O teste ELISA-indirecto em placa revelou ser mais sensível e prático do que o respectivo teste em membrana de nitrocelulose, tanto na detecção de poli(I):poli(C) como de ds-RNA purificado. Ambos se mostraram, no entanto, incapazes de detectar ds-RNA a partir de extractos aquosos de videira, o que dificulta o processo de detecção, uma vez que a extracção de ds-RNA de material vegetal é morosa e de baixo rendimento.
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Ho, Wing-tak, e 何永德. "Glycyrrhizic acid potentiates dsRNA-induced nitric oxide generation inalveolar macrophages". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31971799.

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Stricker, Ruth Lydia Olga [Verfasser], S. E. [Akademischer Betreuer] Behrens, E. [Akademischer Betreuer] Mundt e E. [Akademischer Betreuer] Vahlenkamp. "Influence of cellular dsRNA binding proteins in the replication process of a dsRNA virus / Ruth Lydia Olga Stricker. Betreuer: S.-E. Behrens ; E. Mundt ; E. Vahlenkamp". Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2012. http://d-nb.info/1025352467/34.

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Ho, Wing-tak. "Glycyrrhizic acid potentiates dsRNA-induced nitric oxide generation in alveolar macrophages". Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B31971799.

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Più fonti

Libri sul tema "DsRNA"

1

Michael, Tavantzis Stylianos, a cura di. dsRNA genetic elements: Concepts and applications in agriculture, forestry, and medicine. Boca Raton, FL: CRC Press, 2002.

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2

Van Etten, James L., a cura di. Lesser Known Large dsDNA Viruses. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-68618-7.

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3

L, Van Etten James, Compans Richard W, Honjō Tasuku, Koprowski Hilary, Melchers F. (Fritz) 1936-, Oldstone Michael B. A, Olsnes Sjur, Vogt, P. K. (Peter K.), 1932- e SpringerLink (Online service), a cura di. Lesser Known Large dsDNA Viruses. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009.

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4

Tavantzis, Stellos M. DsRNA Genetic Elements: Concepts and Applications in Agriculture, Forestry, and Medicine. Taylor & Francis Group, 2001.

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5

Tavantzis, Stellos M. Dsrna Genetic Elements: Concepts and Applications in Agriculture, Forestry, and Medicine. Taylor & Francis Group, 2002.

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6

Tavantzis, Stellos M. DsRNA Genetic Elements: Concepts and Applications in Agriculture, Forestry, and Medicine. Taylor & Francis Group, 2001.

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7

McEwan, Deborah Lyn. Mechanisms of intercellular dsRNA transport by SID-1 and SID-2. 2010.

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8

Tavantzis, Stellos M. dsRNA Genetic Elements: Concepts and Applications in Agriculture, Forestry, and Medicine. CRC, 2001.

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9

Chong, Karen Lynn. Characterization of the human, interferon inducible, dsRNA-activated protein kinase (p68 kinase). 1993.

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10

Etten, James L. van. Lesser Known Large dsDNA Viruses. Springer, 2010.

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Capitoli di libri sul tema "DsRNA"

1

Gries, Oliver, e Thomas Ly. "Reoviridae [dsRNA]". In Infektologie - Kompendium humanpathogener Infektionskrankheiten und Erreger, 191–93. Berlin, Heidelberg: Springer Berlin Heidelberg, 2019. http://dx.doi.org/10.1007/978-3-662-58219-0_24.

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2

de Schutter, Kristof, Olivier Christiaens, Clauvis Nji Tizi Taning e Guy Smagghe. "Boosting dsRNA delivery in plant and insect cells with peptide- and polymer-based carriers: case-based current status and future perspectives." In RNAi for plant improvement and protection, 102–16. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789248890.0011.

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Abstract Since the discovery of this naturally occurring endogenous regulatory and defence mechanism, RNA interference (RNAi) has been exploited as a powerful tool for functional genomic research. In addition, it has evolved as a promising candidate for a sustainable, specific and ecofriendly strategy for pest management and plant improvement. A key element in this technology is the efficient delivery of dsRNAs into the pest or plant tissues. While several examples using transgenic plants expressing the dsRNAs have proved the potential of this technology, nontransgenic approaches are investigated as alternatives, allowing flexibility and circumventing technical limitations of the transgenic approach. However, the efficacy of environmental RNAi is affected by several barriers, such as extracellular degradation of the dsRNA, inefficient internalization of the dsRNA in the cell and low endosomal escape into the cytoplasm, resulting in variable or low RNAi responses. In the medical field, carrier systems are commonly used to enhance RNA delivery and these systems are being rapidly adopted by the agricultural industry. Using four case studies, this chapter demonstrates the potential of carriers to improve the RNAi response in pest control for aquatic-living mosquito larvae and RNAi-resilient Lepidoptera and to cross the plant cell wall, allowing efficient environmental RNAi in plants.
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3

de Schutter, Kristof, Olivier Christiaens, Clauvis Nji Tizi Taning e Guy Smagghe. "Boosting dsRNA delivery in plant and insect cells with peptide- and polymer-based carriers: case-based current status and future perspectives." In RNAi for plant improvement and protection, 102–16. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789248890.0102.

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Abstract (sommario):
Abstract Since the discovery of this naturally occurring endogenous regulatory and defence mechanism, RNA interference (RNAi) has been exploited as a powerful tool for functional genomic research. In addition, it has evolved as a promising candidate for a sustainable, specific and ecofriendly strategy for pest management and plant improvement. A key element in this technology is the efficient delivery of dsRNAs into the pest or plant tissues. While several examples using transgenic plants expressing the dsRNAs have proved the potential of this technology, nontransgenic approaches are investigated as alternatives, allowing flexibility and circumventing technical limitations of the transgenic approach. However, the efficacy of environmental RNAi is affected by several barriers, such as extracellular degradation of the dsRNA, inefficient internalization of the dsRNA in the cell and low endosomal escape into the cytoplasm, resulting in variable or low RNAi responses. In the medical field, carrier systems are commonly used to enhance RNA delivery and these systems are being rapidly adopted by the agricultural industry. Using four case studies, this chapter demonstrates the potential of carriers to improve the RNAi response in pest control for aquatic-living mosquito larvae and RNAi-resilient Lepidoptera and to cross the plant cell wall, allowing efficient environmental RNAi in plants.
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4

Kontogiannatos, Dimitrios, Anna Kolliopoulou e Luc Swevers. "The 'Trojan horse' approach for successful RNA interference in insects." In RNAi for plant improvement and protection, 25–39. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789248890.0004a.

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Abstract (sommario):
Abstract Since the discovery of RNA interference in 1998 as a potent molecular tool for the selective downregulation of gene expression in almost all eukaryotes, increasing research is being performed in order to discover applications that are useful for the pharmaceutical and chemical industry. The ease of use of double-stranded RNA for targeted in vivo gene silencing in animal cells and tissues gave birth to a massive interest from industry in order to discover biotechnological applications for human health and plant protection. For insects, RNAi became the 'Holy Grail' of pesticide manufacturing, because this technology is a promising species-specific environmentally friendly approach to killing natural enemies of cultured plants and farmed animals. The general idea to use RNAi as a pest-control agent originated with the realization that dsRNAs that target developmentally or physiologically important insect genes can cause lethal phenotypes as a result of the specific gene downregulation. Most importantly to achieve this, dsRNA is not required to be constitutively expressed via a transgene in the targeted insect but it can be administrated orally after direct spraying on the infested plants. Similarly, dsRNAs can be administered to pests after constitutive expression as a hairpin in plants or bacteria via stable transgenesis. Ideally, this technology could have already been applied in integrated pest management (IPM) if improvements were not essential in order to achieve higher insecticidal effects. There are many limitations that decrease RNAi efficiency in insects, which arise from the biochemical nature of the insect gut as well as from deficiencies in the RNAi core machinery, a common phenomenon mostly observed in lepidopteran species. To overcome these obstacles, new technologies should be assessed to ascertain that the dsRNA will be transferred intact, stable and in high amounts to the targeted insect cells. In this chapter we will review a wide range of recent discoveries that address the delivery issues of dsRNAs in insect cells, with a focus on the most prominent and efficient technologies. We will also review the upcoming and novel use of viral molecular components for the successful and efficient delivery of dsRNA to the insect cell.
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5

Kontogiannatos, Dimitrios, Anna Kolliopoulou e Luc Swevers. "The 'Trojan horse' approach for successful RNA interference in insects." In RNAi for plant improvement and protection, 25–39. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789248890.0025.

Testo completo
Abstract (sommario):
Abstract Since the discovery of RNA interference in 1998 as a potent molecular tool for the selective downregulation of gene expression in almost all eukaryotes, increasing research is being performed in order to discover applications that are useful for the pharmaceutical and chemical industry. The ease of use of double-stranded RNA for targeted in vivo gene silencing in animal cells and tissues gave birth to a massive interest from industry in order to discover biotechnological applications for human health and plant protection. For insects, RNAi became the 'Holy Grail' of pesticide manufacturing, because this technology is a promising species-specific environmentally friendly approach to killing natural enemies of cultured plants and farmed animals. The general idea to use RNAi as a pest-control agent originated with the realization that dsRNAs that target developmentally or physiologically important insect genes can cause lethal phenotypes as a result of the specific gene downregulation. Most importantly to achieve this, dsRNA is not required to be constitutively expressed via a transgene in the targeted insect but it can be administrated orally after direct spraying on the infested plants. Similarly, dsRNAs can be administered to pests after constitutive expression as a hairpin in plants or bacteria via stable transgenesis. Ideally, this technology could have already been applied in integrated pest management (IPM) if improvements were not essential in order to achieve higher insecticidal effects. There are many limitations that decrease RNAi efficiency in insects, which arise from the biochemical nature of the insect gut as well as from deficiencies in the RNAi core machinery, a common phenomenon mostly observed in lepidopteran species. To overcome these obstacles, new technologies should be assessed to ascertain that the dsRNA will be transferred intact, stable and in high amounts to the targeted insect cells. In this chapter we will review a wide range of recent discoveries that address the delivery issues of dsRNAs in insect cells, with a focus on the most prominent and efficient technologies. We will also review the upcoming and novel use of viral molecular components for the successful and efficient delivery of dsRNA to the insect cell.
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6

Mindich, Leonard. "Packaging in dsRNA Viruses". In Viral Molecular Machines, 601–8. Boston, MA: Springer US, 2011. http://dx.doi.org/10.1007/978-1-4614-0980-9_26.

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Pantchev, Ivelin, Goritsa Rakleova e Atanas Atanassov. "The stability of dsRNA during external applications - an overview." In RNAi for plant improvement and protection, 94–101. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789248890.0010.

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Abstract (sommario):
Abstract The research community is deeply convinced that RNA is unstable in the environment. Its roots rise from numerous failed attempts to isolate functional cellular RNA molecules. Further support had originated from the fast turnover of RNA in the cells. The situation changed recently with the discovery that externally applied dsRNA can produce targeted gene silencing in plant-feeding insects. First results have demonstrated that external dsRNA can successfully pass the insect gastrointestinal tract and reach its final destination within the body cells. This was somewhat unexpected and sparked new interest in RNA stability in the environment and its fate in the insect organism. In this brief review we make an attempt to summarize current knowledge and to propose a model of how dsRNA can perform its function under these settings.
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Pantchev, Ivelin, Goritsa Rakleova e Atanas Atanassov. "The stability of dsRNA during external applications - an overview." In RNAi for plant improvement and protection, 94–101. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789248890.0094.

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Abstract (sommario):
Abstract The research community is deeply convinced that RNA is unstable in the environment. Its roots rise from numerous failed attempts to isolate functional cellular RNA molecules. Further support had originated from the fast turnover of RNA in the cells. The situation changed recently with the discovery that externally applied dsRNA can produce targeted gene silencing in plant-feeding insects. First results have demonstrated that external dsRNA can successfully pass the insect gastrointestinal tract and reach its final destination within the body cells. This was somewhat unexpected and sparked new interest in RNA stability in the environment and its fate in the insect organism. In this brief review we make an attempt to summarize current knowledge and to propose a model of how dsRNA can perform its function under these settings.
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9

Obadia, Benjamin, e Maria-Carla Saleh. "dsRNA Uptake in Adult Drosophila". In Antiviral RNAi, 253–63. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61779-037-9_16.

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10

Mitchell, Diane J., e E. Alan Bevan. "dsRNA killer systems in yeast". In Yeast Biotechnology, 104–55. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3119-0_5.

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Atti di convegni sul tema "DsRNA"

1

Suprunova, T. P., N. V. Markin, A. N. Ignatov, A. G. Solovyov, N. O. Kalinina e M. E. Talyansky. "Use of dsRNA-based antiviral compounds to protect potato plants". In Растениеводство и луговодство. Тимирязевская сельскохозяйственная академия, 2020. http://dx.doi.org/10.26897/978-5-9675-1762-4-2020-132.

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One of the most important food crops in the world, the potato (Solanum tuberosum L.) is infected with many viruses, of which the y virus (Potato virus Y, PVY) is the most important economically, causing significant crop losses. Several alternative methods of dsRNA delivery have been tested, with the most promising being spray - induced gene silencing (SIGS). The results showed a high effect of preventive use of dsRNA. Treatment with the initial working concentration of dsRNA protected 100% and 65% of plants from virus propagation for 14 and 21 days, respectively, and 65% of plants were protected by the minimum tested concentration (10 ng/MCL) for 14 days. Therapeutic use of dsRNA 3 days after inoculation did not significantly affect the dynamics of virus accumulation in the plant. Thus, in the course of the experiment, a high biological antiviral effectiveness of dsRNA was demonstrated in the preventive treatment of potato plants against the background of artificial infection of plants with the PVY virus.
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2

Lee, How-Jing. "Oral delivery of dsRNA lipoplexes to German cockroach,Blattella germanica, protects dsRNA from degradation". In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.113415.

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3

Hosseini, Ramtin, Xingyi Yang e Pengtao Xie. "DSRNA: Differentiable Search of Robust Neural Architectures". In 2021 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR). IEEE, 2021. http://dx.doi.org/10.1109/cvpr46437.2021.00613.

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Wong, Colin R. "Environmental fate of dsRNA in an aqueous system". In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.113822.

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Davis, Ian C. "Double-stranded RNA (dsRNA) Impairs Alveolar Fluid Clearance In Mice". In American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans. American Thoracic Society, 2010. http://dx.doi.org/10.1164/ajrccm-conference.2010.181.1_meetingabstracts.a6458.

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Mahmutovic Persson, Irma, Angelica Brandelius e Lena Uller. "DsRNA-Induced TSLP Expression And Neutrophilia In Mouse Asthma Exacerbation Model". In American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California. American Thoracic Society, 2012. http://dx.doi.org/10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a5385.

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Liu, Jisheng. "Transcriptional inhibition of BmToll9-1 by dsRNA in the silkworm larval midgut". In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.108954.

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Gil, M. Maqueda, e M. Ramírez Fernández. "A simple method for simultaneously isolating mitDNA and virus dsRNA from wine yeasts". In Proceedings of the II International Conference on Environmental, Industrial and Applied Microbiology (BioMicroWorld2007). WORLD SCIENTIFIC, 2009. http://dx.doi.org/10.1142/9789812837554_0075.

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9

Asokan, R. "Differential expression of miRNAs in response to dsRNA of various target genes in Noctuidae". In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.94537.

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Muccioli, Maria, Michelle Pate e Fabian Benencia. "Abstract 1659: Characterizing cytokine secretion in response to dsRNA treatment in ovarian cancer cells". In Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1538-7445.am2014-1659.

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Rapporti di organizzazioni sul tema "DsRNA"

1

Bartholomay, Lyric, e D. L. Hank Harris. Evaluation of Highly Targeted dsRNA for the Treatment of Infectious Myonecrosis Virus (IMNV) in Litopenaeus vannamei. Ames (Iowa): Iowa State University, gennaio 2012. http://dx.doi.org/10.31274/ans_air-180814-1050.

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Gonsalves, Dennis, Edna Tanne e Deborah Golino. Isolation, Serological Detection of Closteroviruses Assoc. with Grape Corky Bark, and ELISA-dsRNA Analysis to Monitor Grape Leafroll Elimination Procedures. United States Department of Agriculture, agosto 1994. http://dx.doi.org/10.32747/1994.7604311.bard.

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3

Gal-On, Amit, Shou-Wei Ding, Victor P. Gaba e Harry S. Paris. role of RNA-dependent RNA polymerase 1 in plant virus defense. United States Department of Agriculture, gennaio 2012. http://dx.doi.org/10.32747/2012.7597919.bard.

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Abstract (sommario):
Objectives: Our BARD proposal on the impact of RNA-dependent RNA polymerase 1 (RDR1) in plant defense against viruses was divided into four original objectives. 1. To examine whether a high level of dsRNA expression can stimulate RDR1 transcription independent of salicylic acid (SA) concentration. 2. To determine whether the high or low level of RDR1 transcript accumulation observed in virus resistant and susceptible cultivars is associated with viral resistance and susceptibility. 3. To define the biogenesis and function of RDR1-dependent endogenous siRNAs. 4. To understand why Cucumber mosaic virus (CMV) can overcome RDR1-dependent resistance. The objectives were slightly changed due to the unique finding that cucumber has four different RDR1 genes. Background to the topic: RDR1 is a key plant defense against viruses. RDR1 is induced by virus infection and produces viral and plant dsRNAs which are processed by DICERs to siRNAs. siRNAs guide specific viral and plant RNA cleavage or serve as primers for secondary amplification of viral-dsRNA by RDR. The proposal is based on our preliminary results that a. the association of siRNA and RDR1 accumulation with multiple virus resistance, and b. that virus infection induced the RDR1-dependent production of a new class of endogenous siRNAs. However, the precise mechanisms underlying RDR1 induction and siRNA biogenesis due to virus infection remain to be discovered in plants. Major conclusions, solutions and achievements: We found that in the cucurbit family (cucumber, melon, squash, watermelon) there are 3-4 RDR1 genes not documented in other plant families. This important finding required a change in the emphasis of our objectives. We characterized 4 RDR1s in cucumber and 3 in melon. We demonstrated that in cucumber RDR1b is apparently a new broad spectrum virus resistance gene, independent of SA. In melon RDR1b is truncated, and therefore is assumed to be the reason that melon is highly susceptible to many viruses. RDR1c is dramatically induced due to DNA and RNA virus infection, and inhibition of RDR1c expression led to increased virus accumulation which suggested its important on gene silencing/defense mechanism. We show that induction of antiviral RNAi in Arabidopsis is associated with production of a genetically distinct class of virus-activated siRNAs (vasiRNAs) by RNA dependent RNA polymerase-1 targeting hundreds of host genes for RNA silencing by Argonaute-2. Production of vasiRNAs is induced by viruses from two different super groups of RNA virus families, targeted for inhibition by CMV, and correlated with virus resistance independently of viral siRNAs. We propose that antiviral RNAi activate broad-spectrum antiviral activity via widespread silencing of host genes directed by vasiRNAs, in addition to specific antiviral defense Implications both scientific and agricultural: The RDR1b (resistance) gene can now be used as a transcription marker for broad virus resistance. The discovery of vasiRNAs expands the repertoire of siRNAs and suggests that the siRNA-processing activity of Dicer proteins may play a more important role in the regulation of plant and animal gene expression than is currently known. We assume that precise screening of the vasiRNA host targets will lead in the near future for identification of plant genes associate with virus diseases and perhaps other pathogens.
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4

Aly, Radi, e John I. Yoder. Development of resistant crop plants to parasitic weeds based on trans-specific gene silencing. United States Department of Agriculture, gennaio 2013. http://dx.doi.org/10.32747/2013.7598146.bard.

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Abstract (sommario):
Broomrapes (Orobanche/Phelipanchespp.) are holo parasitic plants that subsist on the roots of a variety of agricultural crops and cause severe losses to the yield quality and quantity. Effective methods for controlling parasitic weeds are scarce, with only a few known cases of genetic resistance. In the current study, we proposed an improved strategy for the control of parasitic weeds based on trans-specific gene-silencing of three parasite genes at once. We used two strategies to express dsRNA containing selected sequences of three Phelipancheaegyptiacagenes PaACS, PaM6PR and PaPrx1 (pma): transient expression using Tobacco rattle virus (TRV:pma) as a virus-induced gene-silencing (VIGS) vector and stable expression in transgenic tomato Solanumlycopersicum(Mill.) plants harboring a hairpin construct (pBINPLUS35:pma). siRNA-mediated transgene-silencing (20–24 nt) was detected in the host plants. Our results demonstrate that the quantities of PaACSand PaM6PR transcripts from P. aegyptiacatubercles grown on transgenic tomato or on Tobacco rattle virus-infected Nicotianabenthamianaplants were significantly reduced. However, only partial reductions in the quantity of PaPrx1 transcripts were observed in the parasite tubercles grown on tomato and on N. benthamianaplants. Concomitant with the suppression of the target genes, there were significant decreases in the number and weight of the parasite tubercles that grew on the host plants, in both the transient and the stable experimental systems. The results of the work carried out using both strategies point to the movement of mobile exogenous siRNA from the host to the parasite, leading to the impaired expression of essential parasite target genes. In light of the importance of parasitic weeds to world agriculture and the difficulty of obtaining resistance by conventional methods, we assume that genetic resistance based on the silencing of key metabolic genes in the parasite is now feasible. BARD Report - Project4622 Page 2 of 60
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Mevarech, Moshe, Jeremy Bruenn e Yigal Koltin. Virus Encoded Toxin of the Corn Smut Ustilago Maydis - Isolation of Receptors and Mapping Functional Domains. United States Department of Agriculture, settembre 1995. http://dx.doi.org/10.32747/1995.7613022.bard.

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Abstract (sommario):
Ustilago maydis is a fungal pathogen of maize. Some strains of U. maydis encode secreted polypeptide toxins capable of killing other susceptible strains of U. maydis. Resistance to the toxins is conferred by recessive nuclear genes. The toxins are encoded by genomic segments of resident double-strande RNA viruses. The best characterized toxin, KP6, is composed of two polypeptides, a and b, which are not covalently linked. It is encoded by P6M2 dsRNA, which has been cloned, sequenced and expressed in a variety of systems. In this study we have shown that the toxin acts on the membranes of sensitive cells and that both polypeptides are required for toxin activity. The toxin has been shown to function by creating new pores in the cell membrane and disrupting ion fluxes. The experiments performed on artificial phospholipid bilayers indicated that KP6 forms large voltage-independent, cation-selective channels. Experiments leading to the resolution of structure-function relationship of the toxin by in vitro analysis have been initiated. During the course of this research the collaboration also yielded X-ray diffracion data of the crystallized a polypeptide. The effect of the toxin on the pathogen has been shown to be receptor-mediated. A potential receptor protein, identified in membrane fractions of sensitive cells, was subjected to tryptic hydrolysis followed by amino-acid analysis. The peptides obtained were used to isolate a cDNA fragment by reverse PCR, which showed 30% sequence homology to the human HLA protein. Analysis of other toxins secreted by U. maydis, KP1 and KP4, have demonstrated that, unlike KP6, they are composed of a single polypeptide. Finally, KP6 has been expressed in transgenic tobacco plants, indicating that accurate processing by Kex2p-like activity occurs in plants as well. Using tobacco as a model system, we determined that active antifungal toxins can be synthesized and targeted to the outside of transgenic plant cells. If this methodology can be applied to other agronomically crop species, then U. maydis toxins may provide a novel means for biological control of pathogenic fungi.
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Davis, Eric L., Yuji Oka, Amit Gal-On, Todd Wehner e Aaron Zelcer. Broad-spectrum Resistance to Root-Knot Nematodes in Transgenic Cucurbits. United States Department of Agriculture, giugno 2013. http://dx.doi.org/10.32747/2013.7593389.bard.

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Abstract (sommario):
Root-knot nematodes (RKN), Meloidogyne spp., are extremely destructive pathogens of cucurbit crops grown in the United States and Israel. The safety and environmental concerns of toxic nematicides, and limited sources of natural cucurbit resistance to the four major species of Meloidogyne that threaten these crops in Israel and the U.S., have emphasized the use of biotechnology to develop cucurbits with novel RKN resistance. The U.S. scientists have identified over 40 unique RKN parasitism genes that encode nematode secretions involved in successful plant root infection by RKN, and they have demonstrated that expression of a double-stranded RNA (dsRNA) complementary to a RKN parasitism gene (called 16DIO) in Arabidopsis thaliana induced RNA interference (RNAi)-mediated silencing of the RKN16DlO gene and produced transgenic plants with strong resistance to all four major RKN species. The expression 8D05 parasitism gene was found to coincide with the timing of upregulation of NtCel7 promoter (identified to be upregulated in giantcells by US scientists). NtCel7 promoter was used to express the genes at the right time (early stages of infection) and in the right place (giant-cells) in transgenic plants. US partners produced NtCel7 (nematode-induced promoter)-driven 16DlO-RNAi and 8DOS-RNAi constructs, pHANNIBAL 4D03-RNAi construct and modified 16DlO-RNAi construct (for increased RNAi expression and efficacy) for cucurbit transformation in Israel. In Arabidopsis, some 16DlO-RNAi plant lines show greater levels of resistance to M. incognita than others, and within these lines resistance of greater than 90% reduction in infection is observed among almost all replicates in US. The level of observed nematode resistance is likely to be directly correlated with the level of RNAi expression in individual plants. In Israel, all the RKN parasitism genes-RNAi constructs were successfully transformed into cucumber and melon. The transgenic lines were evaluated for expression of the transgene siRNA in leaves and roots. Those displaying transgene siRNA accumulation were passed on for nematode resistance analysis. Rl seedlings from different lines were subjected to evaluation for resistance to M. javanica. None of the lines was resistant to the nematode in contrast with US partner's results in Arabidopsis. This could be for the following reasons: a) The level of transgene siRNA was insufficient in cucumber and tomato to cause resislance. b) 111e nemalode species on cucwnber IIlay be different ur act in a different manner. c) The assay was performed in soil with a high level of nematode inoculation, and not in petri dish, which may not permit the observation of a low level of resistance.
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Antignus, Yehezkiel, Ernest Hiebert, Shlomo Cohen e Susan Webb. Approaches for Studying the Interaction of Geminiviruses with Their Whitefly Vector Bemisia tabaci. United States Department of Agriculture, luglio 1995. http://dx.doi.org/10.32747/1995.7604928.bard.

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Abstract (sommario):
The DNA of tomato yellow leaf curl virus (TYLCB) was detected in its whitefly vector, Bemisia tabaci, by dot spot hybridization as early as 1 h after acquisition access. The retention of the virus nucleic acid in the vector was at least 23 days after a 48 h acquisition access. However, the retention of TYLCV coat protein did not exceed 10 days. No replicative forms of TYLCV could be detected in B. tabaci, indicating a non-propagative relationship with the vector. Whiteflies were not able to accumulate naked virion ssDNA, virus cloned dsDNA, or virions with impaired coat protein. Deletion, frameshift, and single amino acid mutations were inserted into open reading frames (ORFs) V1 and V2 (Coat protein) of TYLCV. The ability of these mutants to replicate, to spread and to induce symptoms was tested both in leaf disks and in intact plants. No replication was found in tissues that were infected with a deletion mutant that lacked the carboxy half of the coat protein gene. Residual amounts of ssDNA and dsDNA were detected i tissues infected with a frameshift mutant in which an early termination at the extreme part of the protein. Two other mutants in which a single amino acid was changed in the overlapping part of V1 and V2 were able to spread systemically but infections remained symptomless and the production of ssDNA and dsDNA were significantly lower. These mutants were acquired and transmitted by Bemisia tabaci. Procedures for the the dissection, fixation and embedding of whiteflies were developed. The anatomy and ultrastructure of the salivary gland and the midgut of Bemisia tabaci and Trialeurodes vaporariorum (a vector and non-vector of geminiviruses respectively) was studied and described. Monoclonal antibodies against bean golden mosaic virus (BGMV) with narrow and broad spectrum were prepared. Transmission studies of tomato mottle geminivirus (TMoV) by B. tabaci were carried out. These studies were essential for a further work aimed to understand the interaction of geminiviruses with the insect and their localization in its tissues. To enable the production of transgenic plants procedures were developed for tomato transformation with both Agrobacterium and microparticle bombardment.
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Elizur, Abigail, Amir Sagi, Gideon Hulata, Clive Jones e Wayne Knibb. Improving Crustacean Aquaculture Production Efficiencies through Development of Monosex Populations Using Endocrine and Molecular Manipulations. United States Department of Agriculture, giugno 2010. http://dx.doi.org/10.32747/2010.7613890.bard.

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Abstract (sommario):
Background Most of Australian prawn aquaculture production is based on P. monodon. However, the Australian industry is under intense competition from lower priced overseas imports. The availability of all-female monosex populations, by virtue of their large size and associated premium prize, will offer competitive advantage to the industry which desperately needs to counteract competitors within this market. As for the redclaw production in Israel, although it is at its infancy, the growers realized that the production of males is extremely advantageous and that such management strategy will change the economic assumptions and performances of this aquaculture to attract many more growers. Original objectives (as in original proposal) Investigating the sex inheritance mechanism in the tiger prawn. Identification of genes expressed uniquely in the androgenic gland (AG) of prawns and crayfish. The above genes and/or their products will be used to localize the AG in the prawn and manipulate the AG activity in both species. Production of monosex populations through AG manipulation. In the prawn, production of all-female populations and in the crayfish, all-male populations. Achievements In the crayfish, the AG cDNA library was further screened and a third AG specific transcript, designated Cq-AG3, had been identified. Simultaneously the two AG specific genes, which were previously identified, were further characterized. Tissue specificity of one of those genes, termed Cq-AG2, was demonstrated by northern blot hybridization and RNA in-situ hybridization. Bioinformatics prediction, which suggested a 42 amino acid long signal anchor at the N-terminus of the deduced Cq-AG2, was confirmed by immunolocalization of a recombinant protein. Cq-IAG's functionality was demonstrated by dsRNA in-vivo injections to intersex crayfish. Cq-IAGsilencing induced dramatic sex-related alterations, including male feature feminization, reduced sperm production, extensive testicular apoptosis, induction of the vitellogeningene expression and accumulation of yolk proteins in the ovaries. In the prawn, the AG was identified and a cDNA library was created. The putative P. monodonAG hormone encoding gene (Pm-IAG) was identified, isolated and characterized for time of expression and histological localization. Implantation of the AG into prawn post larvae (PL) and juveniles resulted in phenotypic transformation which included the appearance of appendix masculina and enlarged petasma. The transformation however did not result in sex change or the creation of neo males thus the population genetics stage to be executed with Prof. Hulata did not materialized. Repeated AG implantation is currently being trialed. Major conclusions and Implications, both scientific and agricultural Cq-IAG's involvement in male sexual differentiation had been demonstrated and it is strongly suggested that this gene encodes an AG hormone in this crayfish. A thorough screening of the AG cDNA library shows Cq-IAG is the prominent transcript within the library. However, the identification of two additional transcripts hints that Cq-IAG is not the only gene mediating the AG effects. The successful gene silencing of Cq-IAG, if performed at earlier developmental stages, might accomplish full and functional sex reversal which will enable the production of all-male crayfish populations. Pm-IAG is likely to play a similar role in prawns. It is possible that repeated administration of the AG into prawn will lead to the desired full sex reversal, so that WZ neo males, crossed with WZ females can result in WW females, which will form the basis for monosex all-female population.
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9

Kotler, Moshe, Larry Hanson e Shane Burgess. Replication Defective Cyprinid Herpes Virus-3 (CyHV-3) as a Combined Prophylactic Vaccine in Carps. United States Department of Agriculture, dicembre 2010. http://dx.doi.org/10.32747/2010.7697104.bard.

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Aquacultured koi and common carp fish (Cyprinus carpio) are intensively bred as ornamental and food fish in many countries worldwide. Hatcheries of carp and koi have recently suffered massive financial damages due to two viral diseases caused by the Cyprinid herpesvirus-3 (CyHV-3), previously designated as Carp Interstitial Nephritis and Gill Necrosis Virus (CNGV) and Koi herpesvirus (KHV), and by the Spring Viremia of Carp Virus (SVCV). CyHV-3 is a large dsDNA virus, which is infectious mostly to koi and common carp, while SVCV is a rhabdovirus with a relatively broad host range. Both viruses induce contagious disease with mortality rate up to 90%. Strategies for the control of viral infection in fish are of limited use. While efforts to prevent introduction of infectious agents into culture facilities are desirable, such exclusion strategies are far from fail-safe. Extensive vaccination methods that are useful for use in aquaculture facilities produce weak immunity, when used with proteins or inactivated viruses. Methods to overcome this obstacle are to vaccinate the fish with large amounts of antigen and/or use adjuvant and immune modulators over a long period. These techniques usually require individual handling of the fish. On the other hand, live attenuated virus is efficient and economical when used as an immersionvaccine. However, this technique poses certain environmental risks and thus may be difficult to license and scale up. Another option is a vaccine based on the replication defective virus (RDV) (pseudovirus), which can infect cells, but is unable to produce infectious particles. This vaccine may circumvent many of the problems related to attenuated-live vaccine (e.g., inadvertent infection and reversion to the virulent strain).
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10

Wilson, Thomas E., Avraham A. Levy e Tzvi Tzfira. Controlling Early Stages of DNA Repair for Gene-targeting Enhancement in Plants. United States Department of Agriculture, marzo 2012. http://dx.doi.org/10.32747/2012.7697124.bard.

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Gene targeting (GT) is a much needed technology as a tool for plant research and for the precise engineering of crop species. Recent advances in this field have shown that the presence of a DNA double-strand break (DSB) in a genomic locus is critical for the integration of an exogenous DNA molecule introduced into this locus. This integration can occur via either non-homologous end joining (NHEJ) into the break or homologous recombination (HR) between the broken genomic DNA and the introduced vector. A bottleneck for DNA integration via HR is the machinery responsible for homology search and strand invasion. Important proteins in this pathway are Rad51, Rad52 and Rad54. We proposed to combine our respective expertise: on the US side, in the design of zincfinger nucleases (ZFNs) for the induction of DNA DSBs at any desired genomic locus and in the integration of DNA molecules via NHEJ; and on the Israeli side in the HR events, downstream of the DSB, that lead to homology search and strand invasion. We sought to test three major pathways of targeted DNA integration: (i) integration by NHEJ into DSBs induced at desired sites by specially designed ZFNs; (ii) integration into DSBs induced at desired sites combined with the use of Rad51, Rad52 and Rad54 proteins to maximize the chances for efficient and precise HR-mediated vector insertion; (iii) stimulation of HR by Rad51, Rad52 and Rad54 in the absence of DSB induction. We also proposed to study the formation of dsT-DNA molecules during the transformation of plant cells. dsT-DNA molecules are an important substrate for HR and NHEJ-mediatedGT, yet the mode of their formation from single stranded T-DNA molecules is still obscure. In addition we sought to develop a system for assembly of multi-transgene binary vectors by using ZFNs. The latter may facilitate the production of binary vectors that may be ready for genome editing in transgenic plants. ZFNs were proposed for the induction of DSBs in genomic targets, namely, the FtsH2 gene whose loss of function can easily be identified in somatic tissues as white sectors, and the Cruciferin locus whose targeting by a GFP or RFP reporter vectors can give rise to fluorescent seeds. ZFNs were also proposed for the induction of DSBs in artificial targets and for assembly of multi-gene vectors. We finally sought to address two important cell types in terms of relevance to plant transformation, namely GT of germinal (egg) cells by floral dipping, and GT in somatic cells by root and leave transformation. To be successful, we made use of novel optimized expression cassettes that enable coexpression of all of the genes of interest (ZFNs and Rad genes) in the right tissues (egg or root cells) at the right time, namely when the GT vector is delivered into the cells. Methods were proposed for investigating the complementation of T-strands to dsDNA molecules in living plant cells. During the course of this research, we (i) designed, assembled and tested, in vitro, a pair of new ZFNs capable of targeting the Cruciferin gene, (ii) produced transgenic plants which expresses for ZFN monomers for targeting of the FtsH2 gene. Expression of these enzymes is controlled by constitutive or heat shock induced promoters, (iii) produced a large population of transgenic Arabidopsis lines in which mutated mGUS gene was incorporated into different genomic locations, (iv) designed a system for egg-cell-specific expression of ZFNs and RAD genes and initiate GT experiments, (v) demonstrated that we can achieve NHEJ-mediated gene replacement in plant cells (vi) developed a system for ZFN and homing endonuclease-mediated assembly of multigene plant transformation vectors and (vii) explored the mechanism of dsTDNA formation in plant cells. This work has substantially advanced our understanding of the mechanisms of DNA integration into plants and furthered the development of important new tools for GT in plants.
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