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Artykuły w czasopismach na temat "CTV"
1
Powell, Charles A., i Youjian Lin. "Separation of Citrus Tristeza Virus Isolates in Mixed Infections through Transfer by Single Brown Citrus Aphids". HortScience 40, nr 3 (czerwiec 2005): 694–96. http://dx.doi.org/10.21273/hortsci.40.3.694.
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One hundred single brown citrus aphid (BCA) (Toxoptera citricida Kirkaldy) transmission attempts were made from each of 16 different citrus trees [8 grapefruit (Citrus paradisi Macf.) and 8 sweet orange (C. sinensis (L.) Osbeck)] previously inoculated with decline-inducing (T36-CTV), non-decline-inducing (T30-CTV), a mixture of the two Citrus tristeza virus isolate types, or no CTV. Successful CTV transmission occurred in 1.5% of attempts from grapefruit trees that had been bark-chip-inoculated with T36-CTV, 3% of attempts from orange trees inoculated with T36-CTV, 3% of attempts from grapefruit trees inoculated with both T36- and T30-CTV, 4% of attempts from orange trees inoculated with both T36- and T30-CTV, 1.5% of attempts from grapefruit trees inoculated with T30-CTV, and 3.5% of attempts from orange trees inoculated with T30-CTV. Single BCA were able to recover T30-like-CTV from trees believed to be inoculated only with T36-CTV, and T36-like-CTV from trees believed to be inoculated only with T30-CTV, suggesting that these inoculum sources were also mixtures of T36-CTV and T30-CTV. The T36-CTV was not immunologically detectable in some of the trees from which it was transmitted indicating that single BrCA can recover T36-CTV from a T36-CTV/T30-CTV mixture in which the T36-CTV is an undetectable, minority component.
2
Long, Amy, Francis LeBlanc, Jean-René Arseneau, Nellie Gagne, Katja Einer-Jensen, Jan Lovy, Mark Polinski, Simon Jones i Kyle A. Garver. "Distribution and Pathogenicity of Two Cutthroat Trout Virus (CTV) Genotypes in Canada". Viruses 13, nr 9 (31.08.2021): 1730. http://dx.doi.org/10.3390/v13091730.
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The sole member of the Piscihepevirus genus (family Hepeviridae) is cutthroat trout virus (CTV) but recent metatranscriptomic studies have identified numerous fish hepevirus sequences including CTV-2. In the current study, viruses with sequences resembling both CTV and CTV-2 were isolated from salmonids in eastern and western Canada. Phylogenetic analysis of eight full genomes delineated the Canadian CTV isolates into two genotypes (CTV-1 and CTV-2) within the Piscihepevirus genus. Hepevirus genomes typically have three open reading frames but an ORF3 counterpart was not predicted in the Canadian CTV isolates. In vitro replication of a CTV-2 isolate produced cytopathic effects in the CHSE-214 cell line with similar amplification efficiency as CTV. Likewise, the morphology of the CTV-2 isolate resembled CTV, yet viral replication caused dilation of the endoplasmic reticulum lumen which was not previously observed. Controlled laboratory studies exposing sockeye (Oncorhynchus nerka), pink (O. gorbuscha), and chinook salmon (O. tshawytscha) to CTV-2 resulted in persistent infections without disease and mortality. Infected Atlantic salmon (Salmo salar) and chinook salmon served as hosts and potential reservoirs of CTV-2. The data presented herein provides the first in vitro and in vivo characterization of CTV-2 and reveals greater diversity of piscihepeviruses extending the known host range and geographic distribution of CTV viruses.
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Wu, Fengnian, Mochi Huang, Eduardo G. P. Fox, Jiaquan Huang, Yijing Cen, Xiaoling Deng i Meirong Xu. "Preliminary Report on the Acquisition, Persistence, and Potential Transmission of Citrus tristeza virus by Diaphorina citri". Insects 12, nr 8 (17.08.2021): 735. http://dx.doi.org/10.3390/insects12080735.
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Citrus tristeza virus (CTV) is one of the most important citrus tree viruses: a graft-transmissible virus that can be vectored by several aphid species. Diaphorina citri is the insect vector of “Candidatus Liberibacter spp.”, a bacterium associated with citrus Huanglongbing (HLB). However, no detailed description of the relationship between CTV and D. citri has been reported. In this study, D. citri adults collected from CTV-infected “Shatangju” mandarin, “Newhall” sweet orange, and “fingered citron” trees in different orchards yielded CTV-positive rates of 40%, 65%, and 95%, respectively, upon detection by conventional PCR. Illumina HiSeq sequencing followed by de novo assembly recovered the primary full CTV genome from the RNA of 30 D. citri adults sampled from CTV-positive citrus plants. Molting and adult emergence did not affect the presence or titers of CTV within the D. citri; however, the persistence of CTV in psyllids varied among different host plant species. Groups of 10 D. citri (from a population 85% CTV-positive) were shown to potentially transmit CTV to two citrus species, “Shatangju” mandarin and “Eureka” lemon, yielding 58.33% and 83.33% CTV-positive plants, respectively. No transmission of CTV to orange jasmine plants occurred. Thus, this study reports on the ability of D. citri to acquire and transmit CTV, making D. citri as a vector of two important citrus pathogens, warranting further attention and investigation.
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Biswas, Kajal, Supratik Palchoudhury, Prosenjit Chakraborty, Utpal Bhattacharyya, Dilip Ghosh, Palash Debnath, Chandrika Ramadugu, Manjunath Keremane, Ravi Khetarpal i Richard Lee. "Codon Usage Bias Analysis of Citrus tristeza Virus: Higher Codon Adaptation to Citrus reticulata Host". Viruses 11, nr 4 (8.04.2019): 331. http://dx.doi.org/10.3390/v11040331.
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Citrus tristeza virus (CTV), a member of the aphid-transmitted closterovirus group, is the causal agent of the notorious tristeza disease in several citrus species worldwide. The codon usage patterns of viruses reflect the evolutionary changes for optimization of their survival and adaptation in their fitness to the external environment and the hosts. The codon usage adaptation of CTV to specific citrus hosts remains to be studied; thus, its role in CTV evolution is not clearly comprehended. Therefore, to better explain the host–virus interaction and evolutionary history of CTV, the codon usage patterns of the coat protein (CP) genes of 122 CTV isolates originating from three economically important citrus hosts (55 isolate from Citrus sinensis, 38 from C. reticulata, and 29 from C. aurantifolia) were studied using several codon usage indices and multivariate statistical methods. The present study shows that CTV displays low codon usage bias (CUB) and higher genomic stability. Neutrality plot and relative synonymous codon usage analyses revealed that the overall influence of natural selection was more profound than that of mutation pressure in shaping the CUB of CTV. The contribution of high-frequency codon analysis and codon adaptation index value show that CTV has host-specific codon usage patterns, resulting in higheradaptability of CTV isolates originating from C. reticulata (Cr-CTV), and low adaptability in the isolates originating from C. aurantifolia (Ca-CTV) and C. sinensis (Cs-CTV). The combination of codon analysis of CTV with citrus genealogy suggests that CTV evolved in C. reticulata or other Citrus progenitors. The outcome of the study enhances the understanding of the factors involved in viral adaptation, evolution, and fitness toward their hosts. This information will definitely help devise better management strategies of CTV.
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Okano, Takumi, Naoki Kobayashi, Kazuki Izawa, Tomoya Yoshinari i Yoshiko Sugita-Konishi. "Whole Genome Analysis Revealed the Genes Responsible for Citreoviridin Biosynthesis in Penicillium citreonigrum". Toxins 12, nr 2 (15.02.2020): 125. http://dx.doi.org/10.3390/toxins12020125.
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Citreoviridin (CTV) is a mycotoxin that is produced by Aspergillus terreus, Eupenicillium ochrosalmoneum and Penicillium citreonigrum, and CTV has been detected in a wide range of cereal grains throughout the world. Furthermore, it is especially a serious problem in regions where rice is consumed as a staple food. Moreover, CTV is a well-known yellow rice toxin, and outbreaks of beriberi have occurred due to consumption of rice that is contaminated by CTV even in the recent years. Although CTV biosynthetic genes of A. terreus have been described, those of P. citreonigrum remain unclear, which is concerning since P. citreonigrum is the main cause of CTV contamination in rice. In the present study, we determined the draft genome of the P. citreonigrum strain IMI92228 and revealed the presence of all four genes that form a gene cluster and that are homologous to the CTV biosynthesis genes of A. terreus. The expression of these four homologous genes were highly correlated with CTV production, suggesting that they may play an important role in CTV biosynthesis in P. citreonigrum. We concluded that the gene cluster is a CTV biosynthesis cluster of P. citreonigrum. The findings will contribute to the understanding of the biosynthetic pathway of CTV and will ultimately lead to improvements in the CTV management of agricultural products.
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Roy, Avijit, G. Ananthakrishnan, John S. Hartung i R. H. Brlansky. "Development and Application of a Multiplex Reverse-Transcription Polymerase Chain Reaction Assay for Screening a Global Collection of Citrus tristeza virus Isolates". Phytopathology® 100, nr 10 (październik 2010): 1077–88. http://dx.doi.org/10.1094/phyto-04-10-0102.
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The emerging diversity of Citrus tristeza virus (CTV) genotypes has complicated detection and diagnostic measures and prompted the search for new differentiation methods. To simplify the identification and differentiation of CTV genotypes, a multiplex reverse-transcription polymerase chain reaction (RT-PCR) technique for the screening of CTV isolates was developed. Variable regions within the open reading frame (ORF)-1a of diverse CTV genotypes were identified to develop first a simplex (S) and then a hexaplex (H) RT-PCR. CTV isolates have been grouped previously into five genotypes (namely, T3, T30, T36, VT, and B165) based on the nucleotide sequence comparisons and phylogenetic analyses. Nucleotide sequences from GenBank were used to design species and genotype-specific primers (GSPs). The GSPs were initially used for reliable detection of all CTV genotypes using S-RT-PCR. Furthermore, detection of all five recognized CTV genotypes was established using the H-RT-PCR. Six amplicons, one generic to all CTV isolates and one for each of the five recognized genotypes, were identified on the basis of their size and were confirmed by sequence analysis. In all, 175 CTV isolates from 29 citrus-growing countries were successfully analyzed by S- and H-RT-PCR. Of these, 97 isolates contained T36 genotypes, 95 contained T3 genotypes, 76 contained T30 genotypes, 71 contained VT genotypes, and 24 contained B165 genotype isolates. In total, 126 isolates contained mixed infections of 2 to 5 of the known CTV genotypes. Two of the CTV isolates could not be assigned to a known genotype. H-RT-PCR provides a sensitive, specific, reliable, and rapid way to screen for CTV genotypes compared with other methods for CTV genotype detection. Efficient identification of CTV genotypes will facilitate a better understanding of CTV isolates, including the possible interaction of different genotypes in causing or preventing diseases. The methods described can also be used in virus-free citrus propagation programs and in the development of CTV-resistant cultivars.
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Wallis, Christopher M., Zachary Gorman, Rachel Rattner, Subhas Hajeri i Raymond Yokomi. "Amino acid, sugar, phenolic, and terpenoid profiles are capable of distinguishing Citrus tristeza virus infection status in citrus cultivars: Grapefruit, lemon, mandarin, and sweet orange". PLOS ONE 17, nr 5 (10.05.2022): e0268255. http://dx.doi.org/10.1371/journal.pone.0268255.
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Citrus tristeza virus (CTV) is the most severe viral disease for citrus production. Many strains of CTV have been characterized and their symptomology widely varies, ranging from asymptomatic or mild infections to severe symptomology that results in substantial yield loss or host death. The capacity of the different CTV strains to affect the biochemistry of different citrus species has remained largely unstudied, despite that associated metabolomic shifts would be relevant toward symptom development. Thus, amino acid, sugar, phenolic, and terpenoid levels were assessed in leaves of healthy and CTV-infected grapefruit, lemon, mandarin, and two different sweet orange cultivars. Both mild [VT-negative (VT-)] and severe [VT-positive (VT+)] CTV genotype strains were utilized. When looking at overall totals of these metabolite classes, only amino acid levels were significantly increased by infection of citrus with severe CTV strains, relative to mild CTV strains or healthy plants. No significant trends of CTV infection on summed amounts of all sugar, phenolic, or terpenoid compounds were observed. However, individual compound levels were affected by CTV infections. Subsequent canonical discriminant analysis (CDA) that utilized profiles of individual amino acids, terpenoids, or phenolics successfully distinguished leaf samples to specific citrus varieties and identified infection status with good accuracy. Collectively, this study reveals biochemical patterns associated with severity of CTV infections that can potentially be utilized to help identify in-field CTV infections of economic relevance.
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Fang, D. Q., C. T. Federici i M. L. Roose. "A High-Resolution Linkage Map of the Citrus Tristeza Virus Resistance Gene Region in Poncirus trifoliata (L.) Raf." Genetics 150, nr 2 (1.10.1998): 883–90. http://dx.doi.org/10.1093/genetics/150.2.883.
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Abstract Resistance to citrus tristeza virus (CTV) was evaluated in 554 progeny of 10 populations derived from Poncirus trifoliata. A dominant gene (Ctv) controlled CTV resistance in P. trifoliata. Twenty-one dominant PCR-based DNA markers were identified as linked to Ctv by bulked segregant analysis. Of the 11 closest markers to Ctv, only 2 segregated in all populations. Ten of these markers were cloned and sequenced, and codominant RFLP markers were developed. Seven RFLP markers were then evaluated in 10 populations. Marker orders were consistent in all linkage maps based on data of single populations or on combined data of populations with similar segregation patterns. In a consensus map, the six closest marker loci spanned 5.3 cM of the Ctv region. Z16 cosegregated with Ctv. C19 and AD08 flanked Ctv at distances of 0.5 and 0.8 cM, respectively. These 3 markers were present as single copies in the Poncirus genome, and could be used directly for bacterial artificial chromosome library screening to initiate a walk toward Ctv. BLAST searches of the GenBank database revealed high sequence similarities between 2 markers and known plant disease resistance genes, indicating that a resistance gene cluster exists in the Ctv region in P. trifoliata.
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Maragos, Chris M., Yosuke Uchiyama, Naoki Kobayashi, Fumichika Kominato i Yoshiko Sugita-Konishi. "Development and Characterization of Monoclonal Antibodies for the Mycotoxin Citreoviridin". Toxins 11, nr 11 (30.10.2019): 630. http://dx.doi.org/10.3390/toxins11110630.
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Citreoviridin (CTV) in an inhibitor of mitochondrial ATPase that has been isolated from molded yellow rice and linked to the human disease Shoshin-kakke (acute cardiac beriberi). The disease results from a deficiency of thiamine, however, purified CTV can reproduce the symptoms in experimental animals. The link between CTV and Shoshin-kakke has been difficult to resolve, in part because cases of the disease are rare. In addition to rice, CTV has been found in maize, pecan nuts, and wheat products. A method to screen for CTV and its geometric isomer, iso-CTV, in commodities was developed, based upon the isolation of two novel monoclonal antibodies (mAb). In an antigen-immobilized competitive enzyme-linked immunosorbent assay format (CI-ELISA), the observed IC50s for CTV were 11 ng/mL and 18 ng/mL (mAbs 2-2 and 2-4, respectively). The assays were relatively tolerant to methanol and acetonitrile, which allowed their application to the detection of CTV in spiked polished white rice. For quantification, a standard mixture of CTV and iso-CTV was used, along with matrix matched calibration. The dynamic range of the ELISA using mAb 2-4 was equivalent to 0.23 to 2.22 mg/kg in rice. Recoveries over the range of 0.36 to 7.23 mg/kg averaged 97 ± 10%. The results suggest that the mAb 2-4-based immunoassay can be applied to the screening of white rice for CTV. Both mAbs were also observed to significantly enhance the fluorescence of the toxin.
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Hughes, G., i T. R. Gottwald. "Survey Methods for Assessment of Citrus Tristeza Virus Incidence When Toxoptera citricida Is the Predominant Vector". Phytopathology® 89, nr 6 (czerwiec 1999): 487–94. http://dx.doi.org/10.1094/phyto.1999.89.6.487.
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Citrus tristeza virus (CTV) incidence may be assessed by sampling groups of citrus trees, recording the groups as CTV positive (one or more infected trees) or CTV negative (no infected trees), and then calculating disease incidence at the scale of the individual tree by means of a formula involving incidence at the group scale and the number of trees per group. This procedure works well when the CTV status of a tree can be regarded as independent of the CTV status of other trees in the same group. This is the case when the main vector species is Aphis gossypii and the groups comprise four adjacent trees, because the spatial pattern of CTV incidence at the within-group scale can be regarded as random. However, when the main vector species is Toxoptera citricida, this simple procedure is not appropriate, because the spatial pattern of CTV incidence at the within-group scale cannot be regarded as random. Using field data and computer simulation, an alternative procedure for assessment of CTV incidence when the main vector species is T. citricida was devised and tested. In the alternative procedure, the sampling scheme is operationally identical to that used when the main vector species is A. gossypii, but the calculation of CTV incidence at the scale of the individual tree is based on incidence at the group scale and an effective sample size. The analysis of CTV-incidence data collected from a number of citrus blocks in reasonable geographical and temporal proximity and the use of CTV-detection methods more sensitive than the enzyme-linked immunosorbent assay used here are also discussed.
Rozprawy doktorskie na temat "CTV"
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Read, David Alan. "Overcoming bias in Citrus tristeza virus (CTV) genotype detection and a population study of CTV within Southern African Star Ruby grapefruit orchards". Thesis, University of Pretoria, 2015. http://hdl.handle.net/2263/53554.
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Citrus tristeza virus (CTV) is present in almost all of the major citrus production
areas where it continues to reduce the profitability of citriculture worldwide. Severe
stem-pitting strains are endemic to Southern Africa. In addition to making use of
decline-tolerant rootstocks, the implementation of a mild-strain cross-protection
program has sought to increase the citrus production in the region. Of all the
commercially cultivated citrus species, grapefruit cultivars are among the most
susceptible to the severe stem-pitting strains and infections often lead to a
breakdown of cross-protection. Recent research has shown that CTV crossprotection
operates through a strain-specific mechanism, which relies on a virusspecific
protein, expressed from the p33 gene. The specificity of this mechanism has
highlighted the need for determining the CTV diversity within production areas as
well as accurately characterising CTV cross-protection sources that will be capable
of preventing secondary inoculations of severe strains in the field. The accurate
characterisation of CTV populations, which are usually made up of a number of
disparate strains, requires the use of robust PCR protocols. Mismatches between
primers and their corresponding binding sites may introduce primer-associated bias
during amplification. The primer-associated bias of four sets of CTV specific primers,
targeting the A and F regions and the p23 and p33 genes, were evaluated. This was
done through the amplification of defined templates followed by their characterisation
using the sequencing of multiple clones, as well as Illumina next generation
sequencing. High levels of bias were found to be associated with the primer pairs
targeting the A and F regions. The p33 gene primers were found to be biased
against two genotypes and suggestions for preventing this apparent bias are
discussed. The primer pair targeting the conserved p23 gene was found to have very
little associated bias. The second major aspect of this study was the large scale
survey of CTV diversity of pre-immunised Star Ruby grapefruit orchards in Southern
Africa. Samples were collected from eight Star Ruby production sites throughout
Southern Africa, namely Hoedspruit 1, Hoedspruit 2, Malelane 1, Malelane 2,
Swaziland (Mananga), Northern Cape (Kakamas), Sundays River Valley and
Nkwalini Valley, where between 16 and 32 samples per site were collected. The p33
gene was amplified for each of the collected samples and subjected to direct Sanger
sequencing. A protocol making use of Illumina MiSeq sequencing was established and used to sequence 96 samples. A subset of six samples was selected for cloning,
which resulted in a total of 218 sequenced clones and compared with that of the
Illumina sequencing data. High levels of CTV diversity were observed between
orchards, as well as between different trees within the same orchard. Most of the
populations were made up of a single dominant group, sometimes with several minor
sequence types. Sequence reads corresponding to strains within the Resistance
Breaking (RB) genotype were most numerous, especially in the most recently
planted orchards and were present within all of the populations analysed. The
Kpg3/SP/T3 group appeared to be represented the second most prevalent genotype
and seems to become more common as the orchard ages. Genotypes of the HA 16-
5, VT, AT-1, T36, Taiwan-Pum/M/T5 and T30 types, were represented sporadically
and at variable levels in populations from numerous collection sites. This has been
one of the most extensive diversity studies of CTV to date and has provided
unprecedented baseline knowledge of CTV diversity in Southern Africa.Thesis (PhD)--University of Pretoria, 2015.
Microbiology and Plant Pathology
PhD
Unrestricted
2
Tsunoda, Fabio Silva. "Comissão Teotônio Vilela (CTV): direitos humanos e vocação militante". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/8/8132/tde-18042013-110243/.
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O presente trabalho é uma investigação sobre o processo de profissionalização da defesa em direitos humanos no Brasil, considerado a partir do estudo de caso da Comissão Teotônio Vilela (CTV). Fundada em 1983, em meio à transição democrática, a CTV inicialmente trabalhou com a defesa dos direitos de presos comuns e, conforme o processo de consolidação democrática avançava, sua agenda de reivindicações foi alterada. Paralelamente, a trajetória dos seus membros também é analisada a fim de mostrar como eles se trabalharam individualmente para a promoção e proteção dos direitos humanos no Brasil. A pesquisa foi realizada por meio de entrevista com os membros fundadores da CTV, bem como nos arquivos da entidade sediada no Núcleo de Estudos da Violência (NEV/USP), levando-se em conta os seus relatórios, relatos de visitas, recortes de jornais e processos elaborados a fim de buscar alguma reivindicação. Os resultados sugerem que a defesa dos direitos humanos no Brasil foi perpassada por dois aspectos, a saber: o aumento da participação no Estado e em governos e também no processo de internacionalização das reivindicações.The present work is an investigation about the process of professionalization of human rights defense in Brazil, considered through the case study of Comissão Teotônio Vilela (CTV). Founded in 1983, during the democratic transition, CTV started its work with the defense of regular prisoners and, with the democratic consolidation advancement, its claim agenda was either changed. In parallel, the trajectory of its members is also analyzed to show how they worked individually for the promotion and protection of human rights in Brazil. The research was conducted through interviews with founding members of the CTV, as well as the archives of the entity based at Center for the Study of Violence (NEV / USP), taking into account their reports, reports of visits, newspaper clippings and processes designed to seek some claim. The results suggest that the defense of human rights in Brazil was pervaded by two aspects, namely: increasing participation in state and governments and also in the internationalization process of claims.
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Souza, Amancio José de. "Reação à infecção pelo vírus da tristeza dos citros (CTV) em plantas transgênicas de laranja \'Hamlin\' (Citrus sinensis (L.) Osbeck) expressando seqüências gênicas do CTV". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-25072008-123421/.
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O vírus da tristeza dos citros (CTV) é uma das maiores ameaças à citricultura mundial. No Brasil, mesmo com a pré-imunização e com a substituição de porta-enxertos, estirpes fortes de CTV ainda causam prejuízos consideráveis. Com o aparecimento da Morte Súbita dos Citros em 1999 e a possível relação desta doença com o CTV, este vírus voltou a figurar como patógeno de importância no cenário da citricultura brasileira. Uma das possíveis soluções para o controle de viroses em fruteiras é a obtenção de plantas transgênicas resistentes ou imunes. O objetivo deste trabalho foi avaliar a resistência ao CTV de plantas transgênicas de laranja \'Hamlin\' contendo três construções gênicas oriundas de seqüências do genoma do CTV. Estas construções gênicas visaram ativar rotas de RNAi (hairpin da capa protéica e seqüência conservada antisenso do CTV) e mecanismos de defesa relacionados à expressão da capa protéica do CTV. As plantas transgênicas foram desafiadas com uma estirpe fraca de CTV (CTV-IAC) por meio de borbulhas e pulgões pretos (Toxoptera citricida Kirkaldy) contendo o vírus. A avaliação da resistênica à replicação viral foi feita por análises de ELISA. As plantas transgênicas foram consideradas não resistentes à infecção e translocação viral quando inoculadas com borbulhas. Entretanto algumas plantas mostraram retardamento da infecção. Não foi possível determinar se houve resistência à transmissão de CTV por pulgões já que a técnica utilizada não foi capaz de infectar os controles de maneira uniforme.The Citrus tristeza virus (CTV) is one of the greatest threats to the citrus industry worldwide. In Brazil, CTV continues to cause damage through strong strains despite the use of techniques like cross-protection and substitution of intolerant rootstocks. With the appearance and spread of the Citrus Sudden Death disease in 1999 and its possible relation to CTV, this virus was again among important pathogens within the Brazilian citrus industry. One of the possible solutions for controlling virus diseases in fruit crops is the development of immune or resistant transgenic plants. The objective of this work was to evaluate the resistance to CTV of transgenic \'Hamlin\' sweet orange plants containing three transgenic constructs obtained from CTV genomic sequences. The genetic constructs used aimed to activate RNAi defense routes (coat protein hairpin and a conserved sequence from CTV) and resistance mechanisms related to the coat protein expression. The transgenic plants were challenged with a weak strain of CTV, CTV-IAC, by bud and aphid (Toxoptera citricida Kirkaldy) inoculation. The evaluation of viral replication was done by ELISA analysis. The transgenic plants were considered susceptible to viral replication and translocation when bud inoculated. However, a few plants showed retardation of infection. It was not possible to determine resistance in the aphid transmission assay since the controls were not uniformly inoculated.
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Hjulfors, Emmelie Maria. "Optimal margins between clinical target volume (CTV) and planning target volume (PTV)". Thesis, Umeå universitet, Institutionen för fysik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-44824.
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The purpose of this study was to estimate the CTV-PTV margin required for prostate and head and neck cancer treatments at the radiotherapy departments of Karolinska University Hospital. Portal image data from patients treated at the radiotherapy departments during the period of 2009-2011 was used to estimate the set-up displacements for each treatment area. By using the acquired images the magnitude of the systematic, i.e. preparatory, and random, i.e. execution, error was determined in the anterior-posterior (AP), superior-inferior (SI) and right-left (RL) direction. The calculated PTV margin is based on the systematic and random errors of the entire patient populations. A total of 40 patients were used for the analysis of prostate treatments and 47 patients for head and neck treatments. The evaluation of the PTV margin was done for three different matching protocols; no matching (skin marker alignment), five day matching and daily matching. With no image verification in prostate treatments the calculated PTV margin taking both inter- and intrafractional errors into account was 13.6, 9.2 and 7.9 mm in AP, SI, and RL direction respectively. The corresponding PTV margin in head and neck treatments was found to be 6.7, 5.3 and 4.9 mm. Using a five day matching protocol of the bony anatomy showed no considerable reductions in margins for neither prostate nor head and neck treatments. With daily matching of the bony anatomy in prostate treatments the calculated margins was reduced to 8.1, 7.9 and 2.4 mm in the AP, SI and RL direction respectively. Measurements of the residual deviations of individual cervical vertebrae after daily image verification and correction in head and neck cancer treatments showed that all matching protocols will require larger margins in the lower vertebrae in order to account for the set-up error in the AP direction. The corresponding margins needed using daily matching of the bony anatomy would be 3.9, 5.4 and 6.0 mm for C1, C4 and C5 respectively in the AP direction. In the absence of daily imaging the currently used PTV margins might be inadequate for covering to movement of the targets. The deviations in the AP direction of the cervical vertebrae in head and neck cancer treatments should be investigated further in order to ensure that the motion of the target is covered and that no risk organs are subjected to harmful dose levels.
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Gonçalves, Ana Claudia [UNESP]. "Separação de virus de importância fitopatológica em citros: CTV e CSDaV através de citometria de fluxo". Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/100738.
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Devido a grande importância econômica da citricultura no Brasil e mundo e aos problemas sanitários enfrentados sendo alguns limitantes para o cultivo, como é o caso das doenças causadas por vírus como: a tristeza cítrica, causada pelo vírus da tristeza dos citros (CTV), pertencente ao gênero Closterovirus, família Closteroviridae, uma das maiores ameaças da citricultura mundial, mesmo com a pré imunização através de estirpes fracas do vírus e substituição de porta enxertos, estirpes fortes de CTV ainda causam prejuízos consideráveis. E com o aparecimento da doença morte súbita dos citros (MSC) de etiologia não determinada. Pelo fato de não haver ainda métodos eficientes de separação de ambos os vírus presentes em uma única amostra, levantando se as hipóteses que a causa da MSC esteja relacionada a uma estirpe do vírus CTV, a um vírus do gênero Marafivirus denominado Citrus Sudden Death-associated Virus (CSDaV), pertencente ao gênero Marafivirus, família Tymoviridae, ou a uma associação entre eles. Este trabalho vem propor um método eficaz de separação por citometria de fluxo (FC) de CTV e CSDaV em amostras semi purificadas, diluídas em tampão TE, pH7,5, utilizando marcação de ácidos nucléicos com Iodeto de Propídeo (PI) e conjugação de anticorpos policlonais anti CTV com Isotiocianato de Fluoresceína (FITC), cuja eficácia do método foi comprovada pela reação da polimerase em cadeia (PCR)
Because of high economic importance of citrus in Brazil and the world and health problems being faced some limiting factors for growing as is the case of diseases caused by viruses such as sadness citrus caused by citrus tristeza virus (CTV) belonging to Closterovirus gender, family Closteroviridae, one of the biggest threats to the citrus industry worldwide, even with the pre immunization using mild virus strains and replacement of the rootstocks, strong strains of CTV still cause considerable damage. And with the onset of the disease citrus sudden death (MSC) of undetermined etiology. Because there is not yet efficient methods of separation of the two viruses present in a single sample, raising the hypotheses that the cause of SCD is related to a strain of CTV, a virus Marafivirus group called Citrus Sudden Death-associated Virus (CSDaV) belonging to the genus Marafivirus, Tymoviridae family, or an association between them, this paper proposes an effective method of separation by flow cytometry (FC) and CTV in samples CSDaV semi purified, diluted in TE buffer, pH7, 5, using marking of nucleic acids with propidium iodide (PI) and a combination of polyclonal anti CTV with Fluorescein isothiocyanate (FITC), the effectiveness of the method was confirmed by polymerase reaction chain reaction (PCR)
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Justino-Kuga, Elaine Aparecida. "Avaliação de epitopos na proteina do capsideo de isolados do virus da tristeza dos citros (CTV)". [s.n.], 1999. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314469.
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Orientador: Marcos Antonio MachadoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Estudos preliminares sobre a localização de epítopos na proteína do capsídeo (CP) de três isolados de CTV ('Pêra IAC', 'Pêra CB-22' e 'Pêra CB-104') foram realizados em três etapas. Na primeira, foi realizada a amplificação de oito regiões distintas do gene da CP, codificantes para três regiões Nterminais (aa 1 até 70; aa 1 até 120; aa 1 até 170), três regiões C-terminais (aa 70 até 223; aa 120 até223; aa 170 até 223) e duas regiões internas da CP (aa 37 até 67 e aa 64 até 94) onde haviam sido determinadas diferenças significativas entre as CPs dos três isolados. Na segunda etapa, foram avaliadas duas estratégias para expressão dos peptídeos de interesse: clonagem em vetor de expressão através de ligação AT (vetor Pinpoint TM Xa-1 T, Promega) e clonagem das seqüências alvo em vetores do sistema de expressão pET. O vetor Pinpoint TM Xa-1 T, carreando como inserto o gene inteiro da CPCTV, obtido como produto de PCR após amplificação do cDNA dos três isolados, transformou células competentes de E. coli JM109, mas após indução com IPTG, não houve expressão da proteína de fusão esperada. Os vetores do sistema pET, após ligação das seqüências alvo, não transformaram células competentes de E. coli BL21(DE3)pLysS. Na terceira etapa, três proteínas recombinantes (MBP-CPCTV, CB-22 e CB-104) produzidas a partir da expressão do gene da CP-CTV dos três isolados, foram clivadas com brometo de cianogênio. Os produtos de clivagem foram avaliados através de '¿Western Blotting¿ contra anticorpos monoclonais específicos para CTV. O monoclonal IC-04.6, desenvolvido contra a proteína recombinante CB-22 detectou epítopos, numa reação intensa, em peptídeos com massa estimada em 27 kDa e 18 kDa, originários da CB-22; o monoclonal 39-08, desenvolvido contra a proteína recombinante CB-104 detectou epítopos, numa reação moderada, em peptídeos com massa estimada de 28 kDa e 14 kDa, originários qa CB-104; o monoclonal MCA-13, desenvolvido contra um isolado da Florida, detectou epítopos em peptídeos originários das proteínas recombinantes MBP-CPCTV e CB-104; o monoclonal 3DF1, desenvolvido contra isolados de CTV espanhóis, detectou epítopos em peptídeos originários da CB-22 e CB-104 e o monoclonal 3CA5, desenvolvido contra isolados espanhóis de CTV, detectou epítopos apenas num peptídeo com massa estimada de 18 kDa presente na CB-22. Estes resultados sugerem que diferentes epítopos são reconhecidos pelos cinco monoclonais avaliados e que serão necessárias novas estratégias para avaliá-los
Abstract: Preliminary studies about the epitopes location in the capside protein of the isolates of the citrus tristeza virus of three isolate ('Pêra IAC', 'Pêra CB-22' and 'Pêra CB-104') were accomplished. In the first phase, the amplification was accomplished with specific direct and reverse primers of eight different regions of the CP gene, coding for three N-terminal peptides (aa 1 to 70, aa 1 to 120 and aa 1 to 170), three C-terminal peptides (aa 70 to 223, aa 120 to 223 and aa 170 to 223) and two internal peptides of CP (aa 37 to 64 and aa 64 to 90). In the second phase they were appraised two strategies for expression of the peptides: cloning in expression vector through AT cloning site (vector Pinpoint TM Xa-1 T promega), and cloning of the coding sequences in vectors of the system pET. Vector Pinpoint TM Xa-1, containing as insert the whole gene of CP, obtained as PCR's product after amplification of the three isolates' cDNA, transformed competent cells E. coli JM109, but after induction with IPTG there was not expression of the peptides of interest. The vectors of the pET system didn't transform competent cells E. coli BL21 (DE3)pLysS. In the third phase, three recombinant proteins (MBP-CPC1V, CB-22 and CB-104), produced from the expression of the CP-C1V gene of the three isolates, they were broken with cyanogen bromide. The break products were evaluated through "Western Blotting" against monoclonal antibodies specific for CTV. The monoclonal IC-04.6, developed against the recombinant protein CB-22 detected epitopes, in an intense reaction, in peptides with mass esteemed in 27 kDa and 18 kDa, original of CB-22; the monoclonal 39-08, developed against the recombinant protein CB-104 detected epitopes, in a moderate reaction, in peptides with esteemed mass of 28 kDa and 14 kDa, original of CB-104; the monoclonal MCA-13, developed against the T-36 isolate from Florida, detected epitopes in original peptides of the recombinants proteins MBP-CPCTV and CB-104; the monoclonal 3DF1, developed against Spanish isolates of CTV, detected epitopes in original peptides of CB-22 and CB-104 and the monoclonal 3CA5, developed against Spanish isolates of C1V, just detected epitopes in a peptide with esteemed mass of 18 kDa present in CB-22. These results suggest that the five monoclonal recognizes different epitopes and that will be necessary new strategies to evaluate them
Mestrado
Bioquimica
Mestre em Biologia Funcional e Molecular
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Gonçalves, Ana Claudia. "Separação de virus de importância fitopatológica em citros : CTV e CSDaV através de citometria de fluxo /". Araraquara, 2010. http://hdl.handle.net/11449/100738.
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Orientador: Paulo Inácio da CostaBanca: Henrique Ferreira
Banca: Nelson Wulff
Banca: José Belasque Junior
Banca: Marcel Bellato Spósito
Resumo: Devido a grande importância econômica da citricultura no Brasil e mundo e aos problemas sanitários enfrentados sendo alguns limitantes para o cultivo, como é o caso das doenças causadas por vírus como: a tristeza cítrica, causada pelo vírus da tristeza dos citros (CTV), pertencente ao gênero Closterovirus, família Closteroviridae, uma das maiores ameaças da citricultura mundial, mesmo com a pré imunização através de estirpes fracas do vírus e substituição de porta enxertos, estirpes fortes de CTV ainda causam prejuízos consideráveis. E com o aparecimento da doença morte súbita dos citros (MSC) de etiologia não determinada. Pelo fato de não haver ainda métodos eficientes de separação de ambos os vírus presentes em uma única amostra, levantando se as hipóteses que a causa da MSC esteja relacionada a uma estirpe do vírus CTV, a um vírus do gênero Marafivirus denominado Citrus Sudden Death-associated Virus (CSDaV), pertencente ao gênero Marafivirus, família Tymoviridae, ou a uma associação entre eles. Este trabalho vem propor um método eficaz de separação por citometria de fluxo (FC) de CTV e CSDaV em amostras semi purificadas, diluídas em tampão TE, pH7,5, utilizando marcação de ácidos nucléicos com Iodeto de Propídeo (PI) e conjugação de anticorpos policlonais anti CTV com Isotiocianato de Fluoresceína (FITC), cuja eficácia do método foi comprovada pela reação da polimerase em cadeia (PCR)
Abstract: Because of high economic importance of citrus in Brazil and the world and health problems being faced some limiting factors for growing as is the case of diseases caused by viruses such as sadness citrus caused by citrus tristeza virus (CTV) belonging to Closterovirus gender, family Closteroviridae, one of the biggest threats to the citrus industry worldwide, even with the pre immunization using mild virus strains and replacement of the rootstocks, strong strains of CTV still cause considerable damage. And with the onset of the disease citrus sudden death (MSC) of undetermined etiology. Because there is not yet efficient methods of separation of the two viruses present in a single sample, raising the hypotheses that the cause of SCD is related to a strain of CTV, a virus Marafivirus group called Citrus Sudden Death-associated Virus (CSDaV) belonging to the genus Marafivirus, Tymoviridae family, or an association between them, this paper proposes an effective method of separation by flow cytometry (FC) and CTV in samples CSDaV semi purified, diluted in TE buffer, pH7, 5, using marking of nucleic acids with propidium iodide (PI) and a combination of polyclonal anti CTV with Fluorescein isothiocyanate (FITC), the effectiveness of the method was confirmed by polymerase reaction chain reaction (PCR)
Doutor
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Moya, Gay Patricia. "Variabilidad genética y evolución del virus de la tristeza de los cítricos (CTV) en procesos de transmisión". Doctoral thesis, Universitat de València, 2010. http://hdl.handle.net/10803/41732.
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Los aislados de CTV están formados generalmente por una mezcla de variantes de secuencia, que se generan mediante procesos de mutación y recombinación. Su frecuencia en la población es el resultado de distintas presiones selectivas y de fenómenos de migración y deriva genética, generalmente asociados a los procesos de transmisión. El objetivo de esta tesis era analizar por separado el efecto de diversos factores de los procesos de transmisión sobre la estructura poblacional y la diversidad genética de distintos aislados del virus.
Se analizó el efecto de la transmisión por pulgón. Ésta ocurrió con baja eficiencia y en general, las secuencias de los genes analizados en las plantas receptoras fueron idénticas a las de las plantas donantes y el aislado de colección.
La transmisión por injerto y/o pulgón supone un cuello de botella que puede dar lugar a un efecto fundador. Se analizó el efecto de la transmisión por injerto entre plantas de una misma especie huésped y no se observaron cambios llamativos en la estructura y diversidad poblacional.
También se estudió si la transmisión por injerto de dos aislados de CTV a diferentes especies y variedades comerciales propagadas sobre citrange Carrizo podía inducir cambios en la población. Aunque no observamos cambios significativos en la diversidad genética, la estructura poblacional se vio alterada en algunas plantas. Esta alteración fue debida a la aparición de nuevas variantes de secuencia cercanas filogenéticamente que llegaban a predominar en dichas poblaciones.
Finalmente, se utilizó un aislado clonal de CTV para el estudio de la variación genética de novo en distintos huéspedes a lo largo del tiempo. Se efectuaron pases sucesivos por injerto de dicho aislado desde su huésped original a distintos huéspedes susceptibles, y a un huésped parcialmente resistente (naranjo amargo). Las poblaciones en los huéspedes susceptibles presentaron una elevada estabilidad, pero los pases sucesivos en el huésped naranjo amargo dieron lugar a cambios importantes en la población, debido a la aparición de variantes de secuencias muy divergentes anteriormente halladas en dos aislados naturales del virus. La detección de secuencias minoritarias cuya posición filogenética se sitúa entre los tres genotipos avala la idea de una evolución entre el genotipo original y los otros dos detectados para intentar adaptarse al huésped. El hallazgo de secuencias recombinantes entre los tres genotipos apoya la presencia de éstos en el huésped naranjo amargo.
La inoculación de huéspedes susceptibles a partir de plantas de naranjo amargo puso de manifiesto la progresiva pérdida de infectividad de la población mantenida en esta especie, debido en parte a la baja acumulación de CTV en la misma. Además fue imposible detectar el virus en brotes de lima propagados sobre estas plantas, lo que sugiere que además del bajo título viral algún factor del huésped pudiese dificultar el paso de CTV desde naranjo amargo a lima.CTV isolates are composed of a population of sequence variants, resulting from mutation and recombination events. The frequency of these variants in the population is the outcome of different selective pressures, and migration and genetic drift phenomena generally associated to transmission processes. Here we analyzed separately the effect of different factors of the transmission process on the diversity and population structure of CTV isolates. We studied the effect of aphid transmission by nucleotide sequence comparisons between the donor and receptor plants and the collection CTV isolate. Transmission efficiency was low, and no sequence variation was observed. Aphid and graft transmission are a bottleneck resulting in a founder effect. We analysed the effect of graft transmission to a host of the same species. No obvious changes were observed in the CTV population structure and diversity We also studied if graft-transmission to different varieties propagated on Carrizo citrange could alter the CTV population. Although significant diversity changes were not observed, the population structure was occasionally altered due to the appearance of new sequence variants genetically close that became predominant in these populations. Finally, we used a clonal CTV isolate to study genetic variation generated de novo in different hosts. This isolate was serially passed by graft-transmission in different susceptible hosts and in a partially resistant host (sour orange). While CTV population was stable in the susceptible hosts, passages through sour orange caused major changes due to the appearance of new diverged sequence variants previously found in two natural isolates). Detection of minor variants phylogenetically located between these three genotypes supports the idea of an evolutionary process between the original and two new genotypes to get adapted to sour orange. Recombination events involving the three genotypes supports the presence of more than one genotype in infected sour orange. Inoculation from sour orange to susceptible hosts showed progressive loss of infectivity, due in part to the low virus titer in this host. CTV could neither be detected in Mexican lime propagated on these sour orange plants, suggesting that some host factor might also block CTV movement from sour orange to lime.
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Navarro, López Josep Amadeu. "Estudio preliminar de las interacciones del virus de la tristeza de los cítricos (CTV) y su huésped". Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/90468.
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Citrus tristeza virus (CTV) is a viral species of the Closterovirus genus, having a ¿20 kb single-stranded and positive sense genomic RNA (gRNA) organized into 12 open reading frames (ORFs) potentially coding 17 protein products, some of which of unknown function. CTV proteins p25 and p27 belong to a gene block involved in virion assembly. It has been demonstrated that p25, along with p20 and p23, are RNA silencing suppressors in some species of Nicotiana, being the latter a pathogenesis determinant. CTV host range is very restricted and in nature viral infections are limited to the phloem cells of some citrus species. Consequently, working with this virus-host pathosystem requires an appropriate experimental host and an efficient CTV genetic system. In our laboratory we have developed a new CTV genetic system based on the agroinfection of Nicotiana benthamiana plants, a non-natural host, with infectious clones of the T36 isolate. That infection induces characteristic symptoms, some of which correlate with those caused by the virus in citrus plants.
CTV-N. benthamiana interactions are very variable and genotype-dependent, so only some isolates can replicate in this species and T36 is unique causing systemic infections. In this work, we studied the function of CTV p20 and p25 proteins from three different isolates differing in its pathogenic characteristics. Transient expression of p20 and p25 fused to fluorescent proteins showed an identical subcellular localization for both N. benthamiana and citrus. The p20 protein of T36, T318A and T385 isolates localized in cytoplasm and nucleus forming amorphous aggregates associated with perinuclear regions, together with nuclear punctuate inclusions. On the other hand, subcellular localization of p25 differed depending on the CTV isolate. While p25 of T36 and T385 localized in the nucleus, that of T318A did it in cytoplasm. A detailed analysis of the protein regions involved in this subcellular localization unveiled a leucine-rich nuclear export signal (NES) in the N-terminus (Nt) of the protein.
The pathogenic ability of CTV p20 and p25 in N. benthamiana was tested through a PVX heterologous viral infection, showing that p25 was not a pathogenicity determinant in this species, albeit p20 it was.
Besides, the interactome of p25-T36 was more complex and diverse than that of p25-T318A, involving a greater number of metabolic processes, redox activities, homeostasis and cellular transport, biosynthesis and protein degradation, plastid and nucleic acid protein binding, biotic and oxidative stress, jasmonic-mediated defense, methylation, ROS signalling and HSP proteins. On the other hand, most p25-T318A potential interactors were related to transport/localization and stress response, like apoptosis, pathogenesis-related and HSP proteins, Ca+2-binding proteins and redoxins.
Moreover, the experimental evolution of CTV in N. bethamiana was achieved through serial passages. The evolution process showed adaptative traits as the increase of graft survival, infectivity rates and viral titers, and a decreased time for the onset of symptom development in this species.
Adaptive characteristics of evolved viral populations in N. bethamiana, were also correlated to their genetic variability and population structure. Two different evolved lineages showed convergent evolution processes reflected also at the molecular level.
CTV viruses evolved in N. benthamiana were found to be less infectious at initial stages of infection when they were back-inoculated to citrus plants, and showed a decreased viral titer during the first year post-inoculation. This re-adaptation of N. benthamiana viral populations back to citrus was correlated, at a molecular level, with the progressive loss of the mutations appeared during its evolution process in N. benthamiana.El virus de la tristeza de los cítricos (CTV) es un closterovirus con un RNA genómico (gRNA) de ssRNA (+) y ¿20 Kb organizado en 12 pautas de lectura abierta (ORFs) que codifican al menos 17 proteínas, algunas de función desconocida. Las proteínas p25 y p27 forman parte de un grupo de genes implicados en el ensamblaje del virión, y se ha demostrado que p25 junto con p20 y p23 son supresores de silenciamiento génico en algunas especies de Nicotiana, y la última es también un determinante de patogénesis. CTV tiene una gama de huéspedes muy restringida y de forma natural sólo infecta el floema de algunas especies de cítricos. Por ello, para trabajar con este patosistema virus-huésped, se requiere un huésped experimental adecuado y un sistema genético eficiente de CTV. Durante los últimos años hemos desarrollado un sistema genético de CTV basado en la agroinfección sistémica de Nicotiana benthamiana, una especie no-natural de este virus, con clones infecciosos del genotipo T36. Dicha infección va acompañada de síntomas característicos, algunos de los cuales son similares a los que el virus induce en cítricos. La interacción CTV-N. benthamiana es muy variable y genotipo-dependiente, sólo algunos aislados se replican en esta especie y únicamente T36 la infecta sistémicamente. En este trabajo, abordamos la función de las proteínas p20 y p25 de tres aislados de CTV que difieren en sus características patogénicas. La expresión transitoria de las p20 y p25 fusionadas a proteínas fluorescentes reveló su idéntica localización subcelular en N. benthamiana y cítricos. La proteína p20 se localizó en el citosol y el núcleo celular en agregados amorfos asociados a regiones perinucleares e inclusiones nucleares puntuales. En cambio, la expresión de la p25 de T36, T318A y T385 de CTV reveló una localización diferencial. Mientras la de T36 y T385 fue nuclear, la de T318A fue citosólica. Un análisis detallado de las regiones implicadas en dicha localización, reveló la existencia de una señal de exportación nuclear NES rica en leucinas en la región Nt de la proteína. Un análisis de la capacidad patogénica de p20 y p25 en N. benthamiana en un contexto de infección viral heterólogo a través de PVX, mostró que p25 no es un determinante de patogenicidad en esta especie, pero p20 sí. Por otra parte, el interactoma de la p25-T36 resultó mucho más complejo y diverso que el de la p25-T318A, interviniendo potencialmente en mayor número de procesos metabólicos de fotosíntesis, actividad redox, homeóstasis y transporte celular, biosíntesis y degradación de proteínas, unión a proteínas de los plastidios y ácidos nucleicos o de respuesta a estrés (biótico y oxidativo) o defensa mediada por la ruta del jasmónico, del ciclo de metilación, señalización por ROS y proteínas HSP. Las interacciones mayoritarias de la p25-T318A se relacionaron con transporte/localización y respuesta a estrés, principalmente con interactores implicados en procesos de apoptosis, patogénenis y proteínas HSP, de unión a calcio o redoxinas. También hemos conseguido la evolución experimental de CTV por pases seriados en N. benthamiana. Dicha evolución conlleva un conjunto de características adaptativas significativas como: el aumento del prendimiento de injertos, de la tasa neta de infectividad, del título viral y del adelanto de los síntomas causados en esta especie herbácea con el aumento de los pases. Las características adaptativas también se reflejaron a nivel molecular en la variabilidad genética y estructura de las poblaciones de los virus evolucionados en dos linajes independientes. Virus evolucionados en N. benthamiana resultaron menos infecciosos inicialmente por inoculación mecánica de regreso a cítricos, y se acumularon menos que el virus parental durante el primer año. Dicha re-adaptación de los virus evolucionados se reflejó a nivel molecular en la pérdida progresiva de las m
El virus de la tristesa dels cítrics (CTV) és un closterovirus amb un RNA genòmic de ssRNA(+) i 20 Kb organitzat en 12 pautes de lectura oberta (ORFs) que codifiquen, al menys, 17 proteïnes, algunes de les quals de funció desconeguda. Les proteïnes p25 i p27 formen part d'un grup de gens implicat en l'assemblatge del virió, i s'ha demostrat que p25, junt a p20 i p23, són supressors de silenciament gènic en algunes espècies de Nicotiana, i la última també és un determinant de patogènesi. La gama d'hostes de CTV és molt restringida i de forma natural sols infecta el floema d'algunes espècies de cítrics. Per això, per a treballar amb aquest patosistema virus-hoste, es requereix un hoste experimental adequat i un sistema genètic eficient de CTV. Durant els últims anys hem desenvolupat un sistema genètic de CTV basat en l'agroinfecció sistèmica de Nicotiana benthamiana, una espècie no-natural d'aquest virus, amb clons infecciosos del genotip T36. Aquesta infecció va acompanyada de símptomes característics, alguns dels quals són similars als que el virus indueix en cítrics. La interacció CTV-N. benthamiana és molt variable i genotip depenent, ja que sols alguns aïllats es repliquen en aquesta espècie i únicament T36 la infecta sistèmicament. En aquest treball hem abordat la funció de les proteïnes p20 i p25 de tres aïllats de CTV que difereixen en les seues característiques patogèniques. L'expressió transitòria de les p20 i p25 fusionades a proteïnes fluorescents va revelar la seua idèntica localització subcel·lular en N. benthamiana i cítrics. La proteïna p20 dels aïllats T36, T318A i T385 es va localitzar al citosol i al nucli cel·lular formant agregats amorfs associats a regions perinuclears, i inclusions nuclears puntuals. En canvi, l'expressió de la p25 de T36, T318A i T385 de CTV va revelar una localització diferencial. Mentre la de T36 i T385 fou nuclear, la de T318A fou citosòlica. Una anàlisi detallada de les regions implicades en eixa localització va revelar l'existència d'una senyal d'exportació nuclear (NES) rica en leucines a la regió Nt de la proteïna. L'anàlisi de la capacitat patogènica de p20 i p25 en N. benthamiana en un context d'infecció viral heteròloga a través de PVX, va mostrar que p25 no és un determinant de patogenicitat en aquesta espècie, però p20 sí. D'altra banda, l'interactoma de p25-T36 va resultar molt més complex i divers que el de p25-T318A, intervenint potencialment en un major nombre de processos metabòlics de fotosíntesi, activitat redox, homeòstasi i transport cel·lular, biosíntesi i degradació de proteïnes, unió a proteïnes dels plastidis i àcids nucleics o de resposta a estrés (biòtic i oxidatiu) o defensa mediada per la ruta del jasmònic, del cicle de metilació, senyalització per ROS i proteïnes HSP. Les interaccions majoritàries de la p25-T318A es relacionaren amb transport/localització i resposta a estrés, principalment amb interactors implicats en processos d'apoptosi, patogènesi i proteïnes HSP, d'unió a calci o redoxines. També hem aconseguit l'evolució experimental de CTV per passes seriats en N. benthamiana. Aquesta evolució comporta un conjunt de característiques adaptatives significatives com: l'augment de la supervivència dels empelts, de la taxa neta d'infectivitat, de la càrrega viral i de l'ajornament dels símptomes causats en aquesta espècie herbàcia amb l'augment dels passes. Les característiques adaptatives també es reflectiren a nivell molecular amb la variabilitat genètica i estructura de les poblacions dels virus evolucionats en dos llinatges independents. Virus evolucionats a N. benthamiana resultaren menys infecciosos inicialment per inoculació mecànica de tornada a cítrics, i s'acumularen menys que el virus parental durant el primer any. Aquesta re-adaptació dels virus evolucionats a N. benthamiana de tornada a cítrics es va reflectir a nivell molecular amb
Navarro López, JA. (2017). Estudio preliminar de las interacciones del virus de la tristeza de los cítricos (CTV) y su huésped [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90468
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Kahlon, Amandeep Singh. "Molecular characterization of the population diversity of selected isolates and subisolates of Citrus tristeza virus (CTV) from Florida". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011870.
Pełny tekst źródłaKsiążki na temat "CTV"
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Gittins, Susan. CTV: The television wars. North York, Ont: Stoddart, 1999.
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Michael, Nolan. CTV, the network that means business. Edmonton: University of Alberta Press, 2001.
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Confederación de Trabajadores de Venezuela. CTV, 50 años de historia, 1936-1986. [Caracas?]: Confederación de Trabajadores de Venezuela, 1986.
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Chiappa, Ernestino. CTV: Il corpo truppe volontarie italiane durante la guerra civile spagnola, 1936- 1939 : cronistoria-uniformi. Milano: EMI, 2003.
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C.V. Yerushalayim: Karmel, 2007.
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CCTV. Wyd. 3. Boston: Butterworth-Heinemann, 2000.
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Mangum, L. J. CTD/Ob2s. Seattle, Wash: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, Pacific Marine Environmental Laboratory, 1985.
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Lynch, J. M. CTD/O. Seattle, Wash: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, Pacific Marine Environmental Laboratory, 1988.
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Lynch, J. M. CTD/Ob2s. Seattle, Wash: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, Pacific Marine Environmental Laboratory, 1988.
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México, Confederación de Trabajadores de. Constitución CTM. México: Secretaría del Trabajo y Previsión Social, Subsecretaría "B", Unidad Coordinadora de Políticas, Estudios y Estadísticas del Tabajo, 1987.
Znajdź pełny tekst źródłaCzęści książek na temat "CTV"
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Kim, Denise S., Remy R. Lobo i Alon Kahana. "Orbital CTA/CTV". W Atlas of Orbital Imaging, 1–4. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-41927-1_86-1.
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Kim, Denise S., Remy R. Lobo i Alon Kahana. "Orbital CTA/CTV". W Atlas of Orbital Imaging, 113–16. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-62426-2_86.
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Knowlton, Christin A., Michelle Kolton Mackay, Tod W. Speer, Robyn B. Vera, Douglas W. Arthur, David E. Wazer, Rachelle Lanciano i in. "Clinical Target Volume (CTV)". W Encyclopedia of Radiation Oncology, 125. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-540-85516-3_298.
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Russo, Marcella, i Antonino F. Catara. "Phenotyping Biological Properties of CTV Isolates". W Methods in Molecular Biology, 15–27. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9558-5_3.
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El Attar, Abderrahim, Mostafa El Hachloufi i Zine El Abidine Guennoun. "Optimal Reinsurance Under CTV Risk Measure". W Innovations in Smart Cities and Applications, 919–30. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-74500-8_82.
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Soler, Nuria, Montserrat Plomer, Carmen Fagoaga, Pedro Moreno, Luis Navarro, Ricardo Flores i Leandro Peña. "Methods for Producing Transgenic Plants Resistant to CTV". W Methods in Molecular Biology, 229–43. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9558-5_17.
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Rodrigo, Javier. "Italy, the CTV, and politics on the National side". W Fascist Italy in the Spanish Civil War, 1936–1939, 102–32. Abingdon, Oxon ; New York, NY : Routledge, 2021. | Series: [Routledge/Cañada Blanch studies on contemporary Spain]: Routledge, 2021. http://dx.doi.org/10.4324/9781003166054-4.
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Yokomi, Raymond. "CTV Vectors and Interactions with the Virus and Host Plants". W Methods in Molecular Biology, 29–53. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9558-5_4.
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Davis, R. Eugene, Gerard Duvierre, Yves Boussant-Roux i Michael Nelson. "High-Zirconia Fused Cast Refractory Applications in CTV Panel Glass Melters". W A Collection of Papers Presented at the 61st Conference on Glass Problems: Ceramic Engineering and Science Proceedings, Volume 22, Issue 1, 117–23. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2008. http://dx.doi.org/10.1002/9780470294659.ch10.
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Scalliet, P., L. Renard, B. Lengelé i B. Tombal. "CTV for Lymphatics in Prostate Adenocarcinoma: an Anatomical Description and Clinical Discussion". W Clinical Target Volumes in Conformal and Intensity Modulated Radiation Therapy, 145–56. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-06270-8_7.
Pełny tekst źródłaStreszczenia konferencji na temat "CTV"
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Perrier, P., i G. Durand. "CRV-CTV aerodynamic shape definition". W 8th AIAA International Space Planes and Hypersonic Systems and Technologies Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1998. http://dx.doi.org/10.2514/6.1998-1628.
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Potylitsyn, N. P., A. V. Britkov, Y. A. Krasyuk, N. A. Gorbanov i V. V. Zayanchukovskiy. "CTV optical equipment". W 2005 15th International Crimean Conference Microwave and Telecommunication Technology. IEEE, 2005. http://dx.doi.org/10.1109/crmico.2005.1564825.
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Krasyuk, Y. A., N. P. Potylitsyn, P. A. Rakityanskiy, S. A. Dementenko i A. E. Prokopenko. "Optical assembly for CTV". W 2004 14th International Crimean Conference "Microwave and Telecommunication Technology". IEEE, 2004. http://dx.doi.org/10.1109/crmico.2004.183200.
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"General background: history of CTV". W Virtual City and Territory. Barcelona: Centre de Política de Sòl i Valoracions, 2016. http://dx.doi.org/10.5821/ctv.8110.
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Morozov, A. A., A. V. Prokhorenko, V. N. Dyachenko, A. V. Britkov, V. V. Zayanchukovskiy, V. I. Sviridenko, N. A. Gorbanov i in. "A multifunctional CTV measuring device". W 2003 13th International Crimean Conference 'Microwave and Telecommunication Technology' Conference Proceedings. IEEE, 2003. http://dx.doi.org/10.1109/crmico.2003.158744.
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Britkov, A. V., A. V. Prohorenko, V. N. Dyachenko, D. N. Trembach, V. I. Sviridenko, N. A. Gorbanov i A. S. Nosov. "Multifunctional measuring device for CTV". W 2004 14th International Crimean Conference "Microwave and Telecommunication Technology". IEEE, 2004. http://dx.doi.org/10.1109/crmico.2004.183366.
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Kinney, David, Jeff Bowles, Lily Yang i Cathy Roberts. "Conceptual design of a 'SHARP' - CTV". W 35th AIAA Thermophysics Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2001. http://dx.doi.org/10.2514/6.2001-2887.
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Britkov, A. V., N. A. Gorbanov, V. I. Sviridenko, O. S. Nosov, V. T. Gontarev, M. A. Tarasov, A. V. Prohorenko i V. N. Dyachenko. "LFM-700 multifunctional measuring device for CTV". W 2005 15th International Crimean Conference Microwave and Telecommunication Technology. IEEE, 2005. http://dx.doi.org/10.1109/crmico.2005.1565133.
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Herber, Nikolaus, i Joachim Lucas. "The ECLS Subsystem for the European Crew Transfer Vehicle (CTV)". W International Conference On Environmental Systems. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1996. http://dx.doi.org/10.4271/961373.
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Choudhary, Amit Kumar. "The impact of tumour regression in locally advanced carcinoma cervix during external beam radiotherapy and the need for adaptive planning". W 16th Annual International Conference RGCON. Thieme Medical and Scientific Publishers Private Ltd., 2016. http://dx.doi.org/10.1055/s-0039-1685254.
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Aim: To study the impact of tumour regression occurring during IMRT for locally advanced Carcinoma cervix and study dose distribution to target volume and OARs and hence the need for any replanning. Methods and Materials: 40 patients undergoing IM-IGRT and weekly chemotherapy were included in the study. After 36Gy, a second planning CT-scan was done and target volume and OARs were recontoured. First plan (non-adaptive) was compared with second plan (adaptive plan) to evaluate whether it would still offer sufficient target coverage to the CTV and spare the OARs after having delivered 36Gy. Finally new plan was created based on CT-images to investigate whether creating a new treatment plan would optimize target coverage and critical organ sparing. To measure the response of the primary tumour and pathologic nodes to EBRT, the differences in the volumes of the primary GTV and nodal GTV between the pretreatment and intratreatment CT images was calculated. Second intratreatment IMRT plans was generated, using the delineations of the intratreatment CT images. The first IMRT plan (based on the first CT-scan or non adaptive plan) was compared with second IMRT plan (based on the second CT-scan or adaptive plan). Results: 35% patients had regression in GTV in the range of 4.1% to 5%, 20% in the range of 1.1%-2%, 15% in the range of 2.1%-3% and 20% in the range of 6%-15%. There was significant mean decrease in GTV of 4.63cc (p=0.000). There was a significant decrease in CTV on repeat CT done after 36Gy by 23.31cc (p=0.000) and in PTV by 23.31cc (p=0.000). There was a statistically significant increase in CTV D98, CTV D95, CTV D50 and CTV D2 in repeat planning CT done after 36Gy. There was no significant alteration in OARs doses. Conclusion: Despite tumour regression and increased target coverage in locally advanced carcinoma cervix after a delivery of 36Gy there was no sparing of OARs. Primary advantage of adaptive RT seems to be in greater target coverage with non-significant normal tissue sparing.
Raporty organizacyjne na temat "CTV"
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Dawson, William O., Moshe Bar-Joseph, Charles L. Niblett, Ron Gafny, Richard F. Lee i Munir Mawassi. Citrus Tristeza Virus: Molecular Approaches to Cross Protection. United States Department of Agriculture, styczeń 1994. http://dx.doi.org/10.32747/1994.7570551.bard.
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Citrus tristeza virus (CTV) has the largest genomes among RNA viruses of plants. The 19,296-nt CTV genome codes for eleven open reading frames (ORFs) and can produce at least 19 protein products ranging in size from 6 to 401 kDa. The complex biology of CTV results in an unusual composition of CTV-specific RNAs in infected plants which includes multiple defective RNAs and mixed infections. The complex structure of CTV populations poses special problems for diagnosis, strain differentiation, and studies of pathogenesis. A manipulatable genetic system with the full-length cDNA copy of the CTV genome has been created which allows direct studies of various aspects of the CTV biology and pathology. This genetic system is being used to identify determinants of the decline and stem-pitting disease syndromes, as well as determinants responsible for aphid transmission.
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Lee, Richard, Moshe Bar-Joseph, K. S. Derrick, Aliza Vardi, Roland Brlansky, Yuval Eshdat i Charles Powell. Production of Antibodies to Citrus Tristeza Virus in Transgenic Citrus. United States Department of Agriculture, wrzesień 1995. http://dx.doi.org/10.32747/1995.7613018.bard.
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Citrus tristeza virus (CTV) is the most important virus disease of citrus in the world. CTV causes death of trees on sour orange rootstock and/or stem pitting of scions regardless of rootstock which results in trees of low vigor, reduced yield with reduction in size and quality of fruit. The purpose of this project was to produce monoclonal antibodies (MABs) to CTV coat protein (CP), develop single domain antibodies (dAbs) or Fab fragments which neutralize the infection by binding to the virus, and to produce transformed plants which express the dAbs. The objectives of this research have been met and putative transgenic tobacco and citrus plants have been developed. These putative transgenic plants are presently undergoing evaluation to determine the level of dAbs expression and to determine their resistance to CTV. Additionally, the CTV genome has been sequenced and the CP gene of several biologically characterized CTV strains molecular characterized. This has indicated a correlation between CP sequence homology and biological activity, and the finding of DI RNAs associated with some CTV strains. Several MABs have been produced which enable broad spectrum identification of CTV strains while other MABs enable differentiation between mild and severe strains. The use of selected MAbs and determination of the CP gene sequence has enabled predictions of biological activities of unknown CTV isolates. The epitopes of two MABs, one reacting selectively with severe CTV strains and the other reacting with all strains, have been characterized at the molecular level.
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Bar-Joseph, Moshe, William O. Dawson i Munir Mawassi. Role of Defective RNAs in Citrus Tristeza Virus Diseases. United States Department of Agriculture, wrzesień 2000. http://dx.doi.org/10.32747/2000.7575279.bard.
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This program focused on citrus tristeza virus (CTV), the largest and one of the most complex RNA-plant-viruses. The economic importance of this virus to the US and Israeli citrus industries, its uniqueness among RNA viruses and the possibility to tame the virus and eventually turn it into a useful tool for the protection and genetic improvement of citrus trees justify these continued efforts. Although the overall goal of this project was to study the role(s) of CTV associated defective (d)-RNAs in CTV-induced diseases, considerable research efforts had to be devoted to the engineering of the helper virus which provides the machinery to allow dRNA replication. Considerable progress was made through three main lines of complementary studies. For the first time, the generation of an engineered CTV genetic system that is capable of infecting citrus plants with in vitro modified virus was achieved. Considering that this RNA virus consists of a 20 kb genome, much larger than any other previously developed similar genetic system, completing this goal was an extremely difficult task that was accomplished by the effective collaboration and complementarity of both partners. Other full-length genomic CTV isolates were sequenced and populations examined, resulting in a new level of understanding of population complexities and dynamics in the US and Israel. In addition, this project has now considerably advanced our understanding and ability to manipulate dRNAs, a new class of genetic elements of closteroviruses, which were first found in the Israeli VT isolate and later shown to be omnipresent in CTV populations. We have characterized additional natural dRNAs and have shown that production of subgenomic mRNAs can be involved in the generation of dRNAs. We have molecularly cloned natural dRNAs and directly inoculated citrus plants with 35S-cDNA constructs and have shown that specific dRNAs are correlated with specific disease symptoms. Systems to examine dRNA replication in protoplasts were developed and the requirements for dRNA replication were defined. Several artificial dRNAs that replicate efficiently with a helper virus were created from infectious full-genomic cDNAs. Elements that allow the specific replication of dRNAs by heterologous helper viruses also were defined. The T36-derived dRNAs were replicated efficiently by a range of different wild CTV isolates and hybrid dRNAs with heterologous termini are efficiently replicated with T36 as helper. In addition we found: 1) All CTV genes except of the p6 gene product from the conserved signature block of the Closteroviridae are obligate for assembly, infectivity, and serial protoplast passage; 2) The p20 protein is a major component of the amorphous inclusion bodies of infected cells; and 3) Novel 5'-Co-terminal RNAs in CTV infected cells were characterized. These results have considerably advanced our basic understanding of the molecular biology of CTV and CTV-dRNAs and form the platform for the future manipulation of this complicated virus. As a result of these developments, the way is now open to turn constructs of this viral plant pathogen into new tools for protecting citrus against severe CTV terms and development of virus-based expression vectors for other citrus improvement needs. In conclusion, this research program has accomplished two main interconnected missions, the collection of basic information on the molecular and biological characteristics of the virus and its associated dRNAs toward development of management strategies against severe diseases caused by the virus and building of novel research tools to improve citrus varieties. Reaching these goals will allow us to advance this project to a new phase of turning the virus from a pathogen to an ally.
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Dawson, William O., i Moshe Bar-Joseph. Creating an Ally from an Adversary: Genetic Manipulation of Citrus Tristeza. United States Department of Agriculture, styczeń 2004. http://dx.doi.org/10.32747/2004.7586540.bard.
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Citrus is one of the major agricultural crops common to Israel and the United States, important in terms of nutrition, foreign exchange, and employment. The economy of both citrus industries have been chronically plagued by diseases caused by Citrus tristeza virus (CTV). The short term solution until virus-resistant plants can be used is the use of mild strain cross-protection. We are custom designing "ideal" protecting viruses to immunize trees against severe isolates of CTV by purposely inoculating existing endangered trees and new plantings to be propagated as infected (protected) citrus budwood. We crossed the substantial technological hurdles necessary to accomplish this task which included developing an infectious cDNA clone which allows in vitro manipulation of the virus and methods to then infect citrus plants. We created a series of hybrids between decline-inducing and mild CTV strains, tested them in protoplasts, and are amplifying them to inoculate citrus trees for evaluation and mapping of disease determinants. We also extended this developed technology to begin engineering transient expression vectors based on CTV as tools for genetic improvement of tree crops, in this case citrus. Because of the long periods between genetic transformation and the ultimate assay of mature tree characteristics, there is a great need for an effective system that allows the expression or suppression of target genes in fruiting plants. Virus-based vectors will greatly expedite progress in citrus genetic improvement. We characterized several components of the virus that provides necessary information for designing virus-based vectors. We characterized the requirements of the 3 ’-nontranslated replication promoter and two 3 ’-ORF subgenomic (sg) mRNA controller elements. We discovered a novel type of 5’-terminal sgRNAs and characterized the cis-acting control element that also functions as a strong promoter of a 3 ’-sgRNA. We showed that the p23 gene controls negative-stranded RNA synthesis and expression of 3 ’ genes. We identified which genes are required for infection of plants, which are host range determinants, and which are not needed for plant infection. We continued the characterization of native dRNA populations and showed the presence of five different classes including class III dRNAs that consists of infectious and self-replicating molecules and class V dRNAs that contain all of the 3 ’ ORFs, along with class IV dRNAs that retain non-contiguous internal sequences. We have constructed and tested in protoplasts a series of expression vectors that will be described in this proposal.
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Yin, Xietian, Shichao Zhao, Nan Xiang, Jidong Chen, Jun Xu i Yudan Zhang. Efficacy and Safety of Chinese Herbal Medicines combined with Cyclophosphamide for Connective Tissue Disease-Associated Interstitial Lung Disease: A Meta-Analysis of Randomized Controlled Trials. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, grudzień 2022. http://dx.doi.org/10.37766/inplasy2022.12.0010.
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Review question / Objective: To evaluate the effectiveness and safety of Chinese herbal medicines (CHMs) combined with cyclophosphamide (CTX) for connective tissue disease-associated interstitial lung disease (CTD-ILD) by performing a meta-analysis. Condition being studied: Chinese herbal medicines (CHMs) and cyclophosphamide (CTX) are widely used in the treatment of connective tissue disease-associated interstitial lung disease (CTD-ILD). However, the clinical benefits of CHMs treatment for CTD-ILD are still controversial, and there is no systemic review to summarize and evaluate their efficacy and safety.
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Schat, Karel Antoni, Irit Davidson i Dan Heller. Chicken infectious anemia virus: immunosuppression, transmission and impact on other diseases. United States Department of Agriculture, 2008. http://dx.doi.org/10.32747/2008.7695591.bard.
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1. Original Objectives. The original broad objectives of the grant were to determine A) the impact of CAV on the generation of cytotoxic T lymphocytes (CTL) to reticuloendotheliosis virus (REV) (CU), B). the interactions between chicken anemia virus (CAV) and Marek’s disease virus (MDV) with an emphasis on horizontal spread of CAV through feathers (KVI), and C) the impact of CAV infection on Salmonella typhimurium (STM) (HUJI). During the third year and the one year no cost extension the CU group included some work on the development of an antigen-antibody complex vaccine for CAV, which was partially funded by the US Poultry and Egg Association. 2. Background to the topic. CAV is a major pathogen causing clinical disease if maternal antibody-free chickens are infected vertically or horizontally between 1 and 14 days of age. Infection after 3 weeks of age when maternal antibodies are not longer present can cause severe subclinical immunosuppression affecting CTL and cytokine expression. The subclinical immunosuppression can aggravate many diseases including Marek’s disease (MD) and several bacterial infections. 3. Major conclusions and achievements. The overall project contributed in the following ways to the knowledge about CAV infection in poultry. As expected CAV infections occur frequently in Israel causing problems to the industry. To control subclinical infections vaccination may be needed and our work indicates that the development of an antigen-antibody complex vaccine is feasible. It was previously known that CAV can spread vertically and horizontally, but the exact routes of the latter had not been confirmed. Our results clearly show that CAV can be shed into the environment through feathers. A potential interaction between CAV and MD virus (MDV) in the feathers was noted which may interfere with MDV replication. It was also learned that inoculation of 7-day-old embryos causes growth retardation and lesions. The potential of CAV to cause immunosuppression was further examined using CTL responses to REV. CTL were obtained from chickens between 36 and 44 days of age with REV and CAV given at different time points. In contrast to our earlier studies, in these experiments we were unable to detect a direct impact of CAV on REV-specific CTL, perhaps because the CTL were obtained from older birds. Inoculation of CAV at one day of age decreased the IgG antibody responses to inactivated STM administered at 10 days of age. 4. Scientific and Agricultural Implications The impact of the research was especially important for the poultry industry in Israel. The producers have been educated on the importance of the disease through the many presentations. It is now well known to the stakeholders that CAV can aggravate other diseases, decrease productivity and profitability. As a consequence they monitor the antibody status of the breeders so that the maternal antibody status of the broilers is known. Also vaccination of breeder flock that remain antibody negative may become feasible further reducing the negative impact of CAV infection. Vaccination may become more important because improved biosecurity of the breeder flocks to prevent avian influenza and Salmonella may delay the onset of seroconversion for CAV by natural exposure resulting in CAV susceptible broilers lacking maternal antibodies. Scientifically, the research added important information on the horizontal spread of CAV through feathers, the interactions with Salmonella typhimurium and the demonstration that antigen-antibody complex vaccines may provide protective immunity.
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Chejanovsky, Nor, i Bruce A. Webb. Potentiation of pest control by insect immunosuppression. United States Department of Agriculture, lipiec 2004. http://dx.doi.org/10.32747/2004.7587236.bard.
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Our original aims were to elucidate the mechanisms through which the immunosuppressive insect virus, the Campoletis sonorensis polydnavirus (CsV) promotes replication of a well-characterized pathogenic virus, the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) in hosts that are mildly or non-permissive to virus replication. According to the BARD panels criticism we modified our short-term goals (see below). Thus, in this feasibility study (one-year funding) we aimed to show that: 1. S. littoralis larvae mount an immune response against a baculovirus infection. 2. Immunosuppression of an insect pest improves the ability of a viral pathogen (a baculovirus) to infect the pest. 3. S. littoralis cells constitute an efficient tool to study some aspects of the anti- viral immune response. We achieved the above objectives by: 1. Finding melanized viral foci upon following the baculoviral infection in S . littoralis larvae infected with a polyhedra - positive AcMNPV recombinant that expressed the GFP gene under the control of the Drosophila heat shock promoter. 2. Studying the effect of AcMNPV-infection in S . littoralis immunosuppressed by parasitation with the Braconidae wasp Chelonus inanitus that bears the CiV polydna virus, that resulted in higher susceptibility of S. littoralis to AcMNPV- infection. 3. Proving that S. littoralis hemocytes resist AcMNPV -infection. 4. Defining SL2 as a granulocyte-like cell line and demonstrating that as littoralis hemocytic cell line undergoes apoptosis upon AcMNPV -infection. 5. Showing that some of the recombinant AcMNPV expressing the immuno-suppressive polydna virus CsV- vankyrin genes inhibit baculoviral-induced lysis of SL2 cells. This information paves the way to elucidate the mechanisms through which the immuno- suppressive polydna insect viruses promote replication of pathogenic baculoviruses in lepidopteran hosts that are mildly or non-permissive to virus- replication by: - Assessing the extent to which and the mechanisms whereby the immunosuppressive viruses, CiV and CsV or their genes enhance AcMNPV replication in polydnavirus- immunosuppressed H. zea and S. littoralis insects and S. littoralis cells. - Identifying CiV and CsV genes involved in the above immunosuppression (e.g. inhibiting cellular encapsulation and disrupting humoral immunity). This study will provide insight to the molecular mechanisms of viral pathogenesis and improve our understanding of insect immunity. This knowledge is of fundamental importance to controlling insect vectored diseases of humans, animals and plants and essential to developing novel means for pest control (including baculoviruses) that strategically weaken insect defenses to improve pathogen (i.e. biocontrol agent) infection and virulence.
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Leonard, Talayna, Robert Lemme, Cati Kral, Briana Santiago, Chris Elberts, Stephanie Dewald, Patrick McGonagill i in. High-Percentage of Early Resectable Pancreatic Ductal Adenocarcinoma is Unidentified on Abdominal CT Obtained for Unrelated Diagnosis. Science Repository, grudzień 2021. http://dx.doi.org/10.31487/j.aco.2021.02.03.
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Objective: Pancreatic ductal adenocarcinoma (PDAC) has the best survival when detected early with 5-year survival near 40% for small, resectable PDAC. We evaluate the undiagnosed PDAC imaging features on routine CT and their impact on resectability. Methods: 76 of the screened 134 CTs from 1/1/2012 to 12/31/2018 using our tumor registry were obtained prior to PDAC diagnosis for other indications at least one month before presentation. Each cross-sectional study was reviewed for features of early PDAC: pancreatic mass, pancreatic ductal dilatation, perivascular/peripancreatic soft-tissue infiltration, omental lesions/ascites, and lymphadenopathy. When such features were detectible by the reviewing radiologists, the original CT readings were classified as concordant/discrepant. Descriptive statistics are reported for discrepant reads, tumor resectability, and tumor size. Results: Of the 76 cases from 46 unique subjects (30 male/16 female), 25 CTs (33%) had undetected PDAC imaging features: masses (15/19 unreported), ductal dilatation (16/20 unreported), and peripancreatic/perivascular soft-tissue infiltration (20/36 unreported). 63% of early PDAC features were not identified initially. One year before clinical diagnosis, 75-80% of the PDAC cases were resectable; at < 6 months before clinical diagnosis, only 29% were resectable. Conclusion: Improving early detection of key PDAC features on routine CT examinations can potentially improve patient outcomes.
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Skone, Timothy J. CTL Diesel. Office of Scientific and Technical Information (OSTI), sierpień 2013. http://dx.doi.org/10.2172/1509366.
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McCaffrey, Trevor, i Gordon T. Richards. CIV Distance. GitHub, październik 2021. http://dx.doi.org/10.17918/civdistance.
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