Papers by Conrad Lichtenstein
Endeavour, 1990
Meeting Reports Genetic Engineering of Crop Plants A meeting on "Genetic Engineering of Crop Plan... more Meeting Reports Genetic Engineering of Crop Plants A meeting on "Genetic Engineering of Crop Plants" was held at the University of Nottingham Faculty of Agricultural and Food Science at Sutton Bonington, England on 17-21 April 1989. The meeting was the 49th in the University of Nottingham's long-established Easter School series, but the first on this topic. It was sponsored in part by the ISPMB and attracted over two hundred delegates from eighteen countries. The speakers included representatives from universities, research institutes, and industrial laboratories. The meeting was opened on the Monday eveningby Ted Cocking of Nottingham University, who gave an overview of the state of plant genetic manipulation. One of the most popular areas of study was plant protection; papers on this topic occupied most of the next day. Roger Beachy of Washington University gave an account of his research on resistance to tobacco mosaic virus mediated by coat protein expression in transgenic tobacco. David Baulcombe of the Sainsbury Laboratory told of several important domains identified in cucumber mosaic virus satellite RNA which seem to have different effects in transgenic plants. This work offered the promise of a genetically engineered satellite RNA which would offer good protection without production of any symptoms. By recombining the DNA of phenotypically different strains of cauliflower mosaic virus, Simon Covey of the AFRC IPSR laboratory has identified a number of possible hostpathogen interactions associated with specific regions of the DNA which may be used in plant protection. M.G.K. Jones of the AFRC Institute of Arable Crops Research had approached the problem of virus resistance in a different manner by transferring resistance from Solanum brevidens to Solanum tuberosum by somatic hybridisation. As well as an account of the work itself, there was a full discussion of U.K. regulatory policy as it affected field work. The use of Bacillus thuringiensis toxin to confer resistance of plants to insects was one of the topics discussed by Jan Leemans of Plant Genetic Systems, Gent, and by Chuck Gasser of Monsanto, St. Louis. The issue of B. thuringiensis toxins attracted much attention as one of the aspects of genetic engineering of crops which may be close to practical exploitation, especially in protection against tobacco hornworm and tomato pinworm. Vaughan Hilder of Durham University described a novel approach to insect resistance which depends upon the production in transgenic plants of a trypsin inhibitor from the seeds of cowpea. Initial results were promising, which raised the interesting philosophical problem of why evolution had not provided the vegetative parts of cowpea with resistance of this type. Studies on tomato, ~oybean and rape plants resistant to
Journal of Probiotics & Health, Oct 23, 2017
Archives Of Phytopathology And Plant Protection, 2001
A system combining antisense RNA and RNAseIII‐binding activity was designed. Two antisense RNA ve... more A system combining antisense RNA and RNAseIII‐binding activity was designed. Two antisense RNA vehicles, 7SL RNA and tRNA genes containing the coat protein leader domain (2245–2316) and “zinc finger”; domain (3325–3411) of PVS, respectively were prepared. Both, antisense RNA vehicles were shown to be efficiently transcribed by polymerase III using in vitro assay. It was shown by specific RT PCR,
PubMed, 1984
The nucleotide sequence of a tumor morphology gene, tmr, from the Agrobacterium tumefaciens Ti-pl... more The nucleotide sequence of a tumor morphology gene, tmr, from the Agrobacterium tumefaciens Ti-plasmid, pTiA6NC, and its flanking 5' region was determined by M13 "dideoxy" procedures. The DNA sequence reveals an open reading frame capable of encoding a 240 amino acid protein. We have identified the polyadenylated transcript initiation and termination sits by S1 nuclease mapping. The extent of the sequence required for transcription 5' to the start of transcription has been delimited by two transposon insertions. The first of these maps at -- 121 with respect to transcription initiation and results in the wild-type phenotype, the second insertion maps at about -85 and results in a tmr phenotype.
Archives of Virology, Dec 1, 2003
Cotton, the major cash crop in Pakistan, suffers 30% losses to cotton leaf curl disease, caused b... more Cotton, the major cash crop in Pakistan, suffers 30% losses to cotton leaf curl disease, caused by the geminivirus, cotton leaf curl virus DNA A, plus a satellite component, DNA β responsible for symptom development with plants failing to produce cotton bolls. We constructed transgenic tobacco expressing sense and antisense RNAs representing: [i] the 5 half of the viral DNA replication gene, AC1, [ii] the 3 half of AC1, [iii] two overlapping genes, AC2, a transcription activator, and AC3, a replication enhancer. In contrast to controls, 25% of 72 transgenic tobacco lines tested showed heritable resistance [T 1 − T 3 generations]: symptom-free and no replication of DNA A or DNA β even after 120 days of continuous exposure to viruliferous whiteflies. As geminiviral and transgene RNAs are not detected in resistant lines following infection, and selected uninfected resistant tobacco sense lines reveal double-stranded and small interfering RNAs, the most likely mechanism is via post-transcriptional gene silencing.
Biochemical Society Transactions, Nov 1, 1992
Biological chemistry Hoppe-Seyler, 1995
A high concentration of hop latent viroid (HLVd) was detected in infected mericlones of Osvald's ... more A high concentration of hop latent viroid (HLVd) was detected in infected mericlones of Osvald's hops grown in vitro. This concentration was about 8-fold higher than in leaves of young, field-grown plants, reaching about 30 pg/mg of fresh mass. Treatment of these in wfro-grown plants at high temperature (35 °C) for two weeks lead to a dramatic (about 70-90%) decrease of HLVd content. More detailed investigations performed with mericlone 6147 of Osvald 31 showed that HLVd levels decrease gradually during subsequent cycles of heat treatment. A nuclease activity capable of cleaving HLVd and fully double-stranded RNA was shown to increase significantly in hop tissues during thermotherapy cycles, or after the heat shock. The nuclease activity was found to have similar properties to those extracted earlier from tobacco anthers. This enzyme resembles a sugar-unspecif ic nuclease which has a maximum activity at pH 5.5. Analysis of the activity with viroid and dsRNA showed that both, endo-and exonucleolytic activities were attributable to the enzyme. A strong tissue-specific gradient of viroid (the lowest level in stem apex and the highest level in roots) was observed in young plants, showing a negative correlation with the dsRNAse activity. In senescent plants, the highest viroid concentration was observed in maturated cones and in upper stems. High nuclease activity in the upper stem tissue suggests that viroid RNA must be protected in this tissue against degradation.
The nucleotide sequence of the tumor mor- phology locus, tms, from pTiA6NC has been determined. T... more The nucleotide sequence of the tumor mor- phology locus, tms, from pTiA6NC has been determined. The sequence analysis indicates that each of two polyadenylylated transcripts encoded by this locus contains an open reading frame; the predicted transcript 1 gene product has a molecular size of 83,769 daltons, and the predicted transcript 2 gene product, of 49,588 daltons. The precise start and stop positions of the transcript 2 RNA have been mapped with S1 nuclease. Several insertion mutations have been constructed. One of these localizes the transcript 2 promoter within the 72 base pairs 5' to transcription initiation. Significant homology was observed between the protein encoded by transcript 1 and the adenine binding region of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens, suggesting that the transcript 1 protein binds adenine either as substrate or cofactor.
Plant Molecular Biology, Nov 1, 1993
Let's suppose that you have three 2000 bp DNA sequences that you would like to align and pres... more Let's suppose that you have three 2000 bp DNA sequences that you would like to align and present at a meeting tomorrow. You would like to get a detailed visual representation of the areas of homology between these sequences and keep the representation small enough to fit on one A4 transparency or 35 mm slide. This is a common problem that molecular biologists face when they want to convey their sequence results.
Genes, Chromosomes and Cancer, Oct 29, 2013
VHL is mutated in the majority of patients with clear cell renal cell carcinoma (ccRCC), with con... more VHL is mutated in the majority of patients with clear cell renal cell carcinoma (ccRCC), with conflicting clinical relevance. Recent studies have identified recurrent mutations in histone modifying and chromatin remodeling genes, including BAP1, PBRM1, SETD2, KDM6A, and JARID1c. Current evidence suggests that BAP1 mutations are associated with aggressive disease. The clinical significance of the remaining genes is unknown. In this study, targeted sequencing of VHL and JARID1c (entire genes) and coding regions of BAP1, PBRM1, SETD2, and KDM6A was performed on 132 ccRCCs and matched normal tissues. Associations between mutations and clinical and pathological outcomes were interrogated. Inactivation of VHL (coding mutation or promoter methylation) was seen in 75% of ccRCCs. Somatic noncoding VHL alterations were identified in 29% of ccRCCs and may be associated with improved overall survival. BAP1 (11%), PBRM1 (33%), SETD2 (16%), JARID1c (4%), and KDM6A (3%) mutations were identified. BAP1‐mutated tumors were associated with metastatic disease at presentation (P = 0.023), advanced clinical stage (P = 0.042) and a trend towards shorter recurrence free survival (P = 0.059) when compared with tumors exclusively mutated for PBRM1. Our results support those of recent publications pointing towards a role for BAP1 and PBRM1 mutations in risk stratifying ccRCCs. Further investigation of noncoding alterations in VHL is warranted. © 2013 Wiley Periodicals, Inc.
Archives of Virology, 2003
Cotton, the major cash crop in Pakistan, suffers 30% losses to cotton leaf curl disease, caused b... more Cotton, the major cash crop in Pakistan, suffers 30% losses to cotton leaf curl disease, caused by the geminivirus, cotton leaf curl virus DNA A, plus a satellite component, DNA β responsible for symptom development with plants failing to produce cotton bolls. We constructed transgenic tobacco expressing sense and antisense RNAs representing: [i] the 5 half of the viral DNA replication gene, AC1, [ii] the 3 half of AC1, [iii] two overlapping genes, AC2, a transcription activator, and AC3, a replication enhancer. In contrast to controls, 25% of 72 transgenic tobacco lines tested showed heritable resistance [T 1 − T 3 generations]: symptom-free and no replication of DNA A or DNA β even after 120 days of continuous exposure to viruliferous whiteflies. As geminiviral and transgene RNAs are not detected in resistant lines following infection, and selected uninfected resistant tobacco sense lines reveal double-stranded and small interfering RNAs, the most likely mechanism is via post-transcriptional gene silencing.
Un metodo de estimacion del numero de moleculas de polinucleotidos de partida secuenciadas a part... more Un metodo de estimacion del numero de moleculas de polinucleotidos de partida secuenciadas a partir de multiples muestras, comprendiendo el metodo: unir un adaptador a las moleculas de polinucleotidos de partida de multiples muestras diferentes, en donde el adaptador para cada muestra comprende: una marca de un unico identificador multiplex (MID) especifico para la muestra, haciendo posible la marca del identificador multiplex la identificacion de la muestra a partir de la cual se deriva un polinucleotido; y una region de bases degeneradas (DBR) que comprende al menos una base de nucleotidos seleccionada de: R, Y, S, W, K, M, B, D, H, V, N, y las versiones modificadas de las mismas, siendo la degeneracion de las DBR de tal modo que es probable que cada polinucleotido individual tenga una DBR diferente; reunir las multiples muestras unidas a adaptadores diferentes para generar una muestra conjunta; amplificar los polinucleotidos unidos al adaptador en la muestra conjunta; secuenciar ...
Des aspects de la presente invention concernent des procedes et des compositions pour la determin... more Des aspects de la presente invention concernent des procedes et des compositions pour la determination du nombre de molecules individuelles de polynucleotide issues de la meme region genomique du meme echantillon d'origine qui ont ete sequencees dans une configuration particuliere ou un procede particulier d'analyse de sequence. Dans ces aspects de l'invention, une region de base degeneree (DBR) est fixee aux molecules initiales de polynucleotide qui sont ulterieurement sequencees (par exemple, apres que certaines etapes du procede sont realisees, par exemple, l'amplification et/ou l'enrichissement). Le nombre de sequences DBR differentes presentes dans un cycle de sequencage peut etre utilise pour determiner/estimer le nombre de polynucleotides initiaux differents qui ont ete sequences. Les DBR peuvent etre utilisees pour augmenter de nombreuses applications differentes d'analyse de sequences d'acides nucleiques, permettant notamment des determinations d...
SUMMARY Mutations in the terminal 8-bp (5'-T1G2T3G4GSG6CVGS-3 ') of the inverted repeats ... more SUMMARY Mutations in the terminal 8-bp (5'-T1G2T3G4GSG6CVGS-3 ') of the inverted repeats of the bacterial transposon, Tn7, were analysed by measuring Tn7 transposition to the attachment site, attTn7. The mutation, C 2, present at either end of Tn7 reduces transposition only threefold, but in the double mutant, with C 2 at both ends of Tn7, no transposition is detected. C 6 mutations have no effect on transposition frequency. Replacement with 5'-A3C4GSC6GVCS-3' at the right end of Tn7 apparently abolishes transposition; yet in the double mutant, where the inverted repeats are restored by substituting this sequence at both ends of Tn7, transposition is partially rescued. This suggests that the mechanism of Tn7 transposition requires communication between the two ends. Tn7 transposition has always been seen to generate a 5-bp target duplication. This is presumed to result from a staggered cut, plus repair synthesis during transposition. We found that two of our right-en...
EL DOCTOR CONRAD LICHTENSTEIN, CIENTIFICO DEL CENTRO DE BIOTECNOLOGIA DEL IMPERIAL COLLEGE DEL LO... more EL DOCTOR CONRAD LICHTENSTEIN, CIENTIFICO DEL CENTRO DE BIOTECNOLOGIA DEL IMPERIAL COLLEGE DEL LONDRES, HA CREADO Y COMENZADO A PROBAR UN NUEVO METODO REVOLUCIONARIO DE PROTECCION DE LOS CULTIVOS CONTRA ENFERMEDADES VIRALES, MEDIANTE EL EMPLEO DE TECNICAS DE MANIPULACION GENETICA.
Growth of antibody-secreting hybridomas re-quires special conditions such as serum-free defined m... more Growth of antibody-secreting hybridomas re-quires special conditions such as serum-free defined media containing growth factors and vitamins. However, the surface on which these cells can proliferate has been shown to play an important role. Phosphorylcholine (PC)-based polymers are zwitterionic compounds with non-biofouling properties. These polymers are characterized by having reduced protein absorption properties. Our aim was to determine whether well-established hybri-doma cell lines were able to proliferate and produce measurable amounts of monoclonal antibodies when grown on PC-polymer-coated surfaces. Comparative ex-periments using four well-known hybridoma cell lines (PAb421, PAb246, PAb1801 which recognize p53, and PAb280 which recognizes SV40 small t antigen) grown on PC-polymer-coated, uncoated, and two commercially available tissue culture plates showed that PC-polymer-coated plates were more efficient than uncoated plates in sustaining cell growth and monoclonal antibod...
Homologous Recombination and Gene Silencing in Plants, 1994
Three types of homologous recombination (HR) in plants are reviewed in this book: extrachromosoma... more Three types of homologous recombination (HR) in plants are reviewed in this book: extrachromosomal recombination (ECR) between input DNAs, either viral replicons (reviewed in chapter 2), or non-replicating input DNAs (chapter 5); recombination between input (extrachromosomal) DNA and a chromosomally located target DNA sequence, i.e. gene targeting (GT), either of the nuclear genome (chapter 9) or chloroplast genomes (chapter 4); and intrachromosomal recombination (ICR) of the chloroplast (chapter 4), mitochondrial (chapter 3) or nuclear genomes that we review in this chapter.
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Papers by Conrad Lichtenstein