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Browsing by Author "Varsani, Arvind"

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A deletion and point mutation study of the human papillomavirus type 16 major capsid gene

Author: Varsani, Arvind ; Williamson, Anna-Lise ; Jaffer, Mohamed A ; Rybicki, Edward P Date: 2006 Recombinant human papillomavirus (HPV) virus-like particles (VLPs) made from the major capsid protein L1 are promising vaccine candidates for use as vaccines against genital and other HPV infections, and particularly against HPV-16. However, ... Read more
Adaptive evolution by recombination is not associated with increased mutation rates in Maize streak virus

Author: Monjane, Aderito ; Pande, Daniel ; Lakay, Francisco ; Shepherd, Dionne ; van der Walt, Eric ; Lefeuvre, Pierre ; Lett, Jean-Michel ; Varsani, Arvind ; Rybicki, Edward ; Martin, Darren Date: 2012 BACKGROUND: Single-stranded (ss) DNA viruses in the family Geminiviridae are proving to be very useful in real-time evolution studies. The high mutation rate of geminiviruses and other ssDNA viruses is somewhat mysterious in that their DNA ... Read more c b
The ancient evolutionary history of polyomaviruses

Author: Buck, Christopher B ; Van Doorslaer, Koenraad ; Peretti, Alberto ; Geoghegan, Eileen M ; Tisza, Michael J ; An, Ping ; Katz, Joshua P ; Pipas, James M ; McBride, Alison A ; Camus, Alvin C ; McDermott, Alexa J ; Dill, Jennifer A ; Delwart, Eric ; Ng, Terry F F ; Farkas, Kata ; Austin, Charlotte ; Kraberger, Simona ; Davison, William ; Pastrana, Diana V ; Varsani, Arvind Date: 2016 Author Summary: Polyomaviruses are a family of DNA-based viruses that are known to infect various terrestrial vertebrates, including humans. In this report, we describe our discovery of highly divergent polyomaviruses associated with various ... Read more c b
Architecture and assembly of maize streak virus: insights from 3D electron microscopy

Author: Dent,Kyle Clayton Date: 2014 Maize streak virus (MSV), circular single stranded DNA (ssDNA) virus (~2.7kb), is the causative agent of Maize streak disease, and is a devastating pathogen that causes severe crop losses to subsistence farmers in sub-Saharan Africa. MSV is ... Read more
Comparative analysis of Panicum streak virus and Maize streak virus diversity, recombination patterns and phylogeography

Author: Varsani, Arvind ; Monjane, Aderito ; Donaldson, Lara ; Oluwafemi, Sunday ; Zinga, Innocent ; Komba, Ephrem ; Plakoutene, Didier ; Mandakombo, Noella ; Mboukoulida, Joseph ; Semballa, Silla ; Briddon, Rob ; Markham, Peter ; Lett, Jean-Michel ; Lefeuvre, Pierre ; Ry Date: 2009 BACKGROUND: Panicum streak virus (PanSV; Family Geminiviridae; Genus Mastrevirus) is a close relative of Maize streak virus (MSV), the most serious viral threat to maize production in Africa. PanSV and MSV have the same leafhopper vector ... Read more c b
Complex recombination patterns arising during geminivirus coinfections preserve and demarcate biologically important intra-genome interaction networks

Author: Martin, Darren P ; Lefeuvre, Pierre ; Varsani, Arvind ; Hoareau, Murielle ; Semegni, Jean-Yves ; Dijoux, Betty ; Vincent, Claire ; Reynaud, Bernard ; Lett, Jean-Michel Date: 2011 Author Summary Genetic recombination between viruses is a form of parasexual reproduction during which two parental viruses each contribute genetic information to an offspring, or recombinant, virus. Unlike with sexual reproduction, however, ... Read more c b
Development of candidate Human papillomavirus vaccines

Author: Varsani, Arvind Date: 2003 The objective of this thesis was to investigate novel and plant-based vaccines against the Human papillomavirus type 16 (HPV-16), which is primarily responsible for cervical cancer. As a first study, the L1 gene of a South Africna variant of ... Read more
East African cassava mosaic-like viruses from Africa to Indian ocean islands: molecular diversity, evolutionary history and geographical dissemination of a bipartite begomovirus

Author: De Bruyn, Alexandre ; Villemot, Julie ; Lefeuvre, Pierre ; Villar, Emilie ; Hoareau, Murielle ; Harimalala, Mireille ; Abdoul-Karime, Anli ; Abdou-Chakour, Chadhouliati ; Reynaud, Bernard ; Harkins, Gordon ; Varsani, Arvind ; Martin, Darren ; Lett, Jean-Michel Date: 2012 BACKGROUND: Cassava (Manihot esculenta) is a major food source for over 200 million sub-Saharan Africans. Unfortunately, its cultivation is severely hampered by cassava mosaic disease (CMD). Caused by a complex of bipartite cassava mosaic ... Read more c b
Evidence of ancient papillomavirus recombination

Author: Varsani, Arvind ; van der Walt, Eric ; Heath, Livio ; Rybicki, Edward P ; Williamson, Anna Lise ; Martin, Darren P Date: 2006 An open question amongst papillomavirus taxonomists is whether recombination has featured in the evolutionary history of these viruses. Since the onset of the global AIDS epidemic, the question is somewhat less academic, because immune-compromised ... Read more
Experimental evidence indicating that mastreviruses probably did not co-diverge with their hosts

Author: Harkins, Gordon ; Delport, Wayne ; Duffy, Siobain ; Wood, Natasha ; Monjane, Aderito ; Owor, Betty ; Donaldson, Lara ; Saumtally, Salem ; Triton, Guy ; Briddon, Rob ; Shepherd, Dionne ; Rybicki, Edward ; Martin, Darren ; Varsani, Arvind Date: 2009 BACKGROUND:Despite the demonstration that geminiviruses, like many other single stranded DNA viruses, are evolving at rates similar to those of RNA viruses, a recent study has suggested that grass-infecting species in the genus Mastrevirus ... Read more c b
Experimental observations of rapid Maize streak virus evolution reveal a strand-specific nucleotide substitution bias

Author: van der Walt, Eric ; Martin, Darren ; Varsani, Arvind ; Polston, Jane ; Rybicki, Edward Date: 2008 BACKGROUND: Recent reports have indicated that single-stranded DNA (ssDNA) viruses in the taxonomic families Geminiviridae, Parvoviridae and Anellovirus may be evolving at rates of ~10-4 substitutions per site per year (subs/site/year). These ... Read more c b
Experimental observations of rapid Maize streak virus evolution reveal a strand-specific nucleotide substitution bias

Author: van der Walt, Eric ; Martin, Darren P A ; Varsani, Arvind ; Polston, Jane E ; Rybicki, Edward P Date: 2008 Background: Recent reports have indicated that single-stranded DNA (ssDNA) viruses in the taxonomic families Geminiviridae, Parvoviridae and Anellovirus may be evolving at rates of ~10-4 substitutions per site per year (subs/site/year). These ... Read more c b
A highly divergent South African geminivirus species illuminates the ancient evolutionary history of this family

Author: Varsani, Arvind ; Shepherd, Dionne N ; Dent, Kyle ; Monjane, Aderito L ; Rybicki, Edward P ; Martin, Darren P Date: 2009 Background: We have characterised a new highly divergent geminivirus species, Eragrostis curvula streak virus (ECSV), found infecting a hardy perennial South African wild grass. ECSV represents a new genus-level geminivirus lineage, and has ... Read more c b
A highly divergent South African geminivirus species illuminates the ancient evolutionary history of this family

Author: Varsani, Arvind ; Shepherd, Dionne ; Dent, Kyle ; Monjane, Aderito ; Rybicki, Edward ; Martin, Darren Date: 2009 BACKGROUND:We have characterised a new highly divergent geminivirus species, Eragrostis curvula streak virus (ECSV), found infecting a hardy perennial South African wild grass. ECSV represents a new genus-level geminivirus lineage, and has a ... Read more c b
HIV type 1 subtype C gag and nef diversity in Southern Africa.

Author: Bredell, Helba ; Martin, Darren P ; Van Harmelen Joanne ; Varsani, Arvind ; Sheppard, Haynes W ; Donovan, R ; Gray, C ; HIVNET028 Study Team ; Williamson, C Date: 2007 Several HIV-1 subtype C-specific gag- and/or nef-based vaccines are currently intended for clinical trial in southern Africa. Here we provide sequences of 64 gag and 45 nef genes sampled in Malawi, Zambia, Zimbabwe, and South Africa and assess ... Read more
Identification of phytoplasmas associated with cultivated and ornamental plants in Kerman Province, Iran

Author: Tazehkand, Susan Asghari ; Pour, Akbar Hossein ; Heydarnejad, Jahangir ; Varsani, Arvind ; Massumi, Hossain Date: 2010 Hossain Kerman Province is a major agricultural centre in south-eastern Iran and an increase in agricultural activities results in an increase in disease. We report phytoplasmal infections in Iran of five plant species; spinach (Spinacia ... Read more
Identification of the Begomoviruses Squash Leaf Curl Virus and Watermelon Chlorotic Stunt Virus in Various Plant Samples in North America

Author: Fontenele, Rafaela S ; Bhaskara, Amulya ; Cobb, Ilaria N ; Majure, Lucas C ; Salywon, Andrew M ; Avalos-Calleros, Jesús A ; Argüello-Astorga, Gerardo R ; Schmidlin, Kara ; Roumagnac, Philippe ; Ribeiro, Simone G ; Kraberger, Simona ; Martin, Darren P ; Lefeuvre, Pierre ; Varsani, Arvind Date: 30 Apr 2021 Geminiviruses are a group of plant-infecting viruses with single-stranded DNA genomes. Within this family, viruses in the genus Begomovirus are known to have a worldwide distribution causing a range of severe diseases in a multitude of ... Read more
An investigation into the use of human papillomavirus type 16 virus-like particles as a delivery vector system for foreign proteins: N- and C-terminal fusion of GFP to the L1 and L2 capsid proteins

Author: Windram, Oliver P ; Weber, Brandon ; Jaffer, Mohamed A ; Rybicki, Edward P ; Shepherd, Dionne N ; Varsani, Arvind Date: 2008 Development of vaccine strategies against human papillomavirus (HPV), which causes cervical cancer, is a priority. We investigated the use of virus-like particles (VLPs) of the most prevalent type, HPV-16, as carriers of foreign proteins. ... Read more
Maize streak virus: an old and complex 'emerging' pathogen

Author: Shepherd, Dionne N ; Martin, Darren P ; Van der Walt, Eric ; Dent, Kyle ; Varsani, Arvind ; Rybicki, Edward P Date: 2010 Maize streak virus (MSV; Genus Mastrevirus, Family Geminiviridae) occurs throughout Africa, where it causes what is probably the most serious viral crop disease on the continent. It is obligately transmitted by as many as six leafhopper species ... Read more
The mechanism of the amidases: mutating the glutamate adjacent to the catalytic triad inactivates the enzyme due to substrate mispositioning

Author: Weber, Brandon W ; Kimani, Serah W ; Varsani, Arvind ; Cowan, Donald A ; Hunter, Roger ; Venter, Gerhard A ; Gumbart, James C ; Sewell, Trevor B Date: 2013 All known nitrilase superfamily amidase and carbamoylase structures have an additional glutamate thatis hydrogen bonded to the catalytic lysine in addition to the Glu, Lys, Cys “catalytic triad.” In the amidase from Geobacillus pallidus, ... Read more

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