| the nucleotide sequence of cloned wheat dwarf virus dna. | restriction analysis and cloning of virus-specific double-stranded dna isolated from plants infected with wheat dwarf virus (wdv) indicated that the virus genome, like that of maize streak virus (msv), consists of a single dna circle. the complete nucleotide sequence of cloned wdv dna (2749 nucleotides) has been determined. comparison of the potential coding regions in wdv dna with those in the dna of two strains of msv suggests that these viruses encode at least two functional proteins, the coa ... | 1985 | 15938050 |
| tumor cell pseudopodial protrusions. localized signaling domains coordinating cytoskeleton remodeling, cell adhesion, glycolysis, rna translocation, and protein translation. | the pseudopodial protrusions of moloney sarcoma virus (msv)-madin-darby canine kidney (mdck)-invasive (inv) variant cells were purified on 1-microm pore polycarbonate filters that selectively allow passage of the pseudopodial domains but not the cell body. the purified pseudopodial fraction contains phosphotyrosinated proteins, including met and fak, and various signaling proteins, including raf1, mek1, erk2, pkbalpha (akt1), gsk3alpha, gsk3beta, rb, and stat3. pseudopodial proteins identified b ... | 2005 | 15985431 |
| the evolutionary value of recombination is constrained by genome modularity. | genetic recombination is a fundamental evolutionary mechanism promoting biological adaptation. using engineered recombinants of the small single-stranded dna plant virus, maize streak virus (msv), we experimentally demonstrate that fragments of genetic material only function optimally if they reside within genomes similar to those in which they evolved. the degree of similarity necessary for optimal functionality is correlated with the complexity of intragenomic interaction networks within which ... | 2005 | 16244707 |
| antiviral potential of a new generation of acyclic nucleoside phosphonates, the 6-[2-(phosphonomethoxy)alkoxy]-2,4-diaminopyrimidines. | three acyclic nucleoside phosphonates (anps) have been formally approved for clinical use in the treatment of 1) cytomegalovirus retinitis in aids patients (cidofovir, by the intravenous route), 2) chronic hepatitis b virus (hbv) infections (adefovir dipivoxil, by the oral route), and 3) human immunodeficiency virus (hiv) infections (tenofovir disoproxil fumarate, by the oral route). the activity spectrum of cidofovir {(s)- 1-[3-hydroxy-2-(phosphonomethoxy)propyl]cytosine [(s)-hpmpc)]}, like tha ... | 2005 | 16247948 |
| visualization of a primary anti-tumor immune response by positron emission tomography. | current methodologies that monitor immune responses rely on invasive techniques that sample tissues at a given point in time. new technologies are needed to elucidate the temporal patterns of immune responses and the spatial distribution of immune cells on a whole-body scale. we describe a noninvasive, quantitative, and tomographic approach to visualize a primary anti-tumor immune response by using positron emission tomography (pet). bone marrow chimeric mice were generated by engraftment of hem ... | 2005 | 16293690 |
| restoration of native folding of single-stranded dna sequences through reverse mutations: an indication of a new epigenetic mechanism. | we used in vivo (biological), in silico (computational structure prediction), and in vitro (model sequence folding) analyses of single-stranded dna sequences to show that nucleic acid folding conservation is the selective principle behind a high-frequency single-nucleotide reversion observed in a three-nucleotide mutated motif of the maize streak virus replication associated protein (rep) gene. in silico and in vitro studies showed that the three-nucleotide mutation adversely affected rep nuclei ... | 2006 | 16427599 |
| rho/rock-dependent pseudopodial protrusion and cellular blebbing are regulated by p38 mapk in tumour cells exhibiting autocrine c-met activation. | the c-met-dependent, beta-actin-rich, blebbed pseudopodia of msv-mdck-inv (invasive moloney-sarcoma-virus-transformed madin-darby canine kidney) cells are induced by rho/rock (rho kinase) activation, and are morphologically distinct from flat extended lamellipodia. | 2006 | 16448388 |
| the intergenic region of maize streak virus contains promoter elements involved in rightward transcription of the viral genome. | maize streak virus (msv), a geminivirus with a one-component genome, encodes a major coat protein rna which accumulates in infected plants. using a maize protoplast cell transient expression system, we have defined and studied the promoter which drives rightward transcription of the rna encoding the coat protein. we have identified a 122 bp upstream segment that enhances promoter activity and functions as an upstream activating sequence (uas). the uas lies in the starting intergenic region of th ... | 1988 | 16453851 |
| maize streak virus genes essential for systemic spread and symptom development. | the entire genome of single component geminiviruses such as maize streak virus (msv) consists of a single-stranded circular dna of ~2.7 kb. although this size is sufficient to encode only three average sized proteins, the virus is capable of causing severe disease of many monocots with symptoms of chlorosis and stunting. we have identified viral gene functions essential for systemic spread and symptom development during msv infection. deletions and gene replacement mutants were created by site-d ... | 1989 | 16453874 |
| fluvastatin does not elevate periosteal osteogenesis induce by moloney sarcoma virus (msv) in mice. | several studies have demonstrated the pleiotropic effects of statins. since wang and associates reported that in rabbits lovastatin reduced steroid-induced bone loss, numerous authors have confirmed these data, however, others have reported conflicting results. in this study, the effects of fluvastatin on bone formation were investigated in early and late phase of osteogenesis. in the first set of experiments (early phase of osteogenesis) cfw/ll mice were randomly divided into three groups. two ... | 2006 | 16531631 |
| molecular ecology and emergence of tropical plant viruses. | an appreciation of the risks caused by emergent plant viruses is critical in tropical areas that rely heavily on agriculture for subsistence and rural livelihood. molecular ecology, within 10 years, has unraveled the factors responsible for the emergence of several of the economically most important tropical plant viruses: rice yellow mottle virus (rymv), cassava mosaic geminiviruses (cmgs), maize streak virus (msv), and banana streak virus (bsv). a large range of mechanisms--most unsuspected un ... | 2006 | 16784403 |
| pronounced in vitro and in vivo antiretroviral activity of 5-substituted 2,4-diamino-6-[2-(phosphonomethoxy)ethoxy] pyrimidines. | to discover new potent and selective anti-human immunodeficiency virus (hiv) acyclic nucleoside phosphonate (anp) drugs with in vivo antiretroviral activity. | 2007 | 17124193 |
| inhibition of maize streak virus (msv) replication by transient and transgenic expression of msv replication-associated protein mutants. | maize streak disease is a severe agricultural problem in africa and the development of maize genotypes resistant to the causal agent, maize streak virus (msv), is a priority. a transgenic approach to engineering msv-resistant maize was developed and tested in this study. a pathogen-derived resistance strategy was adopted by using targeted deletions and nucleotide-substitution mutants of the multifunctional msv replication-associated protein gene (rep). various rep gene constructs were tested for ... | 2007 | 17170465 |
| successful application of fta classic card technology and use of bacteriophage phi29 dna polymerase for large-scale field sampling and cloning of complete maize streak virus genomes. | leaf samples from 155 maize streak virus (msv)-infected maize plants were collected from 155 farmers' fields in 23 districts in uganda in may/june 2005 by leaf-pressing infected samples onto fta classic cards. viral dna was successfully extracted from cards stored at room temperature for 9 months. the diversity of 127 msv isolates was analysed by pcr-generated rflps. six representative isolates having different rflp patterns and causing either severe, moderate or mild disease symptoms, were chos ... | 2007 | 17174409 |
| study of the virulence and cross-neutralization capability of recent porcine parvovirus field isolates and vaccine viruses in experimentally infected pregnant gilts. | the pathogenicity of two recent german field isolates of porcine parvovirus (ppv-27a and ppv-143a) and two vaccine viruses [ppv-nadl-2 and ppv-idt (msv)], which are used for the production of inactivated vaccines, was investigated by inoculation of pregnant sows at day 40 of gestation. post-infection sera of these sows as well as antisera prepared in rabbits by immunization with the four above-mentioned ppv isolates and with the virulent strain ppv-challenge (engl.) were tested for their homolog ... | 2007 | 17251558 |
| inhibition of human immunodeficiency virus type 1 transcription by n-aminoimidazole derivatives. | this study describes the mechanism of antiviral action of the n-aminoimidazole derivatives which exclusively inhibit retroviruses such as hiv-1, hiv-2, siv and msv. these antiretroviral compounds, with lead prototype nr-818, were found to inhibit hiv-1 replication at the transcriptional level. analysis of each individual step of viral transcription, including transcriptional activation mediated by nf-kappab, the chromatin remodeling process at the viral promoter and viral mrna transcription medi ... | 2007 | 17459445 |
| identification of long intergenic region sequences involved in maize streak virus replication. | the main cis-acting control regions for replication of the single-stranded dna genome of maize streak virus (msv) are believed to reside within an approximately 310 nt long intergenic region (lir). however, neither the minimum lir sequence required nor the sequence determinants of replication specificity have been determined experimentally. there are iterated sequences, or iterons, both within the conserved inverted-repeat sequences with the potential to form a stem-loop structure at the origin ... | 2007 | 17485545 |
| identification of protein kinase c as an intermediate in na,k-atpase beta-subunit mediated lamellipodia formation and suppression of cell motility in carcinoma cells. | we have shown that repletion of na,k-atpase beta1-subunit (na,k-beta) in moloney sarcoma virus transformed mdck (msv-na,k-beta) cells induced lamellipodia and suppressed motility in a pi3-kinase dependent manner. in this study, we provide evidence that decreased cell motility is due to increased attachment of na,k-beta expressing cells to the substratum. treatment of msv-beta-gfp cells with bisindolylmalemide, a general protein kinase c (pkc) inhibitor, abolished pi3-kinase activation and its do ... | 2006 | 17535735 |
| the role of biotechnology for agricultural sustainability in africa. | sub-saharan africa could have a shortfall of nearly 90mt of cereals by the year 2025 if current agricultural practices are maintained. biotechnology is one of the ways to improve agricultural production. insect-resistant varieties of maize and cotton suitable for the subcontinent have been identified as already having a significant impact. virus-resistant crops are under development. these include maize resistant to the african endemic maize streak virus and cassava resistant to african cassava ... | 2008 | 17761472 |
| maize streak virus-resistant transgenic maize: a first for africa. | in this article, we report transgene-derived resistance in maize to the severe pathogen maize streak virus (msv). the mutated msv replication-associated protein gene that was used to transform maize showed stable expression to the fourth generation. transgenic t2 and t3 plants displayed a significant delay in symptom development, a decrease in symptom severity and higher survival rates than non-transgenic plants after msv challenge, as did a transgenic hybrid made by crossing t2 hi-ii with the w ... | 2007 | 17924935 |
| genetic analysis of maize streak virus isolates from uganda reveals widespread distribution of a recombinant variant. | maize streak virus (msv) contributes significantly to the problem of extremely low african maize yields. whilst a diverse range of msv and msv-like viruses are endemic in sub-saharan africa and neighbouring islands, only a single group of maize-adapted variants - msv subtypes a(1)-a(6) - causes severe enough disease in maize to influence yields substantially. in order to assist in designing effective strategies to control msv in maize, a large survey covering 155 locations was conducted to asses ... | 2007 | 17947543 |
| panicum streak virus diversity is similar to that observed for maize streak virus. | | 2008 | 18172570 |
| novel sugarcane streak and sugarcane streak réunion mastreviruses from southern africa and la réunion. | the sugarcane infecting streak viruses (sisvs) are mastreviruses (family geminiviridae) belonging to a group of "african streak viruses" (afsvs) that includes the economically devastating maize streak virus (msv). although there are three currently described sisv species (sugarcane streak virus [ssv], sugarcane streak egypt virus [ssev] and sugarcane streak réunion virus [ssrv]), only one strain variant has been fully sequenced for each of these species and as a result very little is known about ... | 2008 | 18175043 |
| evidence for a potential tumor suppressor role for the na,k-atpase beta1-subunit. | the na,k-atpase, consisting of two essential subunits (alpha, beta), plays a critical role in the regulation of ion homeostasis in mammalian cells. recent studies indicate that reduced expression of the beta1 isoform (nak-beta1) is commonly observed in carcinoma and is associated with events involved in cancer progression. in this study, we present evidence that repletion of nak-beta1 in moloney sarcoma virus-transformed madin-darby canine kidney cells (msv-mdck), a highly tumorigenic cell line, ... | 2008 | 18228203 |
| a protocol for the rapid isolation of full geminivirus genomes from dried plant tissue. | a high-throughput method of isolating and cloning geminivirus genomes from dried plant material, by combining an extract-n-amp-based dna isolation technique with rolling circle amplification (rca) of viral dna, is presented. using this method an attempt was made to isolate and clone full geminivirus genomes/genome components from 102 plant samples, including dried leaves stored at room temperature for between 6 months and 10 years, with an average hands-on-time to rca-ready dna of 15 min per 20 ... | 2008 | 18280590 |
| viral protein-nucleic acid interaction: south (north)-western blot. | maize streak virus (msv) genome has four open reading frames. c1 and c2 encoded by the complementary sense are required for virus replication, while v1 and v2 encoded by virion sense are required for infectivity. v1 encodes movement protein (mp), while v2 encodes coat protein (cp). deletion or mutation of msv cp does not prevent virus replication in single cells or protoplasts but leads to a loss of infectivity in the inoculated plant suggesting that msv cp is required for virus movement. toward ... | 2008 | 18370271 |
| viable chimaeric viruses confirm the biological importance of sequence specific maize streak virus movement protein and coat protein interactions. | a variety of interactions between up to three different movement proteins (mps), the coat protein (cp) and genomic dna mediate the inter- and intra-cellular movement of geminiviruses in the genus begomovirus. although movement of viruses in the genus mastrevirus is less well characterized, direct interactions between a single mp and the cp of these viruses is also clearly involved in both intra- and intercellular trafficking of virus genomic dna. however, it is currently unknown how specific the ... | 2008 | 18489800 |
| a new african streak virus species from nigeria. | the african streak viruses (afsvs) are a diverse group of mastrevirus species (family geminiviridae) that infect a wide variety of annual and perennial grass species across the african continent and its nearby indian ocean islands. six afsv species (of which maize streak virus is the best known) have been described. here we report the full genome sequences of eight isolates of a seventh afsv species: urochloa streak virus (usv), sampled from various locations in nigeria. despite there being good ... | 2008 | 18521534 |
| infection and transformation of dog cells with a modified sarcoma virus. | dog-embryo cell cultures were infected with a mixture of feline leukemia virus (fellv) and a modified murine (moloney) sarcoma virus msv(fellv). morphological alteration of the cells was observed 3 days post infection. virus progeny from the infected cultures increased 50- to 100-fold in foci of cellular alteration on dog cell cultures pretreated with diethylaminoethyl-dextran, but only twofold on cat embryo cultures similarly treated. the numbers of foci produced corresponded to a dual infectio ... | 1970 | 18605433 |
| revertants of mouse cells transformed by murine sarcoma virus. iii. metastable expression of virus functions in revertants retransformed by murine sarcoma virus. | 3t3fl cells transformed by the moloney murine sarcoma virus (msv) (sarcoma positive, leukemia negative, s+l- cells) segregate spontaneous flat revertants. these s-l- revertants do not release msv upon superinfection with mulv but are susceptible to a second cycle of single-hit msv transformation. the behavior and nature of second-cycle msv transformed revertants were followed by successive clonal generations. the second transformation by msv resulted in a number of metastable states. the simples ... | 1974 | 18620232 |
| murine sarcoma virus defectiveness. viral polymerase expression in murine and nonmurine host cells transformed by s + l - type murine sarcoma virus. | sarcoma virus-positive, leukemia virus-negative (s + l -) mouse cells transformed by defective but rescuable murine sarcoma virus (msv) release noninfectious type c virions with a quantitative deficiency of viral-type rna-dependent dna polymerase (rddp). human s + l - cells containing the same genome fail to express any detectable viral-type reverse transcriptase. to study this difference in msv expression, second-generation msv from the s + l - human cells is recloned in dog, mink, and back int ... | 1975 | 18621353 |
| recombination, decreased host specificity and increased mobility may have driven the emergence of maize streak virus as an agricultural pathogen. | maize streak virus (msv; family geminiviridae, genus mastrevirus), the causal agent of maize streak disease, ranks amongst the most serious biological threats to food security in subsaharan africa. although five distinct msv strains have been currently described, only one of these - msv-a - causes severe disease in maize. due primarily to their not being an obvious threat to agriculture, very little is known about the 'grass-adapted' msv strains, msv-b, -c, -d and -e. since comparing the genetic ... | 2008 | 18753214 |
| experimental observations of rapid maize streak virus evolution reveal a strand-specific nucleotide substitution bias. | recent reports have indicated that single-stranded dna (ssdna) viruses in the taxonomic families geminiviridae, parvoviridae and anellovirus may be evolving at rates of approximately 10(-4) substitutions per site per year (subs/site/year). these evolution rates are similar to those of rna viruses and are surprisingly high given that ssdna virus replication involves host dna polymerases with fidelities approximately 10,000 times greater than those of error-prone viral rna polymerases. although hi ... | 2008 | 18816368 |
| spatial and temporal distribution of geminiviruses in leafhoppers of the genus cicadulina monitored by conventional and quantitative polymerase chain reaction. | abstract spatial and temporal distribution of maize streak virus (msv, family geminiviridae, genus mastrevirus) was monitored in the vector species cicadulina mbila and the nonvector species c. chinaï using conventional and real-time quantitative polymerase chain reaction. sustained feeding on msv-infected plants showed that virus accumulation reaches a maximum in c. chinaï, but not in c. mbila. after a 3-day acquisition access feeding period (aap), msv was detected in the gut, the hemolymph, an ... | 2002 | 18944141 |
| biological and genomic sequence characterization of maize streak virus isolates from wheat. | abstract maize streak virus (msv) is best known as the causal agent of maize streak disease. however, only a genetically uniform subset of the viruses within this diverse species is actually capable of producing severe symptoms in maize. whereas these "maize-type" viruses all share greater than 95% sequence identity, msv strains isolated from grasses may share as little as 79% sequence identity with the maize-type viruses. here, we present the complete genome sequences and biological characteriz ... | 2002 | 18944143 |
| evaluation of maize streak virus pathogenicity in differentially resistant zea mays genotypes. | abstract we devised a rapid technique for the objective and precise assessment of both the pathogenicity of maize streak virus (msv) isolates and the msv resistance of maize genotypes. the technique involves the use of agroinoculation to infect maize seedlings and the objective symptom evaluation by quantification of infection rates, stunting, and chlorotic leaf areas. in assessing the msv resistance of 19 maize genotypes, we describe how the use of differentially virulent virus isolates enables ... | 1999 | 18944683 |
| microcomputer-based quantification of maize streak virus symptoms in zea mays. | abstract we investigated the use of computer-assisted image analysis techniques for the objective quantification of maize streak virus (msv) symptoms in zea mays. we compared independent duplicate evaluations of chlorotic lesion areas occurring on msv-infected leaves using visual assessment, a commercial image analysis system, and a custom image analysis system employing software developed in our laboratory. relative to visual assessments of disease severity, computer-assisted image analysis emp ... | 1998 | 18944921 |
| assessment of codivergence of mastreviruses with their plant hosts. | viruses that have spent most of their evolutionary time associated with a single host lineage should have sequences that reflect codivergence of virus and host. several examples for rna viruses of host-virus tree congruence are being challenged. dna viruses, such as mastreviruses, are more likely than rna viruses to have maintained a record of host lineage association. | 2008 | 19094195 |
| large accumulations of maize streak virus in the filter chamber and midgut cells of the leafhopper vector cicadulina mbila. | maize streak virus (msv, mastrevirus, geminiviridae) is persistently transmitted by cicadulina mbila, apparently without propagation in its leafhopper vector. msv was shown earlier by quantitative pcr to accumulate in the alimentary canal of c. mbila. we examined the alimentary canals of c. mbila leafhoppers that acquired msv from diseased plants for various acquisition access periods (aap) by immunofluorescence confocal laser scanning microscopy (iclsm) and by immunogold labelling transmission ... | 2009 | 19151912 |
| rapid host adaptation by extensive recombination. | experimental investigations into virus recombination can provide valuable insights into the biochemical mechanisms and the evolutionary value of this fundamental biological process. here, we describe an experimental scheme for studying recombination that should be applicable to any recombinogenic viruses amenable to the production of synthetic infectious genomes. our approach is based on differences in fitness that generally exist between synthetic chimaeric genomes and the wild-type viruses fro ... | 2009 | 19218220 |
| experimental evidence indicating that mastreviruses probably did not co-diverge with their hosts. | 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 may have co-diverged with their hosts over millions of years. this "co-divergence hypothesis" requires that long-term mastrevirus substitution rates be at least 100,000-fold lower than their basal mutation rates and 10,000-fold lower than their observable short-term subs ... | 2009 | 19607673 |
| dating the origins of the maize-adapted strain of maize streak virus, msv-a. | maize streak virus (msv), which causes maize streak disease (msd), is one of the most serious biotic threats to african food security. here, we use whole msv genomes sampled over 30 years to estimate the dates of key evolutionary events in the 500 year association of msv and maize. the substitution rates implied by our analyses agree closely with those estimated previously in controlled msv evolution experiments, and we use them to infer the date when the maize-adapted strain, msv-a, was generat ... | 2009 | 19692547 |
| a novel sugarcane-infecting mastrevirus from south africa. | the sugarcane-infecting streak viruses (sisvs) are a diverse collection of mastreviruses (family geminiviridae) within the african streak virus group. four sisvs have currently been described, including the well-characterized maize streak virus. here, we present a full annotated sequence record of an isolate of a new sisv species, saccharum streak virus (sacsv), isolated in south africa. the isolate shares less than 66% identity with any other mastrevirus, but is most closely related to urochloa ... | 2009 | 19756359 |
| immune complex disease in chronic viral infections. | chronic viral infections of animals associated with immune complex disease resemble a number of human disorders. at present, on the basis of showing (a) virus, host antiviral antibody, and c3 deposited in a granular pattern along the glomerular capillary wall and in the mesangia and (b) virus-host ig (presumably antiviral antibody) complexes in the circulation, immune complex disease occurs in chronic murine infections with lcm, ldv, msv, and adm. in addition, granular deposits in the glomeruli ... | 1971 | 19867377 |
| comparative analysis of panicum streak virus and maize streak virus diversity, recombination patterns and phylogeography. | 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 species, largely overlapping natural host ranges and similar geographical distributions across africa and its associated indian ocean islands. unlike msv, however, pansv has no known economic relevance. | 2009 | 19903330 |
| replicative intermediates of maize streak virus found during leaf development. | geminiviruses of the genera begomovirus and curtovirus utilize three replication modes: complementary-strand replication (csr), rolling-circle replication (rcr) and recombination-dependent replication (rdr). using two-dimensional gel electrophoresis, we now show for the first time that maize streak virus (msv), the type member of the most divergent geminivirus genus, mastrevirus, does the same. although mastreviruses have fewer regulatory genes than other geminiviruses and uniquely express their ... | 2010 | 20032206 |
| maize streak virus: an old and complex 'emerging' pathogen. | 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 in the genus cicadulina, but mainly by c. mbila naudé and c. storeyi. in addition to maize, it can infect over 80 other species in the family poaceae. whereas 11 strains of msv are currently known, only the msv-a strain is known to cause economically sign ... | 2010 | 20078771 |
| peripheral blood and lymphatic organs in balb/c mice during the progressive and regressive phases of moloney sarcoma development. | blood cell counts, differential blood cell counts and weights of the spleen and peripheral lymph nodes draining the area of lesions induced by moloney sarcoma virus inoculation into the quadriceps shank muscles of inbred balb/c mice were examined at various stages of tumor development and regression. the blood cell count remained constant through the observation period up to 27 days post tumor development and regression. differential counts revealed some changes in the cellular composition of th ... | 2010 | 20420189 |
| activation of geminivirus v-sense promoters in roots is restricted to nematode feeding sites. | obligate sedentary endoparasitic nematodes, such as the root-knot and cyst nematodes, elicit the differentiation of specialized nematode nurse or feeding cells [nematode feeding sites (nfs), giant cells and syncytia, respectively]. during nfs differentiation, marked changes in cell cycle progression occur, partly similar to those induced by some geminiviruses. in this work, we describe the activation of v-sense promoters from the maize streak virus (msv) and wheat dwarf virus (wdv) in nfs formed ... | 2010 | 20447288 |
| a single amino acid change in the coat protein of maize streak virus abolishes systemic infection, but not interaction with viral dna or movement protein. | summary functional coat protein (cp) is important for host plant infection by monopartite geminiviruses. we identified a proline-cysteine-lysine (pck) motif at amino acids 180-182 of the maize streak virus (msv) cp that is conserved in most of the cereal-infecting mastreviruses. substitution of the lysine (k) with a valine (v) in the cp of msv to produce mutant msvcp182v abolished systemic infection in maize plants, although the mutant replicated around the inoculation site and, unlike other msv ... | 2001 | 20573010 |
| effects of time of initial exposure to msv sarcoma on bone induction by dentine matrix implants and on orthotopic femora. | hcl-demineralized murine lower incisors were implanted intramuscularly into syngeneic balb/c mice to induce heterotopic osteogenesis. implants were exposed at the early, preosteogenic stage (4), or at the later, osteogenic stage (12) to the moloney sarcoma virus (msv), which within 3-4 days results in a sarcoma. the yield of bone induction was determined by weight of dry bone mass following naoh hydrolysis of soft tissues. to verify the effect of this sarcoma on orthotopic local femoral bone, th ... | 2010 | 20957093 |
| behavioral responses of the leafhopper, cicadulina storeyi china, a major vector of maize streak virus, to volatile cues from intact and leafhopper-damaged maize. | the chemical ecology of the leafhopper, cicadulina storeyi china (homoptera: cicadellidae), an important vector of maize streak virus (msv), was studied with a view to developing novel leafhopper control strategies in sub-saharan africa. choice tests using a y-tube olfactometer revealed that odors from uninfested maize seedlings (zea mays cv. delprim) were significantly more attractive to c. storeyi than odors from c. storeyi-infested seedlings. headspace samples of volatile organic compounds (v ... | 2010 | 21191806 |
| synthesis and antiviral activity of n9-[3-fluoro-2-(phosphonomethoxy)propyl] analogues derived from n6-substituted adenines and 2,6-diaminopurines. | an efficient method for the synthesis of n(9)-[3-fluoro-2-(phosphonomethoxy)propyl] (fpmp) derivatives of purine bases has been developed. both (r)- and (s)-enantiomers of the n(6)-substituted fpmp derivatives of adenine and 2,6-diaminopurine were prepared and their anti-human immunodeficiency virus (hiv) and anti-moloney murine sarcoma virus (msv) activity was evaluated. whereas none of the 6-substituted fpmpa derivatives showed any antiviral activity, several fpmpdap derivatives had a moderate ... | 2011 | 21429755 |
| a rep-based hairpin inhibits replication of diverse maize streak virus isolates in a transient assay. | maize streak disease, caused by the a-strain of the african endemic geminivirus, maize streak mastrevirus (msv-a), threatens the food security and livelihoods of subsistence farmers throughout sub-saharan africa. using a well-established transient expression assay, we investigated the potential of a spliceable-intron hairpin rna (hprna) approach to interfere with msv replication. two strategies were explored: (1) an inverted repeat of a 662-bp portion of the msv replication-associated protein ge ... | 2011 | 21653753 |
| reconstructing the history of maize streak virus strain a dispersal to reveal diversification hot spots and its origin in southern africa. | maize streak virus strain a (msv-a), the causal agent of maize streak disease, is today one of the most serious biotic threats to african food security. determining where msv-a originated and how it spread transcontinentally could yield valuable insights into its historical emergence as a crop pathogen. similarly, determining where the major extant msv-a lineages arose could identify geographical hot spots of msv evolution. here, we use model-based phylogeographic analyses of 353 fully sequenced ... | 2011 | 21715477 |
| Recombination hotspots and host susceptibility modulate the adaptive value of recombination during maize streak virus evolution. | ABSTRACT: BACKGROUND: Maize streak virus -strain A (MSV-A; Genus Mastrevirus, Family Geminiviridae), the maize-adapted strain of MSV that causes maize streak disease throughout sub-Saharan Africa, probably arose between 100 and 200 years ago via homologous recombination between two MSV strains adapted to wild grasses. MSV recombination experiments and analyses of natural MSV recombination patterns have revealed that this recombination event entailed the exchange of the movement protein - coat p ... | 2011 | 22136133 |
| adaptive evolution by recombination is not associated with increased mutation rates in maize streak virus. | 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 genomes are replicated in host nuclei by high fidelity host polymerases. although strand specific mutation biases observed in virus species from the geminivirus genus mastrevirus indicate that the high mutation rates in viruses in this genus may be due to mutational proce ... | 2012 | 23268599 |
| computer analysis identifies sequence homologies between potential gene products of maize streak virus and those of cassava latent virus and tomato golden mosaic virus. | the amino acid sequences of the putative polypeptides of maize streak virus (msv) have been systematically compared with those of cassava latent virus (clv) and tomato golden mosaic virus (tgmv) using the programme diagon (8).conserved sequences have been detected between peptides encoded by the complementary (-) sense of msv and those of clv and tgmv, viz; the 40 200 mr polypeptide of clv-1 (3) and the 40 285 mr polypeptide of tgmv-a (4) show extensive homologies with the 17 768 mr and 31 388 m ... | 1985 | 24306572 |
| detection of a non-structural protein of m r 11 000 encoded by the virion dna of maize streak virus. | a polypeptide of approximately 11 000 daltons (11 kda protein) encoded by an open reading frame (10.9 orf) from the virion sense of maize streak virus (msv) dna has been detected among the products of in vitro translation reactions programmed with rna from infected maize plants and also in total protein extracts from infected leaves. the 11 kda protein has not been detected in virions and is therefore proposed to have a nonstructural role.viral dna with an additional in-frame translation stop co ... | 1988 | 24272158 |
| identification and molecular characterization of a novel sugarcane streak mastrevirus and an isolate of the a-strain of maize streak virus from sugarcane in nigeria. | sugarcane and maize plants showing symptoms typical of those described for the so-called "african streak viruses" (afsvs) were encountered during field surveys conducted from february to july 2015 to document viruses infecting both crops across the northern guinea savannah region of nigeria. as part of this study, two categories of complete mastrevirus-like genome sequences were obtained from nine samples (maize = 2; sugarcane = 7). in pairwise comparisons, the full-length genomes of the first s ... | 2017 | 27815694 |
| the role of kenya in the trans-african spread of maize streak virus strain a. | maize streak virus (msv), the causal agent of maize streak disease (msd), is the most important viral pathogen of africa's staple food crop, maize. previous phylogeographic analyses have revealed that the most widely-distributed and common msv variant, msv-a1, has been repeatedly traversing africa over the past fifty years with long-range movements departing from either the lake victoria region of east africa, or the region around the convergence of zimbabwe, south africa and mozambique in south ... | 2017 | 28192163 |
| fine mapping of msv1, a major qtl for resistance to maize streak virus leads to development of production markers for breeding pipelines. | msv1 , the major qtl for msv resistance was delimited to an interval of 0.87 cm on chromosome 1 at 87 mb and production markers with high prediction accuracy were developed. maize streak virus (msv) disease is a devastating disease in the sub-saharan africa (ssa), which causes significant yield loss in maize. resistance to msv has previously been mapped to a major qtl (msv1) on chromosome 1 that is germplasm and environment independent and to several minor loci elsewhere in the genome. in this s ... | 2015 | 26081946 |
| mapping the distribution of maize streak virus genotypes across the forest and transition zones of ghana. | throughout sub-saharan africa, maize streak virus strain a (msv-a), the causal agent of maize streak disease (msd), is an important biological constraint on maize production. in november/december 2010, an msd survey was carried out in the forest and transition zones of ghana in order to obtain msv-a virulence sources for the development of msd-resistant maize genotypes with agronomic properties suitable for these regions. in 79 well-distributed maize fields, the mean msd incidence was 18.544 % a ... | 2015 | 25344899 |
| inducible resistance to maize streak virus. | maize streak virus (msv), which causes maize streak disease (msd), is the major viral pathogenic constraint on maize production in africa. type member of the mastrevirus genus in the family geminiviridae, msv has a 2.7 kb, single-stranded circular dna genome encoding a coat protein, movement protein, and the two replication-associated proteins rep and repa. while we have previously developed msv-resistant transgenic maize lines constitutively expressing "dominant negative mutant" versions of the ... | 2014 | 25166274 |
| a high degree of african streak virus diversity within nigerian maize fields includes a new mastrevirus from axonopus compressus. | the a-strain of maize streak virus (msv-a; genus mastrevirus, family geminiviridae), the causal agent of maize streak disease, places a major constraint on maize production throughout sub-saharan africa. in west-african countries such as nigeria, where maize is not cultivated year-round, this msv strain is forced to overwinter in non-maize hosts. in order to both identify uncultivated grasses that might harbour msv-a during the winter season and further characterise the diversity of related maiz ... | 2014 | 24796552 |
| extensive recombination-induced disruption of genetic interactions is highly deleterious but can be partially reversed by small numbers of secondary recombination events. | although homologous recombination can potentially provide viruses with vastly more evolutionary options than are available through mutation alone, there are considerable limits on the adaptive potential of this important evolutionary process. primary among these is the disruption of favorable coevolved genetic interactions that can occur following the transfer of foreign genetic material into a genome. although the fitness costs of such disruptions can be severe, in some cases they can be rapidl ... | 2014 | 24789787 |
| priming of production in maize of volatile organic defence compounds by the natural plant activator cis-jasmone. | cis-jasmone (cj) is a natural plant product that activates defence against herbivores in model and crop plants. in this study, we investigated whether cj could prime defence in maize, zea mays, against the leafhopper, cicadulina storeyi, responsible for the transmission of maize streak virus (msv). priming occurs when a pre-treatment, in this case cj, increases the potency and speed of a defence response upon subsequent attack on the plant. here, we tested insect responses to plant volatile orga ... | 2013 | 23840295 |
| replication modes of maize streak virus mutants lacking repa or the repa-prbr interaction motif. | the plant-infecting mastreviruses (family geminiviridae) express two distinct replication-initiator proteins, rep and repa. although repa is essential for systemic infectivity, little is known about its precise function. we therefore investigated its role in replication using 2d-gel electrophoresis to discriminate the replicative forms of maize streak virus (msv) mutants that either fail to express repa (repa(-)), or express repa that is unable to bind the plant retinoblastoma related protein, p ... | 2013 | 23679984 |
| a novel maize-infecting mastrevirus from la réunion island. | despite extensive sampling, only one virus belonging to the genus mastrevirus of the family geminiviridae, maize streak virus (msv), has until now been detected in maize with maize streak disease (msd) symptoms. here, we report for the first time a second, highly divergent, mastrevirus isolated from two maize plants displaying characteristic msd-like symptoms, sampled on the south-west indian ocean island, la réunion. the two isolates shared <57 % genome-wide identity with all other known mastre ... | 2012 | 22543634 |
| molecular characterisation of dicot-infecting mastreviruses from australia. | monocotyledonous and dicotyledonous plant infecting mastreviruses threaten various agricultural systems throughout africa, eurasia and australasia. in australia three distinct mastrevirus species are known to infect dicotyledonous hosts such as chickpea, bean and tobacco. amongst 34 new "dicot-infecting" mastrevirus full genome sequences obtained from these hosts we discovered one new species, four new strains, and various variants of previously described mastrevirus species. besides providing a ... | 2012 | 22406325 |
| genetic mapping of maize streak virus resistance from the mascarene source. ii. resistance in line cirad390 and stability across germplasm. | the streak disease has a major effect on maize in sub-saharan africa. various genetic factors for resistance to the virus have been identified and mapped in several populations; these factors derive from different sources of resistance. we have focused on the réunion island source and have recently identified several factors in the d211 line. a second very resistant line, cirad390, was crossed to the same susceptible parent, b73. the linkage map comprised 124 rflp markers, of which 79 were commo ... | 1999 | 22665188 |
| genetic mapping of maize streak virus resistance from the mascarene source. i. resistance in line d211 and stability against different virus clones. | maize streak virus (msv) disease may cause significant grain yield reductions in maize in africa. réunion island maize germplasm is a proven source of strong resistance. its genetic control was investigated using 123 rflp markers in an f(2) population of d211 (resistant) × b73 (susceptible). this population of 165 f(2:3) families was carefully evaluated in harare (zimbabwe) and in réunion. artificial infestation was done with viruliferous leafhoppers. each plant was rated weekly six times after ... | 1999 | 22665187 |
| specificity of agrobacterium-mediated delivery of maize streak virus dna to members of the gramineae. | parameters affecting the efficiency of agroinfection of maize streak virus (msv) in maize have been determined. monomeric units, cloned at a number of sites in the msv genome were not infectious but multimeric units containing partial duplications were equally as infectious as complete tandem dimeric clones. inoculation of tandem dimeric units conjugated into different strains of agrobacterium showed that both a. tumefaciens and a. rhizogenes were able to transfer dna to maize and this ability w ... | 1989 | 24272715 |
| molecular diversity, geographic distribution and host range of monocot-infecting mastreviruses in africa and surrounding islands. | maize streak virus (msv), an important pathogen of maize in africa, is the most extensively studied member of the mastrevirus genus in the family geminiviridae. comparatively little is known about other monocot-infecting african mastreviruses, most of which infect uncultivated grasses. here we determine the complete sequences of 134 full african mastrevirus genomes from predominantly uncultivated poaceae species. based on established taxonomic guidelines for the genus mastrevirus, these genomes ... | 2017 | 28687345 |
| quasicrystalline and crystalline types of local protein order in capsids of small viruses. | like metal alloys and micellar systems in soft matter, the viral capsid structures can be of crystalline and quasicrystalline types. we reveal the local quasicrystalline order of proteins in small spherical viral capsids using their nets of dodecahedral type. we show that the structure of some of the viral shells is well described in terms of a chiral pentagonal tiling, whose nodes coincide with centers of mass of protein molecules. the chiral protein packing found in these capsids originates fr ... | 2017 | 28488589 |