Sample records for maize streak disease

  1. The epidemiology, economic impact and control of maize streak disease

    Microsoft Academic Search

    Darren P. Martin; Dionne N. Shepherd

    2009-01-01

    Maize streak virus (MSV), the causal agent of maize streak disease (MSD), is one of the most significant biological threats\\u000a to food security in sub-Saharan Africa. By reducing yields of Africa’s most important food crop, it seriously undermines the\\u000a already precarious social and economic wellbeing of subsistence farmers throughout the continent. Despite the availability\\u000a of MSD control strategies—ranging from good

  2. MAIZE FINE STREAK VIRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The report outlines the salient features of maize fine streak virus (MFSV) including a general description of the causal virus species, virion properties, genome description, the relationship of the virus to other taxa, biological properties of the disease and agronomic aspects of the disease. Maize...

  3. Wheat streak mosaic virus lacking HC-Pro is competent to produce disease synergism in mixed infections with Maize chlorotic mottle virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Single infections of maize plants with the tritimovirus Wheat streak mosaic virus (WSMV) or the machlomovirus Maize chlorotic mottle virus (MCMV) are characterized by systemic chlorosis but not necrosis. Co-infection of maize with both viruses results in disease synergism and induction of corn leth...

  4. A high degree of African streak virus diversity within Nigerian maize fields includes a new mastrevirus from Axonopus compressus.

    PubMed

    Oluwafemi, Sunday; Kraberger, Simona; Shepherd, Dionne N; Martin, Darren P; Varsani, Arvind

    2014-10-01

    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 maize-associated streak viruses, we collected maize and grass samples displaying streak symptoms in a number of Nigerian maize fields. From these we isolated and cloned 18 full mastrevirus genomes (seven from maize and 11 from various wild grass species). Although only MSV-A isolates were obtained from maize, both MSV-A and MSV-F isolates were obtained from Digitaria ciliaris. Four non-MSV African streak viruses were also sampled, including sugarcane streak Reunion virus and Urochloa streak virus (USV) from Eleusine coacana, USV from Urochloa sp., maize streak Reunion virus (MSRV) from both Setaria barbata and Rottboellia sp., and a novel highly divergent mastrevirus from Axonopus compressus, which we have tentatively named Axonopus compressus streak virus (ACSV). Besides the discovery of this new mastrevirus species and expanding the known geographical and host ranges of MSRV, we have added D. ciliaris to the list of uncultivated species within which Nigerian MSV-A isolates are possibly able to overwinter. PMID:24796552

  5. INFECTIOUS CDNA TRANSCRIPTS OF MAIZE NECROTIC STREAK VIRUS: INFECTIVITY AND TRANSLATIONAL CHARACTERISTICS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The completion of the sequence of Maize necrotic streak virus (MNeSV) indicated a genome of 4094 nt. Northern blotting and primer extension mapping identified two sgRNAs, 1607 nt and 781 nt long. Comparison of the MNeSV and Tomato bushy stunt virus genome sequences indicated that tombusvirus regulat...

  6. MAIZE NECROTIC STREAK VIRUS IS MOST CLOSELY RELATED TO MEMBERS OF THE GENUS TOMBUSVIRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Initial reports indicated that Maize necrotic streak virus (MNeSV) is most closely related to viruses in the family Tombusviridae. The two 5' most open reading frames (ORFs) are most simlar to the corresponding tombusvirus proteins, while the 27.4 kDa coat protein (CP) is more closely related to th...

  7. PHYSICAL CHARACTERIZATION, INSECT VECTOR IDENTIFICATION AND GENOME SEQUENCE ANALYSIS OF MAIZE FINE STREAK RHABDOVIRUS (MFSV): A RECENTLY DISCOVERED PATHOGEN OF MAIZE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have identified a new rhabdovirus in maize plants (Zea mays L.) collected from fields of Syngenta sweet corn near Bainbridge in Decatur County, Georgia in the fall of 1999. The virus is serologically distinct from other maize-infecting rhabdoviruses and was named Maize fine streak virus (MFSV). ...

  8. Cassava brown streak disease re-emerges in Uganda

    Microsoft Academic Search

    C. Omongo; R. J. Hillocks; R. Kawuki; G. W. Otim-Nape

    Cassava brown streak disease (CBSD) is an important virus disease that damages the starch-bearing tuberous roots of cassava. The disease is endemic in the coastal lowlands of Eastern Africa and the coastal strip of Lake Malawi. CBSD has rarely been seen at altitudes above 1000 m above sea level, although the reason for this is unknown. CBSD is maintained through

  9. Strand-specific real-time RT-PCR quantitation of Maize fine streak virus genomic and positive-sense RNAs using high temperature reverse transcription

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Efforts to analyze the replicative RNA produced by Maize fine streak virus (MVSF) within maize tissue was complicated by the lack of specificity during cDNA generation using standard reverse transcriptase protocols. Real-time qRT-PCR using cDNA generated by priming with random hexamers does not dist...

  10. Status of Banana Streak Disease in Africa: Problems and Future Research Needs

    Microsoft Academic Search

    G. Dahal; J. d'A. Hughes; B. E. L. Lockhart

    1998-01-01

    Streak disease of banana and plantain caused by banana streak virus (BSV) was first reported in the Ivory Coast in 1974 and occurs in at least 16 countries in Africa. Based on genomic characteristics, BSV has been shown to be a member of genus Badnavirus. Efficient and reliable diagnostic methods for BSV have recently become widely available. This paper summarizes

  11. REMOTE SENSING OF BARLEY YELLOW DWARF AND WHEAT STREAK MOSAIC DISEASE IN WINTER WHEAT CANOPIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficiency of field monitoring for barley yellow dwarf (BYD) and wheat streak mosaic (WSM) viral diseases would be improved with knowledge of reflected solar radiation from winter wheat crop canopies. Our objective was to characterize canopy spectral reflectance as well as other canopy and yield...

  12. Transgenic RNA interference (RNAi)-derived field resistance to cassava brown streak disease.

    PubMed

    Ogwok, Emmanuel; Odipio, John; Halsey, Mark; Gaitán-Solís, Eliana; Bua, Anton; Taylor, Nigel J; Fauquet, Claude M; Alicai, Titus

    2012-12-01

    Cassava brown streak disease (CBSD), caused by the Ipomoviruses Cassava brown streak virus (CBSV) and Ugandan Cassava brown streak virus (UCBSV), is considered to be an imminent threat to food security in tropical Africa. Cassava plants were transgenically modified to generate small interfering RNAs (siRNAs) from truncated full-length (894-bp) and N-terminal (402-bp) portions of the UCBSV coat protein (?CP) sequence. Seven siRNA-producing lines from each gene construct were tested under confined field trials at Namulonge, Uganda. All nontransgenic control plants (n = 60) developed CBSD symptoms on aerial tissues by 6 months after planting, whereas plants transgenic for the full-length ?CP sequence showed a 3-month delay in disease development, with 98% of clonal replicates within line 718-001 remaining symptom free over the 11-month trial. Reverse transcriptase-polymerase chain reaction (RT-PCR) diagnostics indicated the presence of UCBSV within the leaves of 57% of the nontransgenic controls, but in only two of 413 plants tested (0.5%) across the 14 transgenic lines. All transgenic plants showing CBSD were PCR positive for the presence of CBSV, except for line 781-001, in which 93% of plants were confirmed to be free of both pathogens. At harvest, 90% of storage roots from nontransgenic plants were severely affected by CBSD-induced necrosis. However, transgenic lines 718-005 and 718-001 showed significant suppression of disease, with 95% of roots from the latter line remaining free from necrosis and RT-PCR negative for the presence of both viral pathogens. Cross-protection against CBSV by siRNAs generated from the full-length UCBSV ?CP confirms a previous report in tobacco. The information presented provides proof of principle for the control of CBSD by RNA interference-mediated technology, and progress towards the potential control of this damaging disease. PMID:22845735

  13. Epidemiology of Fusarium Diseases and their Mycotoxins in Maize Ears

    Microsoft Academic Search

    Gary P. Munkvold

    2003-01-01

    Fusarium species cause two distinct diseases on ears of maize, Fusarium ear rot (or pink ear rot) and Gibberella ear rot (or red ear rot), both of which can result in mycotoxin contamination of maize grain. The primary causal agent for Fusarium ear rot is Fusarium verticillioides, but F. subglutinans and F. proliferatum are also important. Gibberella ear rot is

  14. Plant Disease / August 2005 853 The Window of Risk for Emigration of Wheat streak mosaic virus Varies

    E-print Network

    Garrett, Karen A.

    Plant Disease / August 2005 853 The Window of Risk for Emigration of Wheat streak mosaic virus or disease vector. For wheat stem rust, the complete eradication of an alter- nate host has been attempted vectors may be most active. In winter wheat (Triticum aestivum), the "green bridge" provided by volunteer

  15. Molecular interactions and immune responses between Maize fine streak virus and the leafhopper vector Graminella nigrifrons through differential expression and RNA interference.

    PubMed

    Chen, Y; Redinbaugh, M G; Michel, A P

    2015-06-01

    Graminella nigrifrons is the only known vector for Maize fine streak virus (MFSV). In this study, we used real-time quantitative PCR to compare the expression profiles of transcripts that putatively function in the insect immune response: four peptidoglycan recognition proteins (PGRP-SB1, -SD, -LC and LB), Toll, spaetzle, defensin, Dicer-2 (Dcr-2), Argonaut-2 (Ago-2) and Arsenic resistance protein 2 (Ars-2). Except for PGRP-LB and defensin, transcripts involved in humoral pathways were significantly suppressed in G. nigrifrons fed on MFSV-infected maize. The abundance of three RNA interference (RNAi) pathway transcripts (Dcr-2, Ago-2, Ars-2) was significantly lower in nontransmitting relative to transmitting G. nigrifrons. Injection with double-stranded RNA (dsRNA) encoding segments of the PGRP-LC and Dcr-2 transcripts effectively reduced transcript levels by 90 and 75% over 14 and 22 days, respectively. MFSV acquisition and transmission were not significantly affected by injection of either dsRNA. Knock-down of PGRP-LC resulted in significant mortality (greater than 90%) at 27 days postinjection, and resulted in more abnormal moults relative to those injected with Dcr-2 or control dsRNA. The use of RNAi to silence G. nigrifrons transcripts will facilitate the study of gene function and pathogen transmission, and may provide approaches for developing novel targets of RNAi-based pest control. PMID:25693649

  16. Wheat streak mosaic: A classic case of plant disease impact on soil water content and crop water-use efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this article, we describe the relationship between wheat streak mosaic (WSM) severity and soil water content as a prime example of the effect of a plant disease on soil water status and its implications for irrigated agriculture. The present study was part of a larger investigation which included...

  17. Wheat Streak Mosaic: A classic case of plant disease impact on soil water content and crop water-use efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this article, we describe the relationship between wheat streak mosaic (WSM) severity and soil water content as a prime example of the effect of a plant disease on soil water status and its implications for irrigated agriculture. The present study was part of a larger investigation which included...

  18. Role of Dehydrodiferulates in Maize Resistance to Pests and Diseases

    PubMed Central

    Santiago, Rogelio; Malvar, Rosa A.

    2010-01-01

    Phenolic esters have attracted considerable interest due to the potential they offer for peroxidase catalysed cross-linking of cell wall polysaccharides. Particularly, feruloyl residues undergo radical coupling reactions that result in cross-linking (intra-/intermolecular) between polysaccharides, between polysaccharides and lignin and, between polysaccharides and proteins. This review addresses for the first time different studies in which it is established that cross-linking by dehydrodiferulates contributes to maize’s defences to pests and diseases. Dehydrodiferulate cross-links are involved in maize defence mechanisms against insects such as the European, Mediterranean, and tropical corn borers and, storage pest as the maize weevil. In addition, cross-links are also discussed to be involved in genetic resistance of maize to fungus diseases as Gibberella ear and stalk rot. Resistance against insects and fungus attending dehydrodiferulates could go hand in hand. Quantitative trait loci mapping for these cell wall components could be a useful tool for enhancing resistance to pest and diseases in future breeding programs. PMID:20386661

  19. Research of Maize Leaf Disease Identifying Models Based Image Recognition

    Microsoft Academic Search

    Yu-Xia Zhao; Ke-Ru Wang; Zhong-Ying Bai; Shao-Kun Li; Rui-Zhi Xie; Shi-Ju Gao

    \\u000a The methods of recognition and diagnosis of main maize leaf diseases using machine vision were studied in the paper. Threshold\\u000a method was adopted to do image segmentation, and area-marking method was used calculating the num of disease as well as wiping\\u000a off redundancy dots. And then Freeman link code was used to calculate form feature. Finally diseases were deduced according

  20. Seed treatments enhance photosynthesis in maize seedlings by reducing infection with Fusarium spp. and consequent disease development in maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of a seed treatment on early season growth, seedling disease development, incidence Fusarium spp. infection, and photosynthetic performance of maize were evaluated at two locations in Iowa in 2007. Maize seed was either treated with Cruiser 2Extreme 250 ® (fludioxonil + azoxystrobin + me...

  1. Role of dehydrodiferulates in maize resistance to pests and diseases.

    PubMed

    Santiago, Rogelio; Malvar, Rosa A

    2010-01-01

    Phenolic esters have attracted considerable interest due to the potential they offer for peroxidase catalysed cross-linking of cell wall polysaccharides. Particularly, feruloyl residues undergo radical coupling reactions that result in cross-linking (intra-/intermolecular) between polysaccharides, between polysaccharides and lignin and, between polysaccharides and proteins. This review addresses for the first time different studies in which it is established that cross-linking by dehydrodiferulates contributes to maize's defences to pests and diseases. Dehydrodiferulate cross-links are involved in maize defence mechanisms against insects such as the European, Mediterranean, and tropical corn borers and, storage pest as the maize weevil. In addition, cross-links are also discussed to be involved in genetic resistance of maize to fungus diseases as Gibberella ear and stalk rot. Resistance against insects and fungus attending dehydrodiferulates could go hand in hand. Quantitative trait loci mapping for these cell wall components could be a useful tool for enhancing resistance to pest and diseases in future breeding programs. PMID:20386661

  2. A Comparison of Maize Diseases in Temperate and in Tropical Environments

    Microsoft Academic Search

    B. L. Renfro; A. J. Ullstrup

    1976-01-01

    Maize is produced primarily in temperate and warm-temperate zones of the world, but its production is increasing in many tropical regions. Some diseases are common to both of these environmental zones even though their importance may vary greatly. Other diseases are confined to a single zone. The important factors influencing the geographical distribution of maize diseases and some of their

  3. Transcriptional Response of Virus-Infected Cassava and Identification of Putative Sources of Resistance for Cassava Brown Streak Disease

    PubMed Central

    Maruthi, M. N.; Bouvaine, Sophie; Tufan, Hale A.; Mohammed, Ibrahim U.; Hillocks, Rory J.

    2014-01-01

    Cassava (Manihot esculenta) is a major food staple in sub-Saharan Africa, which is severely affected by cassava brown streak disease (CBSD). The aim of this study was to identify resistance for CBSD as well as to understand the mechanism of putative resistance for providing effective control for the disease. Three cassava varieties; Kaleso, Kiroba and Albert were inoculated with cassava brown streak viruses by grafting and also using the natural insect vector the whitefly, Bemisia tabaci. Kaleso expressed mild or no disease symptoms and supported low concentrations of viruses, which is a characteristic of resistant plants. In comparison, Kiroba expressed severe leaf but milder root symptoms, while Albert was susceptible with severe symptoms both on leaves and roots. Real-time PCR was used to estimate virus concentrations in cassava varieties. Virus quantities were higher in Kiroba and Albert compared to Kaleso. The Illumina RNA-sequencing was used to further understand the genetic basis of resistance. More than 700 genes were uniquely overexpressed in Kaleso in response to virus infection compared to Albert. Surprisingly, none of them were similar to known resistant gene orthologs. Some of the overexpressed genes, however, belonged to the hormone signalling pathways and secondary metabolites, both of which are linked to plant resistance. These genes should be further characterised before confirming their role in resistance to CBSD. PMID:24846209

  4. Wheat Streak Mosaic Virus 

    E-print Network

    Morgan, Gaylon

    2005-01-26

    . Infected wheat plants normally are stunted, with leaves mottled and streaked in green-yellow, parallel and discontinuous patterns (Fig. 1). This disease?s negative impact varies from year to year depending on its severity and distribution...; in the Southern Great Plains states, crop losses due to WSMV exceed $30 million in some years but are in- significant in others. High Plains Virus High Plains Virus (HPV), occasionally called High Plains Disease, is a relatively new virus identified...

  5. Identification and fine-mapping of a QTL, qMrdd1, that confers recessive resistance to maize rough dwarf disease

    PubMed Central

    2013-01-01

    Background Maize rough dwarf disease (MRDD) is a devastating viral disease that results in considerable yield losses worldwide. Three major strains of virus cause MRDD, including maize rough dwarf virus in Europe, Mal de Río Cuarto virus in South America, and rice black-streaked dwarf virus in East Asia. These viral pathogens belong to the genus fijivirus in the family Reoviridae. Resistance against MRDD is a complex trait that involves a number of quantitative trait loci (QTL). The primary approach used to minimize yield losses from these viruses is to breed and deploy resistant maize hybrids. Results Of the 50 heterogeneous inbred families (HIFs), 24 showed consistent responses to MRDD across different years and locations, in which 9 were resistant and 15 were susceptible. We performed trait-marker association analysis on the 24 HIFs and found six chromosomal regions which were putatively associated with MRDD resistance. We then conducted QTL analysis and detected a major resistance QTL, qMrdd1, on chromosome 8. By applying recombinant-derived progeny testing to self-pollinated backcrossed families, we fine-mapped the qMrdd1 locus into a 1.2-Mb region flanked by markers M103-4 and M105-3. The qMrdd1 locus acted in a recessive manner to reduce the disease-severity index (DSI) by 24.2–39.3%. The genetic effect of qMrdd1 was validated using another F6 recombinant inbred line (RIL) population in which MRDD resistance was segregating and two genotypes at the qMrdd1 locus differed significantly in DSI values. Conclusions The qMrdd1 locus is a major resistance QTL, acting in a recessive manner to increase maize resistance to MRDD. We mapped qMrdd1 to a 1.2-Mb region, which will enable the introgression of qMrdd1-based resistance into elite maize hybrids and reduce MRDD-related crop losses. PMID:24079304

  6. Wind Streaks

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 17 September 2003

    Bright wind streaks are present in the lee of craters and other obstacles in this image, located in Sinus Sabaeus, near the Martian equator. These streaks indicate that the local winds blow from the northeast (upper right in the image). The brightness of the streaks indicates that either bright material has been deposited in the lee of the craters, or that the surface has eroded preferentially in the lee of craters, exposing an underlying bright material. Because the streaks are bright regardless of the surrounding surface brightness, the first hypothesis most likely. The streaks probably all represent deposits of the same bright material that settled out of the atmosphere in the wind shelter provided by topographic peaks.

    Image information: VIS instrument. Latitude -6.3, Longitude 14.1 East (345.9 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  7. Development of a genetic linkage map of Mycosphaerella fijiensis, the causal agent of black leaf streak disease in bananas (Musa spp.) using SSR and DArT markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycosphaerella fijiensis is the causal agent of black leaf streak (BLS) disease in bananas. This pathogen threatens global banana production as the main export cultivars are highly susceptible. As a consequence, commercial banana plantations must be protected chemically with fungicides; up to 40 app...

  8. Variable Number of Tandem Repeat Markers in the Genome Sequence of Mycosphaerella Fijiensis, the Causal Agent of Black Leaf Streak Disease of Banana (Musa spp.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycosphaerella fijiensis, the causal agent of banana leaf streak disease (commonly known as black Sigatoka), is the most devastating pathogen attacking bananas (Musa spp). Recently the whole genome sequence of M. fijiensis became available. This sequence was screened for the presence of Variable Num...

  9. Fumonisin biomarkers in maize eaters and implications for human disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize is the predominant food source contaminated by fumonisins and this has particular health risks for communities consuming maize as a staple diet. The main biochemical effect of fumonisins is the inhibition of ceramide biosynthesis causing an increase in sphingoid bases and sphingoid base 1-pho...

  10. Genome-wide gene responses in a transgenic rice line carrying the maize resistance gene Rxo1 to the rice bacterial streak pathogen, Xanthomonas oryzae pv. oryzicola

    Microsoft Academic Search

    Yong-Li Zhou; Mei-Rong Xu; Ming-Fu Zhao; Xue-Wen Xie; Ling-Hua Zhu; Bin-Ying Fu; Zhi-Kang Li

    2010-01-01

    BACKGROUND: Non-host resistance in rice to its bacterial pathogen, Xanthomonas oryzae pv. oryzicola (Xoc), mediated by a maize NBS-LRR type R gene, Rxo1 shows a typical hypersensitive reaction (HR) phenotype, but the molecular mechanism(s) underlying this type of non-host resistance remain largely unknown. RESULTS: A microarray experiment was performed to reveal the molecular mechanisms underlying HR of rice to Xoc

  11. The Dynamics and Environmental Influence on Interactions Between Cassava Brown Streak Disease and the Whitefly, Bemisia tabaci.

    PubMed

    Jeremiah, S C; Ndyetabula, I L; Mkamilo, G S; Haji, S; Muhanna, M M; Chuwa, C; Kasele, S; Bouwmeester, H; Ijumba, J N; Legg, J P

    2015-05-01

    Cassava brown streak disease (CBSD) is currently the most significant virus disease phenomenon affecting African agriculture. In this study, we report results from the most extensive set of field data so far presented for CBSD in Africa. From assessments of 515 farmers' plantings of cassava, incidence in the Coastal Zone of Tanzania (46.5% of plants; 87% of fields affected) was higher than in the Lake Zone (22%; 34%), but incidences for both zones were greater than previous published records. The whitefly vector, Bemisia tabaci, was more abundant in the Lake Zone than the Coastal Zone, the reverse of the situation reported previously, and increased B. tabaci abundance is driving CBSD spread in the Lake Zone. The altitudinal "ceiling" previously thought to restrict the occurrence of CBSD to regions <1,000 masl has been broken as a consequence of the greatly increased abundance of B. tabaci in mid-altitude areas. Among environmental variables analyzed, minimum temperature was the strongest determinant of CBSD incidence. B. tabaci in the Coastal and Lake Zones responded differently to environmental variables examined, highlighting the biological differences between B. tabaci genotypes occurring in these regions and the superior adaptation of B. tabaci in the Great Lakes region both to cassava and low temperature conditions. Regression analyses using multi-country data sets could be used to determine the potential environmental limits of CBSD. Approaches such as this offer potential for use in the development of predictive models for CBSD, which could strengthen country- and continent-level CBSD pandemic mitigation strategies. PMID:25585059

  12. Primitive Streak (dorsal view)

    NSDL National Science Digital Library

    PhD Jack D Thatcher (West Virginia School of Osteopathic Medicine Structural Biology)

    2011-06-23

    This FlashTM animation is the first of a seven part series that presents the primitive streak from different angles. This installment displays the dorsal view, which provides an overview of elongation and regression. Epiblast is seen migrating medially, towards and into the streak. The appearance of the neural tube and somites demonstrates that morphogenesis commences before the streak recedes away.

  13. Endophytic Fusarium verticillioides â??reduces disease severity caused by Ustilago maydis on maize

    Microsoft Academic Search

    Keunsub Lee; Jean J. Pan; Georgiana May

    2009-01-01

    Endophytic fungi represent diverse taxa that inhabit plant hosts without causing disease symptoms. We used endophytic isolates of Fusarium verticillioides (Sacc.) Nirenberg to understand how endophytic fungi interact with pathogens, in this case, the corn smut pathogen, Ustilago maydis DC (Corda). Endophytic F. verticillioides strains were inoculated onto maize seedlings before, simulta- neously, or after inoculation with U. maydis, and

  14. A predicted protein interactome identifies conserved global networks and disease resistance subnetworks in maize

    PubMed Central

    Musungu, Bryan; Bhatnagar, Deepak; Brown, Robert L.; Fakhoury, Ahmad M.; Geisler, Matt

    2015-01-01

    Interactomes are genome-wide roadmaps of protein-protein interactions. They have been produced for humans, yeast, the fruit fly, and Arabidopsis thaliana and have become invaluable tools for generating and testing hypotheses. A predicted interactome for Zea mays (PiZeaM) is presented here as an aid to the research community for this valuable crop species. PiZeaM was built using a proven method of interologs (interacting orthologs) that were identified using both one-to-one and many-to-many orthology between genomes of maize and reference species. Where both maize orthologs occurred for an experimentally determined interaction in the reference species, we predicted a likely interaction in maize. A total of 49,026 unique interactions for 6004 maize proteins were predicted. These interactions are enriched for processes that are evolutionarily conserved, but include many otherwise poorly annotated proteins in maize. The predicted maize interactions were further analyzed by comparing annotation of interacting proteins, including different layers of ontology. A map of pairwise gene co-expression was also generated and compared to predicted interactions. Two global subnetworks were constructed for highly conserved interactions. These subnetworks showed clear clustering of proteins by function. Another subnetwork was created for disease response using a bait and prey strategy to capture interacting partners for proteins that respond to other organisms. Closer examination of this subnetwork revealed the connectivity between biotic and abiotic hormone stress pathways. We believe PiZeaM will provide a useful tool for the prediction of protein function and analysis of pathways for Z. mays researchers and is presented in this paper as a reference tool for the exploration of protein interactions in maize.

  15. Expression of the Newcastle disease virus fusion protein in transgenic maize and immunological studies.

    PubMed

    Guerrero-Andrade, Octavio; Loza-Rubio, Elizabeth; Olivera-Flores, Teresa; Fehérvári-Bone, Tamás; Gómez-Lim, Miguel Angel

    2006-08-01

    Transgenic plants have been employed successfully as a low-cost system for the production of therapeutically valuable proteins, including antibodies, antigens and hormones. Here, we report the expression of the fusion (F) gene of the Newcastle disease virus (NDV) in transgenic maize plants. The expression of the transgene, driven by the maize ubiquitin promoter, caused accumulation of the F protein in maize kernels. The presence of the transgene was verified by Southern and western blots. Feeding chickens with kernels containing the F protein induced the production of antibodies, which conferred protection against a viral challenge. This protection was comparable to that conferred by a commercial vaccine. Possible uses of this plant-based F protein as a potential mucosal vaccine are discussed. PMID:16906446

  16. Targeted discovery of quantitative trait loci for resistance to northern leaf blight and other diseases of maize

    Microsoft Academic Search

    Chia-Lin Chung; Jesse Poland; Kristen Kump; Jacqueline Benson; Joy Longfellow; Ellie Walsh; Peter Balint-Kurti; Rebecca Nelson

    2011-01-01

    To capture diverse alleles at a set of loci associated with disease resistance in maize, heterogeneous inbred family (HIF)\\u000a analysis was applied for targeted QTL mapping and near-isogenic line (NIL) development. Tropical maize lines CML52 and DK888\\u000a were chosen as donors of alleles based on their known resistance to multiple diseases. Chromosomal regions (“bins”; n = 39) associated with multiple disease resistance

  17. Maize Chlorotic Mottle Machlomovirus and Wheat Streak Mosaic Rymovirus Concentrations Increase in the Synergistic Disease Corn Lethal Necrosis

    E-print Network

    Scheets, Kay

    - crease or decrease the amount of one of the viruses. The most well studied synergism involves potato potyvirus, tobacco etch poty- virus, and pepper mottle potyvirus (Vance et al., 1995). Cucumber mosaic; Anderson et al., 1996). Most of the studies on synergisms involving potyvi- ruses have been done in dicots

  18. Effect of Inoculation Pressure on Maize Dwarf Mosaic Virus Strain-A Disease Incidence, Severity and Titer in Sorghum. 

    E-print Network

    Mahuku, George S.; Toler, R.W.

    1992-01-01

    Z TA24S.7 8873 :--------------,1 NO.1706 8-1706 May 1992 TEXAS A&M UNIVERSITY LIBRARY Effect of Inoculation Pressure . on Maize Dwarf Mosaic Virus Strain-A Disease Incidence, Severity and Titer in Sorghum The Texas Agricultural Experiment... Station ? J. Charles Lee, Interim Director The Texas A&M University System ? College Station, Texas ~ ? . k ( :_ ., ., (Blank Page in OrigiBatBuUetiol I .I ,. : ::; , :" Effect of Inoculation Pressure on Maize Dwarf Mosaic Virus Strain-A Disease...

  19. Microchannel plate streak camera

    DOEpatents

    Wang, C.L.

    1984-09-28

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (uv to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 keV x-rays.

  20. Microchannel plate streak camera

    DOEpatents

    Wang, C.L.

    1989-03-21

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras is disclosed. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1,000 KeV x-rays. 3 figs.

  1. Microchannel plate streak camera

    DOEpatents

    Wang, Ching L. (Livermore, CA)

    1989-01-01

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 KeV x-rays.

  2. Distribution of disease symptoms and mycotoxins in maize ears infected by Fusarium culmorum and Fusarium graminearum.

    PubMed

    Oldenburg, Elisabeth; Ellner, Frank

    2015-08-01

    Red ear rot an important disease of maize cultivated in Europe is caused by toxigenic Fusarium species like Fusarium graminearum and Fusarium culmorum. To get detailed information on the time course of the infection process leading to the accumulation of Fusarium mycotoxins in maize ears, a field study was conducted over 2 years with two maize varieties, which were inoculated with F. culmorum or F. graminearum isolates at the stage of female flowering. Every fortnight after inoculation, infection and contamination progress in the ears was followed by visually evaluating disease signs and analysing Fusarium toxin concentrations in the infected ear tissues. In principle, infection and mycotoxin distribution were similar in respect of pathogens, varieties, and years. External infection symptoms showing some small pale or brown-marbled kernels with dark brown pedicels were mainly seen at the ear tip, whereas internal infection symptoms on the rachis were much more pronounced and spread in the upper half showing greyish brownish or pink discoloration of the pith. Well correlated with disease symptoms, a top-down gradient from high to low toxin levels within the ear with considerably higher concentrations in the rachis compared with the kernels was observed. It is suggested that both Fusarium pathogens primarily infect the rachis from the tip toward the bottom, whereas the kernels are subsequently infected via the rachillae connected to the rachis. A special focus on the pronounced disease symptoms visible in the rachis may be an approach to improve the evaluation of maize-genotype susceptibility against red ear rot pathogens. It has to be underlined that the accumulation of Fusarium mycotoxins in the rachis greatly accelerated 6 weeks after inoculation; therefore, highest contamination risk is indicated for feedstuffs containing large amounts of rachis (e.g., corn cob mix), especially when cut late in growing season. PMID:25904523

  3. Identification of promoter motifs regulating ZmeIF4E expression level involved in maize rough dwarf disease resistance in maize (Zea Mays L.).

    PubMed

    Shi, Liyu; Weng, Jianfeng; Liu, Changlin; Song, Xinyuan; Miao, Hongqin; Hao, Zhuanfang; Xie, Chuanxiao; Li, Mingshun; Zhang, Degui; Bai, Li; Pan, Guangtang; Li, Xinhai; Zhang, Shihuang

    2013-04-01

    Maize rough dwarf disease (MRDD, a viral disease) results in significant grain yield losses, while genetic basis of which is largely unknown. Based on comparative genomics, eukaryotic translation initiation factor 4E (eIF4E) was considered as a candidate gene for MRDD resistance, validation of which will help to understand the possible genetic mechanism of this disease. ZmeIF4E (orthologs of eIF4E gene in maize) encodes a protein of 218 amino acids, harboring five exons and no variation in the cDNA sequence is identified between the resistant inbred line, X178 and susceptible one, Ye478. ZmeIF4E expression was different in the two lines plants treated with three plant hormones, ethylene, salicylic acid, and jasmonates at V3 developmental stage, suggesting that ZmeIF4E is more likely to be involved in the regulation of defense gene expression and induction of local and systemic resistance. Moreover, four cis-acting elements related to plant defense responses, including DOFCOREZM, EECCRCAH1, GT1GAMSCAM4, and GT1CONSENSUS were detected in ZmeIF4E promoter for harboring sequence variation in the two lines. Association analysis with 163 inbred lines revealed that one SNP in EECCRCAH1 is significantly associated with CSI of MRDD in two environments, which explained 3.33 and 9.04 % of phenotypic variation, respectively. Meanwhile, one SNP in GT-1 motif was found to affect MRDD resistance only in one of the two environments, which explained 5.17 % of phenotypic variation. Collectively, regulatory motifs respectively harboring the two significant SNPs in ZmeIF4E promoter could be involved in the defense process of maize after viral infection. These results contribute to understand maize defense mechanisms against maize rough dwarf virus. PMID:23474695

  4. Visible Embryo: Primitive Streak

    NSDL National Science Digital Library

    Carmen Arbona (Mouseworks)

    2006-09-08

    the page on early placentation and primitive streak formation from a comprehensive resource of information on human development from conception to birth, designed for both medical student and interested lay people.

  5. Oxidative stress response of Mycosphaerella fijiensis, the causal agent of black leaf streak disease in banana plants, to hydrogen peroxide and paraquat.

    PubMed

    Beltrán-García, Miguel J; Manzo-Sanchez, Gilberto; Guzmán-González, Salvador; Arias-Castro, Carlos; Rodríguez-Mendiola, Martha; Avila-Miranda, Martin; Ogura, Tetsuya

    2009-07-01

    Mycosphaerella fijiensis causes black leaf streak disease in banana and plantain. This fungus is usually attacked by reactive oxygen species secreted by the plant or during exposure to fungicide, however, little is known about the antioxidant response of the fungus. In this study, mycelia were observed to totally decompose 30 mmol/L of hydrogen peroxide (H2O2) within 120 min, liberating oxygen bubbles, and also to survive in concentrations as high as 100 mmol/L H2O2. The oxidative stress responses to H2O2, paraquat, and hydroquinone were characterized in terms of the activities of catalase and superoxide dismutase (SOD). Two active catalase bands were seen in native PAGE induced by H2O2. Band I had monofunctional activity and band II had bifunctional catalase-peroxidase activity. Two isozymes of SOD, distinguishable by their cyanide sensitivity, were found; CuZnSOD was the main one. The combination of H2O2 and 3-aminotriazole reduced the accumulation of biomass up to 40% compared with exposure to H2O2 alone, suggesting that catalase is important for the rapid decomposition of H2O2 and has a direct bearing on cell viability. The results also suggest that the superoxide anion formed through the redox of paraquat and hydroquinone has a greater effect than H2O2 on the cellular viability of M. fijiensis. PMID:19767862

  6. Polar Dust Devil Streaks

    NASA Technical Reports Server (NTRS)

    2004-01-01

    30 June 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image of dunes in the martian north polar region is important because it shows one of the highest northern latitude views of streaks thought to be made by passing dust devils. The dark, thin, filamentary streaks on the dunes and on the adjacent plains were probably formed by dust devils. The dunes occur near 76.6oN, 62.7oW. Dust devil streaks are observed on Mars at very high latitudes, such as this, all the way down to the equator. They are also seen at all elevations, from the deepest parts of the Hellas Basin to the summit of Olympus Mons. This picture covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

  7. Devil-Streaked Plain

    NASA Technical Reports Server (NTRS)

    2006-01-01

    19 February 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark streaks on a plain south of the giant impact basin, Hellas Planitia. The streaks map the routes traveled by dozens of individual southern spring and early summer dust devils.

    Location near: 68.4oS, 296.1oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  8. Streak camera receiver definition study

    NASA Technical Reports Server (NTRS)

    Johnson, C. B.; Hunkler, L. T., Sr.; Letzring, S. A.; Jaanimagi, P.

    1990-01-01

    Detailed streak camera definition studies were made as a first step toward full flight qualification of a dual channel picosecond resolution streak camera receiver for the Geoscience Laser Altimeter and Ranging System (GLRS). The streak camera receiver requirements are discussed as they pertain specifically to the GLRS system, and estimates of the characteristics of the streak camera are given, based upon existing and near-term technological capabilities. Important problem areas are highlighted, and possible corresponding solutions are discussed.

  9. Impact of cell wall composition on maize resistance to pests and diseases.

    PubMed

    Santiago, Rogelio; Barros-Rios, Jaime; Malvar, Rosa A

    2013-01-01

    In cereals, the primary cell wall is built of a skeleton of cellulosic microfibrils embedded in a matrix of hemicelluloses and smaller amounts of pectins, glycoproteins and hydroxycinnamates. Later, during secondary wall development, p-coumaryl, coniferyl and sinapyl alcohols are copolymerized to form mixed lignins. Several of these cell wall components show a determinative role in maize resistance to pest and diseases. However, defense mechanisms are very complex and vary among the same plant species, different tissues or even the same tissue at different developmental stages. Thus, it is important to highlight that the role of the cell wall components needs to be tested in diverse genotypes and specific tissues where the feeding or attacking by the pathogen takes place. Understanding the role of cell wall constituents as defense mechanisms may allow modifications of crops to withstand pests and diseases. PMID:23535334

  10. Impact of Cell Wall Composition on Maize Resistance to Pests and Diseases

    PubMed Central

    Santiago, Rogelio; Barros-Rios, Jaime; Malvar, Rosa A.

    2013-01-01

    In cereals, the primary cell wall is built of a skeleton of cellulosic microfibrils embedded in a matrix of hemicelluloses and smaller amounts of pectins, glycoproteins and hydroxycinnamates. Later, during secondary wall development, p-coumaryl, coniferyl and sinapyl alcohols are copolymerized to form mixed lignins. Several of these cell wall components show a determinative role in maize resistance to pest and diseases. However, defense mechanisms are very complex and vary among the same plant species, different tissues or even the same tissue at different developmental stages. Thus, it is important to highlight that the role of the cell wall components needs to be tested in diverse genotypes and specific tissues where the feeding or attacking by the pathogen takes place. Understanding the role of cell wall constituents as defense mechanisms may allow modifications of crops to withstand pests and diseases. PMID:23535334

  11. Effect of Inoculation Pressure on Maize Dwarf Mosaic Virus Strain-A Disease Incidence, Severity and Titer in Sorghum.

    E-print Network

    Mahuku, George S.; Toler, R.W.

    1992-01-01

    Z TA24S.7 8873 :--------------,1 NO.1706 8-1706 May 1992 TEXAS A&M UNIVERSITY LIBRARY Effect of Inoculation Pressure . on Maize Dwarf Mosaic Virus Strain-A Disease Incidence, Severity and Titer in Sorghum The Texas Agricultural Experiment...

  12. Primitive Streak, Oblique Overview

    NSDL National Science Digital Library

    PhD Jack D Thatcher (West Virginia School of Osteopathic Medicine Structural Biology)

    2011-06-23

    This FlashTM animation is the seventh and last of a series that presents the primitive streak from different angles. This installment displays the streak from an oblique angle, which provides an overview of simultaneous processes. Cells that ingress through the steak early insert into the underlying hypoblast and differentiate into endodermal cells. The notochordal process emerges from HensenÂ?s node. Mesenchyme dissociates from the streak and spreads throughout the germ disc. The distal end of the notochordal process fuses with the endoderm and flattens into the notochordal plate. The plate dissociates form the endoderm to form the solid notochord. Eventually the streak completely regresses, leaving the three germ layers; ectoderm, mesoderm, endoderm, with the notochord buried in the paraxial mesoderm. To open the animation using Internet Explorer follow these steps. (1.) Click the link for the animation. (2.) A dialog box may pop up that begins with the statement "Windows cannot open this file:" If this box does not appear proceed to step four. If it does choose "Select the program from a list," then click OK. (3.) Another dialog box will pop up that lists different programs. Make sure "Internet Explorer" is selected, then click OK. (4.) Internet Explorer will pop up. Beneath the toolbars at the top of the window a yellow bar will appear that reads "To help protect your security, Internet Explorer has restricted this webpage from running scripts or Active X controls that could access your computer. Click here for options..." Pass the cursor over this yellow bar and click the right mouse button. (5.) A dialog box will pop up. Left click the option "Allow Blocked Content." (6.) Another dialog box will appear labeled "Security Warning" asking you to confirm that you want to run the content. Click "Yes." (7.) The Flash animation will appear in the Internet Explorer Window. (8.) Instructions for navigating the lesson are provided by the first frame of the animation.

  13. Wheat Streak Mosaic Virus

    E-print Network

    Morgan, Gaylon

    2005-01-26

    Virus First discovered in Nebraska in 1922, wheat streak mosaic virus (WSMV) remains a threat today across most of the U.S. Central Plains. WSMV affects spring wheat, barley, corn, triticale, rye and numerous other annual and perennial grasses... have tre- mendous reproductive capability, enabling large populations to build. The mite is most active during warm weather, with temperatures of 75-80 degrees F optimum for reproduction. Mites require a living grass host to survive the summer; sum...

  14. Dust Devil Streaks

    NASA Technical Reports Server (NTRS)

    2005-01-01

    27 November 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a plethora of dark streaks created by spring and summer dust devil activity in Argyre Planitia.

    Location near: 64.9oS, 8.3oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  15. Dust Devil Streaks

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    At first glance, the dust devil streaks observed in this THEMIS image of the martian northern plains may look similar to many other images. However, what makes this THEMIS image so interesting are the many streaks that trend over hills, mounds, and valleys. Many of the dust devil streaks previously observed occur in very flat and dusty regions. This unique image gives hints to the dynamic nature of the dust devil streak formational process.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 53.8, Longitude 200.9 East (159.1 West). 19 meter/pixel resolution.

  16. Bright Devil Streaks

    NASA Technical Reports Server (NTRS)

    2005-01-01

    4 March 2005 In honor of Giovanni V. Schiaparelli's 170th birthday, we present this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image showing light-toned dust devil streaks on the southern floor of Schiaparelli Crater.

    Location near: 5.3oS, 343.3oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Autumn

  17. A Porphyrin Pathway Impairment Is Responsible for the Phenotype of a Dominant Disease Lesion Mimic Mutant of Maize

    Microsoft Academic Search

    Gongshe Hu; Nasser Yalpani; Steven P. Briggs; Gurmukh S. Johal

    1998-01-01

    The maize lesion mimic gene Les22 is defined by dominant mutations and characterized by the production of minute necrotic spots on leaves in a developmentally specified and light-dependent manner. Phenotypically, Les22 lesions re- semble those that are triggered during a hypersensitive disease resistance response of plants to pathogens. We have cloned Les22 by using a Mutator -tagging technique. It encodes

  18. Root Interactions in a Maize/Soybean Intercropping System Control Soybean Soil-Borne Disease, Red Crown Rot

    PubMed Central

    Gao, Xiang; Wu, Man; Xu, Ruineng; Wang, Xiurong; Pan, Ruqian; Kim, Hye-Ji; Liao, Hong

    2014-01-01

    Background Within-field multiple crop species intercropping is well documented and used for disease control, but the underlying mechanisms are still unclear. As roots are the primary organ for perceiving signals in the soil from neighboring plants, root behavior may play an important role in soil-borne disease control. Principal Findings In two years of field experiments, maize/soybean intercropping suppressed the occurrence of soybean red crown rot, a severe soil-borne disease caused by Cylindrocladium parasiticum (C. parasiticum). The suppressive effects decreased with increasing distance between intercropped plants under both low P and high P supply, suggesting that root interactions play a significant role independent of nutrient status. Further detailed quantitative studies revealed that the diversity and intensity of root interactions altered the expression of important soybean PR genes, as well as, the activity of corresponding enzymes in both P treatments. Furthermore, 5 phenolic acids were detected in root exudates of maize/soybean intercropped plants. Among these phenolic acids, cinnamic acid was released in significantly greater concentrations when intercropped maize with soybean compared to either crop grown in monoculture, and this spike in cinnamic acid was found dramatically constrain C. parasiticum growth in vitro. Conclusions To the best of our knowledge, this study is the first report to demonstrate that intercropping with maize can promote resistance in soybean to red crown rot in a root-dependent manner. This supports the point that intercropping may be an efficient ecological strategy to control soil-borne plant disease and should be incorporated in sustainable agricultural management practices. PMID:24810161

  19. Streak generation in wind tunnels

    NASA Astrophysics Data System (ADS)

    Pook, David A.; Watmuff, Jonathan H.

    2014-07-01

    Computational results are presented which co-validate published experimental observations of steady streaks, deliberately generated by the steady wake of a wire placed upstream of a flat plate with a prescribed leading edge. The largest streak occurs when the wake is generated from a wire placed upstream of the wind tunnel contraction. Normal vorticity passing through the contraction leads to the creation of streamwise vorticity in the test-section via tilting and stretching. The computational results allow the original experiment to be reinterpreted as a receptivity experiment that demonstrates the boundary layer is more receptive to steady streamwise vorticity than normal vorticity. It also suggests an interesting mechanism for the generation of Klebanoff streaks in wind tunnels. The effect of shifting the attachment point at the leading edge on receptivity is also demonstrated. The streak growth is compared to the Optimal streak often used in computational studies. The modal growth of the streak generated by free-stream normal vorticity is found to have a streamwise location of peak energy close to the Optimal streak for wavelengths larger than the leading edge thickness. However, the location of the peak energy for the streamwise vorticity streak varies substantially with wavelength. Differences in wall-normal profiles are also noted.

  20. Light and Dark Slope Streaks

    NASA Technical Reports Server (NTRS)

    2004-01-01

    21 July 2004 Dark slope streaks are a common feature on slopes thickly-mantled by dust, especially in the Tharsis, Arabia, and western Amazonis regions of Mars. Less common are light-toned slope streaks, which often occur in the same area as dark streaks. They are most common in Arabia Terra, and some are shown in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image. Slope streaks are probably the result of sudden avalanches of extremely dry dust. The behavior of the avalanching dust is somewhat fluid-like, and new streaks have been observed to form over intervals of a few months to a Mars year. This image is located near 13.4oN, 340.3oW, and covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

  1. Genetically Modified, Insect Resistant Maize: Implications for Management of Ear and Stalk Diseases

    NSDL National Science Digital Library

    G. P. Munkvold (Iowa State University; )

    2000-09-12

    This article summarizes six years of research that indicate that Bt transformation of maize hybrids enhances the safety of grain for livestock and human food products by reducing the plants' vulnerability to mycotoxin-producing Fusarium fungi.

  2. Molecular Genetic Analysis and Evolution of Segment 7 in Rice Black-Streaked Dwarf Virus in China

    PubMed Central

    Chen, Yanping; Wu, Jirong; Meng, Qingchang; Han, Xiaohua; Hao, Zhuanfang; Li, Mingshun; Yong, Hongjun; Zhang, Degui; Zhang, Shihuang; Li, Xinhai

    2015-01-01

    Rice black-streaked dwarf virus (RBSDV) causes maize rough dwarf disease or rice black-streaked dwarf disease and can lead to severe yield losses in maize and rice. To analyse RBSDV evolution, codon usage bias and genetic structure were investigated in 111 maize and rice RBSDV isolates from eight geographic locations in 2013 and 2014. The linear dsRNA S7 is A+U rich, with overall codon usage biased toward codons ending with A (A3s, S7-1: 32.64%, S7-2: 29.95%) or U (U3s, S7-1: 44.18%, S7-2: 46.06%). Effective number of codons (Nc) values of 45.63 in S7-1 (the first open reading frame of S7) and 39.96 in S7-2 (the second open reading frame of S7) indicate low degrees of RBSDV-S7 codon usage bias, likely driven by mutational bias regardless of year, host, or geographical origin. Twelve optimal codons were detected in S7. The nucleotide diversity (?) of S7 sequences in 2013 isolates (0.0307) was significantly higher than in 2014 isolates (0.0244, P = 0.0226). The nucleotide diversity (?) of S7 sequences in isolates from Jinan (0.0391) was higher than that from the other seven locations (P < 0.01). Only one S7 recombinant was detected in Baoding. RBSDV isolates could be phylogenetically classified into two groups according to S7 sequences, and further classified into two subgroups. S7-1 and S7-2 were under negative and purifying selection, with respective Ka/Ks ratios of 0.0179 and 0.0537. These RBSDV populations were expanding (P < 0.01) as indicated by negative values for Tajima's D, Fu and Li's D, and Fu and Li's F. Genetic differentiation was detected in six RBSDV subpopulations (P < 0.05). Absolute Fst (0.0790) and Nm (65.12) between 2013 and 2014, absolute Fst (0.1720) and Nm (38.49) between maize and rice, and absolute Fst values of 0.0085-0.3069 and Nm values of 0.56-29.61 among these eight geographic locations revealed frequent gene flow between subpopulations. Gene flow between 2013 and 2014 was the most frequent. PMID:26121638

  3. Genome Sequence of Banana Streak MY Virus from the Pacific Ocean Island of Tonga.

    PubMed

    Stainton, Daisy; Halafihi, Mana'ia; Collings, David A; Varsani, Arvind

    2015-01-01

    Banana streak disease is caused by a variety of banana-infecting badnaviruses. A genome of the episomal form of a banana streak MY virus was recovered from an infected banana plant sampled on Vava'u Island, Tonga, and shares >98% pairwise identity with the six other genomes available in public databases. PMID:26021925

  4. Genome Sequence of Banana Streak MY Virus from the Pacific Ocean Island of Tonga

    PubMed Central

    Stainton, Daisy; Halafihi, Mana’ia; Collings, David A.

    2015-01-01

    Banana streak disease is caused by a variety of banana-infecting badnaviruses. A genome of the episomal form of a banana streak MY virus was recovered from an infected banana plant sampled on Vava’u Island, Tonga, and shares >98% pairwise identity with the six other genomes available in public databases. PMID:26021925

  5. Evaluation of maize inbred Iines for resistance to sugarcane mosaic virus (SCMV)

    E-print Network

    Paris-Sud XI, Université de

    Evaluation of maize inbred Iines for resistance to sugarcane mosaic virus (SCMV) and maize dwarf experiments were performed to evaluate 124 maize inbreds for their reaction to inoculation with sugarcane Sugarcane mosaic and maize dwarf mosaic are the most important virus diseases of maize in Europe. Maize

  6. Streaking into middle school science: The Dell Streak pilot project

    NASA Astrophysics Data System (ADS)

    Austin, Susan Eudy

    A case study is conducted implementing the Dell Streak seven-inch android device into eighth grade science classes of one teacher in a rural middle school in the Piedmont region of North Carolina. The purpose of the study is to determine if the use of the Dell Streaks would increase student achievement on standardized subject testing, if the Streak could be used as an effective instructional tool, and if it could be considered an effective instructional resource for reviewing and preparing for the science assessments. A mixed method research design was used for the study to analyze both quantitative and qualitative results to determine if the Dell Streaks' utilization could achieve the following: 1. instructional strategies would change, 2. it would be an effective instructional tool, and 3. a comparison of the students' test scores and benchmark assessments' scores would provide statistically significant difference. Through the use of an ANOVA it was determined a statistically significant difference had occurred. A Post Hoc analysis was conducted to identify where the difference occurred. Finally a T-test determined was there was no statistically significance difference between the mean End-of-Grade tests and four quarterly benchmark scores of the control and the experimental groups. Qualitative research methods were used to gather results to determine if the Streaks were an effective instructional tool. Classroom observations identified that the teacher's teaching styles and new instructional strategies were implemented throughout the pilot project. Students had an opportunity to complete a questionnaire three times during the pilot project. Results revealed what the students liked about using the devices and the challenges they were facing. The teacher completed a reflective questionnaire throughout the pilot project and offered valuable reflections about the use of the devices in an educational setting. The reflection data supporting the case study was drawn from the teacher's statements regarding the change in instructional delivery as a respect of using the students' device. The results section of the study will elaborate upon these findings. The study recommendations on the use of the Dell Streak device will address whether further actions as the use of the Streak technology in the classroom and summary section.

  7. Slope Streaks in Terra Sabaea

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Figure 1 Click on image for larger version

    This HiRISE image shows the rim of a crater in the region of Terra Sabaea in the northern hemisphere of Mars.

    The subimage (figure 1) is a close-up view of the crater rim revealing dark and light-toned slope streaks. Slope streak formation is among the few known processes currently active on Mars. While their mechanism of formation and triggering is debated, they are most commonly believed to form by downslope movement of extremely dry sand or very fine-grained dust in an almost fluidlike manner (analogous to a terrestrial snow avalanche) exposing darker underlying material.

    Other ideas include the triggering of slope streak formation by possible concentrations of near-surface ice or scouring of the surface by running water from aquifers intercepting slope faces, spring discharge (perhaps brines), and/or hydrothermal activity.

    Several of the slope streaks in the subimage, particularly the three longest darker streaks, show evidence that downslope movement is being diverted around obstacles such as large boulders. Several streaks also appear to originate at boulders or clumps of rocky material.

    In general, the slope streaks do not have large deposits of displaced material at their downslope ends and do not run out onto the crater floor suggesting that they have little reserve kinetic energy. The darkest slope streaks are youngest and can be seen to cross cut and superpose older and lighter-toned streaks. The lighter-toned streaks are believed to be dark streaks that have lightened with time as new dust is deposited on their surface.

    Observation Geometry Image PSP_001808_1875 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 15-Dec-2006. The complete image is centered at 7.4 degrees latitude, 47.0 degrees East longitude. The range to the target site was 272.1 km (170.1 miles). At this distance the image scale is 54.4 cm/pixel (with 2 x 2 binning) so objects 163 cm across are resolved. The image shown here has been map-projected to 50 cm/pixel and north is up. The image was taken at a local Mars time of 03:36 PM and the scene is illuminated from the west with a solar incidence angle of 53 degrees, thus the sun was about 37 degrees above the horizon. At a solar longitude of 150.7 degrees, the season on Mars is Northern Summer.

    NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

  8. Dark streaks on talus slopes, Mars

    NASA Technical Reports Server (NTRS)

    Ferguson, H. M.; Lucchitta, B. K.

    1984-01-01

    High-resolution pictures of talus slopes on Mars show small, dark streaks that characteristically widen downward. These streaks are different from the thin and even streaks of various albedos that stream from cliffs on talus slopes, but gradations between the two streak types occur and not all streaks can be classified with confidence. In order to study the nature and origin of the small, widening, dark streaks, all Viking pictures with a resolution of less than 100 m/pixel were surveyed. To date several hundred streaks were located, but only few are of high enough resolution to be confidently identified as widening downwards. The approximate dimensions of the streaks were measured and their shapes, numbers, position, and spacing on slopes were noted. They were plotted on a topographic map, and their relation to topography, geologic units, and regions of distinct thermal inertia and albedo were studied. Also noted was the season at which images containing streaks were acquired and the direction of illumination. Albedo measurements are in progress. Several streaks can be seen stereoscopically, but none are observed on color images. The observation of small dark streaks on talus slopes on Mars is compatible with an interpretation of their origin as eruptions of small masses of wet debris in places where steep walls intersect aquifers or where seasonal equatorial warming permits the local melting of ground ice.

  9. Different Responses of Two Genes Associated with Disease Resistance Loci in Maize (Zea mays L.) to 3-allyloxy-1,2-benzothiazole 1,1-dioxide

    Microsoft Academic Search

    Jiazheng Yuan; Jennifer Tedman; Liakat Ali; Jie Liu; Jeff Taylor; David Lightfoot

    Probenazole (3-allyloxy-1,2-benzothiazole 1,1-dioxide, PBZ) is a bactericide and fungicide that acts by inducing plant defense systems. It has been shown to induce the expression of NBS-LRR genes like RPR1 (rice probenazole-response gene) in rice (Oryza sativa L.) and systemic acquired resistance (SAR)-like disease resistance. Two maize (Zea mays L.) genes Zmnbslrr1 (a NBS-LRR gene, cloned from a disease resistance analog

  10. Maize databases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter is a succinct overview of maize data held in the species-specific database MaizeGDB (the Maize Genomics and Genetics Database), and selected multi-species data repositories, such as Gramene/Ensembl Plants, Phytozome, UniProt and the National Center for Biotechnology Information (NCBI), ...

  11. Secondary threshold amplitudes for sinuous streak breakdown

    NASA Astrophysics Data System (ADS)

    Cossu, Carlo; Brandt, Luca; Bagheri, Shervin; Henningson, Dan S.

    2011-07-01

    The nonlinear stability of laminar sinuously bent streaks is studied for the plane Couette flow at Re = 500 in a nearly minimal box and for the Blasius boundary layer at Re?*=700. The initial perturbations are nonlinearly saturated streamwise streaks of amplitude AU perturbed with sinuous perturbations of amplitude AW. The local boundary of the basin of attraction of the linearly stable laminar flow is computed by bisection and projected in the AU - AW plane providing a well defined critical curve. Different streak transition scenarios are seen to correspond to different regions of the critical curve. The modal instability of the streaks is responsible for transition for AU = 25%-27% for the considered flows, where sinuous perturbations of amplitude below AW ? 1%-2% are sufficient to counteract the streak viscous dissipation and induce breakdown. The critical amplitude of the sinuous perturbations increases when the streamwise streak amplitude is decreased. With secondary perturbations amplitude AW ? 4%, breakdown is induced on stable streamwise streaks with AU ? 13%, following the secondary transient growth scenario first examined by Schoppa and Hussain [J. Fluid Mech. 453, 57 (2002)]. A cross-over, where the critical amplitude of the sinuous perturbation becomes larger than the amplitude of streamwise streaks, is observed for streaks of small amplitude AU < 5%-6%. In this case, the transition is induced by an initial transient amplification of streamwise vortices, forced by the decaying sinuous mode. This is followed by the growth of the streaks and final breakdown. The shape of the critical AU - AW curve is very similar for Couette and boundary layer flows and seems to be relatively insensitive to the nature of the edge states on the basin boundary. The shape of this critical curve indicates that the stability of streamwise streaks should always be assessed in terms of both the streak amplitude and the amplitude of spanwise velocity perturbations.

  12. Overexpression of Rice Black-Streaked Dwarf Virus P7-1 in Arabidopsis Results in Male Sterility Due to Non-Dehiscent Anthers

    PubMed Central

    Sun, Feng; Yuan, Xia; Xu, Qiufang; Zhou, Tong; Fan, Yongjian; Zhou, Yijun

    2013-01-01

    Rice black-streaked dwarf virus (RBSDV), a member of the genus Fijivirus in the family Reoviridae, is propagatively transmitted by the small brown planthopper (Laodelphax striatellus Fallén). RBSDV causes rice black-streaked dwarf and maize rough dwarf diseases, which lead to severe yield losses in crops in China. Although several RBSDV proteins have been studied in detail, the functions of the nonstructural protein P7-1 are still largely unknown. To investigate the role of the P7-1 protein in virus pathogenicity, transgenic Arabidopsis thaliana plants were generated in which the P7-1 gene was expressed under the control of the 35S promoter. The RBSDV P7-1-transgenic Arabidopsis plants (named P7-1-OE) were male sterility. Flowers and pollen from P7-1-transgenic plants were of normal size and shape, and anthers developed to the normal size but failed to dehisce. The non-dehiscent anthers observed in P7-1-OE were attributed to decreased lignin content in the anthers. Furthermore, the reactive oxygen species levels were quite low in the transgenic plants compared with the wild type. These results indicate that ectopic expression of the RBSDV P7-1 protein in A. thaliana causes male sterility, possibly through the disruption of the lignin biosynthesis and H2O2-dependent polymerization pathways. PMID:24260239

  13. Dune and Dust Devil Streaks

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-474, 5 September 2003

    This August 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows a dark sand dune on the floor of a crater at 54.9oS, 342.5oW. Recent dust devils have disrupted a thin coating of dust on the otherwise dark dune; these wind phenomena created the plethora of markings and streaks on the dune. The image covers an area 3 km (1.9 mi) across and is illuminated by sunlight from the upper left.

  14. Enhanced virus resistance in transgenic maize expressing a dsRNA-specific endoribonuclease gene from E. coli.

    PubMed

    Cao, Xiuling; Lu, Yingui; Di, Dianping; Zhang, Zhiyan; Liu, He; Tian, Lanzhi; Zhang, Aihong; Zhang, Yanjing; Shi, Lindan; Guo, Bihong; Xu, Jin; Duan, Xifei; Wang, Xianbing; Han, Chenggui; Miao, Hongqin; Yu, Jialin; Li, Dawei

    2013-01-01

    Maize rough dwarf disease (MRDD), caused by several Fijiviruses in the family Reoviridae, is a global disease that is responsible for substantial yield losses in maize. Although some maize germplasm have low levels of polygenic resistance to MRDD, highly resistant cultivated varieties are not available for agronomic field production in China. In this work, we have generated transgenic maize lines that constitutively express rnc70, a mutant E. coli dsRNA-specific endoribonuclease gene. Transgenic lines were propagated and screened under field conditions for 12 generations. During three years of evaluations, two transgenic lines and their progeny were challenged with Rice black-streaked dwarf virus (RBSDV), the causal agent of MRDD in China, and these plants exhibited reduced levels of disease severity. In two normal years of MRDD abundance, both lines were more resistant than non-transgenic plants. Even in the most serious MRDD year, six out of seven progeny from one line were resistant, whereas non-transgenic plants were highly susceptible. Molecular approaches in the T12 generation revealed that the rnc70 transgene was integrated and expressed stably in transgenic lines. Under artificial conditions permitting heavy virus inoculation, the T12 progeny of two highly resistant lines had a reduced incidence of MRDD and accumulation of RBSDV in infected plants. In addition, we confirmed that the RNC70 protein could bind directly to RBSDV dsRNA in vitro. Overall, our data show that RNC70-mediated resistance in transgenic maize can provide efficient protection against dsRNA virus infection. PMID:23593318

  15. Laminar streak enhancement using streamwise grooves

    NASA Astrophysics Data System (ADS)

    Martel, Carlos; Martín, Juan Ángel

    2011-11-01

    Laminar streak promotion in a flat plate boundary layer results in an increase of the stability of the Tollmien-Schlichting waves with respect to that of the 2D Blasius profile. This stabilization delays the laminar-turbulent transition, increasing the laminar phase of the flow. The stabilization effect is stronger for higher streak amplitudes, and therefore simple ways of generating high amplitude stable streaks are sought to be used as boundary layer flow control methods. In a recent experiment [Tallamelli & Franson,AIAA 2010-4291] high amplitude stable steady streaks have been produced using Miniature Vortex Generators (MGVs), where one array of MGVs is used to excite the streak and a second array is used downstream to enhance their amplitude. In this presentation we numerically explore the possibility of enhancing the streaks using a different passive mechanism: streamwise grooves carved in the plate. We will present some numerical simulations for different values of the spanwise period of the streaks and of the grooves, and we will show the combinations that provide maximum streak amplitude.

  16. Direct readout devices for streak cameras

    Microsoft Academic Search

    J. C. Cheng; S. W. Thomas; E. K. Storm; W. R. McLerran; G. R. Tripp; L. W. Coleman

    1977-01-01

    Two techniques are used to obtain a direct readout of an ultrafast streak camera. The first method uses a linear solid-state Reticon diode array, and the second technique entails the use of a SEC vidicon camera. Both methods use fiber optics to couple the light from the output of the streak camera to the sensor. In addition, the SEC vidicon

  17. Direct readout devices for streak cameras

    Microsoft Academic Search

    J. C. Cheng; S. W. Thomas; E. K. Storm; W. R. McLerran; G. R. Tripp; L. W. Coleman

    1976-01-01

    Two techniques are used to obtain a direct readout of an ultrafast streak camera. The first method uses a linear solid state diode array and the second technique entails the use of a vidicon camera. Both methods use fiber optics to couple the light from the output of the streak camera to the sensor. In addition, the vidicon is interfaced

  18. Wind Streaks on Earth; Exploration and Interpretation

    NASA Astrophysics Data System (ADS)

    Cohen-Zada, Aviv Lee; Blumberg, Dan G.; Maman, Shimrit

    2015-04-01

    Wind streaks, one of the most common aeolian features on planetary surfaces, are observable on the surface of the planets Earth, Mars and Venus. Due to their reflectance properties, wind streaks are distinguishable from their surroundings, and they have thus been widely studied by remote sensing since the early 1970s, particularly on Mars. In imagery, these streaks are interpreted as the presence - or lack thereof - of small loose particles on the surface deposited or eroded by wind. The existence of wind streaks serves as evidence for past or present active aeolian processes. Therefore, wind streaks are thought to represent integrative climate processes. As opposed to the comprehensive and global studies of wind streaks on Mars and Venus, wind streaks on Earth are understudied and poorly investigated, both geomorphologically and by remote sensing. The aim of this study is, thus, to fill the knowledge gap about the wind streaks on Earth by: generating a global map of Earth wind streaks from modern high-resolution remotely sensed imagery; incorporating the streaks in a geographic information system (GIS); and overlaying the GIS layers with boundary layer wind data from general circulation models (GCMs) and data from the ECMWF Reanalysis Interim project. The study defines wind streaks (and thereby distinguishes them from other aeolian features) based not only on their appearance in imagery but more importantly on their surface appearance. This effort is complemented by a focused field investigation to study wind streaks on the ground and from a variety of remotely sensed images (both optical and radar). In this way, we provide a better definition of the physical and geomorphic characteristics of wind streaks and acquire a deeper knowledge of terrestrial wind streaks as a means to better understand global and planetary climate and climate change. In a preliminary study, we detected and mapped over 2,900 wind streaks in the desert regions of Earth distributed in approximately 500 sites. Most terrestrial wind streaks are formed on a relatively young geological surface and are concentrated along the equator (± 30°). They are categorized by the combination of their planform and reflectance; with linear-bright and dark are the most common. A site-specific examination of remote-sensing effects on wind streaks identification has been conducted. The results thus far, indicate that in images with varying spatial and spectral specifications some wind streaks are actually composed of other aeolian bedforms, especially dunes. Specific regions of the Earth were then compared qualitatively to surface wind data extracted from a general circulation model. Understanding the mechanism and spatial and temporal distribution of wind streak formation is important not only for understanding surface modifications in the geomorphological context but also for shedding light on past and present climatic processes and atmospheric circulation on Earth. This study yields an explanation for wind streaks as a geomorphological feature. Moreover, it is in this planet-wide geomorphological research ability to lay down the foundations for comparative planetary research.

  19. Banana streak virus is very diverse in Uganda.

    PubMed

    Harper, Glyn; Hart, Darren; Moult, Sarah; Hull, Roger

    2004-03-01

    Banana streak virus (BSV) is a badnavirus that causes a viral leaf streak disease of banana and plantain (Musa spp.). Identified in essentially all Musa growing areas of the world, it has a deleterious effect on the productivity of infected plants as well as being a major constraint to Musa breeding programmes and germplasm dissemination. Banana is a staple food in Uganda which is, per capita, one of the worlds largest banana producers and consumers. BSV was isolated from infected plants sampled across the Ugandan Musa growing area and the isolates were analysed using molecular and serological techniques. These analyses showed that BSV is very highly variable in Uganda. They suggest that the variability is, in part, due to a series of introductions of banana into Uganda, each with a different complement of infecting viruses. PMID:15036835

  20. Bright Streaks and Dark Fans

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The south polar region of Mars is covered every year by a layer of carbon dioxide ice. In a region called the 'cryptic terrain,' the ice is translucent and sunlight can penetrate through the ice to warm the surface below.

    The ice layer sublimates (evaporates) from the bottom. The dark fans of dust seen in this image come from the surface below the layer of ice, carried to the top by gas venting from below. The translucent ice is 'visible' by virtue of the effect it has on the tone of the surface below, which would otherwise have the same color and reflectivity as the fans.

    Bright streaks in this image are fresh frost. The CRISM team has identified the composition of these streaks to be carbon dioxide.

    Observation Geometry Image PSP_003113_0940 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 26-Mar-2007. The complete image is centered at -85.8 degrees latitude, 106.0 degrees East longitude. The range to the target site was 244.9 km (153.0 miles). At this distance the image scale is 49.0 cm/pixel (with 2 x 2 binning) so objects 147 cm across are resolved. The image shown here has been map-projected to 50 cm/pixel . The image was taken at a local Mars time of 06:20 PM and the scene is illuminated from the west with a solar incidence angle of 79 degrees, thus the sun was about 11 degrees above the horizon. At a solar longitude of 207.6 degrees, the season on Mars is Northern Autumn.

  1. Response to aflatoxin and grain composition of exotic maize germplasm 

    E-print Network

    Corn, Rebecca Joann

    2009-06-02

    Exotic germplasm has potential to provide new alleles for disease and insect resistance. US maize (Zea mays L.) currently lacks genetic resistance to Aspergillus flavus, a fungal pathogen that produces aflatoxin in maize kernels. Aflatoxin is one...

  2. 98 PHYTOPATHOLOGY Genetic Variation of Wheat streak mosaic virus

    E-print Network

    Murray, Timothy D.

    98 PHYTOPATHOLOGY Virology Genetic Variation of Wheat streak mosaic virus in the United States, T. D. 2013. Genetic variation of Wheat streak mosaic virus in the United States Pacific Northwest. Phytopathol- ogy 103:98-104. Wheat streak mosaic virus (WSMV), the cause of wheat streak mosaic

  3. The endobiotic thallus of Physoderma maydis , the causal agent of Physoderma disease of maize

    Microsoft Academic Search

    L. W. Olson; U. M. Edén; L. Lange

    1980-01-01

    Summary The endobiotic thallus ofPhysoderma maydis is characterized by the presence of an extremely fine rhizomycelium which passes through the host cell wall, allowing the spread of the disease, and irregularly shaped “turbinate cells”, which may be septate or nonseptate and which are in close association with developing resting sporangia. The formation of the resting sporangium wall is first seen

  4. Crystal streak camera for infrared light pulse

    Microsoft Academic Search

    Osamu Matsumoto; Yasushi Ohbayashi

    1992-01-01

    A streak camera is used to capture fast light pulses. However, it is limited to the visible and near-infrared regions of the optical spectrum. We investigated deflection of a light beam by use of an electro-optic deflector. The crystal streak camera is based on the direct deflection of light by an electro-optic crystal to an image sensor for recording. The

  5. Wheat Curl Mite and Wheat Streak Mosaic Virus Spread from Volunteer Wheat Figure 2. Spectral profiles at three points identified in Figure

    E-print Network

    Nebraska-Lincoln, University of

    Wheat Curl Mite and Wheat Streak Mosaic Virus Spread from Volunteer Wheat Figure 2. Spectral Management Information Technologies (CALMIT) (apeters@calmit.unl.edu) Background: Wheat streak mosaic (WSM) is the most severe disease of winter wheat in the Great Plains. Estimates indicate WSM causes an average loss

  6. The Primitive Streak, Cross Section

    NSDL National Science Digital Library

    PhD Jack D Thatcher (West Virginia School of Osteopathic Medicine Structural Biology)

    2011-06-23

    This FlashTM animation is the third of a seven part series that presents the primitive streak from different angles. This installment displays the cross section, which is conducive to observing invagination. Epiblast cells ingress through the middle of the germ disc, to differentiate into either endoderm or mesenchymal mesoderm. The endoderm proliferates to drive the hypoblast into the extraembryonic endoderm of the yolk sac. The mesenchyme spreads between the epiblast and endoderm. Although not drawn to scale, the progressive thickening from lateral to paraxial mesoderm is depicted. To open the animation using Internet Explorer follow these steps. (1.) Click the link for the animation. (2.) A dialog box may pop up that begins with the statement "Windows cannot open this file:" If this box does not appear proceed to step four. If it does choose "Select the program from a list," then click OK. (3.) Another dialog box will pop up that lists different programs. Make sure "Internet Explorer" is selected, then click OK. (4.) Internet Explorer will pop up. Beneath the toolbars at the top of the window a yellow bar will appear that reads "To help protect your security, Internet Explorer has restricted this webpage from running scripts or Active X controls that could access your computer. Click here for options..." Pass the cursor over this yellow bar and click the right mouse button. (5.) A dialog box will pop up. Left click the option "Allow Blocked Content." (6.) Another dialog box will appear labeled "Security Warning" asking you to confirm that you want to run the content. Click "Yes." (7.) The Flash animation will appear in the Internet Explorer Window. (8.) Instructions for navigating the lesson are provided by the first frame of the animation.

  7. Different responses of two genes associated with disease resistance loci in maize (Zea mays L.) to 3-allyloxy-1,2-benzothiazole 1,1-dioxide.

    PubMed

    Yuan, Jiazheng; Tedman, Jennifer; Ali, Liakat; Liu, Jie; Taylor, Jeff; Lightfoot, David; Iwata, Michiaki; Pauls, K Peter

    2009-01-01

    Probenazole (3-allyloxy-1,2-benzothiazole 1,1-dioxide, PBZ) is a bactericide and fungicide that acts by inducing plant defense systems. It has been shown to induce the expression of NBS-LRR genes like RPR1 (rice probenazole-response gene) in rice (Oryza sativa L.) and systemic acquired resistance (SAR)-like disease resistance. Two maize (Zea mays L.) genes Zmnbslrr1 (a NBS-LRR gene, cloned from a disease resistance analog PIC11 based) and Zmgc1, (a putative guanylyl cyclase-like gene) have both been associated with quantitative resistance loci (QTL) for resistance to Fusarium graminearum. PIC11 was associated with Fusarium stalk rot and ZmGC1 showed resistance to Gibberella ear rot caused by F. graminearum. The objectives of the current study here were to characterize the Zmnbslrr1 gene and to determine whether it and Zmgc1 respond to the inducer PBZ. The transcript abundance of Zmnbslrr1 expression was significantly reduced in corn seedlings of the Gibberella ear rot resistant genotype CO387 48 h after PBZ treatment. In contrast, the transcript abundance of the maize Zmgc1 gene increased more than 10-fold 8h after the treatment. Therefore, the two genes do not appear to be coordinately regulated by PBZ. PMID:19193968

  8. Mapping QTL Contributing to SCMV Resistance in Tropical Maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugarcane mosaic virus (SCMV) has been increasing in importance as a maize disease in Brazil. In this study, were mapped and characterized quantitative trait loci (QTL) associated to resistance to SCMV in a maize population consisting of 150 F2:3 families from the cross between two tropical maize i...

  9. Hot streak characterization in serpentine exhaust nozzles

    NASA Astrophysics Data System (ADS)

    Crowe, Darrell S.

    Modern aircraft of the United States Air Force face increasingly demanding cost, weight, and survivability requirements. Serpentine exhaust nozzles within an embedded engine allow a weapon system to fulfill mission survivability requirements by providing denial of direct line-of-sight into the high-temperature components of the engine. Recently, aircraft have experienced material degradation and failure along the aft deck due to extreme thermal loading. Failure has occurred in specific regions along the aft deck where concentrations of hot gas have come in contact with the surface causing hot streaks. The prevention of these failures will be aided by the accurate prediction of hot streaks. Additionally, hot streak prediction will improve future designs by identifying areas of the nozzle and aft deck surfaces that require thermal management. To this end, the goal of this research is to observe and characterize the underlying flow physics of hot streak phenomena. The goal is accomplished by applying computational fluid dynamics to determine how hot streak phenomena is affected by changes in nozzle geometry. The present research first validates the computational methods using serpentine inlet experimental and computational studies. A design methodology is then established for creating six serpentine exhaust nozzles investigated in this research. A grid independent solution is obtained on a nozzle using several figures of merit and the grid-convergence index method. An investigation into the application of a second-order closure turbulence model is accomplished. Simulations are performed for all serpentine nozzles at two flow conditions. The research introduces a set of characterization and performance parameters based on the temperature distribution and flow conditions at the nozzle throat and exit. Examination of the temperature distribution on the upper and lower nozzle surfaces reveals critical information concerning changes in hot streak phenomena due to changes in nozzle geometry.

  10. Martian Slope Streaks Form Sporadically Throughout the Year

    NASA Astrophysics Data System (ADS)

    King, C. M.; Schorghofer, N.; Wagstaff, K. L.

    2010-03-01

    Time constraints for the formation of dark slope streaks on Mars are derived from multi-overlap orbital images. We find that slope streaks form sporadically throughout the year, which has implications for possible triggering mechanisms.

  11. Martian crater dark streak lengths - Explanation from wind tunnel experiments

    NASA Astrophysics Data System (ADS)

    Iversen, J. D.; Greeley, R.

    1984-06-01

    The mechanism determining the length of dark erosional (type-Id) streaks near craters and hills on the surface of Mars is investigated using Mariner-9 images and the results of wind-tunnel studies (Greeley et al., 1974; Iversen et al., 1975 and 1976). An empirical model of time-dependent growth of crater-wake streaks in the downwind direction involving deflation by sand-grain saltation is developed and shown to give relatively good agreement with streak growth rates observed over a 38-day period of Mariner observations and with the streak-length/crater-diameter and streak-length/crater-height ratios analyzed statistically by Lee (1984). This time-dependent mechanism is thus considered a reasonable alternative (for dark streaks) to the blocking model proposed by Lee for both bright and dark streaks. Preliminary analysis of further wind-tunnel experiments (Iversen et al., 1982) supports the blocking model of bright-streak formation.

  12. Stable Resistance to Wheat streak mosaic virus in wheat mediated by RNAi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat streak mosaic virus (WSMV) is one of the major wheat viruses in the Great Plains of the United States. Cultural practices are the primary method of disease management, though not fully effective. Genetic resistance is available but is temperature sensitive. Alternative approaches to viral res...

  13. First report of bacterial streak of fennel (Foeniculum vulgare) in California caused by Pseudomonas syringae pv. apii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new bacterial streak disease appeared on fennel leaves, stems and bulbs grown in Salinas California production fields. Initial symptoms consisted of small black lesions on stems that spread down the stem to the bulbs and up the stem to leaves as the disease progressed. The disease rendered the pl...

  14. Comparative characteristics of various phosphor screens in streak tubes

    Microsoft Academic Search

    N. I. Ageeva; G. I. Brykhnevich; B. Z. Gorbenko; S. P. Ivanova; T. P. Kulichenkova; Zoya M. Semichastnova; T. A. Skiballanovich; Mikhail Y. Schelev

    1999-01-01

    Effectiveness decrease of the phosphor screens of the P11 and P20 types for streak tubes in the picosecond region is shown. It is shown that the complete amplification of the circuit 'streak tube + image intensifier + CCD' in the picosecond region is the same as one of the circuit 'streak tube + etched CCD instead of the screen in

  15. Perception of Randomness: On the Time of Streaks

    ERIC Educational Resources Information Center

    Sun, Yanlong; Wang, Hongbin

    2010-01-01

    People tend to think that streaks in random sequential events are rare and remarkable. When they actually encounter streaks, they tend to consider the underlying process as non-random. The present paper examines the time of pattern occurrences in sequences of Bernoulli trials, and shows that among all patterns of the same length, a streak is the…

  16. Streaks Of Colored Water Indicate Surface Airflows

    NASA Technical Reports Server (NTRS)

    Wilcox, Floyd J., Jr.

    1994-01-01

    Response faster and contamination less than in oil-flow technique. Flowing colored water provides accurate and clean way to reveal flows of air on surfaces of models in wind tunnels. Colored water flows from small orifices in model, forming streak lines under influence of air streaming over surface of model.

  17. Structure-Based Computational Study of Two Disease Resistance Gene Homologues (Hm1 and Hm2) in Maize (Zea mays L.) with Implications in Plant-Pathogen Interactions

    PubMed Central

    Maharana, Jitendra; Sahu, Jagajjit; Sen, Priyabrata; Modi, Mahendra Kumar; Choudhury, Manabendra Dutta; Barooah, Madhumita

    2014-01-01

    The NADPH-dependent HC-toxin reductases (HCTR1 and 2) encoded by enzymatic class of disease resistance homologous genes (Hm1 and Hm2) protect maize by detoxifying a cyclic tetrapeptide, HC-toxin, secreted by the fungus Cochliobolus carbonum race 1(CCR1). Unlike the other classes' resistance (R) genes, HCTR-mediated disease resistance is an inimitable mechanism where the avirulence (Avr) component from CCR1 is not involved in toxin degradation. In this study, we attempted to decipher cofactor (NADPH) recognition and mode of HC-toxin binding to HCTRs through molecular docking, molecular dynamics (MD) simulations and binding free energy calculation methods. The rationality and the stability of docked complexes were validated by 30-ns MD simulation. The binding free energy decomposition of enzyme-cofactor complex was calculated to find the driving force behind cofactor recognition. The overall binding free energies of HCTR1-NADPH and HCTR2-NADPH were found to be ?616.989 and ?16.9749 kJ mol?1 respectively. The binding free energy decomposition revealed that the binding of NADPH to the HCTR1 is mainly governed by van der Waals and nonpolar interactions, whereas electrostatic terms play dominant role in stabilizing the binding mode between HCTR2 and NADPH. Further, docking analysis of HC-toxin with HCTR-NADPH complexes showed a distinct mode of binding and the complexes were stabilized by a strong network of hydrogen bond and hydrophobic interactions. This study is the first in silico attempt to unravel the biophysical and biochemical basis of cofactor recognition in enzymatic class of R genes in cereal crop maize. PMID:24847713

  18. Clinical comparison of the Welch Allyn SureSight™ handheld autorefractor versus streak retinoscopy in dogs

    PubMed Central

    Groth, Allyson D.; Hollingsworth, Steven R.; Ofri, Ron; Kass, Philip H.; Reed, Zoe; Murphy, Christopher J.

    2013-01-01

    Objective To compare the Welch Allyn SureSight™ wavefront autorefractor with retinoscopy in normal dogs. Animals studied 50 privately-owned dogs (100 eyes) of 20 breeds, free of ocular disease. Mean ±SD age 5.7 ± 3.25 years (range: 6 months – 13 years). Procedures The refractive error was determined in each eye by two experienced retinoscopists using streak retinoscopy as well as by an autorefractor operated by two different examiners. Measurements were performed before and approximately 30–45 minutes after cycloplegia was induced by cyclopentolate 0.5% and tropicamide 0.5% ophthalmic solutions. Results Mean ±SD non-cyclopleged retinoscopy net sphere was ?0.55 ± 1.14 (range: ?3.75 to 3.5) diopters (D). Mean cyclopleged retinoscopy net sphere was ?0.52 ±1.18 (range: ?4.25 to 2) D. Mean ± SD non-cyclopleged autorefractor spherical equivalent (SE) was ?0.42 ± 1.13D (range: ?3.36 to 2.73) D. Mean cyclopleged autorefractor spherical equivalent was 0.10 ±1.47 (range: ?5.62 to 3.19) D. Non-cyclopleged autorefraction results were not significantly different from streak retinoscopy (whether non-cyclopleged or cyclopleged, p=0.80, 0.26, respectively). Cyclopleged autorefraction results were significantly different from non-cyclopleged or cyclopleged streak retinoscopy (p<0.0001 in both states). There was no significant difference between non-cyclopleged and cyclopleged streak retinoscopy (p= 0.97). Conclusions Non-cyclopleged autorefraction shows good agreement with streak retinoscopy in dogs and may be a useful clinical technique. Cycloplegia does not significantly affect streak retinoscopy results in dogs. PMID:23173899

  19. Black Streak of Edible Burdock Caused by Itersonilia perplexans in Japan

    Microsoft Academic Search

    Harukuni HORITA; Shinji YASUOKA

    2002-01-01

      Black streak disease of edible burdock (Arctium lappa L.) has been observed periodically in Hokkaido Prefecture, Japan since 1988. Symptoms appeared initially as small, dark brown\\u000a to black spots on the leaf veins and petioles. The necrotic spots developed longitudinally along the leaf veins or petioles.\\u000a Diseased leaf veins or petioles occasionally snapped off at the necrotic lesions. An Itersonilia

  20. Association mapping of quantitative trait loci responsible for resistance to Bacterial Leaf Streak and Spot Blotch in spring wheat landraces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial leaf streak (BLS), caused by Xanthomonas translucens pv. undulosa, and spot blotch (SB), caused by Cochliobolus sativus are two major diseases of wheat (Triticum aestivum L.). Planting resistant cultivars is the best approach to manage these diseases and identifying new sources of resistan...

  1. Virus-independent and common transcriptome responses of leafhopper vectors feeding on maize infected with semi-persistently and persistent propagatively transmitted viruses

    PubMed Central

    2014-01-01

    Background Insects are the most important epidemiological factors for plant virus disease spread, with >75% of viruses being dependent on insects for transmission to new hosts. The black-faced leafhopper (Graminella nigrifrons Forbes) transmits two viruses that use different strategies for transmission: Maize chlorotic dwarf virus (MCDV) which is semi-persistently transmitted and Maize fine streak virus (MFSV) which is persistently and propagatively transmitted. To date, little is known regarding the molecular and cellular mechanisms in insects that regulate the process and efficiency of transmission, or how these mechanisms differ based on virus transmission strategy. Results RNA-Seq was used to examine transcript changes in leafhoppers after feeding on MCDV-infected, MFSV-infected and healthy maize for 4 h and 7 d. After sequencing cDNA libraries constructed from whole individuals using Illumina next generation sequencing, the Rnnotator pipeline in Galaxy was used to reassemble the G. nigrifrons transcriptome. Using differential expression analyses, we identified significant changes in transcript abundance in G. nigrifrons. In particular, transcripts implicated in the innate immune response and energy production were more highly expressed in insects fed on virus-infected maize. Leafhoppers fed on MFSV-infected maize also showed an induction of transcripts involved in hemocoel and cell-membrane linked immune responses within four hours of feeding. Patterns of transcript expression were validated for a subset of transcripts by quantitative real-time reverse transcription polymerase chain reaction using RNA samples collected from insects fed on healthy or virus-infected maize for between a 4 h and seven week period. Conclusions We expected, and found, changes in transcript expression in G. nigrifrons feeding of maize infected with a virus (MFSV) that also infects the leafhopper, including induction of immune responses in the hemocoel and at the cell membrane. The significant induction of the innate immune system in G. nigrifrons fed on a foregut-borne virus (MCDV) that does not infect leafhoppers was less expected. The changes in transcript accumulation that occur independent of the mode of pathogen transmission could be key for identifying insect factors that disrupt vector-mediated plant virus transmission. PMID:24524215

  2. X-ray streak crystal spectography

    SciTech Connect

    Kauffman, R.L.; Brown, T.; Medecki, H.

    1983-07-01

    We have built an x-ray streaked crystal spectrograph for making time-resolved x-ray spectral measurements. This instrument can access Bragg angles from 11/sup 0/ to 38/sup 0/ and x-ray spectra from 200 eV to greater than 10 keV. We have demonstrated resolving powers, E/..delta..E > 200 at 1 keV and time resolution less than 20 psec. A description of the instrument and an example of the data is given.

  3. Wind streaks: geological and botanical effects on surface albedo contrast

    NASA Astrophysics Data System (ADS)

    Zimbelman, James R.; Williams, Steven H.

    1996-09-01

    Two wind streaks in the eastern Mojave Desert of California were examined to gain insight into the origin of the surface brightness contrast that makes them visible, both on the ground and in remote sensing data. The two localities are: a 4-km-long dark streak oriented S43E from the Amboy cinder cone (34°32'N, 115°46'W), located on a Quaternary basalt flow covered with aeolian sand, and a 2-km-long dark streak oriented S22E from a low hill near the southwestern base of Sleeping Beauty Mountain (34°48'N, 116°20'W), located on a sand-covered alluvial surface. In both cases, the dark streaks have enhanced rock abundances on the streak surface, relative to the surroundings. At the Amboy streak, slope wash likely contributed to the rock concentration on the streak surface, shielded from burial under aeolian sand by the cinder cone. At the Sleeping Beauty streak, the relative albedo contrast is strongly emphasized by the presence of Big Galleta grass only outside of the streak. The albedo contrast of the Sleeping Beauty streak can be effectively eliminated by the seasonal presence of annual grass preferentially within the streak. Some plants may have reflectances that are strongly dependent upon viewing and illumination geometry, raising the possibility that certain terrestrial aeolian features may appear variable on a diurnal basis. Alluvial processes appear to have been important at both localities for redistributing surface materials, even given the infrequent rain conditions present in the Mojave Desert.

  4. Biolistic Protocol Organism: Maize

    E-print Network

    Raizada, Manish N.

    Biolistic Protocol Organism: Maize In vivo/in vitro/in situ: in vitro Target tissue: Callus Instrument: PDS-1000/He System Tissue preparation: Maize, callus 28°C (N6 salts). Callus is initiated on high

  5. Angioid streaks. I. Ophthalmoscopic variations and diagnostic problems

    Microsoft Academic Search

    J. A. Shields; J. L. Federman; T. L. Tomer; W. H. Annesley

    1975-01-01

    Fifty-six patients with angioid streaks were evaluated ophthalmologically. Most had repeated fundus photography and fluorescein angiography during a follow-up period of 6 months to 7 years. The ophthalmoscopic variations and diagnostic difficulties which occurred were noted. In most instances, the angioid streaks were not initially recognized and the patient was referred with another diagnosis. In several cases, the peripapillary, macular,

  6. AGRONOMIC AND QUALITY EFFECTS IN WINTER WHEAT OF A GENE CONDITIONING RESISTANCE TO WHEAT STREAK MOSAIC VIRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat streak mosaic virus (WSMV) is one of the most important diseases limiting winter wheat (Triticum aestivum L.) production in the western Great Plains of North America. There is no known effective WSMV resistance within the primary gene pool of wheat. However, a resistance gene (Wsm1) has been...

  7. SDOSS: a spatially discriminating, optical streaked spectrograph

    SciTech Connect

    Cobble, J.A.; Evans, S.C.; Fernandez, J.C.; Oertel, J.A.; Watt, R.G.; Wilde, B.H. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1996-05-01

    SDOSS is employed to study broadband laser scattering encompassing SBS, SRS, and the 3/2-{omega} signature of two plasmon decay for ns-scale laser-plasma experiments with 351- or 527-nm drive. It uses a Cassegrain telescope to image scattered light from a laser plasma onto a field stop. The telescope magnification and the stop aperture provide spatial discrimination of target plane scatter. A UV lens relays the image to a 0.25-m spectrograph which is lens coupled to a streak camera with an S-1 photocathode. The streak output is imaged onto a CCD camera. In its 512{times}480 pixel array, the CCD covers a spectral range from 200 to 800 nm with 4-nm resolution and can be adjusted to look from 350 to 1060 nm. The sweep speed is variable with full window values of 30, 12, 6 ns, and faster. An optical fiducial provides a spectral and temporal marker. On the Livermore Nova laser, SDOSS has been used to determine spatial density in gas-filled hohlraums from SRS signals. At Trident in Los Alamos, it has been employed for similar measurements with long scale length plasmas in SBS and SRS seeding experiments. It has proven to be a versatile tool for studying the physics of laser-generated plasmas. {copyright} {ital 1996 American Institute of Physics.}

  8. SDOSS: A spatially discriminating, optical streaked spectrograph

    SciTech Connect

    Cobble, J.; Evans, S.; Fernandez, J.; Oertel, J.; Watt, R.; Wilde, B.

    1995-05-01

    SDOSS is employed to study broadband laser scattering encompassing SBS, SRS, and the 3/2-{omega} signature of two plasmon decay for ns-scale laser-plasma experiments with 351 or 527-nm drive. It uses a Cassegrain telescope to image scattered light from a laser plasma onto a field stop. The telescope magnification and the stop aperture provide spatial discrimination of target plane scatter. A UV lens relays the image to a 0.25-m spectrograph which is lens coupled to a streak camera with an S-1 photocathode. The streak output is imaged onto a CCD camera. In its 512 x 480 pixel array, the CCD covers a spectral range from 200 to 800 nm with 4-nm resolution and can be adjusted to look from 350 to 1,060 nm. The sweep speed is variable with full window values of 30, 12, 6 ns, and faster. An optical fiducial provides a spectral and temporal marker. On the Livermore Nova laser, SDOSS has been used to determine spatial density in gas-filled hohlraums from SRS signals. At Trident in Los Alamos, it has been employed for similar measurements with long scale length plasmas in SBS and SRS seeding experiments. It has proven to be a versatile tool for studying the physics of laser-generated plasmas.

  9. Incidence of Fusarium spp. and Levels of Fumonisin B 1 in Maize in Western Kenya

    Microsoft Academic Search

    C. J. KEDERA; R. D. PLATTNER; A. E. DESJARDINS

    1999-01-01

    Maize kernel samples were collected in 1996 from smallholder farm storages in the districts of Bomet, Bungoma, Kakamega, Kericho, Kisii, Nandi, Siaya, Trans Nzoia, and Vihiga in the tropical highlands of west- ern Kenya. Two-thirds of the samples were good-quality maize, and one-third were poor-quality maize with a high incidence of visibly diseased kernels. One hundred fifty-three maize samples were

  10. Maize resistance to gibberella ear rot: symptoms, deoxynivalenol, and yield

    Microsoft Academic Search

    B. Vigier; L. M. Reid; L. M. Dwyer; D. W. Stewart; R. C. Sinha; J. T. Arnason; G. Butler

    2001-01-01

    To investigate the effect of different environments on maize resistance to gibberella ear rot, disease symptoms, deoxynivalenol (DON) concentration, and grain yield were measured in three maize (Zea mays L.) inbred lines and five hybrids, from 1994 to1996, at six locations in eastern Canada. At each location, all genotypes were inoculated with a three-isolate macroconidial mix of Fusarium graminearum Schwabe

  11. Numerical Simulations of Recently Observed Dark Streaks on Mars

    NASA Astrophysics Data System (ADS)

    Hier Majumder, C. A.; Travis, B.

    2003-12-01

    Recently observed dark streaks on Mars appear to be formed by a flowing fluid, possibly originating from melting ice. These streaks have been seen to form in a matter of months. They are markedly different from dust devil streaks in that they are very straight rather than twisting and curly. The dark streaks also only appear in regions where the temperature is right at 275 K, the triple point of water on Mars. Two hypotheses (of several) for their formation are that lighter dust sticks to a wet surface or brines precipitate a light rock varnish. The purpose of our study is to use numerical models to determine if the patterns associated with these dark streaks can be produced by a fluid flowing from a point source. We have used a 2-D model for fluid flow in a sloping porous medium, using the Richard's approximation of partially saturated fluid flow. The model is calculated using the TRACR3D code with water as the fluid. Our models show patterns similar to the dark streak patterns seen on Mars. We have varied the strength of the fluid source, the slope of the terrain, and the strength of capillary pressure in the porous medium to explore the range of features seen in the dark streaks. We have examined both continous and finite time sources. In future work, we will look at the effect of dissolved CO2 in the fluid along with using brines that may precipitate minerals.

  12. The formation of streak defects on anodized aluminum extrusions

    NASA Astrophysics Data System (ADS)

    Zhu, Hanliang; Zhang, Xinquan; Couper, Malcolm J.; Dahle, Arne K.

    2010-05-01

    Streaking is a common surface defect on anodized extrusions of 6xxx series soft alloys. Very often, the defects only become apparent after anodizing, which makes it difficult to identify their root cause. In industry practice, a trial-and-error method has been taken to reduce the intensities of the streak defects, greatly increasing the fabrication cost. This paper describes the formation mechanism of various streak defects on the basis of a literature review and experimental results. This provides a basis for developing effective measures for preventing the formation of these defects for the extrusion industry.

  13. Gated neutron streak camera with a uranium cathode

    SciTech Connect

    Miyanaga, N.; Oida, H.; Yamanaka, M.; Yamanaka, T.; Nakai, S. (Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565 (Japan)); Yamamoto, T. (Institute for Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567 (Japan)); Iida, T.; Araki, T.; Ohga, T.; Miyake, C. (Department of Nuclear Engineering, Faculty of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565 (Japan))

    1990-11-01

    A gated neutron streak camera with a uranium oxide cathode has been developed for laser fusion experiments. The energy spectrum of secondary electrons was improved by coating the uranium oxide cathode with thin cesium iodine. The tube design was carried out by computer calculation of electron trajectories. The newly developed streak tube showed a temporal resolution of about 70 ps. This streak camera can be applicable to a neutron yield greater than 10{sup 12} with a reasonable signal-to-noise ratio by gating a microchannel plate electron multiplier.

  14. Gated neutron streak camera with a uranium cathode (abstract)

    SciTech Connect

    Miyanaga, N.; Oida, H.; Yamanaka, M.; Yamanaka, T.; Nakai, S. (Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565 (Japan)); Yamamoto, T. (Institute for Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567 (Japan)); Iida, T.; Araki, T.; Ohga, T.; Miyake, C. (Department of Nuclear Engineering, Faculty of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565 (Japan))

    1990-10-01

    A gated neutron streak camera with a uranium oxide cathode has been developed for laser fusion experiments. The energy spectrum of secondary electrons was improved by coating the uranium oxide cathode with thin cesium iodine. The tube design was carried out by computer calculation of electron trajectories. The newly developed streak tube showed a temporal resolution of about 70 ps. This streak camera can be applicable to a neutron yield greater than 10{sup 12} with a reasonable signal-to-noise ratio by gating a microchannel plate electron multiplier.

  15. Progress on Modeling of Ultrafast X-Ray Streak Cameras

    SciTech Connect

    Huang, G.; Byrd, J.M.; Feng, J.; Qiang, J.; Wang, W.

    2007-06-22

    Streak cameras continue to be useful tools for studying phenomena on the picoseconds time scale. We have employed accelerator modeling tools to understand and possibly improve the time resolution of present and future streak cameras. This effort has resulted in an end-to-end model of the camera. This model has contributed to the recent measurement of 230 fsec (FWHM) resolution measured at 266 nm in the Advanced Light Source Streak Camera Laboratory. We describe results from this model that show agreement with the experiments. We also extrapolate the performance of this camera including several possible improvements.

  16. Temporal Contrast Changes in Dark Slope Streaks on Mars

    NASA Astrophysics Data System (ADS)

    Chilton, H.; Phillips, C. B.; Fenton, L. K.; Brown, A. J.

    2012-12-01

    Dark slope streaks on Mars, first observed in Viking images, provide insight into one of the most active and dynamic processes observed on the planet's surface. While various formation models have been suggested [1][2][3], dust avalanches seem to best explain streak origin and characteristics[4][5]. New dark streaks are observed to have the greatest contrast to their surroundings while older streaks have lower contrast, suggesting that streaks fade over time. One theory for this is atmospheric dust fallout slowly raising the albedo of the surface exposed by the dust avalanche, resulting in increased streak albedo over time until the streak becomes indistinguishable from the surrounding surface. In this study, we attempt an initial evaluation of changes in streak brightness relative to surroundings, with a first order correction for incidence angle[6] based on MOLA data. CRISM images were first identified for spatial and temporal overlap, then further selected for those image sets with well-matched viewing geometries. Locations included Nicholson Crater (CRISM images: frt0000c287_07_de165l, hrl0000d0f1_7_de165l, frt00018c69_07_de165l) and South of Nestus Valles (CRISM images: hrl00004a5e_07_de181l, hrl0000812a_07_de182l) as well as Naktong Vallis (CRISM images: hrl0000898d_07_de182l, hrl00005337_07_de182l) and an area in Lycus Sulci (CRISM images: hrl0000a52a_07_de166l, hrl0000ce5f_07_if175l). We focused on 1 micron wavelength CRISM images in order to reduce atmosphric interference. From here, brightness (observed radiance divided by solar irradiance at Mars divided by pi) values were collected along individual streaks, with measurements at multiple locations along the streak length and alongside at points of similar elevation to streak measurements to establish an average contrast ratio. Both on-streak and off-streak values were divided by the cosine of their respective local MOLA incidence angles to correct for brightness variation due to solar flux and topographic angles. These measurements were then repeated for overlapping temporal images, establishing local and overall averages for the rate of change in this contrast ratio. While our initial hypothesis was for linear streak fading, results showed a range of trends, including streaks and imaged areas with streaks that darkened, brightened, and brightened then darkened or vice versa. We continue to explore the possibility of non-linear brightening as well as streak reactivation and localized events, surface characteristics, and topography. Further study will focus on these and other morphological changes observed from vast data sets of other instruments including the Mars Reconnaissance Orbter HiRISE and CTX, Mars Express HRSC, Mars Odyssey THEMIS (visible), and the Mars Global Surveyor MOC. [1] Morris (1982) JGR, 87, 1164-1178. [2] Ferguson and Lucchita (1984) NASA Tech. Memo., TM-86246, 188-190. [3] Miyamoto, H. et al. (2004) JGR, 109, E06008. [4] Sullivan, R. et al. (2001) JGR, 106, 23607-23633. [5] Baratoux, N. M. et al. (2006) Icarus, 183, 30-45. [6] Brown, A. et al. (2010) JGR, 115, E00D13.

  17. Vascular Streak Dieback of cacao in Southeast Asia detection and Melanesia: in planta detection of the pathogen and a new taxonomy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vascular Streak Dieback (VSD) disease of cacao (Theobroma cacao) in Southeast Asia and Melanesia is caused by a basidiomycete (Ceratobasidiales) fungus described in a monotypic genus as Oncobasidium theobromae (syn. =Thanatephorus theobromae). The symptoms of the disease include green-spotted chloro...

  18. Wheat Diseases Atlas.

    E-print Network

    McCoy, Norman L.; Berry, Robert W.

    1982-01-01

    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Barley Yellow Dwarf (Virus) . . . . . . . . . . . . . . . . 9 Wheat Streak Mosaic (Virus) . . . . . . . . . . . . . . . IO Wheat (Soilborne) Mosaic (Virus) . . . . . . . . . . . IO STEM AND HEAD DISEASES .............. II Glume Blotch... . . . . . . . . . . . . . . . . . . . . . . . . . . . I5 Yellow Berry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I5 Storage Molds . . . . . . . . . . . . . . . . . . . . . . . . . . . . I6 HERBICIDE INJURY TO WHEAT . . . . . . . . . . . 16 Low Fertility...

  19. Active Processes: Bright Streaks and Dark Fans

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2

    In a region of the south pole known informally as 'Ithaca' numerous fans of dark frost form every spring. HiRISE collected a time lapse series of these images, starting at Ls = 185 and culminating at Ls = 294. 'Ls' is the way we measure time on Mars: at Ls = 180 the sun passes the equator on its way south; at Ls = 270 it reaches its maximum subsolar latitude and summer begins.

    In the earliest image (figure 1) fans are dark, but small narrow bright streaks can be detected. In the next image (figure 2), acquired at Ls = 187, just 106 hours later, dramatic differences are apparent. The dark fans are larger and the bright fans are more pronounced and easily detectable. The third image in the sequence shows no bright fans at all.

    We believe that the bright streaks are fine frost condensed from the gas exiting the vent. The conditions must be just right for the bright frost to condense.

    Observation Geometry Image PSP_002622_0945 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 16-Feb-2007. The complete image is centered at -85.2 degrees latitude, 181.5 degrees East longitude. The range to the target site was 246.9 km (154.3 miles). At this distance the image scale is 49.4 cm/pixel (with 2 x 2 binning) so objects 148 cm across are resolved. The image shown here has been map-projected to 50 cm/pixel . The image was taken at a local Mars time of 05:46 PM and the scene is illuminated from the west with a solar incidence angle of 88 degrees, thus the sun was about 2 degrees above the horizon. At a solar longitude of 185.1 degrees, the season on Mars is Northern Autumn.

  20. Study of Geometric Parameters of Slope Streaks on Mars.

    NASA Astrophysics Data System (ADS)

    Brusnikin, Eugene; Kreslavsky, Mikhail; Karachevtseva, Irina; Zubarev, Anatoliy; Patratiy, Vyacheslav

    2015-04-01

    Slope streaks are a unique active phenomenon observed in low-latitude dusty regions on Mars. They are dark markings formed by an unknown type of run-away downslope propagation of surface disturbance. There are two kinds of hypotheses of their formation mechanism: "dry", involving granular follow, in particular, dust avalanche, and "wet", involving liquid flow, in particular, percolation of concentrated brines in shallow subsurface (1). Study of geometric characteristics of the slope streaks, especially their slopes, is a way to decipher their origin. We are carrying out an extensive set of measurements of geometric parameters of the slope streaks. We use stereo pairs of images obtained by High Resolution Imaging Science Experiment (HiRISE) onboard MRO orbital mission to Mars. These stereo pairs potentially allow geometric measurements (both horizontal and vertical) with accuracy on an order of a meter. Unfortunately, the digital terrain model is currently released for only one stereo pair in the regions of slope streak occurrence, and we have to work with raw, unprocessed stereo pairs. We perform direct photogrammetric measurements using PHOTOMOD software complex (http://www.racurs.ru/). We use our custom software to import "raw" HiRISE imgas (EDRs) and supplementary geometric information from SPICE into PHOTOMOD (2). We select tens to a hundred meters long segments in the beginning and the end of selected streaks and register length, azimuth, and slope of each segment. We also search for anomalously gentle parts of streaks. We analyze the obtained results by means of ESRI ArcGIS software. Our survey is in progress. So far we registered over a hundred of streaks. We found that the extent of the streaks varies from several meters to hundreds of meters. The streaks are formed in locales with a slope from 17 to 37 degrees. The lower boundary indicates that the streaks can propagate on slopes that are significantly gentler than the static angle of repose. Distal (downslope) termini of the streaks often are in rather flat sites. So far we have not found any convincing example of a streak propagating uphill. This is consistent with earlier conclusions that the streaks do not have appreciable inertia. We will continue our survey. With more data we will correlate streak formation and their slopes with slope orientation, latitude, etc. This work was carried out in MIIGAiK and supported by Russian Science Foundation, project 14-22-00197. References: 1. Kreslavsky A.M. and J. W. Head, Slope streaks on Mars: A new "wet" mechanism, Icarus 201, 517-527 (2009). 2. Zubarev A., Nadezhdina I. Alignment-Calibration and Processing of HIRISE CCD Data // ISPRS Meeting of the Working Group IV/8 "Advances in Planetary Mapping and Spatial Databases", Moscow, Russia, October 09-12, 2013

  1. First report of Maize chlorotic mottle virus and maize (corn) lethal necrosis in Kenya

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In September 2011, high incidence of a new maize (Zea mays L.) disease was reported at lower elevations (1900 masl) in the Longisa division of Bomet County, Southern Rift Valley of Kenya. Later the disease was noted in Bomet Central division, spreading into the neighboring Chepalungu and Narok South...

  2. Semiclassical model for attosecond angular streaking.

    PubMed

    Smolarski, M; Eckle, P; Keller, U; Dörner, R

    2010-08-16

    Attosecond angular streaking is a new technique to achieve unsurpassed time accuracy of only a few attoseconds. Recently this has been successfully used to set an upper limit on the electron tunneling delay time in strong laser field ionization. The measurement technique can be modeled with either the time-dependent Schrödinger equation (TDSE) or a more simple semiclassical approach that describes the process in two steps in analogy to the three-step model in high harmonic generation (HHG): step one is the tunnel ionization and step two is the classical motion in the strong laser field. Here we describe in detail a semiclassical model which is based on the ADK theory for the tunneling step, with subsequent classical propagation of the electron in the laser field. We take into account different ellipticities of the laser field and a possible wavelength-dependent ellipticity that is typically observed for pulses in the two-optical-cycle regime. This semiclassical model shows excellent agreement with the experimental result. PMID:20721150

  3. Identification of multiple ear-colonizing insect and disease resistance in CIMMYT maize inbred lines with varying levels of silk maysin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ninety four corn inbred lines selected from International Center for the Improvement of Maize and Wheat (CIMMYT) in Mexico were evaluated for levels of silk maysin in 2001 and 2002. Damage by major ear-feeding insects [i.e., the corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), the m...

  4. Dynamics of low-speed streak evolution and interaction in laminar boundary layer

    NASA Astrophysics Data System (ADS)

    Deng, Si-Chao; Pan, Chong; Wang, Jin-Jun

    2014-10-01

    The present paper presents an experimental effort on the regeneration process of two low-speed laminar streaks in a zero-pressure-gradient laminar boundary layer. Two vertical thin wires separated by a spanwise distance of 30mm are used to introduce disturbances of two rolls of transitional Kármán vortex street to the downstream boundary layer. Both hydrogen bubble visualization and particle image velocimetry (PIV) measurement show that two low-speed streaks are induced through leading-edge receptivity process. As these streaks develop in the downstream, two additional low-speed streaks begin to appear outboard of the flank of the original two, together with complex dynamics of streak splitting and merging. A flow pattern of four streaks aligned along the spanwise direction occurs finally in the far downstream. It is found that besides the mechanisms of streak breakdown, the streak interaction is also an important factor characterizing the instability of low speed streaks and their regeneration process.

  5. MAIZE ALLELIC DIVERSITY PROJECT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Of the estimated 250-300 races of maize, only 24 races are represented in materials utilized by the Germplasm Enhancement of Maize (GEM) project, a collaborative effort between USDA-ARS and public and private sector research scientists. This is largely a result of poor performance of many races in ...

  6. Sorghum and Maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sorghum and maize are closely related cereal grains grown throughout the world. Sorghum, a drought tolerant crop grown in semi-arid regions, is a basic food staple in many parts of the developing world, while primarily an animal feed in western countries. Maize, a major worldwide crop, is used for...

  7. Genetic structure of rice black-streaked dwarf virus populations in China.

    PubMed

    Yin, Xiao; Zheng, Fang-Qiang; Tang, Wei; Zhu, Qin-Qin; Li, Xiang-Dong; Zhang, Guang-Min; Liu, Huan-Ting; Liu, Bao-Shen

    2013-12-01

    Rice black-streaked dwarf virus (RBSDV) is a double-stranded RNA (dsRNA) virus belonging to the genus Fijivirus in the family Reoviridae. The genome of RBSDV consists of ten dsRNA segments. Although RBSDV has caused significant economic losses to rice and maize production in the past few years in China, its molecular diversity and evolution remain largely unknown. To elucidate the factor(s) underlying the evolution of RBSDV, we determined segment 8 (S8; carrying ORF8 encoding the minor core capsid protein) sequences of 101 samples and segment 10 (S10; carrying ORF10 encoding the major capsid protein) sequences of 103 samples. The results show that both ORF8 and ORF10 are under negative selection. The S8 of three isolates and S10 of two isolates are recombinants. The RBSDV population in China can be classified into three groups according to S8 sequences or into two groups according to S10 sequences, irrespective of host or geographical origin. Of the RBSDV isolates with both S8 and S10 sequences available, 17 are between-group reassortants and 30 are between-subgroup reassortants. The RBSDV subpopulations from different geographical regions and hosts show frequent gene flow within or between subpopulations. The RBSDV population from maize is in a state of expansion. In this study, no new emergent population was detected. Taken together, the results indicate that, in addition to recombination and negative selection, reassortment and gene flow are important factors that drive evolution of RBSDV in China. PMID:23807744

  8. Hitting Is Contagious in Baseball: Evidence from Long Hitting Streaks

    PubMed Central

    Bock, Joel R.; Maewal, Akhilesh; Gough, David A.

    2012-01-01

    Data analysis is used to test the hypothesis that “hitting is contagious”. A statistical model is described to study the effect of a hot hitter upon his teammates’ batting during a consecutive game hitting streak. Box score data for entire seasons comprising streaks of length games, including a total observations were compiled. Treatment and control sample groups () were constructed from core lineups of players on the streaking batter’s team. The percentile method bootstrap was used to calculate confidence intervals for statistics representing differences in the mean distributions of two batting statistics between groups. Batters in the treatment group (hot streak active) showed statistically significant improvements in hitting performance, as compared against the control. Mean for the treatment group was found to be to percentage points higher during hot streaks (mean difference increased points), while the batting heat index introduced here was observed to increase by points. For each performance statistic, the null hypothesis was rejected at the significance level. We conclude that the evidence suggests the potential existence of a “statistical contagion effect”. Psychological mechanisms essential to the empirical results are suggested, as several studies from the scientific literature lend credence to contagious phenomena in sports. Causal inference from these results is difficult, but we suggest and discuss several latent variables that may contribute to the observed results, and offer possible directions for future research. PMID:23251507

  9. Effects of the Fusarium verticillioides mycotoxin, fumonisin B1, on maize stomatal behavior

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium verticillioides is a non-obligate plant pathogen causing a number of maize diseases and is responsible for the production of fumonisin B1 (FB1), a potential human carcinogen and agent of fatal farm animal diseases. The effect of FB1 on the health and development of maize seedlings was recen...

  10. Experimental observations of rapid Maize streak virus evolution reveal a strand-specific nucleotide substitution bias

    Microsoft Academic Search

    Eric van der Walt; Darren P Martin; Arvind Varsani; Jane E Polston; Edward P Rybicki

    2008-01-01

    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 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

  11. Mars - Wind streak production as related to obstacle type and size

    NASA Astrophysics Data System (ADS)

    Lee, S. W.

    1984-06-01

    The characteristics of wind streaks associated with Martian craters and hills in the size range of 100 m to 80 km (corresponding to obstacle heights of a few to several hundred meters) have been analyzed from Viking Orbiter images. Both dark erosional and bright depositional streaks form over the entire obstacle size range, but there are preferred obstacle sizes for producing streaks. Bright streaks form more readily in association with relatively smaller obstacles than do dark streaks. Small obstacles produce both types of streaks more effectively than do large ones. Hills produce streaks as effectively as do craters of comparable height. Alternative explanations of bright streak formation are evaluated in terms of their ability to account for these observations. The most satisfactory models invoke blocking of atmospheric flow downwind of an obstacle and consequent deposition of dust within the sheltered zone.

  12. Wheat streak mosaic virus-Structural parameters for a Potyvirus

    SciTech Connect

    Parker, Lauren [Center for Structural Biology, Vanderbilt University, Nashville, TN 37232 (United States); Kendall, Amy [Center for Structural Biology, Vanderbilt University, Nashville, TN 37232 (United States); Berger, P.H. [Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339 (United States); Shiel, P.J. [Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339 (United States); Stubbs, Gerald [Center for Structural Biology, Vanderbilt University, Nashville, TN 37232 (United States)]. E-mail: gerald.stubbs@vanderbilt.edu

    2005-09-15

    Wheat streak mosaic virus is a Tritimovirus, a member of the Potyviridae family, which includes the very large Potyvirus genus. We have examined wheat streak mosaic virus by electron microscopy and fiber diffraction from partially oriented sols, and analyzed the results to estimate the symmetry and structural parameters of the viral helix. The virions have an apparent radius of 63 {+-} 5 A. The viral helix has a pitch of 33.4 A {+-} 0.6 A. There appear to be 6.9 subunits per turn of the helix, although we cannot completely eliminate values of 5.9 or 7.9 for this parameter.

  13. Hot streaks and phantom cooling in a turbine rotor passage. I - Separate effects

    NASA Technical Reports Server (NTRS)

    Roback, Richard J.; Dring, Robert P.

    1992-01-01

    Experimental documentation and analytical correlations demonstrating the effects of hot streak accumulation and phantom cooling on turbine rotor airfoil surface temperature. Test results are shown for a range of controlling variables to identify where streak accumulation and phantom cooling are most likely to be strongest. These variables include streak injection location, streak-to-free stream density ratio and coolant-to-free stream density and velocity ratios.

  14. Global maize trade and food security: implications from a social network model.

    PubMed

    Wu, Felicia; Guclu, Hasan

    2013-12-01

    In this study, we developed a social network model of the global trade of maize: one of the most important food, feed, and industrial crops worldwide, and critical to food security. We used this model to analyze patterns of maize trade among nations, and to determine where vulnerabilities in food security might arise if maize availability was decreased due to factors such as diversion to nonfood uses, climatic factors, or plant diseases. Using data on imports and exports from the U.N. Commodity Trade Statistics Database for each year from 2000 to 2009 inclusive, we summarized statistics on volumes of maize trade between pairs of nations for 217 nations. There is evidence of market segregation among clusters of nations; with three prominent clusters representing Europe, Brazil and Argentina, and the United States. The United States is by far the largest exporter of maize worldwide, whereas Japan and the Republic of Korea are the largest maize importers. In particular, the star-shaped cluster of the network that represents U.S. maize trade to other nations indicates the potential for food security risks because of the lack of trade these other nations conduct with other maize exporters. If a scenario arose in which U.S. maize could not be exported in as large quantities, maize supplies in many nations could be jeopardized. We discuss this in the context of recent maize ethanol production and its attendant impacts on food prices elsewhere worldwide. PMID:23656551

  15. Global Maize Trade and Food Security: Implications from a Social Network Model

    PubMed Central

    Wu, Felicia; Guclu, Hasan

    2013-01-01

    In this study, we developed a social network model of the global trade of maize: one of the most important food, feed, and industrial crops worldwide, and critical to food security. We used this model to analyze patterns of maize trade among nations, and to determine where vulnerabilities in food security might arise if maize availability were decreased due to factors such as diversion to non-food uses, climatic factors, or plant diseases. Using data on imports and exports from the United Nations Commodity Trade Statistics Database for each year from 2000 to 2009 inclusive, we summarized statistics on volumes of maize trade between pairs of nations for 217 nations. There is evidence of market segregation among clusters of nations; with three prominent clusters representing Europe, Brazil and Argentina, and the United States. The United States is by far the largest exporter of maize worldwide, while Japan and the Republic of Korea are the largest maize importers. In particular, the star-shaped cluster of the network that represents US maize trade to other nations indicates the potential for food security risks because of the lack of trade these other nations conduct with other maize exporters. If a scenario arose in which US maize could not be exported in as large quantities, maize supplies in many nations could be jeopardized. We discuss this in the context of recent maize ethanol production and its attendant impacts on food prices elsewhere worldwide. PMID:23656551

  16. Mass movement within a slope streak on Mars Cynthia B. Phillips,1

    E-print Network

    Perfect, Ed

    Mass movement within a slope streak on Mars Cynthia B. Phillips,1 Devon M. Burr,1 and Ross A. Beyer 2007. [1] Slope streaks on Mars represent a currently active geological process. Various theories streak on Mars, Geophys. Res. Lett., 34, L21202, doi:10.1029/2007GL031577. 1. Introduction [2] Slope

  17. A Diet High in Saturated Fat and Sucrose Alters Glucoregulation and Induces Aortic Fatty Streaks in New Zealand White Rabbits

    PubMed Central

    Yuan, Zhonghua; Wang, Zongbao; Yang, Baotang; Yang, Yongzong

    2002-01-01

    A new and convenient animal model for studying peripheral vascular and coronary artery disease in diabetes was established in this study. Male New Zealand White rabbits weighing approximately 2 kg were divided into 2 groups: a normal control group fed standard laboratory chow and a diabetogenic diet–fed group received a high-fat/high-sucrose diet. The high-fat/high-sucrose diet (contained 10% lard and 37% sucrose) feeding was maintained for 6 months. Plasma total cholesterol, high-density lipoprotein (HDL) cholesterol, triglyceride, superoxide dismutase, nitric oxide, nitric oxide synthase, insulin, and glucose were quantitated at monthly or bimonthly intervals. The aortic fatty streak lesions were quantified following lipid staining with Sudan IV. The aortic samples were observed by electron microscopy. High plasma triglyceride and glucose concentrations were induced. At the end of 6 months, the aortic fatty streak lesions were present in the animals' vascular specimens. As far as we know, this is the first report that demonstrates that New Zealand White rabbits can develop obvious aortic fatty streaks by feeding a high-fat/high-sucrose diet. Our results suggest that NewZealand White rabbits fed a high-fat/high-sucrose diet would provide a convenient model for studying peripheral vascular and coronary artery disease in diabetes. PMID:12458659

  18. Sporadic formation of slope streaks on Mars Norbert Schorghofer a,

    E-print Network

    Schörghofer, Norbert

    formation is not caused by any global event. With the arrival of Mars Odyssey, Mars Express, and the MarsSporadic formation of slope streaks on Mars Norbert Schorghofer a, , Christina M. King b online 7 September 2011 Keywords: Mars, Surface Geological processes Data reduction techniques a b s t r

  19. Microrobotic Streak Seeding For Protein Crystal Growth CUCS04104

    E-print Network

    Microrobotic Streak Seeding For Protein Crystal Growth CUCS­041­04 Atanas Georgiev 1 Peter Allen 1 that consists of picking individual protein crystal from growth solution the purpose X­ray data collection) transferred protein solution that optimized their growth. building high­throughput protein crystal production

  20. Wind Tunnel Simulations of Light and Dark Streaks on Mars

    Microsoft Academic Search

    Ronald Greeley; James D. Iversen; James B. Pollack; Nancy Udovich; Bruce White

    1974-01-01

    Wind tunnel experiments have revealed a characteristic flow field pattern over raised-rim craters which causes distinctive zones of aeolian erosion and deposition. Comparisons of the results with Mariner 9 images of Mars show that some crater-associated dark zones result from wind erosion and that some crater-associated light streaks are depositional.

  1. Maize microarray annotation database

    PubMed Central

    2011-01-01

    Background Microarray technology has matured over the past fifteen years into a cost-effective solution with established data analysis protocols for global gene expression profiling. The Agilent-016047 maize 44 K microarray was custom-designed from EST sequences, but only reporter sequences with EST accession numbers are publicly available. The following information is lacking: (a) reporter - gene model match, (b) number of reporters per gene model, (c) potential for cross hybridization, (d) sense/antisense orientation of reporters, (e) position of reporter on B73 genome sequence (for eQTL studies), and (f) functional annotations of genes represented by reporters. To address this, we developed a strategy to annotate the Agilent-016047 maize microarray, and built a publicly accessible annotation database. Description Genomic annotation of the 42,034 reporters on the Agilent-016047 maize microarray was based on BLASTN results of the 60-mer reporter sequences and their corresponding ESTs against the maize B73 RefGen v2 "Working Gene Set" (WGS) predicted transcripts and the genome sequence. The agreement between the EST, WGS transcript and gDNA BLASTN results were used to assign the reporters into six genomic annotation groups. These annotation groups were: (i) "annotation by sense gene model" (23,668 reporters), (ii) "annotation by antisense gene model" (4,330); (iii) "annotation by gDNA" without a WGS transcript hit (1,549); (iv) "annotation by EST", in which case the EST from which the reporter was designed, but not the reporter itself, has a WGS transcript hit (3,390); (v) "ambiguous annotation" (2,608); and (vi) "inconclusive annotation" (6,489). Functional annotations of reporters were obtained by BLASTX and Blast2GO analysis of corresponding WGS transcripts against GenBank. The annotations are available in the Maize Microarray Annotation Database http://MaizeArrayAnnot.bi.up.ac.za/, as well as through a GBrowse annotation file that can be uploaded to the MaizeGDB genome browser as a custom track. The database was used to re-annotate lists of differentially expressed genes reported in case studies of published work using the Agilent-016047 maize microarray. Up to 85% of reporters in each list could be annotated with confidence by a single gene model, however up to 10% of reporters had ambiguous annotations. Overall, more than 57% of reporters gave a measurable signal in tissues as diverse as anthers and leaves. Conclusions The Maize Microarray Annotation Database will assist users of the Agilent-016047 maize microarray in (i) refining gene lists for global expression analysis, and (ii) confirming the annotation of candidate genes before functional studies. PMID:21961731

  2. Increased resistance to Ustilago zeae and Fusarium verticilliodes in maize inbred lines bred for Fusarium graminearum resistance

    Microsoft Academic Search

    L. M. Reid; X. Zhu; A. Parker; W. Yan

    2009-01-01

    Preliminary field observations in our maize breeding nurseries indicated that breeding for improved resistance to gibberella\\u000a ear rot (Fusarium graminearum) in maize may indirectly select for resistance to another ear disease, common smut (Ustilago zeae). To investigate this, we compared the disease severity ratings obtained on 189 maize inbreds, eight of which included our\\u000a inbreds developed with selection for gibberella

  3. Use of an Advanced Intercross Line Population for Precise Mapping of Quantitative Trait Loci for Gray Leaf Spot Resistance in Maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grey leaf spot (GLS) (caused by Cercospora zeae-maydis) of maize (Zea mays L.)is an important fungal disease of maize in the U.S. and worldwide. The IBM population, an advanced intercross recombinant inbred line population derived from a cross between the maize lines Mo17 (resistant) and B73 (sus...

  4. Fusarium graminearum: an pathogen of maize in Nepal, pathogenic variability and mycotoxins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium graminearum is an important pathogen of maize in hills of Nepal. It predominantly occurs on maize grown in cool and humid environment of high hills. The pathogen is also known to infect other cereal crops including wheat and rice causing important diseases. The incidence of ear rot is hi...

  5. Quality Protein Maize for Africa: Closing the Protein Inadequacy Gap in Vulnerable Populations12

    PubMed Central

    Nuss, Emily T.; Tanumihardjo, Sherry A.

    2011-01-01

    Africa shares a unique relationship with maize (Zea mays). After its introduction from New World explorers, maize was quickly adopted as the cornerstone of local cuisine, especially in sub-Saharan countries. Although maize provides macro- and micronutrients required for humans, it lacks adequate amounts of the essential amino acids lysine and tryptophan. For those consuming >50% of their daily energy from maize, pandemic protein malnutrition may exist. Severe protein and energy malnutrition increases susceptibility to life-threatening diseases such as tuberculosis and gastroenteritis. A nutritionally superior maize cultivar named quality protein maize (QPM) represents nearly one-half century of research dedicated to malnutrition eradication. Compared with traditional maize types, QPM has twice the amount of lysine and tryptophan, as well as protein bioavailability that rivals milk casein. Animal and human studies suggest that substituting QPM for common maize results in improved health. However, QPM’s practical contribution to maize-subsisting populations remains unresolved. Herein, total protein and essential amino acid requirements recommended by the WHO and the Institute of Medicine were applied to estimate QPM target intake levels for young children and adults, and these were compared with mean daily maize intakes by African country. The comparisons revealed that ?100 g QPM is required for children to maintain adequacy of lysine, the most limiting amino acid, and nearly 500 g is required for adults. This represents a 40% reduction in maize intake relative to common maize to meet protein requirements. The importance of maize in Africa underlines the potential for QPM to assist in closing the protein inadequacy gap. PMID:22332054

  6. Characteristics of uranium-oxide cathode for neutron streak camera

    SciTech Connect

    Niki, H.; Itoga, K.; Miyanaga, N.; Yamanaka, M.; Yamanaka, T.; Yamanaka, C.; Iida, T.; Takahashi, A.; Sumita, K.; Kinoshita, K.; Takiguchi, Y.; Hayashi, I.; Oba, K.

    1986-08-01

    Detection efficiency and secondary electron yield of the uranium-oxide cathode for a neutron streak camera were measured and found to be 2.3 x 10/sup -7/--1.6 x 10/sup -6/ events/neutron/..mu..m and 60--150/fission, respectively. These measurements were performed for 14-MeV neutrons from a D-T neutron source (OKTAVIAN) by using neutron-imaging techniques. By defocusing an image due to a single fission event, each electron from the cathode was clearly distinguished, and the number of electrons could be counted. From the neutron images in the streak-mode operation, time dispersions due to the electron transit-time spread fell in the range of estimated values.

  7. Megahertz streak-mode Fourier domain optical coherence tomography

    PubMed Central

    Wang, Rui; Yun, Julie X.; Yuan, Xiaocong; Goodwin, Richard; Markwald, Roger R.; Gao, Bruce Z.

    2011-01-01

    Here we present an ultrahigh-speed Fourier-domain optical coherence tomography (OCT) that records the OCT spectrum in streak mode with a high-speed area scan camera, which allows higher OCT imaging speed than can be achieved with a line-scan camera. Unlike parallel OCT techniques that also use area scan cameras, the conventional single-mode fiber-based point-scanning mechanism is retained to provide a confocal gate that rejects multiply scattered photons from the sample. When using a 1000 Hz resonant scanner as the streak scanner, 1,016,000 A-scans have been obtained in 1 s. This method's effectiveness has been demonstrated by recording in vivo OCT-image sequences of embryonic chick hearts at 1000 frames/s. In addition, 2-megahertz OCT data have been obtained with another high speed camera. PMID:21721817

  8. Timing between streak cameras with a precision of 10 ps

    SciTech Connect

    Lerche, R.A.

    1990-12-07

    The laser beams irradiating a target at the Nova laser facility comprise a set of ten simultaneous events. Two streak cameras, whose resolutions are 40 ps, record the power history for each beam, five beams to a camera; their time bases are cross-timed with a fiducial pulse. Analysis of data recorded for target experiments conducted over a six month period show the precision for cross-timing signals between two streak cameras to be {plus minus}9 ps and for characterizing a single temporal feature of a pulse to be {plus minus}5 ps. Beam synchronization at the end of six months was within 20 ps of the synchronization at the beginning of the experiments. A beam timing shift greater than 25 ps can be detected on a single laser shot; shifts of 10 to 20 ps require several shots to detect. 2 refs., 6 figs.

  9. Detection of episomal banana streak badnavirus by IC-PCR

    Microsoft Academic Search

    Glyn Harper; Ganesh Dahal; George Thottappilly; R. Hull

    1999-01-01

    A polymerase chain reaction (PCR) based strategy to detect episomal banana streak badnavirus (BSV) in banana and plantain plants that carry integrated BSV sequences was developed. Antisera used in immuno-capture polymerase chain reaction (IC-PCR) are capable of binding a large number of BSV serotypes. The primers used for PCR are capable of annealing to and amplifying across the aspartic protease-reverse

  10. Design of microcontroller based system for automation of streak camera

    NASA Astrophysics Data System (ADS)

    Joshi, M. J.; Upadhyay, J.; Deshpande, P. P.; Sharma, M. L.; Navathe, C. P.

    2010-08-01

    A microcontroller based system has been developed for automation of the S-20 optical streak camera, which is used as a diagnostic tool to measure ultrafast light phenomenon. An 8 bit MCS family microcontroller is employed to generate all control signals for the streak camera. All biasing voltages required for various electrodes of the tubes are generated using dc-to-dc converters. A high voltage ramp signal is generated through a step generator unit followed by an integrator circuit and is applied to the camera's deflecting plates. The slope of the ramp can be changed by varying values of the capacitor and inductor. A programmable digital delay generator has been developed for synchronization of ramp signal with the optical signal. An independent hardwired interlock circuit has been developed for machine safety. A LABVIEW based graphical user interface has been developed which enables the user to program the settings of the camera and capture the image. The image is displayed with intensity profiles along horizontal and vertical axes. The streak camera was calibrated using nanosecond and femtosecond lasers.

  11. Automatic coil selection for streak artifact reduction in radial MRI.

    PubMed

    Xue, Yiqun; Yu, Jiangsheng; Kang, Hyun Seon; Englander, Sarah; Rosen, Mark A; Song, Hee Kwon

    2012-02-01

    In radial MR imaging, streaking artifacts contaminating the entire field of view can arise from regions at the outer edges of the prescribed field of view. This can occur even when the Nyquist criterion is satisfied within the desired field of view. These artifacts become exacerbated when parts of the object lie in the superior/inferior regions of the scanner where the gradient strengths become weakened. When multiple coil arrays are used for signal reception, coils at the outer edges can be disabled before data acquisition to reduce the artifact levels. However, as the weakened gradient strengths near the edges often distort the object, causing the signal to become highly concentrated into a small region, the streaks are often not completely removed. Data from certain coils can also be excluded during reconstruction by visually inspecting the individual coil images, but this is impractical for routine use. In this work, a postprocessing method is proposed to automatically identify those coils whose images contain high levels of streaking for subsequent exclusion during reconstruction. The proposed method was demonstrated in vivo dynamic contrast enhanced MRI datasets acquired using a three-dimensional hybrid radial sequence. The results demonstrate that the proposed strategy substantially improves the image quality and show excellent agreement with images reconstructed with manually determined coil selection. PMID:21656562

  12. Hot streaks and phantom cooling in a turbine rotor passage. II - Combined effects and analytical modelling

    NASA Technical Reports Server (NTRS)

    Roback, Richard J.; Dring, Robert P.

    1992-01-01

    Experimental documentation and analytical correlations demonstrating the effects of hot streak accumulation and phantom cooling on turbine rotor airfoil surface temperature are presented. Results are shown which quantify the impact of a nonuniform temperature profile at the entrance of a turbine due to combustor-generated hot and cold streaks, and cooling air discharged from the trailing edge of the upstream stator. Experimental results are shown for a range of controlling variables to identify where streak accumulation and phantom cooling were most likely to be strongest. These variables include streak-to-free stream density ratio, streak injection location, and coolant-to-free stream density and velocity ratios. Experimental results are shown for the combined effects of hot streak and stator coolant on the adiabatic recovery temperature of the rotor.

  13. On the streak spacing and vortex roll size in a turbulent channel flow

    NASA Astrophysics Data System (ADS)

    Rajaee, M.; Karlsson, S.; Sirovich, L.

    1995-10-01

    Streamwise high vorticity rolls and streaks in the turbulent channel flows have been the subject of many studies due to their important role in turbulence production, as a result of sweeping, ejection, and bursting of these structures. Understanding the physics of these streamwise structures is important in controlling drag producing events. Investigations of the average streak spacing of the low-speed streaks have resulted in the generally accepted range of ?+=?¯u?/?=100±20, where ?¯ is the mean spanwise spacing between streaks, normalized to the viscous length ?/u?. It is also reported, for y+?30, that the streak spacing grows nearly linearly with distance from the wall. The previous studies mostly have focused on distances close to the wall. Here we report on correlation measurements extended into the log layer, which show that the linear growth of the vortex diameter and the streak spacing extends well in the log layer. Arguments are presented to distinguish these two measures.

  14. Paramutation in maize

    Microsoft Academic Search

    Vicki L. Chandler; William B. Eggleston; Jane E. Dorweiler

    2000-01-01

    Paramutation is a heritable change in gene expression induced by allele interactions. This review summarizes key experiments on three maize loci, which undergo paramutation. Similarities and differences between the phenomenology at the three loci are described. In spite of many differences with respect to the stability of the reduced expression states at each locus or whether paramutation correlates with DNA

  15. Density-driven spontaneous streak segregation patterns in a thin rotating drum

    NASA Astrophysics Data System (ADS)

    Liao, C. C.; Hsiau, S. S.; Nien, H. C.

    2014-06-01

    Granular mixtures may segregate because of external driving forces, which play an important role in industry and geophysics. We investigate experimentally the mechanism of density-driven spontaneous streak segregation patterns in a thin rotating drum. We find that a spontaneous streak segregation pattern can occur in such a system, which we call a D-system. A phase diagram identifies three segregation pattern regimes in this study: the mixing regime, the core segregation regime, and the streak segregation regime.

  16. Surface properties of the Pettit wind streak on Mars Implications for sediment transport

    NASA Astrophysics Data System (ADS)

    Zimbelman, J. R.

    1986-04-01

    Satellite imagery of the Pettit streak on Amazonis Planitia are discussed in terms of the details of wind streaks and their associated sediments. Increasingly more detailed blow-ups of the available imagery demonstrate that the Pettit streak holds both a Type I bright streak (at the crater rim) and a Type II dark streak beginning at the dark patch within the crater. The lowest albedos measured, 0.20-0.22, are associated with the highest thermal inertia, indicative of grain diameters similar to medium sand, i.e., ranging from 250-350 microns. The brightest portions of the streak have albedos over 0.26 and a low thermal inertia, in the range 3-4, which implies the presence of fine-grained sand, diameters from 50-100 microns. The particle grains are less than 50 microns diameter in the surrounding plains, which have an approximately uniform albedo (0.27) and a thermal inertia of 2.5, characteristics typical of silt or clay. Current streak models describe the dark streak well, but do not account for the bright streak, which may be optically thick patches of very fine dust.

  17. A guanylyl cyclase-like gene is associated with Gibberella ear rot resistance in maize ( Zea mays L.)

    Microsoft Academic Search

    J. Yuan; M. Liakat Ali; J. Taylor; J. Liu; G. Sun; W. Liu; P. Masilimany; A. Gulati-Sakhuja; K. P. Pauls

    2008-01-01

    Gibberella ear rot, caused by the fungal pathogen Fusarium graminearum Schwabe, is a serious disease of maize (Zea mays L.) grown in northern climates. The infected maize grain contains toxins that are very harmful to livestock and humans. A\\u000a maize gene that encodes a putative 267-amino acid guanylyl cyclase-like protein (ZmGC1) was characterized and shown to be\\u000a associated with resistance

  18. The Function of the Lipoxygenase ZmLOX10 in Maize Interactions with Insects and Pathogens 

    E-print Network

    Christensen, Shawn A.

    2011-02-22

    -mediated GLVs may contribute to the development of disease symptoms to the economically important maize pathogens, Aspergillus flavus and Colletotrichum graminicola. Specifically, LOX10-derived GLVs may facilitate aflatoxin accumulation in response to A...

  19. Incidence of Fusarium Species and Mycotoxins in Silage Maize

    PubMed Central

    Eckard, Sonja; Wettstein, Felix E.; Forrer, Hans-Rudolf; Vogelgsang, Susanne

    2011-01-01

    Maize is frequently infected by the Fusarium species producing mycotoxins. Numerous investigations have focused on grain maize, but little is known about the Fusarium species in the entire plant used for silage. Furthermore, mycotoxins persist during the ensiling process and thus endanger feed safety. In the current study, we analyzed 20 Swiss silage maize samples from growers’ fields for the incidence of Fusarium species and mycotoxins. The species spectrum was analyzed morphologically and mycotoxins were measured by LC-MS/MS. A pre-harvest visual disease rating showed few disease symptoms. In contrast, the infection rate of two-thirds of the harvest samples ranged from 25 to 75% and twelve different Fusarium species were isolated. The prevailing species were F. sporotrichioides, F. verticillioides and F. graminearum. No infection specificity for certain plant parts was observed. The trichothecene deoxynivalenol (DON) was found in each sample (ranging from 780 to 2990 µg kg?1). Other toxins detected in descending order were zearalenone, further trichothecenes (nivalenol, HT-2 and T-2 toxin, acetylated DON) and fumonisins. A generalized linear regression model containing the three cropping factors harvest date, pre-precrop and seed treatment was established, to explain DON contamination of silage maize. Based on these findings, we suggest a European-wide survey on silage maize. PMID:22069750

  20. Brown ring formation and streak mottle, two distinct syndromes in lilies associated with complex infections of lily symptomless virus and tulip breaking virus

    Microsoft Academic Search

    C. J. Asjes; Neeltje P. de Vos; D. H. M. van Slogteren

    1973-01-01

    Brown ring formation in bulbs of lilies, particularly of Mid-century hybrids, is described as a newly recognized disease. Symptoms of streak mottle in cultivars ofLilium speciosum Thunb., not associated with abnormalities of bulbs, are briefly described with reference to the literature. Sometimes the two syndromes occur in the same crop such as in the Mid-century hybrid ‘Enchantment’, showing brown ring

  1. Attosecond streaking of core lines of copper dihalides

    E-print Network

    J. D. Lee

    2011-09-26

    In the attosecond (as) streaking of Cu 3s core-level photoemission of copper dihalides, we predict theoretically that the satellite ($3d^9$) is emitted later than the main line ($3d^{10}L^{-1}$; $L$: ligand). The emission time delay is originated from the electron correlation between the core level and 3d shell, which leads to the difference in core-hole screening between satellite and main lines. Further, we find that the time delay corresponds to a quantification of the extrinsic loss of photoemission.

  2. VISAR: Interferometer quadrature signal recording by electronic streak camera

    NASA Astrophysics Data System (ADS)

    Hemsing, W. F.

    This short paper describes a demonstration to record the four quadrature signals from a push-pull VISAR velocity interferometer using an electronic streak camera. Optical fibers were used to transmit the interferometer outputs to the camera photocathode. Brightness variations of these signals were recorded on film during the experiment. Velocity information was later recovered from this record to give a continuous velocity history. Anticipated advantages over previous methods are increased time resolution, the ability to record multiple velocities simultaneously and greater dynamic range.

  3. Streaks of Aftershocks Following the 2004 Sumatra-Andaman Earthquake

    NASA Astrophysics Data System (ADS)

    Waldhauser, F.; Schaff, D. P.; Engdahl, E. R.; Diehl, T.

    2009-12-01

    Five years after the devastating 26 December, 2004 M 9.3 Sumatra-Andaman earthquake, regional and global seismic networks have recorded tens of thousands of aftershocks. We use bulletin data from the International Seismological Centre (ISC) and the National Earthquake Information Center (NEIC), and waveforms from IRIS, to relocate more than 20,000 hypocenters between 1964 and 2008 using teleseimic cross-correlation and double-difference methods. Relative location uncertainties of a few km or less allow for detailed analysis of the seismogenic faults activated as a result of the massive stress changes associated with the mega-thrust event. We focus our interest on an area of intense aftershock activity off-shore Banda Aceh in northern Sumatra, where the relocated epicenters reveal a pattern of northeast oriented streaks. The two most prominent streaks are ~70 km long with widths of only a few km. Some sections of the streaks are formed by what appear to be small, NNE striking sub-streaks. Hypocenter depths indicate that the events locate both on the plate interface and in the overriding Sunda plate, within a ~20 km wide band overlying the plate interface. Events on the plate interface indicate that the slab dip changes from ~20° to ~30° at around 50 km depth. Locations of the larger events in the overriding plate indicate an extension of the steeper dipping mega thrust fault to the surface, imaging what appears to be a major splay fault that reaches the surface somewhere near the western edge of the Aceh basin. Additional secondary splay faults, which branch off the plate interface at shallower depths, may explain the diffuse distribution of smaller events in the overriding plate, although their relative locations are less well constrained. Focal mechanisms support the relocation results. They show a narrowing range of fault dips with increasing distance from the trench. Specifically, they show reverse faulting on ~30° dipping faults above the shallow (20°) dipping plate interface. The observation of active splay faults associated with the mega thrust event is consistent with co- and post-seismic motion data, and may have significant implications on the generation and size of the tsunami that caused 300,000 deaths.

  4. Ethanol Production from Maize

    Microsoft Academic Search

    Stefan Schwietzke; Youngmi Kim; Eduardo Ximenes; Nathan Mosier; Michael Ladisch

    The production of fuel ethanol from corn grain is widely carried out in the US, with total current production at 7 billion\\u000a gallons. This may soon reach 10 billion gallons or more. This chapter addresses the potential of fuel ethanol as an additional\\u000a source of product based on utilization of the cellulosic (non-food) portions of maize, and in particular the

  5. Genetic mechanisms of Maize dwarf mosaic virus resistance in maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize resistance to viruses has been well-characterized at the genetic level, and loci responsible for resistance to potyviruses including Maize dwarf mosaic virus (MDMV), Sugarcane mosaic virus (SCMV), Sorghum mosaic virus (SrMV), and Johnsongrass mosaic virus (JGMV), have been mapped in several ge...

  6. MaizeGDB: The Maize Genetics and Genomics Database

    Technology Transfer Automated Retrieval System (TEKTRAN)

    MaizeGDB is the community database for biological information about the crop plant Zea mays. Genetic, genomic, sequence, gene product, functional characterization, literature reference, and person/organization contact information are among the datatypes stored at MaizeGDB. At the project's website...

  7. THE MAIZE GENETICS AND GENOMICS DATABASE. THE COMMUNITY RESOURCE FOR ACCESS TO DIVERSE MAIZE DATA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Maize Genetics and Genomics Database (MaizeGDB) serves the maize (Zea mays) research community by making a wealth of genetics and genomics data available through an intuitive Web-based interface. The goals of the MaizeGDB project are three-fold: to provide a central repository for public maize ...

  8. Root Infection and Systemic Colonization of Maize by Colletotrichum graminicola?

    PubMed Central

    Sukno, Serenella A.; García, Verónica M.; Shaw, Brian D.; Thon, Michael R.

    2008-01-01

    Colletotrichum graminicola is a filamentous ascomycete that causes anthracnose disease of maize. While the fungus can cause devastating foliar leaf blight and stalk rot diseases, little is known about its ability to infect roots. Previously published reports suggest that C. graminicola may infect maize roots and that root infections may contribute to the colonization of aboveground plant tissues, leading to disease. To determine whether C. graminicola can infect maize roots and whether root infections can result in the colonization of aboveground plant tissues, we developed a green fluorescent protein-tagged strain and used it to study the plant root colonization and infection process in vivo. We observed structures produced by other root pathogenic fungi, including runner hyphae, hyphopodia, and microsclerotia. A mosaic pattern of infection resulted from specific epidermal and cortical cells becoming infected by intercellular hyphae while surrounding cells were uninfected, a pattern that is distinctly different from that described for leaves. Interestingly, falcate conidia, normally restricted to acervuli, were also found filling epidermal cells and root hairs. Twenty-eight percent of plants challenged with soilborne inoculum became infected in aboveground plant parts (stem and/or leaves), indicating that root infection can lead to asymptomatic systemic colonization of the plants. Many of the traits observed for C. graminicola have been previously reported for other root-pathogenic fungi, suggesting that these traits are evolutionally conserved in multiple fungal lineages. These observations suggest that root infection may be an important component of the maize anthracnose disease cycle. PMID:18065625

  9. Aflatoxin resistance in maize: what have we learned lately?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin contamination of maize grain is a huge economic and health problem, causing death and increased disease burden in much of the developing world and income loss in the developed world. Despite the gravity of the problem, deployable solutions are still being sought. In the past 15 years, much...

  10. Observation of hard X-ray pulses with a highly sensitive streak camera

    Microsoft Academic Search

    T. Hara; Y. Tanaka; H. Kitamura; T. Ishikawa

    2001-01-01

    We have developed a highly sensitive X-ray streak camera system, which synchronously operates with the RF signal of the SPring-8 storage ring. The streak camera was installed at an undulator beamline of SPring-8, and the beam loading effect for various electron bunch structures (filling pattern) has been observed. The camera has also been operated as a timing monitor for a

  11. Optical Comb Generation for Streak Camera Calibration for Inertial Confinement Fusion Experiments

    Microsoft Academic Search

    Ronald Justin; Terence Davies; Frans Janson; Bruce Marshall; Perry Bell; Daniel Kalantar; Joseph Kimbrough; Stephen Vernon; Oliver Sweningsen

    2008-01-01

    The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is coming on-line to support physics experimentation for the U.S. Department of Energy (DOE) programs in Inertial Confinement Fusion (ICF) and Stockpile Stewardship (SS). Optical streak cameras are an integral part of the experimental diagnostics instrumentation at NIF. To accurately reduce streak camera data a highly accurate temporal calibration

  12. BUNCH LENGTH MEASUREMENTS AT THE TESLA TEST FACILITY USING A STREAK CAMERA

    E-print Network

    BUNCH LENGTH MEASUREMENTS AT THE TESLA TEST FACILITY USING A STREAK CAMERA K. Honkavaara, Ph. Piot and convenient way to measure bunch lengths in the millimeter and submil- limeter range. At the TESLA Test Facility (TTF) a streak camera with a subpicosecond resolution is in operation. A bunch compressor is used

  13. Efficient and stable expression of GFP through Wheat streak mosaic virus-based vectors in cereal hosts using a range of cleavage sites: Formation of dense fluorescent aggregates for sensitive virus tracking

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of Wheat streak mosaic virus (WSMV)-based expression vectors were developed by engineering cycle 3 GFP (GFP) cistron between P1 and HC-Pro cistrons with several catalytic/cleavage peptides at the C-terminus of GFP. WSMV-GFP vectors with the Foot-and-mouth disease virus 1D/2A or 2A catalytic...

  14. Microprocessor-controlled, wide-range streak camera

    SciTech Connect

    Amy E. Lewis, Craig Hollabaugh

    2006-09-01

    Bechtel Nevada/NSTec recently announced deployment of their fifth generation streak camera. This camera incorporates many advanced features beyond those currently available for streak cameras. The arc-resistant driver includes a trigger lockout mechanism, actively monitors input trigger levels, and incorporates a high-voltage fault interrupter for user safety and tube protection. The camera is completely modular and may deflect over a variable full-sweep time of 15 nanoseconds to 500 microseconds. The camera design is compatible with both large- and small-format commercial tubes from several vendors. The embedded microprocessor offers Ethernet connectivity, and XML [extensible markup language]-based configuration management with non-volatile parameter storage using flash-based storage media. The camera’s user interface is platform-independent (Microsoft Windows, Unix, Linux, Macintosh OSX) and is accessible using an AJAX [asynchronous Javascript and XML]-equipped modem browser, such as Internet Explorer 6, Firefox, or Safari. User interface operation requires no installation of client software or browser plug-in technology. Automation software can also access the camera configuration and control using HTTP [hypertext transfer protocol]. The software architecture supports multiple-simultaneous clients, multiple cameras, and multiple module access with a standard browser. The entire user interface can be customized.

  15. Metabolic pathway resources at MaizeGDB

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two maize metabolic networks are available at MaizeGDB: MaizeCyc (http://maizecyc.maizegdb.org, also at Gramene) and CornCyc (http://corncyc.maizegdb.org, also at the Plant Metabolic Network). MaizeCyc was developed by Gramene, and CornCyc by the Plant Metabolic Network, both in collaboration with M...

  16. Maize Genetics and Genomics Database

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This report is provided each year to our stakeholders in the maize genetic community. In this report, we describe the five-year plan for MaizeGDB reviewed in early 2008 by the USDA-ARS peer review process and which was developed with inputs from our Working Group and the Allerton 2007 Report (MNL 82...

  17. The enigmatic primitive streak: prevailing notions and challenges concerning the body axis of mammals

    PubMed Central

    Downs, Karen M.

    2010-01-01

    The primitive streak establishes the antero-posterior body axis in all amniote species. It is thought to be the conduit through which mesoderm and endoderm progenitors ingress and migrate to their ultimate destinations. Despite its importance, the streak remains poorly defined and one of the most enigmatic structures of the animal kingdom. In particular, the posterior end of the primitive streak has not been satisfactorily identified in any species. Unexpectedly, and contrary to prevailing notions, recent evidence suggests that the murine posterior primitive streak extends beyond the embryo proper. In its extraembryonic site, the streak creates a node-like cell reservoir from which the allantois, a universal caudal appendage of all amniotes and the future umbilical cord of placental mammals, emerges. This new insight into the fetal/umbilical relationship may explain the etiology of a large number of umbilical-associated birth defects, many of which are correlated with abnormalities of the embryonic midline. PMID:19609969

  18. Maize seedling blight induced by Fusarium verticillioides: accumulation of fumonisin B1 in leaves without colonization of the leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium verticillioides produces fumonisin mycotoxins during the colonization of maize, and fumonisin B1 (FB1) production is necessary for manifestation of maize seedling blight disease. The objective of this study was to assess the in planta occurrence of fumonisin, fungal colonization, and disea...

  19. Early Events in the Fusarium verticillioides-Maize Interaction Characterized by Using a Green Fluorescent Protein-Expressing Transgenic Isolate

    Microsoft Academic Search

    Liat Oren; Smadar Ezrati; David Cohen; Amir Sharon

    2003-01-01

    The infection of maize by Fusarium verticillioides can result in highly variable disease symptoms ranging from asymptomatic plants to severe rotting and wilting. We produced F. verticillioides green fluorescent protein- expressing transgenic isolates and used them to characterize early events in the F. verticillioides-maize inter- action that may affect later symptom appearance. Plants grown in F. verticillioides-infested soil were smaller

  20. Roles of Stolbur phytoplasma and Reptalus panzeri (Cixiinae, Auchenorrhyncha) in the epidemiology of Maize redness in Serbia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize redness (MR), a disease causing midrib, leaf and stalk reddening and abnormal ear development in maize, has been reported from Serbia, Romania and Bulgaria for 50 years. Recent epiphytotics reduced yields by 40-90% in southern Banat, Serbia. MR was recently associated with the presence of th...

  1. Roles of Stolbur Phytoplasma and Reptalus Panzeri (Cixiinae, Auchenorrhyncha) in the Epidemiology of Maize Redness in Serbia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize redness (MR), a disease causing midrib, leaf and stalk reddening and abnormal ear development in maize, has been reported from Serbia, Romania and Bulgaria for 50 years. Recent epiphytotics reduced yields by 40-90% in southern Banat, Serbia. MR was recently associated with the presence of th...

  2. DESCRIPTION OF A COMPLEX DISEASE: CORN STUNT COMPLEX

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The corn stunt disease complex is considered to be caused by two or more of a complex of maize rayado fino virus, corn stunt spiroplasma, and maize bushy stunt phytoplasma, and is also known by the names achaparramiento, maize stunt, and red stunt, among others. This complex appears to be restricte...

  3. StreakDet data processing and analysis pipeline for space debris optical observations

    NASA Astrophysics Data System (ADS)

    Virtanen, Jenni; Flohrer, Tim; Muinonen, Karri; Granvik, Mikael; Torppa, Johanna; Poikonen, Jonne; Lehti, Jussi; Santti, Tero; Komulainen, Tuomo; Naranen, Jyri

    We describe a novel data processing and analysis pipeline for optical observations of space debris. The monitoring of space object populations requires reliable acquisition of observational data, to support the development and validation of space debris environment models, the build-up and maintenance of a catalogue of orbital elements. In addition, data is needed for the assessment of conjunction events and for the support of contingency situations or launches. The currently available, mature image processing algorithms for detection and astrometric reduction of optical data cover objects that cross the sensor field-of-view comparably slowly, and within a rather narrow, predefined range of angular velocities. By applying specific tracking techniques, the objects appear point-like or as short trails in the exposures. However, the general survey scenario is always a “track before detect” problem, resulting in streaks, i.e., object trails of arbitrary lengths, in the images. The scope of the ESA-funded StreakDet (Streak detection and astrometric reduction) project is to investigate solutions for detecting and reducing streaks from optical images, particularly in the low signal-to-noise ratio (SNR) domain, where algorithms are not readily available yet. For long streaks, the challenge is to extract precise position information and related registered epochs with sufficient precision. Although some considerations for low-SNR processing of streak-like features are available in the current image processing and computer vision literature, there is a need to discuss and compare these approaches for space debris analysis, in order to develop and evaluate prototype implementations. In the StreakDet project, we develop algorithms applicable to single images (as compared to consecutive frames of the same field) obtained with any observing scenario, including space-based surveys and both low- and high-altitude populations. The proposed processing pipeline starts from the segmentation of the acquired image (i.e., the extraction of all sources), followed by the astrometric and photometric characterization of the candidate streaks, and ends with orbital validation of the detected streaks. A central concept of the pipeline is streak classification which guides the actual characterization process by aiming to identify the interesting sources and to filter out the uninteresting ones, as well as by allowing the tailoring of algorithms for specific streak classes (e.g. point-like vs. long, disintegrated streaks). To validate the single-image detections, the processing is finalized by orbital analysis, resulting in preliminary orbital classification (Earth-bound vs. non-Earth-bound orbit) for the detected streaks.

  4. Roles of stolbur phytoplasma and Reptalus panzeri (Cixiinae, Auchenorrhyncha) in the epidemiology of Maize redness in Serbia

    Microsoft Academic Search

    J. Jovi?; T. Cvrkovic ´; M. Mitrovi?; S. Krnjajic ´; Margaret G. Redinbaugh; R. C. Pratt; R. E. Gingery; S. A. Hogenhout; I. Toševski

    2007-01-01

    Maize redness (MR), a disease causing midrib, leaf and stalk reddening and abnormal ear development in maize, has been reported\\u000a from Serbia, Romania and Bulgaria for 50 years. Recent epiphytotics reduced yields by 40%–90% in southern Banat, Serbia. MR\\u000a was recently associated with the presence of the stolbur phytoplasma, although the epidemiology of the disease remained unknown.\\u000a Diseased fields in southern

  5. High-speed TV cameras for streak tube readout

    SciTech Connect

    Yates, G.J.; Gallegos, R.A.; Holmes, V.H. (Los Alamos National Lab., NM (United States)); Turko, B.T. (Lawrence Berkeley Lab., CA (United States))

    1991-01-01

    Two fast framing TV cameras have been characterized and compared as readout media for imaging of 40 mm diameter streak tube (P-11) phosphor screens. One camera is based upon a Focus-Projection-Scan (FPS) high-speed electrostatic deflected vidicon with 30-mm-diameter PbO target. The other uses an interline transfer charge-coupled device (CCD) with 8.8 {times} 11.4 mm rectangular Si target. The field-of-view (FOV), resolution, responsivity, and dynamic range provided by both cameras when exposed to short duration ({approx} 10 {mu} full width at half maximum (FWHM)) transient illumination followed by a single field readout period of {lt}3 ms are presented. 11 refs., 8 figs., 3 tabs.

  6. Streaking in Cascadia ETS Events and Implications for the Subduction Plate Interface

    NASA Astrophysics Data System (ADS)

    Houston, H.; Ghosh, A.

    2011-12-01

    The manner in which episodic tremor and slow slip (ETS) propagates across the subduction plate interface provides constraints on its properties and the physical processes involved. We have been examining catalogs of tremor locations to study propagation patterns during ETS. Tremor in the large Cascadia ETS events propagates mainly via three modes: 1) the slow along-strike advance of ETS, 2) rapid tremor reversals (RTRs) that propagate back from the tremor front in an opposite direction to the along-strike advance, but at speeds 10-40 times faster (Houston et al., Nature Geoscience, 2011), and 3) streaks, even faster migrations of tremor parallel to the plate-convergence direction at speeds ~ 70 km/hr (Ghosh et al., G3, 2011). The UW Seismology group has recently deployed an EarthScope-funded seismic experiment, the Array of Arrays, to image tremor more precisely with eight subarrays. A 15-month catalog of high-resolution tremor locations has been generated based on the triangulation of back-projected beams from the subarrays. We detect tremor streaks in this catalog automatically and systematically determine streak propagation properties. Key issues for constraining streak-generation processes include systematic differences between up- and down-dip traveling streaks, how streak properties may depend on depth, and whether streaks accelerate or decelerate during propagation. Stacking automatically-detected streaks can address some of these issues. Two approaches to automatically detecting streaks have been developed and applied to the M6.8 2010 ETS. One method declares a streak when averaged epicenters continue to move in a roughly constant direction for more than 10 km. The second declares a streak if epicenters during a specified time interval, say 20 min, are sufficiently well-correlated with time. The two methods agree well and detect several streaks per day of 15-30 min duration with speeds consistent with those inferred for the 2008 ETS. Although the detection methods have no azimuthal bias, most of the detected streaks align with one direction; furthermore, that direction lies much closer to the plate convergence direction than directly down-dip (the down-dip and plate convergence directions differ significantly along most of Cascadia). Many more streaks are detected in the actual catalog than in randomized versions, in which the times within each hour are permuted. These results lend substantial credence to convergence-parallel streaks as real features of ETS. Streak propagation patterns suggest the plate interface is anisotropic along the slip direction. The ubiquity of streaking parallel to plate convergence implies control by corrugated or smeared structures on the plate interface. This could occur via such structures controlling the orientation of an advancing slip pulse, which could carry streaks along its peak (Rubin, G3, 2011), or more directly via heterogeneous physical properties (such as rheology or permeability) elongated in the convergence direction. In this connection, we note that daily tremor bands in Cascadia ETS are also often oriented parallel to the convergence direction whether the ETS is advancing north or south, even though the direction of ETS advance would be expected to affect the orientation of a slip pulse on a homogeneous interface.

  7. Dust Devils Seen Streaking Across Mars: PART 1--What Are These?

    NASA Technical Reports Server (NTRS)

    2000-01-01

    PIA02376 [figure removed for brevity, see original site]

    Dark streaks, everywhere! Many Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images of the middle latitudes of the northern and southern hemispheres of Mars show wild patterns of criss-crossing dark streaks. Many of these streaks are straight and narrow, others exhibit curly arcs, twists, and loops. They often cross over hills, run straight across dunes and ripples, and go through fields of house-sized boulders. The two examples shown above were acquired in the last three months. Both pictures are illuminated by sunlight from the upper left. The first picture (left), showing dark streaks on the rippled flats of Argyre Planitia, covers an area 3 km by 5 km (1.9 by 3.1 miles) at a latitude of 51oS. The second picture (right) shows an area approximately 3 km by 5 km in Promethei Terra at a latitude of 58oS.

    For many months the MOC science team was seeing streaks such as these, but were uncertain how they formed. One speculation was that they might result from the passage of dust devils. Each dust devil would leave a dark streak by removing bright dust from the terrain in its path, revealing a darker surface underneath. An image described by the MOC team in July 1998 showed examples of streaks that were, at the time, speculated to be caused by dust devils.

  8. Streaking and Wigner time delays in photoemission from atoms and surfaces

    SciTech Connect

    Zhang, C.-H.; Thumm, U. [Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States)

    2011-09-15

    Streaked photoemission metrology allows the observation of an apparent relative time delay between the detection of photoelectrons from different initial electronic states. This relative delay is obtained by recording the photoelectron yield as a function of the delay between an ionizing ultrashort extended ultraviolet pulse and a streaking infrared (IR) pulse. Theoretically, photoemission delays can be defined based on (i) the phase shift the photoelectron wave function accumulates during the release and propagation of the photoelectron (''Wigner delay'') and, alternatively, (ii) the streaking trace in the calculated photoemission spectrum (''streaking delay''). We investigate the relation between Wigner and streaking delays in the photoemission from atomic and solid-surface targets. For solid targets and assuming a vanishing IR skin depth, both Wigner and streaking delays can be interpreted as an average propagation time needed by photoelectrons to reach the surface, while the two delays differ for nonvanishing skin depths. For atomic targets, the difference between Wigner and streaking delays depends on the range of the ionic potential.

  9. Ultra fast x-ray streak camera for ten inch manipulator based platforms

    SciTech Connect

    Marley, E. V. [Physics and Life Science, Lawrence Livermore National Laboratory, M.S. L-490, Livermore, California 94550 (United States); University of California Davis, One Shields Avenue, Davis, California 95616 (United States); Shepherd, R.; Fulkerson, S.; James, L.; Emig, J.; Norman, D. [Physics and Life Science, Lawrence Livermore National Laboratory, M.S. L-490, Livermore, California 94550 (United States)

    2012-10-15

    Ultra fast x-ray streak cameras are a staple for time resolved x-ray measurements. There is a need for a ten inch manipulator (TIM) based streak camera that can be fielded in a newer large scale laser facility. The Lawrence Livermore National Laboratory ultra fast streak camera's drive electronics have been upgraded and redesigned to fit inside a TIM tube. The camera also has a new user interface that allows for remote control and data acquisition. The system has been outfitted with a new sensor package that gives the user more operational awareness and control.

  10. Ultra Fast X-ray Streak Camera for TIM Based Platforms

    SciTech Connect

    Marley, E; Shepherd, R; Fulkerson, E S; James, L; Emig, J; Norman, D

    2012-05-02

    Ultra fast x-ray streak cameras are a staple for time resolved x-ray measurements. There is a need for a ten inch manipulator (TIM) based streak camera that can be fielded in a newer large scale laser facility. The LLNL ultra fast streak camera's drive electronics have been upgraded and redesigned to fit inside a TIM tube. The camera also has a new user interface that allows for remote control and data acquisition. The system has been outfitted with a new sensor package that gives the user more operational awareness and control.

  11. Emissivity spectrum of a large "dark streak" from themis infrared imagery

    SciTech Connect

    Brumby, Steven P.; Vaniman, D. T. (David T.); Bish, D. L. (David L.)

    2003-01-01

    'Dark streaks', also known as 'slope streaks', are unusual surface features found on Mars that are known to appear and fade away on timescales of years. Various explanations have been proposed for their origin and composition, including dry avalanches and wet debris or precipitates from brines. Previous investigations have been based on analysis of panchromatic imagery and altimetry from Viking and Mars Global Surveyor missions. We have obtained an infrared emissivity spectrum of a large dark streak on the north western edge of Olympus Mons, using imagery from the THEMIS instrument on the Mars Odyssey 2001 spacecraft.

  12. Attosecond streaking of Cohen-Fano interferences in the photoionization of H2+

    NASA Astrophysics Data System (ADS)

    Ning, Qi-Cheng; Peng, Liang-You; Song, Shu-Na; Jiang, Wei-Chao; Nagele, Stefan; Pazourek, Renate; Burgdörfer, Joachim; Gong, Qihuang

    2014-07-01

    We present a numerical ab-initio simulation of the time delay in the photoionization of the simplest diatomic molecule H2+ as observed by attosecond streaking. We show that the strong variation of the Eisenbud-Wigner-Smith time delay tEWS as a function of energy and emission angle becomes observable in the streaking time shift tS provided laser field induced components are accounted for. The strongly enhanced photoemission time shifts are traced to destructive Cohen-Fano (or two-center) interferences. Signatures of these interferences in the streaking trace are shown to be enhanced when the ionic fragments are detected in coincidence.

  13. Estimating maize nutrient uptake requirements

    Microsoft Academic Search

    T. D. Setiyono; D. T. Walters; K. G. Cassman; C. Witt; A. Dobermann

    2010-01-01

    Generic, robust models are needed for estimating crop nutrient uptake requirements. We quantified and modeled grain yield–nutrient uptake relations in maize grown without significant biotic and abiotic stresses. Grain yield and plant nutrient accumulation in above-ground plant dry matter (DM) of commercial maize hybrids were measured at physiological maturity in on-station and on-farm experiments in Nebraska (USA), Indonesia, and Vietnam

  14. Effect of Process Variables on the Formation of Streak Defects on Anodized Aluminum Extrusions: An Overview

    NASA Astrophysics Data System (ADS)

    Zhu, Hanliang; Couper, Malcolm J.; Dahle, Arne K.

    2012-04-01

    Streak defects are often present on anodized extrusions of 6xxx series aluminum alloys, increasing the fabrication cost of these products. Moreover, streaking often only becomes visible after etching and anodizing treatments, rather than in the as-extruded condition, making it difficult to identify the original causes and influencing factors of these defects. In this paper, various process variables that influence the formation of streak defects on anodized aluminium extrusions are reviewed on the basis of a literature review, industrial practice and experimental results. The influencing factors involved in various processing steps such as billet quality, extrusion process, die design and etching process are considered. Effective measures for preventing the formation of streak defects in industrial extrusion products are discussed.

  15. Wind streaks in Tharsis and Elysium - Implications for sediment transport by slope winds

    NASA Technical Reports Server (NTRS)

    Lee, S. W.; Thomas, P. C.; Veverka, J.

    1982-01-01

    Detailed maps of wind streaks in Tharsis and Elysium have been compiled from Viking Orbiter observations spanning one complete Martian year. The streak pattern is controlled by slope winds on the central volcanoes and on the flanks of the Tharsis bulge, while the global circulation dominates in Elysium. Dust erosion by downslope winds occurs over much of Tharsis and in the vicinity of Elysium Mons; this process is effective even at the low atmospheric pressures found near the summits of the large volcanoes. Erosional streaks are largely absent in Elysium Planitia; net deposition of dust might have occurred during the period of the observations. Surface properties such as slope, thermal inertia, and roughness may influence the efficiency of slope wind production sufficiently to account for the pronounced differences in streak types and patterns present in these two regions.

  16. Standard design for National Ignition Facility x-ray streak and framing cameras

    SciTech Connect

    Kimbrough, J. R.; Bell, P. M.; Bradley, D. K.; Holder, J. P.; Kalantar, D. K.; MacPhee, A. G.; Telford, S. [Lawrence Livermore National Laboratory, Livermore, California 94551-0808 (United States)

    2010-10-15

    The x-ray streak camera and x-ray framing camera for the National Ignition Facility were redesigned to improve electromagnetic pulse hardening, protect high voltage circuits from pressure transients, and maximize the use of common parts and operational software. Both instruments use the same PC104 based controller, interface, power supply, charge coupled device camera, protective hermetically sealed housing, and mechanical interfaces. Communication is over fiber optics with identical facility hardware for both instruments. Each has three triggers that can be either fiber optic or coax. High voltage protection consists of a vacuum sensor to enable the high voltage and pulsed microchannel plate phosphor voltage. In the streak camera, the high voltage is removed after the sweep. Both rely on the hardened aluminum box and a custom power supply to reduce electromagnetic pulse/electromagnetic interference (EMP/EMI) getting into the electronics. In addition, the streak camera has an EMP/EMI shield enclosing the front of the streak tube.

  17. Film-thickness-dependent attosecond streaking time delays for photoemission from adsorbate-covered surfaces

    NASA Astrophysics Data System (ADS)

    Liao, Qing; Thumm, Uwe

    2014-05-01

    We analyze streaked photoelectron spectra and attosecond time delays for the streaked photoemission the from valence band (VB) and core levels (CLs) of Mg(0001) covered W(110) surfaces within a quantum-mechanical model. The relative streaking time delay between Mg(VB) and Mg(2p) CL photoelectrons (PEs) is found to be sensitive to Mg coverage for film thicknesses below ~ 100 layers. The relative streaking time delay between Mg(2p) and W(4f) CL PEs is shown to strongly depend on the Mg film thickness and thus on transport effects of PEs inside this solid, in particular, on the scattering of released PEs off the substrate and thin film lattices. Supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy under Grant No. DE-FG02-86ER13491 and NSF Grant PHY-1068752.

  18. Time and Streak Surfaces for Flow Visualization in Large Time-Varying Data Sets

    E-print Network

    Utah, University of

    to the surface. They are analogous to streak lines in that they originate from wind tunnel experiments with line to improve surface depiction through advanced rendering and texturing, while preserving interactivity

  19. Rip-current Persistent-foam Streaks Outside of the Surf Zone

    NASA Astrophysics Data System (ADS)

    Benbow, C.; MacMahan, J. H.; Reniers, A.; Brouwer, R.; Rynne, P.; de Schipper, M. A.

    2014-12-01

    Rip currents induce episodic pulses that transport surface material from the surf zone into the inner shelf. During certain energetic storm events for the rip-channeled system at Sand City, Monterey Bay, persistent-foam surface streaks are observed outside of the surf zone that outline the exiting rip current pulses. The persistent foam develops in the surf zone from mucus that is shed from diatoms in the breaking waves. The persistent foam streaks outside of the surf zone are surface convergences of the rip current front, and represent Lagrangian Coherent Structures. Aerial images are collected during these energetic events to explore the cross-shore mixing patterns. The images are geo-rectified and digitally enhanced for evaluating the surface streaks. The temporal and spatial evolution of the rip-current foam streaks is evaluated for their patterns, velocity, and offshore extent.

  20. Many maize genes are expressed in an oat background carrying a specific maize chromosome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oat-maize addition (OMA) lines are derived from oat x maize sexual hybrids in which individual maize chromosomes have been retained in plants containing a full complement of oat chromosomes. Many of the OMA lines display specific phenotypes, which indicate that maize genes are likely expressed and c...

  1. Update on the Maize Genome Sequencing Project The Maize Genome Sequencing Project

    E-print Network

    Brendel, Volker

    Update on the Maize Genome Sequencing Project The Maize Genome Sequencing Project Vicki L. Chandler Genome Sequencing Project. The momentum for this endeavor has been building within the maize (Zea mays and human genomes (Gregory et al., 2002). Our current picture of the maize genome is largely derived from

  2. Split ring resonator based THz-driven electron streak camera featuring femtosecond resolution

    PubMed Central

    Fabia?ska, Justyna; Kassier, Günther; Feurer, Thomas

    2014-01-01

    Through combined three-dimensional electromagnetic and particle tracking simulations we demonstrate a THz driven electron streak camera featuring a temporal resolution on the order of a femtosecond. The ultrafast streaking field is generated in a resonant THz sub-wavelength antenna which is illuminated by an intense single-cycle THz pulse. Since electron bunches and THz pulses are generated with parts of the same laser system, synchronization between the two is inherently guaranteed. PMID:25010060

  3. High time resolution X-ray streak camera with X-ray microscope

    Microsoft Academic Search

    N. Fleurot; J. P. Gex; M. Lamy; C. Quinnesiere; R. Sauneuf

    1977-01-01

    The paper reports characteristics and applications of high resolution X-ray streak cameras used to study plasmas. The camera structure is examined, and a device for converting X-rays into photocathode tube images is described. The ability of each of two X-ray microscopes with cylindrical mirrors to improve streak camera data quality was tested, and resolution properties are indicated. X-ray images and

  4. Effects of method of wheat streak mosaic virus transmission on the resistance of selected hosts 

    E-print Network

    Cho, Han Yong

    1969-01-01

    EFFECTS OF METHOD OF WHEAT STREAK MOSAIC VIRUS TRANSMISSION ON THE RESISTANCE OF SELECTED HOSTS A Thesis by HAN YONG CHO Submitted to the Graduate College of Texas A&K University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE May 1969 Major Subject: Plant Pathology EFFECTS OF METHOD OF NHEAT STREAK MOSAIC VIRUS TRANSMISSION ON THE RESISTANCE OF SELECTED HOSTS A Thesis HAN YONG CHO Approved as to style and content by: J (Chairman of Committee...

  5. Effects of Hot Streak Shape on Rotor Heating in a High-Subsonic Single-Stage Turbine

    NASA Technical Reports Server (NTRS)

    Dorney, Daniel J.; Gundy-Burlet, Karen L.; Norvig, Peter (Technical Monitor)

    1999-01-01

    Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-stage rotor blades in turbines. This heating of the rotor blades can lead to thermal fatigue and degrade turbine performance. The results of recent studies have shown that variations in the circumferential location (clocking) of the hot streak relative to the first-stage vane airfoils can be used to minimize the adverse effects of the hot streak. The effects of the hot streak/airfoil count ratio on the heating patterns of turbine airfoils have also been evaluated. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a single-stage high-pressure turbine operating in high subsonic flow. In addition to a simulation of the baseline turbine, simulations have been performed for circular and elliptical hot streaks of varying sizes in an effort to represent different combustor designs. The predicted results for the baseline simulation show good agreement with the available experimental data. The results of the hot streak simulations indicate: that a) elliptical hot streaks mix more rapidly than circular hot streaks, b) for small hot streak surface area the average rotor temperature is not a strong function of hot streak temperature ratio or shape, and c) hot streaks with larger surface area interact with the secondary flows at the rotor hub endwall, generating an additional high temperature region.

  6. Molecular characterization of Indian sugarcane streak mosaic virus isolate.

    PubMed

    Parameswari, B; Bagyalakshmi, K; Viswanathan, R; Chinnaraja, C

    2013-02-01

    Sugarcane streak mosaic virus (SCSMV), a member of the genus Poacevirus, family Potyviridae, is an important viral pathogen affecting sugarcane cultivation in India. The complete nucleotide sequence of a SCSMV isolate from India (SCSMV-IND) was determined. The linear, assembled, single-stranded positive-sense RNA genome of SCSMV-IND was 9,786 nucleotides in length (excluding the poly (A) tail) and encoded a polyprotein of 3,131 amino acid residues. The genome of SCSMV-IND shared high degree of sequence identity with SCSMV-PAK (93 % at nucleotide and 97 % at amino acid), and shared only 81 % nucleotide and 94 % amino acid identities with all the four SCSMV isolates (SCSMV-JP1, -JP2, -ID, and -THA). Phylogenetic tree analysis of the complete genome sequences of SCSMV isolates revealed that they can be clustered into two groups. SCSMV-IND and -AP isolates showed 18 % (nucleotide) divergence within the highly conserved 3' partial genome, suggesting a high level of genetic diversity among the Indian SCSMV isolates. PMID:23011777

  7. The Genetic Architecture of Maize Flowering Time

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flowering time is the key trait controlling adaptation of plants to their local environment, and, in an outcrossing species like maize, it is a complex trait. Variation for this complex trait was dissected in maize using a novel set of 5000 recombinant inbred lines (maize Nested Association Mapping...

  8. MaizeGDB Becomes Sequence-centric

    Technology Transfer Automated Retrieval System (TEKTRAN)

    MaizeGDB is the maize research community’s central repository for genetic and genomic information about the crop plant and research model Zea mays ssp. mays. The MaizeGDB team endeavors to meet research needs as they evolve based on researcher feedback and guidance. Recent work has focused on bett...

  9. Thc6 protein, isolated from Trichoderma harzianum, can induce maize defense response against Curvularia lunata.

    PubMed

    Fan, Lili; Fu, Kehe; Yu, Chuanjin; Li, Yingying; Li, Yaqian; Chen, Jie

    2015-05-01

    Mutant T66 was isolated from 450 mutants (constructed with Agrobacterium tumefaciens-mediated transformation method) of Trichoderma harzianum. Maize seeds coated with T66 were more susceptible to Curvularia lunata when compared with those coated with wild-type (WT) strain. The disease index of maize treated with T66 and WT were 62.5 and 42.1%, respectively. Further research showed T-DNA has inserted into the ORF of one gene, which resulted in the functional difference between WT and T66. The gene was cloned and named Thc6, which encodes a novel 327 amino acid protein. To investigate its function, we obtained knockout, complementation, and overexpression mutants of Thc6. Challenge inoculation studies suggested that the Thc6 overexpression mutant can reduce the disease index of maize inbred line Huangzao 4 against the leaf spot pathogen (C. lunata). Meanwhile, The Thc6 mutants were found to affect the resistance of maize inbred line Huangzao 4 against C. lunata by enhancing the activation of jasmonate-responsive genes expression. Liquid chromatography-mass spectrometry (LC-MS) data further confirmed that the concentration of jasmonate in the induced maize exhibits a parallel change tendency with the expression level of defense-related genes. Hence, the Thc6 gene could be participated in the induced resistance of maize inbred line Huangzao 4 against C. lunata infection through a jasmonic acid-dependent pathway. PMID:24771614

  10. A single extraction method for the analysis by liquid chromatography/tandem mass spectrometry of fumonisins and biomarkers of disrupted sphingolipid metabolism in tissues of maize seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus Fusarium verticillioides is a pathogen of many plants and produces fumonisins. In addition to their well-studied animal toxicoses these toxins contribute to the development of maize seedling disease in susceptible maize varieties. Fumonisin disruption of sphingolipid biosynthesis occurs ...

  11. Incidence of Fusarium spp. and levels of fumonisin B1 in maize in western Kenya.

    PubMed

    Kedera, C J; Plattner, R D; Desjardins, A E

    1999-01-01

    Maize kernel samples were collected in 1996 from smallholder farm storages in the districts of Bomet, Bungoma, Kakamega, Kericho, Kisii, Nandi, Siaya, Trans Nzoia, and Vihiga in the tropical highlands of western Kenya. Two-thirds of the samples were good-quality maize, and one-third were poor-quality maize with a high incidence of visibly diseased kernels. One hundred fifty-three maize samples were assessed for Fusarium infection by culturing kernels on a selective medium. The isolates obtained were identified to the species level based on morphology and on formation of the sexual stage in Gibberella fujikuroi mating population tests. Fusarium moniliforme (G. fujikuroi mating population A) was isolated most frequently, but F. subglutinans (G. fujikuroi mating population E), F. graminearum, F. oxysporum, F. solani, and other Fusarium species were also isolated. The high incidence of kernel infection with the fumonisin-producing species F. moniliforme indicated a potential for fumonisin contamination of Kenyan maize. However, analysis of 197 maize kernel samples by high-performance liquid chromatography found little fumonisin B1 in most of the samples. Forty-seven percent of the samples contained fumonisin B1 at levels above the detection limit (100 ng/g), but only 5% were above 1,000 ng/g, a proposed level of concern for human consumption. The four most-contaminated samples, with fumonisin B1 levels ranging from 3, 600 to 11,600 ng/g, were from poor-quality maize collected in the Kisii district. Many samples with a high incidence of visibly diseased kernels contained little or no fumonisin B1, despite the presence of F. moniliforme. This result may be attributable to the inability of F. moniliforme isolates present in Kenyan maize to produce fumonisins, to the presence of other ear rot fungi, and/or to environmental conditions unfavorable for fumonisin production. PMID:9872757

  12. Mars Eolian Geology at Airphoto Scales: The Large Wind Streaks of Western Arabia Terra

    NASA Technical Reports Server (NTRS)

    Edgett, Kenneth S.

    2001-01-01

    More than 27,000 pictures at aerial photograph scales (1.5-12 m/pixel) have been acquired by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) since September 1997. The pictures are valuable for testing hypotheses about geologic history and processes of Mars. Of particular interest are eolian features connected to surface albedo patterns. This work is focused on low-albedo wind streaks, some over 100 km long, in western Arabia Terra. Each streak is widest where it originates at an impact crater (typically 25-150 km diameter). The streaks taper downwind. Within the associated craters there is a lower-albedo surface that, in nearly all observed cases, includes barchan dunes indicative of transport in the same direction as the wind streaks. Upwind of the dunes there is usually an outcrop of layered material that might have served as a source for dune sand. MOC images show that the west Arabia streaks consist of a smooth-surfaced, multiple-meters-thick, mantle (smooth at 1.5 m/pixel) that appears to be superposed on local surfaces. No dunes are present, indicating that down-streak transport of sediment via saltation and traction have not occurred. Two models might explain the observed properties: (1) the streaks consist of dark silt- and clay-sized grains deflated from the adjacent crater interiors and deposited from suspension or (2) they are remnants (protected in the lee of impact crater rims) of a formerly much larger, regional covering of low albedo, smooth-surfaced mantle. The latter hypothesis is based on observation of low albedo mantled surfaces occurring south of west Arabia in Terra Meridiani. For reasons yet unknown, a large fraction of the martian equatorial regions are covered by low albedo, mesa-forming material that lies unconformably atop eroded layered and cratered terrain. Both hypotheses are being explored via continued selective targeting of new MOC images as well as analyses of the new data.

  13. Dust Devils Seen Streaking Across Mars: PART 1--What Are These?

    NASA Technical Reports Server (NTRS)

    2000-01-01

    PIA02376 [figure removed for brevity, see original site]

    PIA02377 [figure removed for brevity, see original site]

    Dark streaks, everywhere! Many Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images of the middle latitudes of the northern and southern hemispheres of Mars show wild patterns of criss-crossing dark streaks. Many of these streaks are straight and narrow, others exhibit curly arcs, twists, and loops. They often cross over hills, run straight across dunes and ripples, and go through fields of house-sized boulders. The two examples shown above were acquired in the last three months. Both pictures are illuminated by sunlight from the upper left. The first picture (left), showing dark streaks on the rippled flats of Argyre Planitia, covers an area 3 km by 5 km (1.9 by 3.1 miles) at a latitude of 51oS. The second picture (right) shows an area approximately 3 km by 5 km in Promethei Terra at a latitude of 58oS.

    For many months the MOC science team was seeing streaks such as these, but were uncertain how they formed. One speculation was that they might result from the passage of dust devils. Each dust devil would leave a dark streak by removing bright dust from the terrain in its path, revealing a darker surface underneath. An image described by the MOC team in July 1998 showed examples of streaks that were, at the time, speculated to be caused by dust devils.

  14. Complete genome sequence of nine isolates of canna yellow streak virus reveals its relationship to the sugarcane mosaic virus (SCMV) subgroup of potyviruses.

    PubMed

    Chauhan, Ravendra P; Rajakaruna, Punsasi; Verchot, Jeanmarie

    2015-03-01

    Complete genome sequences were obtained from nine isolates of canna yellow streak virus (CaYSV). CaYSV belongs to the sugarcane mosaic virus (SCMV) subgroup of potyviruses with johnsongrass mosaic virus (JGMV) as its closest relative. Multiple sequence alignments showed a pattern of amino acid substitutions in the CP sequences, which enabled us to relate these isolates to South East Asian or European isolates. Biological characterization of CaYSV identified Nicotiana benthamiana, Chenopodium quinoa and Phaseolus vulgaris as experimental hosts. Given the popularity and global trade of cannas, a clear picture of the genetic diversity of CaYSV is critical to disease management. PMID:25567205

  15. An Optical Streaking Method for Measuring Femtosecond Electron Bunches

    SciTech Connect

    Ding, Yuantao; Bane, Karl L.F.; Huang, Zhirong; /SLAC

    2011-12-14

    The measurement of the ultra-short electron bunch length on the femtosecond time scale constitutes a very challenging problem. In the x-ray free electron laser facilities such as the Linac Coherent Light Source, generation of a sub-ten femtoseconds electron beam with 20pC charge is possible, but direct measurements are very difficult due to the resolution limit of the present diagnostics. We propose a new method here based on the measurement of the electron beam energy modulation induced from laser-electron interaction in a short wiggler. A typical optical streaking method requires a laser wavelength much longer than the electron bunch length. In this paper a laser with its wavelength shorter than the electron bunch length has been adopted, while the slope on the laser intensity envelope is used to distinguish the different periods. With this technique it is possible to reconstruct the bunch longitudinal profile from a single shot measurement. Generation of ultrashort x-ray pulses at femtoseconds (fs) scale is of great interest within synchrotron radiation and free electron laser (FEL) user community. One of the simple methods is to operate the FEL facility at low charge. At the Linac Coherent Light Source (LCLS), we have demonstrated the capability of generating ultrashort electron-beam (e-beam) with a duration of less than 10 fs fwhm using 20 pC charge. The x-ray pulses have been delivered to the x-ray users with a similar or even shorter pulse duration. However, The measurement of such short electron or x-ray pulse length at the fs time-scale constitutes a challenging problem. A standard method using an S-band radio-frequency (rf) transverse deflector has been established at LCLS, which works like a streak camera for electrons and is capable of resolving bunch lengths as short as 25 fs fwhm. With this device, the electrons are transversely deflected by the high-frequency time-variation of the deflecting fields. Increasing the deflecting voltage and rf frequency are the right direction to achieve a better resolution. For example, by choosing an X-band transverse deflecting cavity, the expected resolution for LCLS beam with 4.3 GeV is about 1 fs rms. Typically the rf breakdown threshold and the power source availability prevent going to even higher voltage and frequency. With the highly-developed laser techniques, we can choose to streak the beam at optical frequencies. By jumping from rf to optical frequency, the wavelength is shortening by 4 to 5 orders. With an electron bunch length shorter than half period of the laser, we can apply the similar rf deflecting or zero-phasing method for e-beam bunch length measurements using a high-power laser. A short wiggler is required to provide interaction between the electron and the laser. For example, to measure the e-beam at the order of 1 m rms length, a laser with its wavelength of 10 {mu}m may be considered. For a typical few GeV e-beam, the wiggler period has to be large to satisfy the resonance condition. Also, if the e-beam is longer than one laser period, the different modulation periods will overlap and we cannot distinguish them. So this method is so far limited by the achievable long-wavelength laser power. To get an effective modulation on an e-beam of 4.3 GeV, the required laser power is about a few tens GW. In this paper we propose to adopt a high-power Ti:Sapphire laser (wavelength of 800 nm), and use the slope in the intensity envelope to distinguish the different modulation periods. First an ultrashort electron beam interacts with the Ti:Sapphire laser in a wiggler, where the electron energy is modulated at the same periods of the laser. If the laser pulse is long and the short electron bunch is overlapped (in time) with the middle part of the laser, such as the setup at LCLS laser heater, the different energy modulation periods on the electron beam will be overlapped on the energy profile. In this conditionwe typically have a double-horn distribution of the energy profile, and the electron-bunch length information cannot be retrieved. But if the laser pulse (

  16. Temporal Integration of Movement: The Time-Course of Motion Streaks Revealed by Masking

    PubMed Central

    Alais, David; Apthorp, Deborah; Karmann, Anna; Cass, John

    2011-01-01

    Temporal integration in the visual system causes fast-moving objects to leave oriented ‘motion streaks’ in their wake, which could be used to facilitate motion direction perception. Temporal integration is thought to occur over 100 ms in early cortex, although this has never been tested for motion streaks. Here we compare the ability of fast-moving (‘streaky’) and slow-moving fields of dots to mask briefly flashed gratings either parallel or orthogonal to the motion trajectory. Gratings were presented at various asynchronies relative to motion onset (from to ms) to sample the time-course of the accumulating streaks. Predictions were that masking would be strongest for the fast parallel condition, and would be weak at early asynchronies and strengthen over time as integration rendered the translating dots more streaky and grating-like. The asynchrony where the masking function reached a plateau would correspond to the temporal integration period. As expected, fast-moving dots caused greater masking of parallel gratings than orthogonal gratings, and slow motion produced only modest masking of either grating orientation. Masking strength in the fast, parallel condition increased with time and reached a plateau after 77 ms, providing an estimate of the temporal integration period for mechanisms encoding motion streaks. Interestingly, the greater masking by fast motion of parallel compared with orthogonal gratings first reached significance at 48 ms before motion onset, indicating an effect of backward masking by motion streaks. PMID:22205961

  17. Maize ZmRACK1 Is Involved in the Plant Response to Fungal Phytopathogens

    PubMed Central

    Wang, Baosheng; Yu, Jingjuan; Zhu, Dengyun; Chang, Yujie; Zhao, Qian

    2014-01-01

    The receptor for activated C kinase 1 (RACK1) belongs to a protein subfamily containing a tryptophan-aspartic acid-domain (WD) repeat structure. Compelling evidence indicates that RACK1 can interact with many signal molecules and affect different signal transduction pathways. In this study, we cloned a maize RACK1 gene (ZmRACK1) by RT-PCR. The amino acid sequence of ZmRACK1 had seven WD repeats in which there were typical GH (glycine-histidine) and WD dipeptides. Comparison with OsRACK1 from rice revealed 89% identity at the amino acid level. Expression pattern analysis by RT-PCR showed that ZmRACK1 was expressed in all analyzed tissues of maize and that its transcription in leaves was induced by abscisic acid and jasmonate at a high concentration. Overexpression of ZmRACK1 in maize led to a reduction in symptoms caused by Exserohilum turcicum (Pass.) on maize leaves. The expression levels of the pathogenesis-related protein genes, PR-1 and PR-5, increased 2.5–3 times in transgenic maize, and reactive oxygen species production was more active than in the wild-type. Yeast two-hybrid assays showed that ZmRACK1 could interact with RAC1, RAR1 and SGT1. This study and previous work leads us to believe that ZmRACK1 may form a complex with regulators of plant disease resistance to coordinate maize reactions to pathogens. PMID:24865494

  18. Maize Genetics and Genomics Database

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 2007 report for MaizeGDB lists the new hires who will focus on curation/outreach and the genome sequence, respectively. Currently all sequence in the database comes from a PlantGDB pipeline and is presented with deep links to external resources such as PlantGDB, Dana Farber, GenBank, the Arizona...

  19. Male gametophytic selection in maize

    Microsoft Academic Search

    E. Ottaviano; M. Sari Gorla; E. Pe

    1982-01-01

    There is evidence that male gametophyte selection is a widespread phenomenon in higher plants. The pollen tube growth rate is one of the main components of gametophyte selective value; genetic variability for this trait, due to the effect of single genes or to quantitative variation, has been described in maize. However, indication of gametophytic selection has been indirectly obtained; its

  20. Absolute calibration method for fast-streaked, fiber optic light collection, spectroscopy systems.

    SciTech Connect

    Johnston, Mark D.; Frogget, Brent (National Security Technologies, Las Vegas, NV); Oliver, Bryan Velten; Maron, Yitzhak (Weizmann Institute of Science, Rehovot, Israel); Droemer, Darryl W. (National Security Technologies, Las Vegas, NV); Crain, Marlon D. (National Security Technologies, Las Vegas, NV)

    2010-04-01

    This report outlines a convenient method to calibrate fast (<1ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such a system is used to collect spectral data on plasmas generated in the A-K gap of electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA). On RITS, light is collected through a small diameter (200 micron) optical fiber and recorded on a fast streak camera at the output of 1 meter Czerny-Turner monochromator (F/7 optics). To calibrate such a system, it is necessary to efficiently couple light from a spectral lamp into a 200 micron diameter fiber, split it into its spectral components, with 10 Angstroms or less resolution, and record it on a streak camera with 1ns or less temporal resolution.

  1. System for photometric calibration of optoelectronic imaging devices especially streak cameras

    DOEpatents

    Boni, Robert; Jaanimagi, Paul

    2003-11-04

    A system for the photometric calibration of streak cameras and similar imaging devices provides a precise knowledge of the camera's flat-field response as well as a mapping of the geometric distortions. The system provides the flat-field response, representing the spatial variations in the sensitivity of the recorded output, with a signal-to-noise ratio (SNR) greater than can be achieved in a single submicrosecond streak record. The measurement of the flat-field response is carried out by illuminating the input slit of the streak camera with a signal that is uniform in space and constant in time. This signal is generated by passing a continuous wave source through an optical homogenizer made up of a light pipe or pipes in which the illumination typically makes several bounces before exiting as a spatially uniform source field. The rectangular cross-section of the homogenizer is matched to the usable photocathode area of the streak tube. The flat-field data set is obtained by using a slow streak ramp that may have a period from one millisecond (ms) to ten seconds (s), but may be nominally one second in duration. The system also provides a mapping of the geometric distortions, by spatially and temporarily modulating the output of the homogenizer and obtaining a data set using the slow streak ramps. All data sets are acquired using a CCD camera and stored on a computer, which is used to calculate all relevant corrections to the signal data sets. The signal and flat-field data sets are both corrected for geometric distortions prior to applying the flat-field correction. Absolute photometric calibration is obtained by measuring the output fluence of the homogenizer with a "standard-traceable" meter and relating that to the CCD pixel values for a self-corrected flat-field data set.

  2. Signal averaging x-ray streak camera with picosecond jitter A. Maksimchuk, M. Kim, J. Workman, G. Korn,a)

    E-print Network

    Umstadter, Donald

    Signal averaging x-ray streak camera with picosecond jitter A. Maksimchuk, M. Kim, J. Workman, G pulse laser-produced plasma. Accumulation of the streaked x-ray signals significantly improved the signal-to-noise ratio of the data obtained. © 1996 American Institute of Physics. S0034-6748 96 02803-0 I

  3. A grazing incidence x-ray streak camera for ultrafast, single-shot measurements

    SciTech Connect

    Feng, Jun; Engelhorn, K.; Cho, B.I.; Lee, H.J.; Greaves, M.; Weber, C.P.; Falcone, R.W.; Padmore, H. A.; Heimann, P.A.

    2010-02-18

    An ultrafast x-ray streak camera has been realized using a grazing incidence reflection photocathode. X-rays are incident on a gold photocathode at a grazing angle of 20 degree and photoemitted electrons are focused by a large aperture magnetic solenoid lens. The streak camera has high quantum efficiency, 600fs temporal resolution, and 6mm imaging length in the spectral direction. Its single shot capability eliminates temporal smearing due to sweep jitter, and allows recording of the ultrafast dynamics of samples that undergo non-reversible changes.

  4. STUDY OF DIC HYDROTHERMAL TREATMENT EFFECT ON RHEOLOGICAL PROPERTIES OF STANDARD MAIZE (SMS), WAXY MAIZE (WMS), WHEAT (WTS)

    E-print Network

    Paris-Sud XI, Université de

    MAIZE (WMS), WHEAT (WTS) AND POTATO (PTS) STARCHES Z. Maache-Rezzouga* , I. Zarguilia ,C. Loiselb , J Standard maize (SMS), waxy maize (WMS), wheat (WTS) and potato (PTS) starches were2 hydrothermally treated

  5. The Effects of Government Maize Marketing Policies on Maize Market Prices in Kenya

    Microsoft Academic Search

    Thomas S. Jayne; Robert J. Meyers; James K. Nyoro

    2006-01-01

    The Government of Kenya pursues maize marketing policy objectives through the National Cereals and Produce Board (NCPB) which procures and sells maize at administratively determined prices, and stores maize as a contingency against future shortages. A private sector marketing channel competes with the NCPB and prices in this channel are set by supply and demand forces. This paper estimates the

  6. CHROMOSOME-BY-CHROMOSOME MAIZE GENOME ANALYSIS USING OAT-MAIZE ADDITION LINES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oat-maize Addition lines (OMA 1 through 10) are available where one maize chromosome has been individually added to the oat genome by a wide cross. By gamma irradiation, several hundred Radiation Hybrid (RH) lines now exist with only a fragment of the maize chromosome resulting from deletions of the...

  7. Kernel Composition, Starch Structure, and Enzyme Digestibility of Opaque-2 Maize and Quality Protein Maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objectives of this study were to understand how opaque-2 (o2) mutation and quality protein maize (QPM) affect maize kernel composition and starch structure, property, and enzyme digestibility. Kernels of o2 maize contained less protein (9.6−12.5%) than those of the wild-type (WT) counterparts (12...

  8. Comparison of wheat spindle streak mosaic virus (WSSMV) and barley yellow mosaic virus (BaYMV)

    E-print Network

    Paris-Sud XI, Université de

    Comparison of wheat spindle streak mosaic virus (WSSMV) and barley yellow mosaic virus (BaYMV): 2, we made a comparison of the closely related barley yellow mosaic bymovirus (BaYMV) and wheat spindle. Leaves of BaYMV-infected winter barley and WSSMV-infected wheat typically showed similar symptoms

  9. Multiplex Real Time PCR For Detection of Wheat Streak Mosaic Virus and Triticum Mosaic Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TRIMV) are widespread throughout the southwestern Great Plains states. Using conventional diagnostics such as Enzyme-Linked Immunosorbent Assays (ELISA), these two viruses are commonly found together in infected wheat samples. Methods for m...

  10. Resistance to wheat streak mosaic virus in transgenic wheat expressing the viral replicase (NIb) gene

    Microsoft Academic Search

    Elumalai Sivamani; Christopher W. Brey; William E. Dyer; Luther E. Talbert; Rongda Qu

    2000-01-01

    Wheat (Triticum aestivum L. cv. Hi-Line) immature embryos were transformed with the replicase gene (NIb) of wheat streak mosaic virus (WSMV) by the biolistic method. Six independent transgenic plant lines were analyzed for transgene expression and for resistance to mechanical inoculation of WSMV at R3 or R4 generation. Four out of the six lines showed various degree of resistance to

  11. WHEAT STREAK MOSAIC VIRUS (DESCRIPTIONS OF PLANT VIRUSES NO. 48, REVISED)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological and physical properties of Wheat streak mosaic virus (genus Tritimovirus) are presented in brief monograph form. The publication represents an updated revision of The Description of Plant Viruses No. 48, originally published in 1971 by the Association of Applied Biologists. Topics cover...

  12. Cryopreservation for the elimination of cucumber mosaic and banana streak viruses from banana ( Musa spp.)

    Microsoft Academic Search

    B. Helliot; B. Panis; Y. Poumay; R. Swennen; P. Lepoivre; E. Frison

    2002-01-01

    The utilisation of cryopreservation for the eradication of cucumber mosaic virus (CMV) or banana streak virus (BSV) from Musa spp. was investigated. Banana plants, cv. Williams (AAA, Cavendish subgroup), were mechanically infected with CMV or naturally infected with BSV, and proliferating meristems were produced from the infected plants. Excised meristematic clumps were cryopreserved through vitrification using PVS-2 solution. The health

  13. Carotenoid-based status signaling by females in the tropical streak-backed oriole

    Microsoft Academic Search

    Troy G. Murphy; Diego Hernández-Muciño; Marcela Osorio-Beristain; Robert Montgomerie; Kevin E. Omland

    2009-01-01

    In many tropical bird species, both males and females maintain elaborate plumage traits. Although there is considerable evidence that many male plumage traits function as status signals that convey information about fighting ability, less is known about status signaling in females. We tested whether the carotenoid-based orange breast coloration of the female streak-backed oriole (Icterus pustulatus pustulatus) signals status during

  14. Microrobotic Streak Seeding For Protein Crystal Growth CUCS-041-04

    E-print Network

    Microrobotic Streak Seeding For Protein Crystal Growth CUCS-041-04 Atanas Georgiev1 , Peter K the task known as crystal mounting that consists of picking an individual protein crystal from its growth Abstract We present a microrobotic system for protein crystal micromanipulation tasks. The focus

  15. Streak-Detection in Dermoscopic Color Images using Localized Radial Flux of

    E-print Network

    Hamarneh, Ghassan

    -painting on dermoscopic images, e.g. using color [7] and texture [8] diffusion. Example in-painted (hair disoccludedChapter 1 Streak-Detection in Dermoscopic Color Images using Localized Radial Flux of Principal) (g) (h) Figure 1.1: Examples of real (a) and simulated (e) hair occluded images. (b) and (f

  16. Under consideration for publication in J. Fluid Mech. 1 Transient growth on boundary layer streaks

    E-print Network

    Hoepffner, Jérôme

    By J ´E R ^O M E H OE P F F N E R, L U C A B R A N D T, AND D A N S. H E N N I N G S O N KTH Mechanics. The most amplified perturbations closely resemble the un- stable eigenfunctions obtained for streaks

  17. EVOLUTION OF WHEAT STREAK MOSAIC VIRUS: Dynamics of Population Growth Within Plants May Explain Limited Variation

    Microsoft Academic Search

    Roy C. French; Drake C. Stenger

    2003-01-01

    Like many other plant RNA viruses, Wheat streak mosaic virus (WSMV) sequence diversity within and among infected plants is low given the large number of virions produced. This may be explained by considering aspects of plant virus life history. Intracellular replication of RNA viruses is predominately linear, not exponential, which means that the rate at which mutations accumulate also is

  18. On Maize and the Sunflower

    NSDL National Science Digital Library

    Dolores R. Piperno (Smithsonian Tropical Research Institute; )

    2001-06-22

    Agriculture is believed to have arisen independently in six to eight independent centers, including both hemispheres of the Americas. In her Perspective, Piperno discusses recent work, which indicates that maize was domesticated at least 7100 years ago in tropical Mexico, 1000 years earlier than previous data indicated. The sunflower also seems to have been domesticated in Mexico, as well as in eastern North America. Molecular evidence is required to establish the origin of the sunflower with greater certainty.

  19. Resistance of maize landraces to the maize weevil Sitophilus zeamais Motsch. (Coleoptera: Curculionidae).

    PubMed

    Mikami, A Y; Carpentieri-Pípolo, V; Ventura, Maurício Ursi

    2012-10-01

    The maize weevil Sitophilus zeamais Motsch. is an important pest of maize that attacks the grain both in the field and during storage. The damage caused by the maize weevil S. zeamais on maize landraces, Amarelo Antigo, Asteca, Caiano, Carioca, and Ferrinho, was evaluated by no-choice tests under laboratory conditions. The commercial varieties Sol da Manhã, BR 106, BR 451, and the synthetics PC 0203 and PC 9903 were evaluated for comparisons with the maize landraces. The parameters evaluated were susceptibility index, number of weevil progeny, development time, weevil progeny dry weight, and grain dry weight loss. The landraces were more susceptible to the maize weevil as compared to the commercial varieties. Based on the cluster analysis, two groups of susceptibility to the maize weevil were observed: one of more susceptible populations formed by local landraces and BR 451, and another less susceptible, with commercial varieties, synthetics, and the landrace Amarelo. PMID:23950091

  20. Laboratory Simulations and Spectral Analyses of Recurring Slope Streaks on Mars

    NASA Astrophysics Data System (ADS)

    Wing, B.; Irvin, B.; Hibbitts, C.; Mushkin, A.

    2014-12-01

    Low albedo streaks on Martian slopes have been cited as possible evidence for present-day intermittent and repeated surface flow of water, or brine (Mushkin et al., 2010). Also termed as Recurring Slope Lineae (1), such streaks can grow, fade, and recur repeatedly on the same slopes. Although distinguishable by being darker than surrounding terrain slope streaks have no diagnostic spectral absorption features (2). A leading hypothesis is formation by multiple wetting and drying events. Laboratory investigations have previously explored this possibility (e.g 3). When wetted with brines, soils darken, but as the sample dries, it brightens again. Wetting also results in absorption bands near 1.5 and 2 microns, which are not detected in spectra of slope streaks. Additionally, dried brines of most salts such as MgSO4, or other sulfates and many chlorides are brighter than Martian soils. However, iron chlorides are a salt that have lower albedo than most other salts and may present a mechanism for darkening slope streaks without inducing a spectral absorption feature. To explore this hypothesis, we have begun to conduct experiments investigating the spectra of iron chloride chloride solutions wetting palagonite and subsequently drying under Martian atmospheric conditions. Preliminary experiments demonstrate that FeIII chloride dried onto palagonite has no absorption features in the NIR and SWIR and remains dark and red. However, these chlorides will oxidize under terrestrial conditions forming Fe2O3 as they dry. We have constructed an environmental chamber that mimics Martian oxygen fugacity though a combination of vacuum and N2 purging, allowing for sample wetting and drying while concurrently taking spectra from 0.4 to 2.4 microns. Results from this experimental setup under Martian atmospheric conditions will be presented. References: (1) McEwen et al., (2011) Science, 333, 740-743, (2) Mushkin et al., (2010) Geophys. Res. Lett., 37, L22201, doi: 10.1029/2010GL044535, (3) Masse et al., (2012), 43rd LPSC, #1856.

  1. Twelve signals multiplexed with the Lawrence Livermore National Laboratory (LLNL) optical streak camera

    SciTech Connect

    Lerche, R.A.; Griffith, R.L.

    1990-08-28

    At our Nova laser facility, the temporal history of incident and reflected laser energy is recorded on LLNL optical streak cameras. Currently, six cameras are used to record the incident 1.06-{mu}m, incident 0.35{mu}m power of each of the ten Nova beams. Each camera records seven multiplexed signals: typically one signal from each of five beam lines, a fiducial pulse, and time mark generator signal. The optical signals are transported to the camera through optical fibers. The output end of each fiber is placed in the slit plane of the camera. The light exiting the fiber is focused to the streak camera photocathode by the streak camera relay lens. One camera can record a signal from each of the ten Nova beams plus a fiducial and time mark generator signal if the number of multiplexed channels can be increased from seven to twelve. This would allow one camera to record the same data that currently requires two cameras. At a savings of $150 per camera/CCD system, this represents a savings of $450K. Additionally, camera/CCD maintenance and operation complexity would be cut in half and three streak cameras would be freed for use in other experiments. Recent laboratory measurements suggest that the number of multiplexed signals per camera can indeed be increased from seven to twelve without noticeably increasing the crosstalk between signal channels. In this memorandum, we describe recent work in which seven and twelve signals were multiplexed to one streak camera. We describe the effect focusing has on the crosstalk channels and the effect wavelength has on focusing. We conclude the memorandum with suggestions concerning the implementation of a twelve channel system.

  2. Identification and validation of sugarcane streak mosaic virus-encoded microRNAs and their targets in sugarcane.

    PubMed

    Viswanathan, Chandran; Anburaj, Jeyaraj; Prabu, Gajjeraman

    2014-02-01

    Plants have developed several defense mechanisms to cope with various pathogens (bacteria, fungi, virus, and phytoplasma). Among these, RNA interference (RNAi)-mediated defense against viral infection was found to be a major innate immune response. As a counter attack strategy against the host defense, viruses produce suppressors of host RNAi pathway. MicroRNAs (miRNAs) are an abundant class of short (~18-22 nucleotide) non-coding single-stranded RNAs involved in RNAi pathway leading to post-transcriptional regulation of gene expression. Sugarcane streak mosaic virus (SCSMV) is a distinct strain of Potyviridae family which has a single-stranded positive-sense RNA genome causing mosaic disease in sugarcane. In this study, we computationally predicted and experimentally validated the miRNA encoded by the SCSMV genome with detection efficiency of 99.9 % in stem-loop RT-qPCR and predicted their potential gene targets in sugarcane. These sugarcane target genes considerably broaden future investigation of the SCSMV-encoded miRNA function during viral pathogenesis and might be applied as a new strategy for controlling mosaic disease in sugarcane. PMID:24145912

  3. Interaction of fusaric acid and maize seedling lesion development and reduction by isolates of Bacillus mogavensis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to autoinfection and alloinfection, maize is parasitized by Fusarium verticillioides and subject to contamination from its mycotoxins, the fumonisins. Attempts at controlling both the disease and mycotoxins resulting from infection are desirable since in some cultivars infections do not always ...

  4. Characterization of strains of Bacillus mojavensis for biocontrol of a maize pathogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The endophytic bacterium, Bacillus mojavensis controls fungal diseases in maize and other plants. The bacterium and its cultural extracts have been shown to be antagonistic to a pathogenic and mycotoxic fungus, Fusarium verticillioides. Extracts prepared from cultures of B. mojavensis contained an...

  5. Fusarium verticillioides gene clusters associated with biotransformation of maize allelopathic compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize produces the benzoxazinones DIMBOA and DIBOA, which naturally transform into the more stable benzoxazolinones MBOA and BOA, respectively. These weed-suppressive allelopathic compounds are also implicated in resistance to microbial diseases and insect feeding. Fusarium verticillioides is able t...

  6. Maize maturity and the development of gibberella ear rot symptoms and deoxynivalenol after inoculation

    Microsoft Academic Search

    L. M. Reid; R. C. Sinha

    1998-01-01

    Development of gibberella ear rot disease symptoms and the accumulation of the mycotoxin deoxynivalenol (DON) in maize ears inoculated via the silk with Fusarium graminearum was determined at various times after inoculation. Ten hybrids ranging in maturity from early to late, were inoculated with a conidial suspension in 1993 and 1994 and harvested every 2 weeks for 14 weeks after

  7. FUNCTIONAL GENOMICS OF ENDOSPERM DEVELOPMENT IN MAIZE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Maize Endosperm Functional Genomics Project is developing tools for the molecular cloning of seed mutants in maize. Specifically, we are developing normalized and subtracted ESTs from endopserm cDNA libraries, identifying transposon-tagged endosperm mutants from the mutagenic inbred, UniformMu, ...

  8. Germplasm Enhancement of Maize (GEM) Project Overview

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Germplasm Enhancement of Maize Project (GEM) is a collaborative effort of public and private sector researchers to broaden and enhance the maize germplasm base. The GEM Project has cooperators from 26 private companies, 17 Universities, 7 USDA-ARS Research Units, 1 NGO, and 12 international pub...

  9. Benzoxazinoids in Root Exudates of Maize Attract Pseudomonas putida to the Rhizosphere

    PubMed Central

    Neal, Andrew L.; Ahmad, Shakoor; Gordon-Weeks, Ruth; Ton, Jurriaan

    2012-01-01

    Benzoxazinoids, such as 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), are secondary metabolites in grasses. In addition to their function in plant defence against pests and diseases above-ground, benzoxazinoids (BXs) have also been implicated in defence below-ground, where they can exert allelochemical or antimicrobial activities. We have studied the impact of BXs on the interaction between maize and Pseudomonas putida KT2440, a competitive coloniser of the maize rhizosphere with plant-beneficial traits. Chromatographic analyses revealed that DIMBOA is the main BX compound in root exudates of maize. In vitro analysis of DIMBOA stability indicated that KT2440 tolerance of DIMBOA is based on metabolism-dependent breakdown of this BX compound. Transcriptome analysis of DIMBOA-exposed P. putida identified increased transcription of genes controlling benzoate catabolism and chemotaxis. Chemotaxis assays confirmed motility of P. putida towards DIMBOA. Moreover, colonisation essays in soil with Green Fluorescent Protein (GFP)-expressing P. putida showed that DIMBOA-producing roots of wild-type maize attract significantly higher numbers of P. putida cells than roots of the DIMBOA-deficient bx1 mutant. Our results demonstrate a central role for DIMBOA as a below-ground semiochemical for recruitment of plant-beneficial rhizobacteria during the relatively young and vulnerable growth stages of maize. PMID:22545111

  10. Plant growth hormones suppress the development of Harpophora maydis, the cause of late wilt in maize.

    PubMed

    Degani, Ofir; Drori, Ran; Goldblat, Yuval

    2015-01-01

    Late wilt, a severe vascular disease of maize caused by the fungus Harpophora maydis, is characterized by rapid wilting of maize plants before tasseling and until shortly before maturity. The pathogen is currently controlled by resistant maize cultivars, but the disease is constantly spreading to new areas. The plant's late phenological stage at which the disease appears suggests that plant hormones may be involved in the pathogenesis. This work revealed that plant growth hormones, auxin (Indole-3-acetic acid) and cytokinin (kinetin), suppress H. maydis in culture media and in a detached root assay. Kinetin, and even more auxin, caused significant suppression of fungus spore germination. Gibberellic acid did not alter colony growth rate but had a signal suppressive effect on the pathogens' spore germination. In comparison, ethylene and jasmonic acid, plant senescing and defense response regulators, had minor effects on colony growth and spore germination rate. Their associate hormone, salicylic acid, had a moderate suppressive effect on spore germination and colony growth rate, and a strong influence when combined with auxin. Despite the anti-fungal auxin success in vitro, field experiments with dimethylamine salt of  2,4-dichlorophenoxyacetic acid (that mimics the influence of auxin) failed to suppress the late wilt. The lines of evidence presented here reveal the suppressive influence of the three growth hormones studied on fungal development and are important to encourage further and more in-depth examinations of this intriguing hormonal complex regulatory and its role in the maize-H. maydis interactions. PMID:25649030

  11. The mouse primitive streak forms in situ by initiation of epithelial to mesenchymal transition without migration of a cell population

    PubMed Central

    Williams, Margot; Burdsal, Carol; Periasamy, Ammasi; Lewandoski, Mark; Sutherland, Ann

    2011-01-01

    During gastrulation, an embryo acquires the three primordial germ layers that will give rise to all of the tissues in the body. In amniote embryos, this process occurs via an epithelial to mesenchymal transition (EMT) of epiblast cells at the primitive streak. Although the primitive streak is vital to development, many aspects of how it forms and functions remain poorly understood. Using live imaging and immunohistochemistry, we have shown that the murine primitive streak arises in situ by progressive initiation of EMT beginning in the posterior epiblast, without large-scale movement or convergence and extension of epiblast cells. Loss of basal lamina (BL) is the first step of this EMT, and is strictly correlated with ingression of nascent mesoderm. This is the first description of dynamic cell behavior during primitive streak formation in the mouse embryo, and reveals mechanisms that are quite distinct from those observed in other amniote model systems. PMID:22170865

  12. Extra-embryonic Wnt3 regulates the establishment of the primitive streak in mice.

    PubMed

    Yoon, Yeonsoo; Huang, Tingting; Tortelote, Giovane G; Wakamiya, Maki; Hadjantonakis, Anna-Katerina; Behringer, Richard R; Rivera-Pérez, Jaime A

    2015-07-01

    The establishment of the head to tail axis at early stages of development is a fundamental aspect of vertebrate embryogenesis. In mice, experimental embryology, genetics and expression studies have suggested that the visceral endoderm, an extra-embryonic tissue, plays an important role in anteroposterior axial development. Here we show that absence of Wnt3 in the posterior visceral endoderm leads to delayed formation of the primitive streak and that interplay between anterior and posterior visceral endoderm restricts the position of the primitive streak. Embryos lacking Wnt3 in the visceral endoderm, however, appear normal by E9.5. Our results suggest a model for axial development in which multiple signals are required for anteroposterior axial development in mammals. PMID:25907228

  13. A novel compact high speed x-ray streak camera (invited)

    SciTech Connect

    Hares, J. D.; Dymoke-Bradshaw, A. K. L. [Kentech Instruments Ltd., Howbery Park, Wallingford, Oxfordshire OX10 8BA (United Kingdom)

    2008-10-15

    Conventional in-line high speed streak cameras have fundamental issues when their performance is extended below a picosecond. The transit time spread caused by both the spread in the photoelectron (PE) ''birth'' energy and space charge effects causes significant electron pulse broadening along the axis of the streak camera and limits the time resolution. Also it is difficult to generate a sufficiently large sweep speed. This paper describes a new instrument in which the extraction electrostatic field at the photocathode increases with time, converting time to PE energy. A uniform magnetic field is used to measure the PE energy, and thus time, and also focuses in one dimension. Design calculations are presented for the factors limiting the time resolution. With our design, subpicosecond resolution with high dynamic range is expected.

  14. Drag reduction of a 3D bluff body using coherent streamwise streaks

    NASA Astrophysics Data System (ADS)

    Pujals, G.; Depardon, S.; Cossu, C.

    2010-11-01

    Separation on the rear-end of an Ahmed body is suppressed by means of large-scale coherent streaks forced on the roof of the model. These streaks originate from an array of suitably shaped cylindrical roughness elements and are amplified by the mean shear through the lift-up effect. Interacting with the mean velocity field at leading order, they induce a strong controlled spanwise modulation. The resulting streaky base flow is observed to sustain the adverse pressure gradient since PIV measurements as well as static wall pressure distributions show that the re-circulation bubble completely vanishes. These modifications of the topology of the flow are associated with a substantial drag reduction, which can be of about 10% when the roughness array is optimally placed on the roof of the bluff body.

  15. Time-resolved two-photon excited fluorescence spectroscopy based on a streak camera

    NASA Astrophysics Data System (ADS)

    Liu, Lixin; Qu, Junle; Chen, Danni; Lin, Ziyang; Xu, Gaixia; Guo, Baoping; Niu, Hanben

    2006-09-01

    Combination of fluorescence spectral and temporal resolutions can improve the sensitivity and specificity of biomedical diagnostics. In this paper, we present the development of a time resolved two-photon excited fluorescence spectroscopy system that consists of a Ti: Sapphire femtosecond laser, a fluorescence microscope objective, a prism spectrophotometer and a high repetition rate picosecond streak camera. The streak camera and the time-resolved fluorescence spectroscopy system. have been calibrated with an F-P etalon and a spectral line lamp respectively. Validation experiment of the system is also performed on two standard fluorescent dyes (Rhodamine 6G and Coumarin 314), and the results agree well with those reported in the literatures. Preliminary experimental results on autofluorescence spectra and lifetimes of freshly picked leaves and in vivo human skin are also presented, which demonstrates the potential applications of this system in tissue discrimination and clinical diagnostics.

  16. Single-shot visualization of evolving laser wakefields using an all-optical streak camera.

    PubMed

    Li, Zhengyan; Tsai, Hai-En; Zhang, Xi; Pai, Chih-Hao; Chang, Yen-Yu; Zgadzaj, Rafal; Wang, Xiaoming; Khudik, V; Shvets, G; Downer, M C

    2014-08-22

    We visualize ps-time-scale evolution of an electron density bubble--a wake structure created in atmospheric density plasma by an intense ultrashort laser pulse--from the phase "streak" that the bubble imprints onto a probe pulse that crosses its path obliquely. Phase streaks, recovered in one shot using frequency-domain interferometric techniques, reveal the formation, propagation, and coalescence of the bubble within a 3 mm long ionized helium gas target. 3D particle-in-cell simulations validate the observed density-dependent bubble evolution, and correlate it with the generation of a quasimonoenergetic ? 100 MeV electron beam. The results provide a basis for understanding optimized electron acceleration at a plasma density n(e) ? 2 × 10(19) cm(-3), inefficient acceleration at lower density, and dephasing limits at higher density. PMID:25192102

  17. Reshaping of the maize transcriptome by domestication

    PubMed Central

    Swanson-Wagner, Ruth; Briskine, Roman; Schaefer, Robert; Hufford, Matthew B.; Ross-Ibarra, Jeffrey; Myers, Chad L.; Tiffin, Peter; Springer, Nathan M.

    2012-01-01

    Through domestication, humans have substantially altered the morphology of Zea mays ssp. parviglumis (teosinte) into the currently recognizable maize. This system serves as a model for studying adaptation, genome evolution, and the genetics and evolution of complex traits. To examine how domestication has reshaped the transcriptome of maize seedlings, we used expression profiling of 18,242 genes for 38 diverse maize genotypes and 24 teosinte genotypes. We detected evidence for more than 600 genes having significantly different expression levels in maize compared with teosinte. Moreover, more than 1,100 genes showed significantly altered coexpression profiles, reflective of substantial rewiring of the transcriptome since domestication. The genes with altered expression show a significant enrichment for genes previously identified through population genetic analyses as likely targets of selection during maize domestication and improvement; 46 genes previously identified as putative targets of selection also exhibit altered expression levels and coexpression relationships. We also identified 45 genes with altered, primarily higher, expression in inbred relative to outcrossed teosinte. These genes are enriched for functions related to biotic stress and may reflect responses to the effects of inbreeding. This study not only documents alterations in the maize transcriptome following domestication, identifying several genes that may have contributed to the evolution of maize, but highlights the complementary information that can be gained by combining gene expression with population genetic analyses. PMID:22753482

  18. Hybridization of maize and teosinte, in mexico and guatemala and the improvement of maize

    Microsoft Academic Search

    H. G. Wllkes

    1977-01-01

    The recognition and subsequent detection of the importance of teosinte introgression in the racial diversity and heterotic\\u000a gene architecture of maize has been one of the outstanding achievements of Paul C. Mangelsdorf’s investigations into the origin\\u000a of maize. This paper documents three areas in Mexico and Guatemala where maize and teosinte hybridize and where there is a\\u000a system by which

  19. Tissue-specific expression in transgenic maize of four endosperm promoters from maize and rice

    Microsoft Academic Search

    Douglas A. Russell; Michael E. Fromm

    1997-01-01

    The tissue-specific, developmental, and genetic control of four endosperm-active genes was studied via expression of GUS reporter genes in transgenic maize plants. The transgenes included promoters from the maize granule-bound starch synthase (Waxy) gene (zmGBS), a maize 27 kDa zein gene (zmZ27), a rice small subunit ADP-glucose pyrophosphorylase gene (osAGP) and the rice glutelin 1 gene (osGT1). Most plants had

  20. Optical laser-based THz streaking for full FEL pulse characterization

    NASA Astrophysics Data System (ADS)

    Cavalieri, Adrian

    2012-06-01

    Full temporal characterization of ultrashort, high brilliance x-ray pulses at Free Electron Laser (FEL) facilities, while elusive, will underpin their future use in experiments ranging from single-molecule imaging to extreme timescale x-ray science. This issue is especially acute when confronted with the characteristics of current generation FELs operating on the principle of self-amplified spontaneous emission, as most parameters fluctuate from pulse to pulse. We have achieved this crucial characterization by extending the techniques of photoelectron streaking originally developed for attosecond spectroscopy. In our experiments, high-intensity, optical laser generated single-cycle THz pulses were used to broaden and shift -- or streak -- the photoelectron spectrum of a noble gas target ionized by the incident FEL pulse. Due to the relatively long rise time of the THz streaking field (˜600 fs), these measurements allow for the arrival-time and temporal profile of femtosecond to hundred-femtosecond FEL pulses to be determined simultaneously and on a single-shot basis. Optical laser-based THz streaking is suited for use over the full range of photon energies and pulse durations produced at FELs, from XUV to the hard x-ray regime. Experiments have now been performed at the hard x-ray Linac-Coherent Light Source at the SLAC National Accelerator Laboratory as well as at the XUV Free Electron Laser in Hamburg. Distinct temporal features as short as 50 fs FWHM have been observed in the raw pulse profile prior to any correction for instrument resolution. While these first measurements have been resolution-limited, the potential for improvement to access the sub 10-fs range has also been demonstrated, which would allow for characterization and effective application of the shortest predicted, few-femtosecond x-ray pulses in the near future.

  1. Streak camera coupled with a high-resolution x-ray crystal imager

    Microsoft Academic Search

    V. Serlin; M. Karasik; C. J. Pawley; A. N. Mostovych; S. P. Obenschain; Y. Aglitskiy

    2001-01-01

    An addition of a streak camera to the Nike monochromatic x-ray imaging system makes it possible to analyze continuous time behavior of mass variation, which is necessary to reveal the non-monotonic evolution of the processes under study. Backlighter energy of ~500 J is delivered to a silicon target, producing x-rays that backlight the main target for about 5 ns. The

  2. Fluorescence measurement by a streak camera in a single-photon-counting mode

    Microsoft Academic Search

    Masayuki Komura; Shigeru Itoh

    2009-01-01

    We describe here a recently developed fluorescence measurement system that uses a streak camera to detect fluorescence decay\\u000a in a single photon-counting mode. This system allows for easy measurements of various samples and provides 2D images of fluorescence\\u000a in the wavelength and time domains. The great advantage of the system is that the data can be handled with ease; furthermore,

  3. An innovative approach to reduce streaking artifacts in FDK based 3D cone-beam tomography

    Microsoft Academic Search

    Ujjal Kumar Bhowmik; Araveti Venkata Sudeepth; Reza R. Adhami

    2011-01-01

    In this paper, we propose a method to detect and eliminate the streaking artifacts, present in Feldkamp-David- Kress (FDK) based 3D cone-beam tomography, by comparing and combining two synthetic data sets. The data sets, which are 3D reconstructed volume data, are created from the original and negative of the X-ray projections of 3D Sheep-Logan model. The 2 nd data set,

  4. Signs of the principle body axes prior to primitive streak formation in the rabbit embryo

    Microsoft Academic Search

    Christoph Viebahn; Barbara Mayer; Martin Hrabé Angelis

    1995-01-01

    An early common element during anterior-posterior axis formation amongst amniotes is the primitive streak, running longitudinally in the two-layered embryonic disc. In mammals the primordium of this transient structure is the first definite morphological sign of the anterior-posterior axis, while in avian embryos the axis is visible and apparently defined earlier. Here we scrutinize suggestions that in mammals also there

  5. Integration of Banana Streak Badnavirus into the MusaGenome: Molecular and Cytogenetic Evidence

    Microsoft Academic Search

    Glyn Harper; Julian O. Osuji; Roger Hull

    1999-01-01

    Breeding and tissue culture of certain cultivars of bananas (Musa) have led to high levels of banana streak badnavirus (BSV) infection in progeny from symptomless parents. BSV DNA hybridized to genomic DNA of one such parent, Obino l'Ewai, suggesting integration of viral sequences. Sequencing of clones of Obino l'Ewai genomic DNA revealed an interface between BSV andMusasequences and a complex

  6. Structure and Temporal Dynamics of Populations within Wheat Streak Mosaic Virus Isolates

    Microsoft Academic Search

    JEFFREY S. HALL; ROY FRENCH; T. JACK MORRIS; DRAKE C. STENGER

    2001-01-01

    Variation within the Type and Sidney 81 strains of wheat streak mosaic virus was assessed by single-strand conformation polymorphism (SSCP) analysis and confirmed by nucleotide sequencing. Limiting-dilution subisolates (LDSIs) of each strain were evaluated for polymorphism in the P1, P3, NIa, and CP cistrons. Different SSCP patterns among LDSIs of a strain were associated with single-nucleotide substitutions. Sidney 81 LDSI-S10

  7. Complete Genome Sequence of an Emerging Genotype of Tobacco Streak Virus in the United States

    PubMed Central

    Padmanabhan, Chellappan; Gao, Shan; Li, Rugang; Zhang, Shouan; Fei, Zhangjun

    2014-01-01

    We report here the complete genome sequence of an emerging genotype of tobacco streak virus (TSV) infecting zucchini squash in Florida (TSV_FL13-07), obtained using deep sequencing of short RNAs (sRNAs) and validation by Sanger sequencing. TSV_FL13-07 shares only <90% sequence identity in all three genomic RNAs to several known U.S. isolates. PMID:25377714

  8. Molecular organization of the cholesteryl ester droplets in the fatty streaks of human aorta.

    PubMed Central

    Engelman, D M; Hillman, G M

    1976-01-01

    X-ray diffraction patterns from human arterial specimens containing atherosclerotic fatty streak lesions exhibited a single sharp reflection, corresponding to a structural spacing of about 35 A. Specimens without lesions did not. When specimens with fatty streaks were heated, an order-to-disorder phase transition was revealed by the disappearance of the sharp reflection. The transition was thermally reversible and its temperature varied from aorta to aorta over a range from 28 degrees to 42 degrees C. Since cholesteryl ester droplets are a major component of fatty streaks, comparison studies were made of the diffraction behavior from pure cholesteryl esters. We found that the diffraction patterns of the fatty streak material could be accounted for by the organization of the cholesteryl esters into a liquid-crystalline smectic phase that melts from the smectic to a less ordered phase upon heating. When combined with the conclusions of others from polarized light microscopy, our study shows that a droplet in the smectic phase has well-defined concentric layers of lipid molecules. In each layer, the long axes of the molecules have a net radial orientation with respect to the droplet, but the side-to-side organization is disordered. We suggest that the accessibility of portions of the lipids for specific binding to enzymes or transport proteins may be restricted when they are in the smectic state, and that exchange of lipids with surrounding membranes or other potential binding sites may likewise be inhibited. The restriction in the smectic phase should be greater than in the less ordered phases that exist at higher temperatures. Images PMID:965500

  9. Optimizing data recording for the NIF core diagnostic x-ray streak camera

    Microsoft Academic Search

    D. H. Kalantar; P. M. Bell; T. S. Perry; N. Sewall; J. Kimbrough; F. Weber; C. Diamond; K. Piston

    2001-01-01

    Quantitative measurements of the sensitivity, dynamic range, and image resolution of a Nova secondary ion mass-based x-ray streak camera have been made. Comparisons were made using film versus a 4k×4k optical charge-coupled device for data readout. These tests were performed with and without an optical image intensifier tube, and with a direct electron-sensitive microchannel plate. We present results from these

  10. The complete sequence of the genome of Cocksfoot streak virus (CSV), a grass infecting Potyvirus

    Microsoft Academic Search

    R. Götz; E. Maiss

    2002-01-01

    Summary.  ?The complete nucleotide sequence of Cocksfoot streak virus (CSV) has been determined. The viral genome comprises 9663 nucleotides,\\u000a excluding a 3?-terminal poly(A) sequence. The genome of CSV has a 133?nt 5?-non coding and a 260?nt 3?-non coding region.\\u000a The RNA of CSV encodes a single polyprotein of 3089 amino acid residues and has a deduced genome organization typical for\\u000a a

  11. Femtosecond streaking of electron diffraction patterns to study structural dynamics in crystalline matter

    NASA Astrophysics Data System (ADS)

    Eichberger, M.; Erasmus, N.; Haupt, K.; Kassier, G.; von Flotow, A.; Demsar, J.; Schwoerer, H.

    2013-03-01

    A table-top femtosecond, non-relativistic, electron diffraction setup is combined with a low-jitter, photo-triggered streak camera to follow the optically induced structural dynamics in complex solids. A temporal resolution of 550 fs is experimentally demonstrated, while the route to streaking with sub-250 fs temporal resolution is outlined. The streaking technique allows for parallel capturing of temporal information as opposed to the serial data acquisition in a conventional scanning femtosecond electron diffraction. Moreover, its temporal resolution is not corrupted by increasing the number of electrons per pulse. Thus, compared to the conventional scanning approach, a substantial increase in signal-to-noise ratio (SNR) can be achieved. These benefits are demonstrated by studying a photo-induced charge density wave phase transition in 4Hb-TaSe2 using both methods. Within the same data acquisition time a three-fold increase in SNR is achieved when compared to the scanning method, with ways for a further improvement outlined.

  12. Rho kinase activity controls directional cell movements during primitive streak formation in the rabbit embryo

    PubMed Central

    Stankova, Viktoria; Tsikolia, Nikoloz; Viebahn, Christoph

    2015-01-01

    During animal gastrulation, the specification of the embryonic axes is accompanied by epithelio-mesenchymal transition (EMT), the first major change in cell shape after fertilization. EMT takes place in disparate topographical arrangements, such as the circular blastopore of amphibians, the straight primitive streak of birds and mammals or in intermediate gastrulation forms of other amniotes such as reptiles. Planar cell movements are prime candidates to arrange specific modes of gastrulation but there is no consensus view on their role in different vertebrate classes. Here, we test the impact of interfering with Rho kinase-mediated cell movements on gastrulation topography in blastocysts of the rabbit, which has a flat embryonic disc typical for most mammals. Time-lapse video microscopy, electron microscopy, gene expression and morphometric analyses of the effect of inhibiting ROCK activity showed – besides normal specification of the organizer region – a dose-dependent disruption of primitive streak formation; this disruption resulted in circular, arc-shaped or intermediate forms, reminiscent of those found in amphibians, fishes and reptiles. Our results reveal a crucial role of ROCK-controlled directional cell movements during rabbit primitive streak formation and highlight the possibility that temporal and spatial modulation of cell movements were instrumental for the evolution of gastrulation forms. PMID:25516971

  13. Oct4 Is Required ?E7.5 for Proliferation in the Primitive Streak

    PubMed Central

    DeVeale, Brian; Brokhman, Irina; Mohseni, Paria; Babak, Tomas; Yoon, Charles; Lin, Anthony; Onishi, Kento; Tomilin, Alexey; Pevny, Larysa; Zandstra, Peter W.; Nagy, Andras; van der Kooy, Derek

    2013-01-01

    Oct4 is a widely recognized pluripotency factor as it maintains Embryonic Stem (ES) cells in a pluripotent state, and, in vivo, prevents the inner cell mass (ICM) in murine embryos from differentiating into trophectoderm. However, its function in somatic tissue after this developmental stage is not well characterized. Using a tamoxifen-inducible Cre recombinase and floxed alleles of Oct4, we investigated the effect of depleting Oct4 in mouse embryos between the pre-streak and headfold stages, ?E6.0–E8.0, when Oct4 is found in dynamic patterns throughout the embryonic compartment of the mouse egg cylinder. We found that depletion of Oct4 ?E7.5 resulted in a severe phenotype, comprised of craniorachischisis, random heart tube orientation, failed turning, defective somitogenesis and posterior truncation. Unlike in ES cells, depletion of the pluripotency factors Sox2 and Oct4 after E7.0 does not phenocopy, suggesting that ?E7.5 Oct4 is required within a network that is altered relative to the pluripotency network. Oct4 is not required in extraembryonic tissue for these processes, but is required to maintain cell viability in the embryo and normal proliferation within the primitive streak. Impaired expansion of the primitive streak occurs coincident with Oct4 depletion ?E7.5 and precedes deficient convergent extension which contributes to several aspects of the phenotype. PMID:24244203

  14. Streak-camera reflection high-energy electron diffraction for dynamics of surface crystallography

    NASA Astrophysics Data System (ADS)

    Mukojima, Kenta; Kanzaki, Shinji; Kawanishi, Kota; Sato, Katsuyoshi; Abukawa, Tadashi

    2015-06-01

    A new technique for ultrafast dynamics of surface crystallography was developed by combining reflection high-energy electron diffraction with the electron deflectors of a streak camera system. A one-dimensional distribution of electrons scattered by a crystal surface is selected by a linear slit on a screen, and then the electrons are quickly deflected by the sweep electrodes behind the slit. Thus, a temporal evolution of the one-dimensional diffraction pattern can be displayed as a streak image on a screen. This is a unique method of time-resolved electron diffraction, as a pulsed electron beam is not required to obtain a temporal evolution. The temporal evolution of the diffraction pattern can be projected on a screen from single-shot measurements. The technique was tested on an Si(111)-7 × 7 surface, and the dynamics of the surface structure were successively obtained from changes in spot intensities. Although the present time time-resolution was limited by the present pumping laser ~ 5 ns, the nominal resolution of the streak system is expected to be ~100 ps.

  15. Direct evidence for encoding of motion streaks in human visual cortex

    PubMed Central

    Apthorp, Deborah; Schwarzkopf, D. Samuel; Kaul, Christian; Bahrami, Bahador; Alais, David; Rees, Geraint

    2013-01-01

    Temporal integration in the visual system causes fast-moving objects to generate static, oriented traces (‘motion streaks’), which could be used to help judge direction of motion. While human psychophysics and single-unit studies in non-human primates are consistent with this hypothesis, direct neural evidence from the human cortex is still lacking. First, we provide psychophysical evidence that faster and slower motions are processed by distinct neural mechanisms: faster motion raised human perceptual thresholds for static orientations parallel to the direction of motion, whereas slower motion raised thresholds for orthogonal orientations. We then used functional magnetic resonance imaging to measure brain activity while human observers viewed either fast (‘streaky’) or slow random dot stimuli moving in different directions, or corresponding static-oriented stimuli. We found that local spatial patterns of brain activity in early retinotopic visual cortex reliably distinguished between static orientations. Critically, a multivariate pattern classifier trained on brain activity evoked by these static stimuli could then successfully distinguish the direction of fast (‘streaky’) but not slow motion. Thus, signals encoding static-oriented streak information are present in human early visual cortex when viewing fast motion. These experiments show that motion streaks are present in the human visual system for faster motion. PMID:23222445

  16. The maize Dof protein PBF activates transcription of ?-zein during maize seed development

    Microsoft Academic Search

    Pau Marzábal; Elisabet Gas; Pilar Fontanet; Jesús Vicente-Carbajosa; Margarita Torrent; M. Dolores Ludevid

    2008-01-01

    Maize PBF (prolamin-box binding factor) belongs to the Dof class of plant specific transcription factors containing one highly\\u000a conserved zinc finger DNA-binding domain, called Dof (DNA binding with one finger) domain. Maize PBF trans-activates the ?-zein\\u000a gene (?Z) promoter in developing maize seeds as shown by transient expression in maize endosperms. Co-transfection of a ?Z:GUS\\u000a construct with 35S:PBF resulted in

  17. Impact of enhanced ultraviolet-B irradiance on maize yield and its seed qualities: a field evaluation

    NASA Astrophysics Data System (ADS)

    Gao, Wei; Zheng, Youfei; Slusser, James R.; Heisler, Gordon M.; He, Douliang; Xu, Jianqiang

    2003-06-01

    Stratospheric ozone depletion has caused an increase in the amount of UV-B radiation reaching the earth"s surface. Numerous investigations have demonstrated that the effect of UV-B enhancements on plants includes reduction in grain yield, alteration in species competition, susceptibility to disease, and changes in plant structure and pigmentation. Many experiments examining UV-B radiation effects on plants were conducted in growth chambers or greenhouses. It has been questioned if the effect of UV-B radiation on plants can be extrapolated to field responses from indoor studies because of the unnaturally high ratios of UV-B/UV-A and UV-B/PAR in many indoor studies. Field studies on UV-B radiation effect on plants has been recommended in order to use the UV and PAR irradiance provided by natural light. This study reported the growth and yield responses of a maize crop exposed to enhanced UV-B radiation and the UV-B effects on maize seed qualities under field conditions. Enhanced UV-B radiation caused a significant reduction of the dry matter accumulation, and the maize yield in turn was affected. With increased UV-B radiation the flavonoid accumulation in maize leaves increased, and the contents of chlorophyll a, b, and (a+b) of maize leaves were reduced. The levels of protein, sugar, and starch of maize seed decreased with enhanced UV-B radiation, while the level of lysine increased with enhanced UV-B radiation.

  18. No Adjuvant Effect of Bacillus thuringiensis-Maize on Allergic Responses in Mice

    PubMed Central

    Dekan, Gerhard; Epstein, Michelle M.

    2014-01-01

    Genetically modified (GM) foods are evaluated carefully for their ability to induce allergic disease. However, few studies have tested the capacity of a GM food to act as an adjuvant, i.e. influencing allergic responses to other unrelated allergens at acute onset and in individuals with pre-existing allergy. We sought to evaluate the effect of short-term feeding of GM Bacillus thuringiensis (Bt)-maize (MON810) on the initiation and relapse of allergic asthma in mice. BALB/c mice were provided a diet containing 33% GM or non-GM maize for up to 34 days either before ovalbumin (OVA)-induced experimental allergic asthma or disease relapse in mice with pre-existing allergy. We observed that GM-maize feeding did not affect OVA-induced eosinophilic airway and lung inflammation, mucus hypersecretion or OVA-specific antibody production at initiation or relapse of allergic asthma. There was no adjuvant effect upon GM-maize consumption on the onset or severity of allergic responses in a mouse model of allergic asthma. PMID:25084284

  19. Cassava virus diseases and their control with special reference to southern Tanzania

    Microsoft Academic Search

    R. J. HILLOCKS

    1997-01-01

    Cassava is a major smallholder crop in much of Africa where it is attacked by two main virus diseases. African cassava mosaic disease (ACMD) occurs almost everywhere that the crop is grown causing severe losses in some countries. Cassava brown streak disease (CBSD) is of more restricted distribution being prevalent mainly on the east African coast and shores of Lake

  20. A single extraction method for the analysis by liquid chromatography\\/tandem mass spectrometry of fumonisins and biomarkers of disrupted sphingolipid metabolism in tissues of maize seedlings

    Microsoft Academic Search

    Nicholas C. Zitomer; Anthony E. Glenn; Charles W. Bacon; Ronald T. Riley

    2008-01-01

    The fungus Fusarium verticillioides is a pathogen of many plants and produces fumonisins. In addition to their well-studied animal toxicoses, these toxins contribute\\u000a to the development of maize seedling disease in susceptible maize varieties. Fumonisin disruption of sphingolipid biosynthesis\\u000a occurs during pathogenesis. An extraction method was developed for the simultaneous analysis of fumonisins B1 (FB1), B2 (FB2) and B3 (FB3),

  1. Molecular Genetics of Mitochondrial Biogenesis in Maize.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The mitochondrial genome encodes proteins essential for mitochondrial respiration and ATP synthesis. Nuclear gene products, however, are required for the expression of mitochondrial genes and the elaboration of functional mitochondrial protein complexes. We are exploiting a unique collection of maiz...

  2. Perturbation of Maize Phenylpropanoid Metabolism by an AvrE Family Type III Effector from Pantoea stewartii1[OPEN

    PubMed Central

    Asselin, Jo Ann E.; Lin, Jinshan; Perez-Quintero, Alvaro L.; Gentzel, Irene; Majerczak, Doris; Opiyo, Stephen O.; Zhao, Wanying; Paek, Seung-Mann; Kim, Min Gab; Coplin, David L.; Blakeslee, Joshua J.; Mackey, David

    2015-01-01

    AvrE family type III effector proteins share the ability to suppress host defenses, induce disease-associated cell death, and promote bacterial growth. However, despite widespread contributions to numerous bacterial diseases in agriculturally important plants, the mode of action of these effectors remains largely unknown. WtsE is an AvrE family member required for the ability of Pantoea stewartii ssp. stewartii (Pnss) to proliferate efficiently and cause wilt and leaf blight symptoms in maize (Zea mays) plants. Notably, when WtsE is delivered by a heterologous system into the leaf cells of susceptible maize seedlings, it alone produces water-soaked disease symptoms reminiscent of those produced by Pnss. Thus, WtsE is a pathogenicity and virulence factor in maize, and an Escherichia coli heterologous delivery system can be used to study the activity of WtsE in isolation from other factors produced by Pnss. Transcriptional profiling of maize revealed the effects of WtsE, including induction of genes involved in secondary metabolism and suppression of genes involved in photosynthesis. Targeted metabolite quantification revealed that WtsE perturbs maize metabolism, including the induction of coumaroyl tyramine. The ability of mutant WtsE derivatives to elicit transcriptional and metabolic changes in susceptible maize seedlings correlated with their ability to promote disease. Furthermore, chemical inhibitors that block metabolic flux into the phenylpropanoid pathways targeted by WtsE also disrupted the pathogenicity and virulence activity of WtsE. While numerous metabolites produced downstream of the shikimate pathway are known to promote plant defense, our results indicate that misregulated induction of phenylpropanoid metabolism also can be used to promote pathogen virulence. PMID:25635112

  3. Comparison of Gene Expressions of Maize Kernel Pathogenesis-Related Proteins in Different Maize Genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are carcinogenic mycotoxins produced by the fungus Aspergillus flavus during infection of various grain crops including maize (Zea mays). Contamination of maize with aflatoxins has been shown to be exasperated by late season drought stress. Previous studies have identified numerous resist...

  4. Impact of 9 years of Bt-maize cultivation on the distribution of maize viruses.

    PubMed

    Achon, Maria Angeles; Alonso-Dueñas, Natalia

    2009-06-01

    This study assesses the effect of Bt-maize on the distribution of maize viruses. Random surveys were conducted in Spain between 2001 and 2006 to evaluate the occurrence of maize viruses in Bt-maize cultivation areas and in areas where this crop had not been introduced. Maize dwarf mosaic virus (MDMV) was the predominant virus in Bt-areas, and Maize rough dwarf virus (MRDV) was the most predominant one in non-Bt-areas, with MRDV an emergent virus in both types of areas. A decline in the occurrence of MDMV and an increase in that of Sugarcane mosaic virus was observed in Bt-areas. Additionally, data obtained over 6 years in experimental fields showed non-significant differences between the infection rates exhibited by two generations of Bt varieties and the non-transformed isogenics varieties for any of the viruses. Our data suggest that differences in virus distribution are linked to the genetic background of the maize varieties and the distribution of virus reservoirs rather than to Bt-maize cultivation. PMID:19067216

  5. Expression of an anthranilate synthase from maize mutant bf-1 in maize line HiII

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize mutant bf-1 was one of a series of maize mutants generated by radiation from the Bikini Atoll atomic bomb test in 1946. It is characterized by blue fluorescence in seedlings and anthers under ultraviolet illumination and by mutant plants giving off a characteristic grape-like odor due to the ...

  6. Food quality and properties of quality protein maize.

    E-print Network

    Leal Diaz, Ana Maria

    2004-09-30

    Quality protein maize (QPM), high protein corn (HPC) and food grade maize (FGM) were processed into tortillas and direct expanded extruded snacks. QPM had similar test weight, density and kernel size with 45% more lysine and 38% more tryptophan...

  7. Study Progress on Tissue Culture of Maize Mature Embryo

    NASA Astrophysics Data System (ADS)

    Wang, Hongzhen; Cheng, Jun; Cheng, Yanping; Zhou, Xioafu

    It has been paid more and more attention on maize tissue culture as it is a basic work in maize genetic transformation, especially huge breakthrough has been made in maize tissue culture utilizing mature embryos as explants in the recent years. This paper reviewed the study progress on maize tissue culture and plant regeneration utilizing mature embryos as explants from callus induction, subculture, plant regeneration and browning reduction and so on.

  8. Flavone-rich maize: an opportunity to improve the nutritional value of an important commodity crop

    PubMed Central

    Casas, María I.; Duarte, Silvia; Doseff, Andrea I.; Grotewold, Erich

    2014-01-01

    Agricultural outputs have resulted in food production continuously expanding. To satisfy the needs of a fast growing human population, higher yields, more efficient food processing, and food esthetic value, new crop varieties with higher caloric intake have and continue to be developed, but which lack many phytochemicals important for plant protection and adequate human nutrition. The increasing incidence of chronic diseases such as obesity, diabetes and cardiovascular diseases, combined with social disparity worldwide prompted the interest in developing enhanced crops that can simultaneously address the two sides of the current malnutrition sword, increasing yield while providing added nutritional value. Flavones, phytochemicals associated with the beneficial effects of the Mediterranean diet, have potent anti-inflammatory and anti-carcinogenic activities. However, many Mediterranean diet-associated vegetables are inaccessible, or lowly consumed, in many parts of the world. Maize is the most widely grown cereal crop, yet most lines used for hybrid maize production lack flavones. As a first step toward a sustainable strategy to increasing the nutritional value of maize-based diets, we investigated the accumulation and chemical properties of flavones in maize seeds of defined genotypes. We show that the pericarps of the P1-rr genotype accumulate flavones at levels comparable to those present in some flavone-rich vegetables, and are mostly present in their C- and O-glycosylated forms. Some of these glycosides can be readily converted into the corresponding more active health beneficial aglycones during food processing. Our results provide evidence that nutritionally beneficial flavones could be re-introduced into elite lines to increase the dietary benefits of maize. PMID:25250036

  9. Absolute calibration method for nanosecond-resolved, time-streaked, fiber optic light collection, spectroscopy systems

    SciTech Connect

    Johnston, Mark D.; Oliver, Bryan V. [Advanced Radiographic Technologies, Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185-1195 (United States); Droemer, Darryl W.; Frogget, Brent; Crain, Marlon D. [National Security Technologies, LLC, P.O. Box 98521, Las Vegas, Nevada 89193 (United States); Maron, Yitzhak [Weizmann Institute of Science, Rehovot, Israel 76100 (Israel)

    2012-08-15

    This paper describes a convenient and accurate method to calibrate fast (<1 ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such systems are inherently difficult to calibrate due to the lack of sufficiently intense, calibrated light sources. Such a system is used to collect spectral data on plasmas generated in electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA) at Sandia National Laboratories. On RITS, plasma light is collected through a small diameter (200 {mu}m) optical fiber and recorded on a fast streak camera at the output of a 1 meter Czerny-Turner monochromator. For this paper, a 300 W xenon short arc lamp (Oriel Model 6258) was used as the calibration source. Since the radiance of the xenon arc varies from cathode to anode, just the area around the tip of the cathode ('hotspot') was imaged onto the fiber, to produce the highest intensity output. To compensate for chromatic aberrations, the signal was optimized at each wavelength measured. Output power was measured using 10 nm bandpass interference filters and a calibrated photodetector. These measurements give power at discrete wavelengths across the spectrum, and when linearly interpolated, provide a calibration curve for the lamp. The shape of the spectrum is determined by the collective response of the optics, monochromator, and streak tube across the spectral region of interest. The ratio of the spectral curve to the measured bandpass filter curve at each wavelength produces a correction factor (Q) curve. This curve is then applied to the experimental data and the resultant spectra are given in absolute intensity units (photons/sec/cm{sup 2}/steradian/nm). Error analysis shows this method to be accurate to within +/- 20%, which represents a high level of accuracy for this type of measurement.

  10. Absolute calibration method for nanosecond-resolved, time-streaked, fiber optic light collection, spectroscopy systems

    NASA Astrophysics Data System (ADS)

    Johnston, Mark D.; Oliver, Bryan V.; Droemer, Darryl W.; Frogget, Brent; Crain, Marlon D.; Maron, Yitzhak

    2012-08-01

    This paper describes a convenient and accurate method to calibrate fast (<1 ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such systems are inherently difficult to calibrate due to the lack of sufficiently intense, calibrated light sources. Such a system is used to collect spectral data on plasmas generated in electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA) at Sandia National Laboratories. On RITS, plasma light is collected through a small diameter (200 ?m) optical fiber and recorded on a fast streak camera at the output of a 1 meter Czerny-Turner monochromator. For this paper, a 300 W xenon short arc lamp (Oriel Model 6258) was used as the calibration source. Since the radiance of the xenon arc varies from cathode to anode, just the area around the tip of the cathode ("hotspot") was imaged onto the fiber, to produce the highest intensity output. To compensate for chromatic aberrations, the signal was optimized at each wavelength measured. Output power was measured using 10 nm bandpass interference filters and a calibrated photodetector. These measurements give power at discrete wavelengths across the spectrum, and when linearly interpolated, provide a calibration curve for the lamp. The shape of the spectrum is determined by the collective response of the optics, monochromator, and streak tube across the spectral region of interest. The ratio of the spectral curve to the measured bandpass filter curve at each wavelength produces a correction factor (Q) curve. This curve is then applied to the experimental data and the resultant spectra are given in absolute intensity units (photons/sec/cm2/steradian/nm). Error analysis shows this method to be accurate to within +/- 20%, which represents a high level of accuracy for this type of measurement.

  11. Significant seismic streaks corresponding to lithological contrasts in Mesozoic and Paleozoic accretion units, southwest Japan

    NASA Astrophysics Data System (ADS)

    Maeda, S.; Toda, S.; Katao, H.

    2014-12-01

    While high-density seismic streaks are commonly seen in aftershocks of a strike-slip earthquake, significant linear clusters in background seismicity are rare. A typical example of such sustained streaks is observed along the creeping section of the San Andreas fault, in which strain localization associated with frictional heterogeneity takes a responsibility. Here we show other examples from Tamba and Wakayama regions, around Osaka-Kyoto district, where a number of several-to-20-km-long seismic streaks are observed. We explore the role of geologic heterogeneity into the seismicity comparing spatial distribution of earthquakes with geologic structure in both regions, where a significant high background rate of seismicity has been continuously recorded since the mid-1900. Epicenters of numerous small earthquakes are located mainly on the Mesozoic metamorphic rocks and Mesozoic-Paleozoic accretion units, whereas low seismicity is characterized in granite and ultra-mafic rocks. Within the Wakayama seismic zone, in particular, we observe many E-W and ENE-WSW trending dense seismic clusters in hypocenters of Japan Meteorological Agency (JMA) data relocated with the hypo DD algorithm of Waldhauser and Ellsworth (2000). Most of the E-W trending seismic clusters possibly correspond to the E-W trending local scale geologic faults, folds, bedding planes, and schistosity. However, well-determined fault plane solutions by JMA and the National Research Institute for Earth Science and Disaster Prevention (NIED) show NS-trending reverse faults corresponding to EW compression. We further sought the focal mechanisms for smaller earthquakes using waveform data recorded in the SATARN seismic network system of DPRI, Kyoto University. As a result, among the many reverse fault mechanisms, we found some amounts of strike-slip ones, which may associate with the visible EW-trending seismic clusters.

  12. A new tubeless nanosecond streak camera based on optical deflection and direct CCD imaging

    SciTech Connect

    Lai, C.C.

    1992-12-01

    A new optically deflected streaking camera with performance of nanosecond-range resolution, superior imaging quality, high signal detectability, and large format recording has been conceived and developed. Its construction is composed of an optomechanical deflector that deflects the line-shape image of spatial-distributed time-varying signals across the sensing surface of a cooled scientific two-dimensional CCD array with slow readout driving electronics, a lens assembly, and a desk-top computer for prompt digital data acquisition and processing. Its development utilizes the synergism of modern technologies in sensor, optical deflector, optics and microcomputer. With laser light as signal carrier, the deflecting optics produces near diffraction-limited streak images resolving to a single pixel size of 25[mu]. A 1kx1k-pixel array can thus provide a vast record of 1,000 digital data points along each spatial or temporal axis. Since only one photon-to-electron conversion exists in the entire signal recording path, the camera responses linearly to the incident light over a wide dynamic range in excess of 10[sup 4]:1. Various image deflection techniques are assessed for imaging fidelity, deflection speed, and capacity for external triggering. Innovative multiple-pass deflection methods for utilizing optomechanical deflector have been conceived and developed to attain multi-fold amplification for the optical scanning. speed across the CCD surface at a given angular deflector speed. Without significantly compromising imaging. quality or flux throughput efficiency, these optical methods enable a sub-10 ns/pixel streak speed with the deflector moving benignly at 500 radians/second, or equivalently 80 revolutions /second. Test results of the prototype performance are summarized including a spatial resolution of 10 lp/mm at 65% CTF and a temporal resolution of 11.4 ns at 3.8 ns/pixel.

  13. A new tubeless nanosecond streak camera based on optical deflection and direct CCD imaging

    SciTech Connect

    Lai, C.C.

    1992-12-01

    A new optically deflected streaking camera with performance of nanosecond-range resolution, superior imaging quality, high signal detectability, and large format recording has been conceived and developed. Its construction is composed of an optomechanical deflector that deflects the line-shape image of spatial-distributed time-varying signals across the sensing surface of a cooled scientific two-dimensional CCD array with slow readout driving electronics, a lens assembly, and a desk-top computer for prompt digital data acquisition and processing. Its development utilizes the synergism of modern technologies in sensor, optical deflector, optics and microcomputer. With laser light as signal carrier, the deflecting optics produces near diffraction-limited streak images resolving to a single pixel size of 25{mu}. A 1kx1k-pixel array can thus provide a vast record of 1,000 digital data points along each spatial or temporal axis. Since only one photon-to-electron conversion exists in the entire signal recording path, the camera responses linearly to the incident light over a wide dynamic range in excess of 10{sup 4}:1. Various image deflection techniques are assessed for imaging fidelity, deflection speed, and capacity for external triggering. Innovative multiple-pass deflection methods for utilizing optomechanical deflector have been conceived and developed to attain multi-fold amplification for the optical scanning. speed across the CCD surface at a given angular deflector speed. Without significantly compromising imaging. quality or flux throughput efficiency, these optical methods enable a sub-10 ns/pixel streak speed with the deflector moving benignly at 500 radians/second, or equivalently 80 revolutions /second. Test results of the prototype performance are summarized including a spatial resolution of 10 lp/mm at 65% CTF and a temporal resolution of 11.4 ns at 3.8 ns/pixel.

  14. The Genetic Architecture Of Maize Height

    PubMed Central

    Peiffer, Jason A.; Romay, Maria C.; Gore, Michael A.; Flint-Garcia, Sherry A.; Zhang, Zhiwu; Millard, Mark J.; Gardner, Candice A. C.; McMullen, Michael D.; Holland, James B.; Bradbury, Peter J.; Buckler, Edward S.

    2014-01-01

    Height is one of the most heritable and easily measured traits in maize (Zea mays L.). Given a pedigree or estimates of the genomic identity-by-state among related plants, height is also accurately predictable. But, mapping alleles explaining natural variation in maize height remains a formidable challenge. To address this challenge, we measured the plant height, ear height, flowering time, and node counts of plants grown in >64,500 plots across 13 environments. These plots contained >7300 inbreds representing most publically available maize inbreds in the United States and families of the maize Nested Association Mapping (NAM) panel. Joint-linkage mapping of quantitative trait loci (QTL), fine mapping in near isogenic lines (NILs), genome-wide association studies (GWAS), and genomic best linear unbiased prediction (GBLUP) were performed. The heritability of maize height was estimated to be >90%. Mapping NAM family-nested QTL revealed the largest explained 2.1 ± 0.9% of height variation. The effects of two tropical alleles at this QTL were independently validated by fine mapping in NIL families. Several significant associations found by GWAS colocalized with established height loci, including brassinosteroid-deficient dwarf1, dwarf plant1, and semi-dwarf2. GBLUP explained >80% of height variation in the panels and outperformed bootstrap aggregation of family-nested QTL models in evaluations of prediction accuracy. These results revealed maize height was under strong genetic control and had a highly polygenic genetic architecture. They also showed that multiple models of genetic architecture differing in polygenicity and effect sizes can plausibly explain a population’s variation in maize height, but they may vary in predictive efficacy. PMID:24514905

  15. Real-time quantitative polymerase chain reaction methods for four genetically modified maize varieties and maize DNA content in food.

    PubMed

    Brodmann, Peter D; Ilg, Evelyn C; Berthoud, Hélène; Herrmann, Andre

    2002-01-01

    Quantitative detection methods are needed for enforcement of the recently introduced labeling threshold for genetically modified organisms (GMOs) in food ingredients. This labeling threshold, which is set to 1% in the European Union and Switzerland, must be applied to all approved GMOs. Four different varieties of maize are approved in the European Union: the insect-resistant Bt176 maize (Maximizer), Btl 1 maize, Mon810 (YieldGard) maize, and the herbicide-tolerant T25 (Liberty Link) maize. Because the labeling must be considered individually for each ingredient, a quantitation system for the endogenous maize content is needed in addition to the GMO-specific detection systems. Quantitative real-time polymerase chain reaction detection methods were developed for the 4 approved genetically modified maize varieties and for an endogenous maize (invertase) gene system. PMID:12083257

  16. Design of a streaked radiography instrument for ICF ablator tuning measurements

    SciTech Connect

    Olson, R. E.; Geissel, M.; Kellogg, J. W.; Bennett, G. R.; Edens, A. D.; Atherton, B. W.; Leeper, R. J. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Hicks, D. G.; Spears, B. K.; Celliers, P. M.; Holder, J. P.; Landen, O. L. [Lawrence Livermore National Laboratories, Livermore, California 94550 (United States)

    2008-10-15

    A streaked radiography diagnostic has been proposed as a technique to determine the ablator mass remaining in an inertial confinement fusion ignition capsule at peak velocity. This instrument, the 'HXRI-5', has been designed to fit within a National Ignition Facility Diagnostic Instrument Manipulator. The HXRI-5 will be built at Sandia National Laboratories (SNL), and initial testing will be done at the SNL Z-Beamlet Facility. In this paper, we will describe the National Ignition Campaign requirements for this diagnostic, the instrument design, and the planned test experiments.

  17. Temporal Characterization of individual Harmonics of an attosecond pulse train by THz Streaking

    E-print Network

    Ardana-Lamas, F; Stepanov, A; Gorgisyan, I; Juranic, P; Abela, R; Hauri, C P

    2015-01-01

    We report on the global temporal pulse characteristics of individual harmonics in an attosecond pulse train by means of photo-electron streaking in a strong low-frequency transient. The scheme allows direct retrieval of pulse durations and first order chirp of individual harmonics without the need of temporal scanning. The measurements were performed using an intense THz field generated by tilted phase front technique in LiNbO_3 . Pulse properties for harmonics of order 23, 25 and 27 show that the individual pulse durations and linear chirp are decreasing by the harmonic order.

  18. Modes on a short SPEAR bunch as observed with a streak camera

    SciTech Connect

    Sabersky, A.P.; Donald, M.H.R.

    1981-02-01

    The longitudinal structure of electron bunches in the storage ring SPEAR on a single pass was studied with time resolution approx. 10 ps. The measuring instrument used is an image-converter streak camera, a specialized device heretofore used mostly by laser workers. Unexpectedly, under some conditions the charge in a single RF bucket breaks up into two short sub-bunches which seem to rotate about a common center in energy-phase space. No evidence is seen for other, higher-frequency structure on the bunches.

  19. Temporal Characterization of Electron Beam Bunches with a Fast Streak Camera at the JLab FEL Facility

    SciTech Connect

    S. Zhang; S.V. Benson; D. Douglas; D. Hardy; C. Hernandez-Garcia; K. Jordan; G. Neil; Michelle D. Shinn

    2005-08-21

    The design and construction of an optical transport that brings synchrotron radiation from electron bunches to a fast streak camera in a remote area has become a useful tool for online observation of bunch length and stability. This paper will report on the temporal measurements we have done, comparison with simulations, and the on-going work for another imaging optical transport system that will make possible the direct measurement of the longitudinal phase space by measuring the bunch length as a function of energy

  20. Follow-up Observatory for Low Earth Orbit Objects with a Detection Algorithm Using Streaks

    NASA Astrophysics Data System (ADS)

    Tagawa, M.; Yanagisawa, T.; Kurosaki, H.; Oda, H.; Hanada, T.

    2014-09-01

    This paper proposes a simplified facility for a follow-up observation method. A tri-axis altazimuth mount instrument is required in the conventional observation facility to keep a target as a light spot during a visible pass. The tri-axis instrument enables the facility to observe the target with a high signal-to-noise-ratio. However, such instrument becomes costly due to its complexity. The proposed method uses a bi-axis altazimuth to guide a telescope into an observation target region. It should be noted that the bi-axis altazimth does not guide the telescope toward the target continuously therefore the target appears as streaks in images. Intensities in the streak are degraded in signal-to-noise-ratio in comparison to that in the light spot taken by a telescope on a tri-axis altazimuth because original intensity was divided into the pixels. The proposed method recovers such low signal-to-noise-ratio using 1) an image-processing algorithm and 2) multi-telescope. The image-processing algorithm developed for this study aims to detect an object appeared as faint streaks in images. The initial study also found that the algorithm requires primary orbit information of the target to complete detection calculation in reasonable time consumption. The algorithm can recovers signal-to-noise-ratio. However, it is still lower than that of continuous guiding observation result. The multi-telescope denotes an observation using two or more telescopes toward same region. We can improve signal-to-noise-ratio by summing images taken by the telescopes. We found that the image-processing algorithm improves signal-to-noise-ratio proportional to square root of streaks length. The multi-telescope observation method also improves signal-to-noise-ratio proportional to square root of number of the telescope. The proposed method combines the algorithm and the technique to recover degraded signal-to-noise-ratio. This paper discusses a feasibility of the proposed method and summarizes a mission scenario.

  1. Maize Authentication: Quality Control Methods and Multivariate Analysis (Chemometrics)

    Microsoft Academic Search

    Ioannis S. Arvanitoyannis; Antonios Vlachos

    2009-01-01

    Maize is one of the most important cereals because of its numerous applications in processed foods where it is the major or minor component. Apart from maize authenticity issues related to cultivar and geographical origin (national and\\/or international level), there is another important issue related to genetically modified maize. Various objective parameters such as fatty acids, phenolic compounds, pigments, heavy

  2. Characterization of high temperature tolerance mechanisms in Maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High temperature, combined with drought, is a major environmental stress that greatly depresses yield and reduces the quality of maize plants in the Southern Plains area. Maize inbred lines vary greatly in thermotolerance based on field observations. Two contrasting maize inbred lines, B76, heat-to...

  3. OATS WITH MAIZE CHROMOSOME AND CHROMOSOME SEGMENT ADDITIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oat (Avena sativa L., 2n = 6x = 42) plants crossed with maize (Zea mays L., 2n = 2x = 20) yields both haploid oat plants and plants with one or more maize chromosomes added to a haploid oat genome. Recovery of plants requires embryo rescue following partial or full elimination of the maize chromosom...

  4. BREEDING MAIZE FOR RESISTANCE TO MYCOTOXINS AT IITA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ear rot causing fungi including Aspergillus and Fusarium are common in maize in West and Central Africa. These fungi contaminate maize with mycotoxins that pose serious potential health hazards to humans in the sub-region. In an effort to develop maize germplasm with resistance to aflatoxin contam...

  5. Prosperity, power, and change: Modeling maize at Postclassic Xaltocan, Mexico

    Microsoft Academic Search

    Christopher T. Morehart; Dan T. A. Eisenberg

    2010-01-01

    Documenting the relationship between agriculture and political economy occupies the center of much research and debate in anthropological archaeology. This study examines this issue by focusing on maize at Xaltocan, a Postclassic community located in the northern Basin of Mexico. We consider how different mechanisms of distribution, circulation, and production can influence maize variation. We analyze maize variability through time

  6. Evaluating commercial maize hybrids for resistance to gibberella ear rot

    Microsoft Academic Search

    A. W. Schaafsma; R. W. Nicol; L. M. Reid

    1997-01-01

    An integral component of breeding maize for resistance to Fusarium graminearum ear rot is the identification of resistant genotypes. Since natural infection is not consistent from year to year, maize researchers must use manual techniques to inoculate the plant material with fungal spores. Information is presented here on site resistance of commercial maize hybrids to F. graminearum over three years

  7. MaizeGDB: everything old is new again! [abstract

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The focus of genetic, genomic, and breeding research evolves over time, making it necessary to continually redefine the paradigm for data access and data analysis tools. Here we report the reinvention of MaizeGDB, the maize genetics and genomics database, to meet maize researchers’ ever changing nee...

  8. INTRODUCTION The maize leaf is a photosynthetic organ comprising three

    E-print Network

    Pawlowski, Wojtek

    INTRODUCTION The maize leaf is a photosynthetic organ comprising three basic parts; the proximal. The leaf is one component of a phytomer, the basic, repeating structural unit of the maize plant (Galinat prophyll), the node, and the leaf. In maize, the tubular base of the leaf extends into the node

  9. Surfactin A production and isoforms characterizations in strains of Bacillus mojavensis for control of a maize pathogen, Fusarium verticillioides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The endophytic bacterium, Bacillus mojavensis, RRC 101 controls fungal diseases in maize and other plants. The bacterium and its cultural extracts have been shown to be antagonistic to the pathogenic and mycotoxic fungus, Fusarium verticillioides. An antifungal cyclic lipopeptide produced by B. moj...

  10. Colonization of maize seedlings under drought conditions by two ochratoxin A producers species within the A. section Nigri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some species of black-spored aspergilli (Aspergillus section Nigri) are able to cause disease in several plant hosts, including peanut and maize seedlings. Besides the economical impact of black-spored aspergilli infections, several species within this section are well known mycotoxin producers, spe...

  11. Maize Dwarf Mosaic Can Reduce Weed Suppressive Ability of Sweet Corn Martin M. Williams II and Jerald K. Pataky*

    E-print Network

    Sims, Gerald K.

    Maize Dwarf Mosaic Can Reduce Weed Suppressive Ability of Sweet Corn Martin M. Williams II prevalent viral disease of sweet corn grown in many regions of North America and Europe. Although some weeds escape control in most sweet corn fields, the extent to which MDM influences the weed suppressive ability

  12. A genome-wide association study reveals genes associated with fusarium ear rot resistance in a maize core diversity panel.

    PubMed

    Zila, Charles T; Samayoa, L Fernando; Santiago, Rogelio; Butrón, Ana; Holland, James B

    2013-11-01

    Fusarium ear rot is a common disease of maize that affects food and feed quality globally. Resistance to the disease is highly quantitative, and maize breeders have difficulty incorporating polygenic resistance alleles from unadapted donor sources into elite breeding populations without having a negative impact on agronomic performance. Identification of specific allele variants contributing to improved resistance may be useful to breeders by allowing selection of resistance alleles in coupling phase linkage with favorable agronomic characteristics. We report the results of a genome-wide association study to detect allele variants associated with increased resistance to Fusarium ear rot in a maize core diversity panel of 267 inbred lines evaluated in two sets of environments. We performed association tests with 47,445 single-nucleotide polymorphisms (SNPs) while controlling for background genomic relationships with a mixed model and identified three marker loci significantly associated with disease resistance in at least one subset of environments. Each associated SNP locus had relatively small additive effects on disease resistance (±1.1% on a 0-100% scale), but nevertheless were associated with 3 to 12% of the genotypic variation within or across environment subsets. Two of three identified SNPs colocalized with genes that have been implicated with programmed cell death. An analysis of associated allele frequencies within the major maize subpopulations revealed enrichment for resistance alleles in the tropical/subtropical and popcorn subpopulations compared with other temperate breeding pools. PMID:24048647

  13. Complete Genome Sequence of “Candidatus Sulcia muelleri” ML, an Obligate Nutritional Symbiont of Maize Leafhopper (Dalbulus maidis)

    PubMed Central

    Chang, Hsing-Hua; Cho, Shu-Ting; Canale, Maria C.; Mugford, Sam T.; Lopes, João R. S.; Hogenhout, Saskia A.

    2015-01-01

    “Candidatus Sulcia muelleri” is a symbiont of sap-feeding insects in the suborder Auchenorrhyncha. The strain “Ca. Sulcia muelleri” ML is associated with the maize leafhopper (Dalbulus maidis), collected in Brazil, which is a disease vector that affects corn production. Here, we report the complete genome sequence of this bacterium. PMID:25635014

  14. A Genome-Wide Association Study Reveals Genes Associated with Fusarium Ear Rot Resistance in a Maize Core Diversity Panel

    PubMed Central

    Zila, Charles T.; Samayoa, L. Fernando; Santiago, Rogelio; Butrón, Ana; Holland, James B.

    2013-01-01

    Fusarium ear rot is a common disease of maize that affects food and feed quality globally. Resistance to the disease is highly quantitative, and maize breeders have difficulty incorporating polygenic resistance alleles from unadapted donor sources into elite breeding populations without having a negative impact on agronomic performance. Identification of specific allele variants contributing to improved resistance may be useful to breeders by allowing selection of resistance alleles in coupling phase linkage with favorable agronomic characteristics. We report the results of a genome-wide association study to detect allele variants associated with increased resistance to Fusarium ear rot in a maize core diversity panel of 267 inbred lines evaluated in two sets of environments. We performed association tests with 47,445 single-nucleotide polymorphisms (SNPs) while controlling for background genomic relationships with a mixed model and identified three marker loci significantly associated with disease resistance in at least one subset of environments. Each associated SNP locus had relatively small additive effects on disease resistance (±1.1% on a 0–100% scale), but nevertheless were associated with 3 to 12% of the genotypic variation within or across environment subsets. Two of three identified SNPs colocalized with genes that have been implicated with programmed cell death. An analysis of associated allele frequencies within the major maize subpopulations revealed enrichment for resistance alleles in the tropical/subtropical and popcorn subpopulations compared with other temperate breeding pools. PMID:24048647

  15. DISTRIBUTION OF AND ASSOCIATION BETWEEN THE LARGER GRAIN BORER PROSTEPHANUS TRUNCATUS (HORN) (COLEOPTERA: BOSTRICHIDAE) AND THE MAIZE WEEVIL SITOPHILUS ZEAMAIS MOTSCHULSKY (COLEOPTERA: CURCULIONIDAE) IN MAIZE STORES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interspecific interactions between the larger grain borer Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) and the maize weevil Sitophilus zeamais Motschulsky (Coleoptera Curculionidae) were studied during two storage seasons in maize stores, in Bénin. Maize ears, randomly sampled from far...

  16. Genome-wide nested association mapping of quantitative resistance to northern leaf blight in maize

    PubMed Central

    Poland, Jesse A.; Bradbury, Peter J.; Buckler, Edward S.; Nelson, Rebecca J.

    2011-01-01

    Quantitative resistance to plant pathogens, controlled by multiple loci of small effect, is important for food production, food security, and food safety but is poorly understood. To gain insights into the genetic architecture of quantitative resistance in maize, we evaluated a 5,000-inbred-line nested association mapping population for resistance to northern leaf blight, a maize disease of global economic importance. Twenty-nine quantitative trait loci were identified, and most had multiple alleles. The large variation in resistance phenotypes could be attributed to the accumulation of numerous loci of small additive effects. Genome-wide nested association mapping, using 1.6 million SNPs, identified multiple candidate genes related to plant defense, including receptor-like kinase genes similar to those involved in basal defense. These results are consistent with the hypothesis that quantitative disease resistance in plants is conditioned by a range of mechanisms and could have considerable mechanistic overlap with basal resistance. PMID:21482771

  17. Two genes conferring resistance to Pythium stalk rot in maize inbred line Qi319.

    PubMed

    Song, Feng-Jing; Xiao, Ming-Gang; Duan, Can-Xing; Li, Hong-Jie; Zhu, Zhen-Dong; Liu, Bao-Tao; Sun, Su-Li; Wu, Xiao-Fei; Wang, Xiao-Ming

    2015-08-01

    Stalk rots are destructive diseases in maize around the world, and are most often caused by the pathogen Pythium, Fusarium and other fungi. The most efficient management for controlling stalk rots is to breed resistant cultivars. Pythium stalk rot can cause serious yield loss on maize, and to find the resistance genes from the existing germplasm is the basis to develop Pythium-resistance hybrid lines. In this study, we investigated the genetic resistance to Pythium stalk rot in inbred line Qi319 using F2 and F2:3 population, and found that the resistance to Pythium inflatum in Qi319 was conferred by two independently inherited dominant genes, RpiQI319-1 and RpiQI319-2. Linkage analysis uncovered that the RpiQI319-1 co-segregated with markers bnlg1203, and bnlg2057 on chromosome 1, and that the RpiQI319-2 locus co-segregated with markers umc2069 and bnlg1716 on chromosome 10. The RpiQI319-1 locus was further mapped into a ~500-kb interval flanked by markers SSRZ33 and SSRZ47. These results will facilitate marker-assisted selection of Pythium stalk rot-resistant cultivars in maize breeding. To our knowledge, this is the first report on the resistance to P. inflatum in the inbred line Qi319, and is also the first description of two independently inherited dominant genes conferring the resistance of Pythium stalk rot in maize. PMID:25724693

  18. Picosecond-resolved X-ray absorption spectroscopy at low signal contrast using a hard X-ray streak camera.

    PubMed

    Adams, Bernhard W; Rose-Petruck, Christoph; Jiao, Yishuo

    2015-07-01

    A picosecond-resolving hard-X-ray streak camera has been in operation for several years at Sector 7 of the Advanced Photon Source (APS). Several upgrades have been implemented over the past few years to optimize integration into the beamline, reduce the timing jitter, and improve the signal-to-noise ratio. These include the development of X-ray optics for focusing the X-rays into the sample and the entrance slit of the streak camera, and measures to minimize the amount of laser light needed to generate the deflection-voltage ramp. For the latter, the photoconductive switch generating the deflection ramp was replaced with microwave power electronics. With these, the streak camera operates routinely at 88?MHz repetition rate, thus making it compatible with all of the APS fill patterns including use of all the X-rays in the 324-bunch mode. Sample data are shown to demonstrate the performance. PMID:26134806

  19. Rice black-streaked dwarf virus P6 self-interacts to form punctate, viroplasm-like structures in the cytoplasm and recruits viroplasm-associated protein P9-1

    PubMed Central

    2011-01-01

    Background Rice black-streaked dwarf virus (RBSDV), a member of the genus Fijivirus within the family Reoviridae, can infect several graminaceous plant species including rice, maize and wheat, and is transmitted by planthoppers. Although several RBSDV proteins have been studied in detail, functions of the nonstructural protein P6 are still largely unknown. Results In the current study, we employed yeast two-hybrid assays, bimolecular fluorescence complementation and subcellular localization experiments to show that P6 can self-interact to form punctate, cytoplasmic viroplasm-like structures (VLS) when expressed alone in plant cells. The region from residues 395 to 659 is necessary for P6 self-interaction, whereas two polypeptides (residues 580-620 and 615-655) are involved in the subcellular localization of P6. Furthermore, P6 strongly interacts with the viroplasm-associated protein P9-1 and recruits P9-1 to localize in VLS. The P6 395-659 region is also important for the P6-P9-1 interaction, and deleting any region of P9-1 abolishes this heterologous interaction. Conclusions RBSDV P6 protein has an intrinsic ability to self-interact and forms VLS without other RBSDV proteins or RNAs. P6 recruits P9-1 to VLS by direct protein-protein interaction. This is the first report on the functionality of RBSDV P6 protein. P6 may be involved in the process of viroplasm nucleation and virus morphogenesis. PMID:21241517

  20. The dynamic nature and spectral characteristics of low-albedo slope streaks on Mars and their possible hydrologic implications

    NASA Astrophysics Data System (ADS)

    Mushkin, A.; Stillman, D. E.; Gillespie, A. R.; Montgomery, D. R.; Schreiber, B. C.; Hibbitts, C.

    2014-12-01

    Low-albedo down-slope streaks that form repeatedly within weekly time-scales and subsequently fade over seasonal to decadal periods are commonly observed in the tropical and mid-latitudes of Mars. 'Dry' mass-wasting processes vs. 'wet' modification of the surface by aqueous phases are the mechanisms typically considered to explain their formation. Recently, high frequency HiRISE image time-series of seasonal recurrence, incremental growth and fading of small (meter-decameter scale) slope streaks, also termed 'recurring slope lineae' (RSL), have been presented in support of a 'wet' origin likely associated with brine seepage. Here, we present new results that demonstrate comparable recurrence, incremental growth and fading characteristics over yearly time-scales for decameter-kilometer scale low-albedo slope-streaks in Lycus Sulci, Amazonis Planitia and Arabia Terra. These dynamic characteristics support the previous association of low-albedo slope streaks with brine seepage based on their geomorphic and spectral relations with surrounding unaffected slopes. Low-albedo slope streaks are typically not associated with detectable erosion or terminal, down-slope depositional activity at the resolution of 25 cm/pixel HiRISE images. CRISM observations consistently indicate that darkened slope-streak surfaces are spectrally enriched in FeOx and are void of detectable water/ice spectral absorption bands. Thus, the liquid seeps considered for the formation of meter to kilometer scale slope streaks are likely low-volume transient events that evaporate and/or freeze and sublime leaving behind a meta-stable dry precipitate that 'stains' the surface dark and may provide insights into the possible composition of such brines. Slope streak formation through a 'wet' brine seepage mechanism supports the possible presence of pressurized sub-surface aquifers that may be released via faults or cracks able to produce recurring transient discharge events during favorably warm daily/seasonal surface conditions. First-order calculations for the liquid volumes that would be associated with such transient brine extrusions suggest the presence of regional-scale extensive aquifers and/or effective recharge mechanism for local-scale aquifers perhaps during high obliquity periods.

  1. Immunodiagnosis of episomal Banana streak MY virus using polyclonal antibodies to an expressed putative coat protein.

    PubMed

    Sharma, Susheel Kumar; Kumar, P Vignesh; Baranwal, Virendra Kumar

    2014-10-01

    A cryptic Badnavirus species complex, known as banana streak viruses (BSV) poses a serious threat to banana production and genetic improvement worldwide. Due to the presence of integrated BSV sequences in the banana genome, routine detection is largely based on serological and nucleo-serological diagnostic methods which require high titre specific polyclonal antiserum. Viral structural proteins like coat protein (CP) are the best target for in vitro expression, to be used as antigen for antiserum production. However, in badnaviruses precise CP sequences are not known. In this study, two putative CP coding regions (p48 and p37) of Banana streak MY virus (BSMYV) were identified in silico by comparison with caulimoviruses, retroviruses and Rice tungro bacilliform virus. The putative CP coding region (p37) was in vitro expressed in pMAL system and affinity purified. The purified fusion protein was used as antigen for raising polyclonal antiserum in rabbit. The specificity of antiserum was confirmed in Western blots, immunosorbent electron microscopy (ISEM) and antigen coated plate-enzyme linked immunosorbent assay (ACP-ELISA). The antiserum (1:2000) was successfully used in ACP-ELISA for specific detection of BSMYV infection in field and tissue culture raised banana plants. The antiserum was also utilized in immuno-capture PCR (IC-PCR) based indexing of episomal BSMYV infection. This is the first report of in silico identification of putative CP region of BSMYV, production of polyclonal antiserum against recombinant p37 and its successful use in immunodetection. PMID:24977315

  2. Single-shot visualization of evolving laser wakefields using an all-optical streak camera

    NASA Astrophysics Data System (ADS)

    Li, Zhengyan; Tsai, Hai-En; Zhang, Xi; Pai, Chih-Hao; Chang, Yen-Yu; Zgadzaj, Rafal; Wang, Xiaoming; Khudik, Vladimir; Shvets, Gennady; Downer, Michael

    2014-10-01

    We visualize ps-time-scale evolution of an electron density bubble, a wake structure created in atmospheric density plasma by an intense ultrashort laser pulse, from the phase ``streak'' that the bubble imprints onto a probe pulse that crosses its path obliquely. Phase streaks, recovered in one shot using frequency-domain interferometry, reveal formation, propagation and coalescence of the bubble within a 3 mm long ionized helium gas target. 3D particle-in-cell (PIC) simulations validate the observed density-dependent bubble evolution, and correlate it with generation of a quasi-monoenergetic ~100 MeV electron beam. The results provide a basis for understanding optimized electron acceleration at plasma density ne ~2e19 cm-3, at which the bubble formed and persisted until the jet exit, enabling acceleration over a distance slightly exceeding the dephasing length. In contrast, at lower density, electrons accelerated inefficiently due to weak laser self-focusing and late bubble formation. At higher density, overly strong self-focusing also led to low quality electrons due to early bubble formation and strong dephasing. Bubble coalescence due to beam loading further degraded electron acceleration. This work was supported by DOE grants DESC0011617 and DE-SC0007889 and by the NSF-DOE Partnership in Plasma Science program.

  3. Nonlinear response of the photocathode of an x-ray streak camera to UV light

    SciTech Connect

    Kyrala, G.A.; Oro, D.M.; Studebaker, J.K.; Wood, W.M.; Schappert, G.T.; Watts, S.; Fulton, R.D.

    1994-09-01

    We have found that a potassium-iodide photocathode of an x-ray streak camera responds to UV light at {lambda}=308 nm. The photocathode surface work function, 6.5 eV, is larger than the 4 eV energy of the UV photon, hence the source of the response is interesting. We will present results on the response of a transmission type potassium-iodide photocathode to the UV light from a {lambda}308 nm, subpicosecond XeCl laser and from a {lambda}=326 nm HeCd laser. We will test for the nonlinearity of the yield to measure of the number of photons that are needed to be absorbed before a signal is recorded. We will present data on the effect of the UV irradiance on the yield, as well as on the temporal width of the recorded signal. We will give an explanation of the observation and its effect on the dynamic-range response of the streak-camera. We will show that the response is linear with the incident irradiance, up to an incident irradiance of 10{sup 8} W/cm{sup 2} and we will explain the observation.

  4. Foliar Diseases of Apiaceae Crops in Coastal California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The number of outbreaks of leaf spot, blight and streak diseases on celery, cilantro, fennel and parsley has been increasing throughout central coastal California and particularly in Monterey County since 2002. Two different bacterial pathogens (Pseudomonas syringae pv. apii, and P. syringae pv. cor...

  5. Transcriptome analysis of maize leaf systemic symptom infected by Bipolaris zeicola.

    PubMed

    Liu, Ming; Gao, Jian; Yin, Fuqiang; Gong, Guoshu; Qin, Cheng; Ye, Kunhao; Zhang, Min; Sun, Xiaofang; Zhou, You; Zhang, Youju

    2015-01-01

    Bipolaris zeicola is a fungal pathogen that causes Northern corn leaf spot (NCLS), which is a serious foliar disease in maize and one of the most significant pathogens affecting global food security. Here, we report a genome-wide transcriptional profile analysis using next-generation sequencing (NGS) of maize leaf development after inoculation with B. zeicola. We performed High-Throughput Digital Gene Expression analysis to identify differentially expressed genes (DEGs) in resistant inbred Mo17 lines after infection with B. zeicola at four successive disease development stages--CP (contact period), PP (penetration period), IP (incubation period), and DP (disease period); the expression of the genes was compared with those in a CK (mock-treatment) control. In addition, a sensitive maize line (Zheng58) was used for the comparisons with the Mo17. Among all tested genes, 466 differentially expressed genes were identified in all libraries, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of these genes suggested that they are involved in many biological processes related to systemic symptom development, such as plant hormone signal transduction, starch and sucrose metabolism, phenylpropanoid biosynthesis and photosynthesis. Our systematic analysis provides comprehensive transcriptomic information regarding systemic symptom development in fungal-infected plants. This information will help in furthering our understanding of the detailed mechanisms of plant responses to fungal infection. PMID:25781606

  6. Transcriptome Analysis of Maize Leaf Systemic Symptom Infected by Bipolaris zeicola

    PubMed Central

    Gong, Guoshu; Qin, Cheng; Ye, Kunhao; Zhang, Min; Sun, Xiaofang; Zhou, You; Zhang, Youju

    2015-01-01

    Bipolaris zeicola is a fungal pathogen that causes Northern corn leaf spot (NCLS), which is a serious foliar disease in maize and one of the most significant pathogens affecting global food security. Here, we report a genome-wide transcriptional profile analysis using next-generation sequencing (NGS) of maize leaf development after inoculation with B. zeicola. We performed High-Throughput Digital Gene Expression analysis to identify differentially expressed genes (DEGs) in resistant inbred Mo17 lines after infection with B. zeicola at four successive disease development stages—CP (contact period), PP (penetration period), IP (incubation period), and DP (disease period); the expression of the genes was compared with those in a CK (mock-treatment) control. In addition, a sensitive maize line (Zheng58) was used for the comparisons with the Mo17. Among all tested genes, 466 differentially expressed genes were identified in all libraries, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of these genes suggested that they are involved in many biological processes related to systemic symptom development, such as plant hormone signal transduction, starch and sucrose metabolism, phenylpropanoid biosynthesis and photosynthesis. Our systematic analysis provides comprehensive transcriptomic information regarding systemic symptom development in fungal-infected plants. This information will help in furthering our understanding of the detailed mechanisms of plant responses to fungal infection. PMID:25781606

  7. Digital gene expression signatures for maize development.

    PubMed

    Eveland, Andrea L; Satoh-Nagasawa, Namiko; Goldshmidt, Alexander; Meyer, Sandra; Beatty, Mary; Sakai, Hajime; Ware, Doreen; Jackson, David

    2010-11-01

    Genome-wide expression signatures detect specific perturbations in developmental programs and contribute to functional resolution of key regulatory networks. In maize (Zea mays) inflorescences, mutations in the RAMOSA (RA) genes affect the determinacy of axillary meristems and thus alter branching patterns, an important agronomic trait. In this work, we developed and tested a framework for analysis of tag-based, digital gene expression profiles using Illumina's high-throughput sequencing technology and the newly assembled B73 maize reference genome. We also used a mutation in the RA3 gene to identify putative expression signatures specific to stem cell fate in axillary meristem determinacy. The RA3 gene encodes a trehalose-6-phosphate phosphatase and may act at the interface between developmental and metabolic processes. Deep sequencing of digital gene expression libraries, representing three biological replicate ear samples from wild-type and ra3 plants, generated 27 million 20- to 21-nucleotide reads with frequencies spanning 4 orders of magnitude. Unique sequence tags were anchored to 3'-ends of individual transcripts by DpnII and NlaIII digests, which were multiplexed during sequencing. We mapped 86% of nonredundant signature tags to the maize genome, which associated with 37,117 gene models and unannotated regions of expression. In total, 66% of genes were detected by at least nine reads in immature maize ears. We used comparative genomics to leverage existing information from Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) in functional analyses of differentially expressed maize genes. Results from this study provide a basis for the analysis of short-read expression data in maize and resolved specific expression signatures that will help define mechanisms of action for the RA3 gene. PMID:20833728

  8. Impact of deficit irrigation on maize physical and chemical properties and ethanol yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research was to study the effect of irrigation levels (five levels from 102 to 457 mm of water) on the physical and chemical properties and ethanol fermentation performance of maize. Twenty maize samples with two crop rotation systems, grain sorghum–maize and maize–maize, were ...

  9. Rapid decomposition of maize detritus in agricultural headwater streams.

    PubMed

    Griffiths, Natalie A; Tank, Jennifer L; Royer, Todd V; Rosi-Marshall, Emma J; Whiles, Matt R; Chambers, Catherine P; Frauendorf, Therese C; Evans-White, Michelle A

    2009-01-01

    Headwater streams draining agricultural landscapes receive maize leaves (Zea mays L.) via wind and surface runoff, yet the contribution of maize detritus to organic-matter processing in agricultural streams is largely unknown. We quantified decomposition and microbial respiration rates on conventional (non-Bt) and genetically engineered (Bt) maize in three low-order agricultural streams in northwestern Indiana, USA. We also examined how substrate quality and in-stream nutrient concentrations influenced microbial respiration on maize by comparing respiration on maize and red maple leaves (Acer rubrum) in three nutrient-rich agricultural streams and three low-nutrient forested streams. We found significantly higher rates of microbial respiration on maize vs. red maple leaves and higher rates in agricultural vs. forested streams. Thus both the elevated nutrient status of agricultural streams and the lability of maize detritus (e.g., low carbon-to-nitrogen ratio and low lignin content) result in a rapid incorporation of maize leaves into the aquatic microbial food web. We found that Bt maize had a faster decomposition rate than non-Bt maize, while microbial respiration rates did not differ between Bt and non-Bt maize. Decomposition rates were not negatively affected by genetic engineering, perhaps because the Bt toxin does not adversely affect the aquatic microbial assemblage involved in maize decomposition. Additionally, shredding caddisflies, which are known to have suppressed growth rates when fed Bt maize, were depauperate in these agricultural streams, and likely did not play a major role in maize decomposition. Overall, the conversion of native vegetation to row-crop agriculture appears to have altered the quantity, quality, and predictability of allochthonous carbon inputs to headwater streams, with unexplored effects on stream ecosystem structure and function. PMID:19323178

  10. Production and characterization of maize chromosome 9 radiation hybrids derived from an oat-maize addition line.

    PubMed Central

    Riera-Lizarazu, O; Vales, M I; Ananiev, E V; Rines, H W; Phillips, R L

    2000-01-01

    In maize (Zea mays L., 2n = 2x = 20), map-based cloning and genome organization studies are often complicated because of the complexity of the genome. Maize chromosome addition lines of hexaploid cultivated oat (Avena sativa L., 2n = 6x = 42), where maize chromosomes can be individually manipulated, represent unique materials for maize genome analysis. Maize chromosome addition lines are particularly suitable for the dissection of a single maize chromosome using radiation because cultivated oat is an allohexaploid in which multiple copies of the oat basic genome provide buffering to chromosomal aberrations and other mutations. Irradiation (gamma rays at 30, 40, and 50 krad) of a monosomic maize chromosome 9 addition line produced maize chromosome 9 radiation hybrids (M9RHs)-oat lines possessing different fragments of maize chromosome 9 including intergenomic translocations and modified maize addition chromosomes with internal and terminal deletions. M9RHs with 1 to 10 radiation-induced breaks per chromosome were identified. We estimated that a panel of 100 informative M9RHs (with an average of 3 breaks per chromosome) would allow mapping at the 0. 5- to 1.0-Mb level of resolution. Because mapping with maize chromosome addition lines and radiation hybrid derivatives involves assays for the presence or absence of a given marker, monomorphic markers can be quickly and efficiently mapped to a chromosome region. Radiation hybrid derivatives also represent sources of region-specific DNA for cloning of genes or DNA markers. PMID:10978296

  11. Characterization and fine-mapping of a resistance locus for northern leaf blight in maize bin 8.06

    Microsoft Academic Search

    Chia-Lin Chung; Tiffany Jamann; Joy Longfellow; Rebecca Nelson

    2010-01-01

    As part of a larger effort to capture diverse alleles at a set of loci associated with disease resistance in maize, DK888,\\u000a a hybrid known to possess resistance to multiple diseases, was used as a donor in constructing near-isogenic lines (NILs).\\u000a A NIL pair contrasting for resistance to northern leaf blight (NLB), caused by Setosphaeria turcica, was identified and associated

  12. Biodiversity of Fusarium species in Mexico associated with ear rot in maize, and their identification using a phylogenetic approach

    Microsoft Academic Search

    Irma Morales-Rodríguez; María J. de Yañz-Morales; Hilda V. Silva-Rojas; Gabino García-de-los-Santos; Doralinda A. Guzmán-de-Peña

    2007-01-01

    Fusarium\\u000a proliferatum, F. subglutinans, and F. verticillioides are known causes of ear and kernel rot in maize worldwide. In Mexico, only F. verticillioides and F. subglutinans, have been reported previously as causal agents of this disease. However, Fusarium isolates with different morphological characteristics to the species that are known to cause this disease were obtained in\\u000a the Highland-Valley region of

  13. Mycotoxins in ingredients of animal feeding stuffs: II. determination of mycotoxins in maize and maize products

    Microsoft Academic Search

    K. A. Scudamore; S. Nawaz; M. T. Hetmanski

    1998-01-01

    Analytical methods have been developed for the reliable detection and estimation of 22 mycotoxins in maize gluten and other maize products used in the animal feed industry. The mycotoxins are aflatoxins B1 B2, G1and G2, ochratoxins A and B, citrinin, cyclopiazonic acid, zearalenone, sterigmatocystin, deoxynivalenol, nivalenol together with seven related trichothecene mycotoxins, fumonisins B1 and B2 and moniliformin. For most

  14. RNA Interference-Based Transgenic Maize Resistant to Maize Dwarf Mosaic Virus

    Microsoft Academic Search

    Zhi-Yong Zhang; Feng-Ling Fu; Lin Gou; Han-Guang Wang; Wan-Chen Li

    2010-01-01

    Maize dwarf mosaic virus (MDMV) is a widespread pathogenic virus that causes serious loss of yield in maize (Zea mays). RNA interference (RNAi) triggered by hairpin RNA (hpRNA) transcribed from a transgenic inverted-repeat sequence is an effective\\u000a way to defend against viruses in plants. In this study, an hpRNA expression vector containing a sense arm and an antisense\\u000a arm of

  15. Effects of wheat streak mosaic virus on root development and water-use efficiency of hard red winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Greenhouse and field studies were conducted to determine the effects of Wheat streak mosaic virus (WSMV), a member of the family Potyviridae, on root development and water-use efficiency (WUE) of two hard red winter wheat (Triticum aestivum) cultivars, one susceptible and one resistant to WSMV. In t...

  16. Winter wheat cultivars with temperature sensitive resistance to wheat streak mosaic virus do not recover from early season infections

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat streak mosaic virus (WSMV), Triticum mosaic virus, and Wheat mosaic virus, all vectored by the wheat curl mite Aceria tosichella Keifer, frequently cause devastating losses to winter wheat production throughout the central and western Great Plains. Resistant 'Mace' and 'RonL' are commercially ...

  17. 1 Introduction Gazing at a flower garden through a window streaked with rain, one is aware of the

    E-print Network

    Holcombe, Alex O.

    1 Introduction Gazing at a flower garden through a window streaked with rain, one is aware of the properties of two surfaces in one direction, albeit at different depths. In this situation, monocular before being combined for awareness by a process that integrates over about 120 ms. A final experiment

  18. Modified ecometric technique (four-quadrant sequential streak) to evaluate Campylobacter enrichment broth proficiency in suppressing background microflora

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ecometric technique is a semi-quantitative scoring method used for quality control of culture media in microbiological laboratories. The technique involves inoculation with defined populations of specific culture onto solid media via a standardized chronological streaking technique, leading to ever-...

  19. The transcriptome landscape of early maize meiosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Meiosis, particularly meiotic recombination, is a major factor affecting yield and breeding of plants. To gain insight into the transcriptome landscape during early initiation steps of meiotic recombination, we profiled early prophase I meiocytes from maize using RNA-seq. Our analyses of genes prefe...

  20. REGISTRATION OF MAIZE GERMPLASM LINE GEMS-0067

    Technology Transfer Automated Retrieval System (TEKTRAN)

    GEMS-0067 is a partially inbred germplasm line released by Truman State University (TSU) in accordance with the Germplasm Enhancement of Maize (GEM) protocol. This line is being released for use in the development of genetically diverse, elite, amylomaize class VII parental lines possessing modifie...

  1. Gene expression in physically impeded maize roots 

    E-print Network

    Huang, Ying-Fei

    1996-01-01

    Two approaches were used to search for genes which respond to physical impedance. First, cDNA clones induced by mechanical stress or drought stress of other plant species were hybridized to mRNA from maize root tips. The results showed that only two...

  2. Genetic perturbation of the maize methylome.

    PubMed

    Li, Qing; Eichten, Steven R; Hermanson, Peter J; Zaunbrecher, Virginia M; Song, Jawon; Wendt, Jennifer; Rosenbaum, Heidi; Madzima, Thelma F; Sloan, Amy E; Huang, Ji; Burgess, Daniel L; Richmond, Todd A; McGinnis, Karen M; Meeley, Robert B; Danilevskaya, Olga N; Vaughn, Matthew W; Kaeppler, Shawn M; Jeddeloh, Jeffrey A; Springer, Nathan M

    2014-12-01

    DNA methylation can play important roles in the regulation of transposable elements and genes. A collection of mutant alleles for 11 maize (Zea mays) genes predicted to play roles in controlling DNA methylation were isolated through forward- or reverse-genetic approaches. Low-coverage whole-genome bisulfite sequencing and high-coverage sequence-capture bisulfite sequencing were applied to mutant lines to determine context- and locus-specific effects of these mutations on DNA methylation profiles. Plants containing mutant alleles for components of the RNA-directed DNA methylation pathway exhibit loss of CHH methylation at many loci as well as CG and CHG methylation at a small number of loci. Plants containing loss-of-function alleles for chromomethylase (CMT) genes exhibit strong genome-wide reductions in CHG methylation and some locus-specific loss of CHH methylation. In an attempt to identify stocks with stronger reductions in DNA methylation levels than provided by single gene mutations, we performed crosses to create double mutants for the maize CMT3 orthologs, Zmet2 and Zmet5, and for the maize DDM1 orthologs, Chr101 and Chr106. While loss-of-function alleles are viable as single gene mutants, the double mutants were not recovered, suggesting that severe perturbations of the maize methylome may have stronger deleterious phenotypic effects than in Arabidopsis thaliana. PMID:25527708

  3. Gene expression in physically impeded maize roots

    E-print Network

    Huang, Ying-Fei

    1996-01-01

    Two approaches were used to search for genes which respond to physical impedance. First, cDNA clones induced by mechanical stress or drought stress of other plant species were hybridized to mRNA from maize root tips. The results showed that only two...

  4. GENETIC VARIABILITY IN MAIZE CHLOROTIC DWARF VIRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize chlorotic dwarf virus (MCDV) (genus Waikavirus; family Sequiviridae) is a picorna-like virus transmitted by the black-faced leafhopper, Graminella nigrifrons, in a semi-persistent manner using a virus-encoded helper protein. The MCDV genome contains one large open reading frame encoding a poly...

  5. Registration of maize inbred line GT603

    Technology Transfer Automated Retrieval System (TEKTRAN)

    GT603 (Reg. No. xxxx, PI xxxxxx) is a yellow dent maize (Zea mays L.) inbred line developed and released by the USDA-ARS Crop Protection and Management Research Unit in cooperation with the University of Georgia Coastal Plain Experiment Station in 2010. GT603 was developed through seven generations ...

  6. High frequency callus formation from maize protoplasts

    Microsoft Academic Search

    S. R. Ludwig; D. A. Somers; W. L. Petersen; R. F. Pohlman; M. A. Zarowitz; B. G. Gengenbach; J. Messing

    1985-01-01

    A solid feeder layer technique was developed to improve callus formation of Black Mexican Sweet maize (Zea mays L.) suspension culture protoplasts. Protoplasts were plated in 0.2 ml liquid media onto a cellulose nitrate filter on top of agarose-solidified media in which Black Mexican Sweet suspension feeder cells were embedded. Callus colony formation frequencies exceeding 10% of the plated protoplasts

  7. Interaction between maize seed and Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is an opportunistic fungal pathogen that colonizes maize seeds and contaminates them with aflatoxin. The fungus is localized in the endosperm and aleurone. To investigate the plant microbe interaction, we conducted histological and molecular studies to characterize the internal co...

  8. Aflatoxin contamination of maize kernels before harvest

    Microsoft Academic Search

    E. B. Lillehoj; W. W. McMillian; N. W. Widstrom; W. D. Guthrie; J. L. Jarvis; D. Barry; W. F. Kwolek

    1984-01-01

    Two maize (Zea mays L.) hybrids with varying degrees of resistance to damage by corn earworm (CEW) (Heliothis zea Boddie) were grown in Iowa, Georgia, and Missouri. Treatments included: introduction of Aspergillus flavus Link ex. Fr. spores onto newly-emerged silks, application of a fungicide as an aqueous spray onto test ears during the first three weeks after flowering, infestation of

  9. Intercropping of Different Secondary Crops in Maize

    Microsoft Academic Search

    Villy Jørgensen; Erik Møller

    2000-01-01

    Intercropping and bicropping are common cultivation systems in many countries. Maize (Zea mays L.) as a main crop combined with a legume as secondary crop is in general use in many countries. These systems may contribute to a higher biodiversity, and reduced import of fertilizer, concentrates and agrochemicals. The objective of this research was to select an appropriate secondary crop

  10. Domestication process of maize continues in guatemala

    Microsoft Academic Search

    Carl L. Johannessen

    1982-01-01

    The early Amerind, prescientific farmer, without the knowledge of sexual reproduction in plants, improved maize from a wild ancestor, and modern plant breeders are continuing to improve it in a similar continuum. I consider domestication to be a process, not an act. The domestication process is defined here as the continuing, human-controlled, evolutionary process of the modification of the genotype

  11. Diallel Analysis of Fumonisin Accumulation in Maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of maize (Zea mays L.) grain with aflatoxin, produced by the fungus Aspergillus flavus Link:Fries, or fumonisin, produced by the fungus Fusarium verticillioides (Saccardo) Nirenberg (Syn=F. moniliforme Sheldon), greatly reduces its value and marketability. Host resistance to fungal inf...

  12. Maize Genetics Outreach to American Indians

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize is an excellent vehicle for plant genomics outreach to those American Indian tribes who use and appreciate it nutritionally, culturally, and spiritually. During the summer 2006 season we mentored six Native American Indian students for eight weeks. All six worked at the USDA-ARS North Centra...

  13. Maize and tripsacum: experiments in intergeneric hybridization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research in maize-Tripsacum hybridization is extensive and encompasses a period of more than 60 years of collective research. The publication “The origin of Indian corn and its relatives” describes some of the initial research in this area (Mangelsdorf and Reeves, 1939) and is recommended reading f...

  14. Evaluation of Argentine maize hybrids and exotic x temperate testcrosses across environments

    E-print Network

    Ochs, Brett Allen

    2005-11-01

    Maize (Zea mays L.) is grown in a wide range of environments and altitudes worldwide. Maize has transitioned from open pollinated varieties to single cross hybrids over the last century. While maize production and genetic gain has increased, genetic...

  15. ?-Catenin Regulates Primitive Streak Induction through Collaborative Interactions with SMAD2/SMAD3 and OCT4.

    PubMed

    Funa, Nina S; Schachter, Karen A; Lerdrup, Mads; Ekberg, Jenny; Hess, Katja; Dietrich, Nikolaj; Honoré, Christian; Hansen, Klaus; Semb, Henrik

    2015-06-01

    Canonical Wnt and Nodal signaling are both required for induction of the primitive streak (PS), which guides organization of the early embryo. The Wnt effector ?-catenin is thought to function in these early lineage specification decisions via transcriptional activation of Nodal signaling. Here, we demonstrate a broader role for ?-catenin in PS formation by analyzing its genome-wide binding in a human embryonic stem cell model of PS induction. ?-catenin occupies regulatory regions in numerous PS and neural crest genes, and direct interactions between ?-catenin and the Nodal effectors SMAD2/SMAD3 are required at these regions for PS gene activation. Furthermore, OCT4 binding in proximity to these sites is likewise required for PS induction, suggesting a collaborative interaction between ?-catenin and OCT4. Induction of neural crest genes by ?-catenin is repressed by SMAD2/SMAD3, ensuring proper lineage specification. This study provides mechanistic insight into how Wnt signaling controls early cell lineage decisions. PMID:25921273

  16. Myosin-II-mediated cell shape changes and cell intercalation contribute to primitive streak formation.

    PubMed

    Rozbicki, Emil; Chuai, Manli; Karjalainen, Antti I; Song, Feifei; Sang, Helen M; Martin, René; Knölker, Hans-Joachim; MacDonald, Michael P; Weijer, Cornelis J

    2015-04-01

    Primitive streak formation in the chick embryo involves large-scale highly coordinated flows of more than 100,000 cells in the epiblast. These large-scale tissue flows and deformations can be correlated with specific anisotropic cell behaviours in the forming mesendoderm through a combination of light-sheet microscopy and computational analysis. Relevant behaviours include apical contraction, elongation along the apical-basal axis followed by ingression, and asynchronous directional cell intercalation of small groups of mesendoderm cells. Cell intercalation is associated with sequential, directional contraction of apical junctions, the onset, localization and direction of which correlate strongly with the appearance of active myosin II cables in aligned apical junctions in neighbouring cells. Use of class specific myosin inhibitors and gene-specific knockdown shows that apical contraction and intercalation are myosin II dependent and also reveal critical roles for myosin I and myosin V family members in the assembly of junctional myosin II cables. PMID:25812521

  17. Investigation of thin laser-driven flyer plates using streak imaging and stop motion microphotography

    SciTech Connect

    Frank, A.M. [Lawrence Livermore National Lab., CA (United States); Trott, W.M. [Sandia National Labs., Albuquerque, NM (United States)

    1995-09-01

    The dynamic behavior of laser-accelerator flyers has been studied using high-speed streak imaging in combination with stop motion microphotography. With very thin targets, melting and plasma penetration of the flyer material occur in rapid sequence. The time delay from the onset of motion to flyer breakup increases with flyer thickness and decreasing incident energy. Flyer materials examined include pure aluminum (0.25-2.6 {mu}m thick) and composite targets (0.5-2.0 {mu}m thick) containing an insulating layer of aluminum oxide. While flyer breakup is observed in both types of material, the Al{sub 2}O{sub 3} barrier significantly delays the deleterious effects of deep thermal diffusion.

  18. Posterior Malformations in Dact1 mutant mice arise through misregulated Vangl2 at the Primitive Streak

    PubMed Central

    Suriben, Rowena; Kivimäe, Saul; Fisher, Daniel A.; Moon, Randall T.; Cheyette, Benjamin N.R.

    2009-01-01

    Mice homozygous for mutations in Dact1 (Dpr/Frodo) phenocopy human malformations involving the spine, genitourinary system, and distal digestive tract. We trace this phenotype to disrupted germ layer morphogenesis at the primitive streak (PS). Remarkably, heterozygous mutation of Vangl2, a transmembrane component of the Planar Cell Polarity (PCP) pathway, rescues recessive Dact1 phenotypes, whereas loss of Dact1 reciprocally rescues semidominant Vangl2 phenotypes. We show that Dact1, an intracellular protein, forms a complex with Vangl2. In Dact1 mutants, Vangl2 is increased at the PS where cells ordinarily undergo an epithelial-mesenchymal transition. This is associated with abnormal E-cadherin distribution and changes in biochemical measures of the PCP pathway. We conclude that Dact1 contributes to morphogenesis at the PS by regulating Vangl2 upstream of cell adhesion and the PCP pathway. PMID:19701191

  19. First detection of wheat streak mosaic virus in Germany: molecular and biological characteristics.

    PubMed

    Schubert, Jörg; Ziegler, Angelika; Rabenstein, Frank

    2015-07-01

    Wheat streak mosaic virus is a serious threat in wheat-producing countries. In Germany, the virus was first recorded in 2013 near Hoym. The complete sequence of isolate Hoym was obtained and compared to all other known complete WSMV sequences, including newly collected and sequenced isolates from France and Austria. Phylogenetic analysis revealed that the European isolates group together with those from the Middle East to form a separate cluster characterized by a distinct putative P1 protease cleavage site. By means of quantitative reverse transcription polymerase chain reaction, it was shown that RNA of the USA type strain PV57 accumulated to higher levels in infected wheat cv. Alcedo than did RNA of isolate Hoym. PMID:25913690

  20. A self-calibrating, multichannel streak camera for inertial confinement fusion applications

    NASA Astrophysics Data System (ADS)

    Donaldson, W. R.; Boni, R.; Keck, R. L.; Jaanimagi, P. A.

    2002-07-01

    Self-calibrating, multichannel UV streak cameras have been designed, and six units have been deployed on the OMEGA laser system. These instruments acquire 12 channels simultaneously on a low-noise, charge-coupled-device camera in single-shot operation. The instruments can discern temporal features out to a bandwidth of 11 GHz, and the peak signal-to-noise ratio in each channel is 200:1. The unique feature of this system is the self-calibration ability built into it. The geometric distortions, flat field, and sweep speed of each channel can be measured and adjusted on a routine basis. By maintaining a strick regime of weekly calibrations, accurate power-balance measurements on the OMEGA laser can be obtained. These cameras represent a cost-effective solution for power balancing the OMEGA laser system.

  1. Development of a multispectral multiphoton fluorescence lifetime imaging microscopy system using a streak camera

    NASA Astrophysics Data System (ADS)

    Qu, Junle; Liu, Lixin; Guo, Baoping; Lin, Ziyang; Hu, Tao; Tian, Jindong; Wang, Shuyan; Zhang, Jikang; Niu, Hanben

    2005-01-01

    We report on the development of a multispectral multiphoton fluorescence lifetime imaging microscopy (MM-FLIM) system that is the combination a streak camera, a prism spectrophotometer, a femtosecond Ti: Sapphire laser and a fluorescence microscope. This system is versatile with multispectral capability, high temporal (10ps) and spatial (0.36?m) resolution and can be used to make 3-dimensional (3D) (x-y-z) multiphoton fluorescence intensity, spectrally resolved intensity and lifetime measurements with a single detector. The system was calibrated with a F-P etalon and a standard fluorescent dye and the lifetime value obtained was in good agreement with the value reported in the literature. Preliminary results suggest that this MM-FLIM system has integrated high temporal, spatial, and spectral resolution fluorescence detection in one microscopy system. Potential applications of this system include multiwell imaging, tissue discrimination, intracellular physiology and fluorescence resonance energy transfer imaging.

  2. Time-resolved measurements with streaked diffraction patterns from electrons generated in laser plasma wakefield

    NASA Astrophysics Data System (ADS)

    He, Zhaohan; Nees, John; Hou, Bixue; Krushelnick, Karl; Thomas, Alec; Beaurepaire, Benoît; Malka, Victor; Faure, Jérôme

    2013-10-01

    Femtosecond bunches of electrons with relativistic to ultra-relativistic energies can be robustly produced in laser plasma wakefield accelerators (LWFA). Scaling the electron energy down to sub-relativistic and MeV level using a millijoule laser system will make such electron source a promising candidate for ultrafast electron diffraction (UED) applications due to the intrinsic short bunch duration and perfect synchronization with the optical pump. Recent results of electron diffraction from a single crystal gold foil, using LWFA electrons driven by 8-mJ, 35-fs laser pulses at 500 Hz, will be presented. The accelerated electrons were collimated with a solenoid magnetic lens. By applying a small-angle tilt to the magnetic lens, the diffraction pattern can be streaked such that the temporal evolution is separated spatially on the detector screen after propagation. The observable time window and achievable temporal resolution are studied in pump-probe measurements of photo-induced heating on the gold foil.

  3. Streaked x-ray spectrometer having a discrete selection of Bragg geometries for Omega

    SciTech Connect

    Millecchia, M.; Regan, S. P.; Bahr, R. E.; Romanofsky, M.; Sorce, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)

    2012-10-15

    The streaked x-ray spectrometer (SXS) is used with streak cameras [D. H. Kalantar, P. M. Bell, R. L. Costa, B. A. Hammel, O. L. Landen, T. J. Orzechowski, J. D. Hares, and A. K. L. Dymoke-Bradshaw, in 22nd International Congress on High-Speed Photography and Photonics, edited by D. L. Paisley and A. M. Frank (SPIE, Bellingham, WA, 1997), Vol. 2869, p. 680] positioned with a ten-inch manipulator on OMEGA [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] and OMEGA EP [L. J. Waxer et al., Presented at CLEO/QELS 2008, San Jose, CA, 4-9 May 2008 (Paper JThB1)] for time-resolved, x-ray spectroscopy of laser-produced plasmas in the 1.4- to 20-keV photon-energy range. These experiments require measuring a portion of this photon-energy range to monitor a particular emission or absorption feature of interest. The SXS relies on a pinned mechanical reference system to create a discrete set of Bragg reflection geometries for a variety of crystals. A wide selection of spectral windows is achieved accurately and efficiently using this technique. It replaces the previous spectrometer designs that had a continuous Bragg angle adjustment and required a tedious alignment calibration procedure. The number of spectral windows needed for the SXS was determined by studying the spectral ranges selected by OMEGA users over the last decade. These selections are easily configured in the SXS using one of the 25 discrete Bragg reflection geometries and one of the six types of Bragg crystals, including two curved crystals.

  4. Addition of Individual Chromosomes of Maize Inbreds B73 and Mo17 to Oat Cultivars Starter and SunII: Maize Chromosome Retention, Transmission, and Plant Phenotype

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oat-maize addition (OMA) lines with one, or occasionally more, chromosomes of maize (Zea mays L., 2n = 2x = 20) added to an oat (Avena sativa L., 2n = 6x = 42) genomic background can be produced from sexual crosses of oat x maize. Self-fertile disomic addition lines for maize chromosomes 1, 2, 3, 4,...

  5. Genetic Characterization of a Core Set of a Tropical Maize Race Tuxpeño for Further Use in Maize Improvement

    PubMed Central

    Chavez-Tovar, Victor H.; Yan, Jianbing; Taba, Suketoshi

    2012-01-01

    The tropical maize race Tuxpeño is a well-known race of Mexican dent germplasm which has greatly contributed to the development of tropical and subtropical maize gene pools. In order to investigate how it could be exploited in future maize improvement, a panel of maize germplasm accessions was assembled and characterized using genome-wide Single Nucleotide Polymorphism (SNP) markers. This panel included 321 core accessions of Tuxpeño race from the International Maize and Wheat Improvement Center (CIMMYT) germplasm bank collection, 94 CIMMYT maize lines (CMLs) and 54 U.S. Germplasm Enhancement of Maize (GEM) lines. The panel also included other diverse sources of reference germplasm: 14 U.S. maize landrace accessions, 4 temperate inbred lines from the U.S. and China, and 11 CIMMYT populations (a total of 498 entries with 795 plants). Clustering analyses (CA) based on Modified Rogers Distance (MRD) clearly partitioned all 498 entries into their corresponding groups. No sub clusters were observed within the Tuxpeño core set. Various breeding strategies for using the Tuxpeño core set, based on grouping of the studied germplasm and genetic distance among them, were discussed. In order to facilitate sampling diversity within the Tuxpeño core, a minicore subset of 64 Tuxpeño accessions (20% of its usual size) representing the diversity of the core set was developed, using an approach combining phenotypic and molecular data. Untapped diversity represents further use of the Tuxpeño landrace for maize improvement through the core and/or minicore subset available to the maize community. PMID:22412898

  6. Dietary linoleic acid, immune inhibition and disease

    PubMed Central

    Sammon, A.

    1999-01-01

    Review of the evidence available in published literature supports a radical change in viewpoint with respect to disease in countries where maize is the predominant dietary component. In these countries, the pattern of disease is largely determined by a change in immune profile caused by metabolites of dietary linoleic acid. High intake of linoleic acid in a diet deficient in other polyunsaturated fatty acids and in riboflavin results in high tissue production of prostaglandin E2, which in turn causes inhibition of the proliferation and cytokine production of Th1 cells, mediators of cellular immunity. Tuberculosis, measles, hepatoma, secondary infection in HIV and kwashiorkor are all favoured by this reduction in cellular immunity. Diet-associated inhibition of the Th1 subset is a major contributor to the high prevalence of these diseases found in areas of sub-Saharan Africa where maize is the staple.???Keywords: maize; linoleic acid; prostaglandin E2; cellular immunity; kwashiorkor; diet PMID:10448487

  7. Evaluation of fall armyworm resistance in maize germplasm lines using visual leaf injury rating and predator survey.

    PubMed

    Ni, Xinzhi; Xu, Wenwei; Blanco, Michael H; Williams, W Paul

    2014-10-01

    After examining ear-colonizing pest resistance, 20 maize lines from the USDA-ARS Germplasm Enhancement of Maize (GEM) Program were evaluated for whorl-feeding fall armyworm (FAW) (Spodoptera frugiperda) resistance using 4 maize inbred lines as the resistant and susceptible controls. Both FAW injury ratings at 7- and 14-d after infestation, and predator abundance and diversity at whorl stage (V6-V8) were recorded in 2009 and 2010. The survey of the diversity and abundance of predators in each experimental plot were conducted 7 d after the FAW infestation. Of the 20 germplasm lines examined, 3 of them (i.e., entries 9, 15, and 19 that were derived from tropical maize germplasm lines were originated from Uruguay, Cuba, and Thailand, respectively) were identified as the best FAW-resistant germplasm lines using the leaf injury ratings and predator survey data. In addition, the abundance and diversity of the predators were greater in 2010 than in 2009, which might have caused the low level of the FAW injury ratings on all lines examined in 2010. The 2-year data showed that the FAW injury ratings were negatively correlated to the predator abundance and diversity, which is also influence by genotype × environment interactions. The findings suggested that tropical germplasm is an important source of native resistance to the FAW and the corn earworm. At the same time, the maize genotype × environment interaction (e.g., predator attractiveness, and varying weather conditions) should be included in the multiple-year evaluations of insect and disease resistance of maize germplasm lines under field conditions. PMID:24318539

  8. Post-Domestication Selection in the Maize Starch Pathway

    Microsoft Academic Search

    Longjiang Fan; Jiandong Bao; Yu Wang; Jianqiang Yao; Yijie Gui; Weiming Hu; Jinqing Zhu; Mengqian Zeng; Yu Li; Yunbi Xu; Pär K. Ingvarsson

    2009-01-01

    Modern crops have usually experienced domestication selection and subsequent genetic improvement (post-domestication selection). Chinese waxy maize, which originated from non-glutinous domesticated maize (Zea mays ssp. mays), provides a unique model for investigating the post-domestication selection of maize. In this study, the genetic diversity of six key genes in the starch pathway was investigated in a glutinous population that included 55

  9. Thin porridges (atoles) prepared from maize and sorghum 

    E-print Network

    Vivas Rodriguez, Nancy Esther

    1985-01-01

    were evaluated in atoles prepared following modified traditional methods. Commercial atole flours from maize were used as standards for the preparation of the experimental atole flours and atoles. Flours and atoles were prepared in the laboratory... Prepared from Sorghum and Maize Evaluated in a Taste Panel. . . . . . . . . . . 63 Table XX Sensory Evaluation by Latin Americans of Experimental Atoles Prepared from Maize and Sorghum . . . . . . . . . . . . . . . . 64 Table XXI Sensory Evaluation...

  10. Classification of Peruvian highland maize races using plant traits

    Microsoft Academic Search

    R. Ortiz; José Crossa; Jorge Franco; Ricardo Sevilla; Juan Burgueño

    2008-01-01

    The maize of Latin America, with its enormous diversity, has played an important role in the development of modern maize cultivars\\u000a of the American continent. Peruvian highland maize shows a high degree of variation stemming from its history of cultivation\\u000a by Andean farmers. Multivariate statistical methods for classifying accessions have become powerful tools for classifying\\u000a genetic resources conservation and the

  11. Comparative diversity of arthropods on Bt maize and non-Bt maize in two different cropping systems in South Africa.

    PubMed

    Truter, J; Van Hamburg, H; Van Den Berg, J

    2014-02-01

    The biodiversity of an agroecosystem is not only important for its intrinsic value but also because it influences ecological functions that are vital for crop production in sustainable agricultural systems and the surrounding environment. A concern about genetically modified (GM) crops is the potential negative impact that such crops could have on diversity and abundance of nontarget organisms, and subsequently on ecosystem functions. Therefore, it is essential to assess the potential environmental risk of the release of a GM crop and to study its effect on species assemblages within that ecosystem. Assessment of the impact of Bt maize on the environment is hampered by the lack of basic checklists of species present in maize agroecosystems. The aims of the study were to compile a checklist of arthropods that occur on maize in South Africa and to compare the diversity and abundance of arthropods and functional groups on Bt maize and non-Bt maize. Collections of arthropods were carried out during two growing seasons on Bt maize and non-Bt maize plants at two localities. Three maize fields were sampled per locality during each season. Twenty plants, each of Bt maize and non-Bt maize, were randomly selected from the fields at each site. The arthropods collected during this study were classified to morphospecies level and grouped into the following functional groups: detritivores, herbivores, predators, and parasitoids. Based on feeding strategy, herbivores and predators were further divided into sucking herbivores or predators (piercing-sucking mouthparts) and chewing herbivores or predators (chewing mouthparts). A total of 8,771 arthropod individuals, comprising 288 morphospecies and presenting 20 orders, were collected. Results from this short-term study indicated that abundance and diversity of arthropods in maize and the different functional guilds were not significantly affected by Bt maize, either in terms of diversity or abundance. PMID:24472209

  12. One- and two-dimensional fast x-ray imaging of laser-driven implosion dynamics with x-ray streak cameras

    SciTech Connect

    Shiraga, H.; Heya, M.; Nakasuji, M.; Miyanaga, N.; Azechi, H.; Takabe, H.; Yamanaka, T.; Mima, K. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-Oka, Suita, Osaka 565 (Japan)] [Institute of Laser Engineering, Osaka University, 2-6 Yamada-Oka, Suita, Osaka 565 (Japan)

    1997-01-01

    One- (1D) and two-dimensional (2D) x-ray imaging techniques with x-ray streak cameras have been developed and utilized for investigating implosion dynamics of laser fusion targets. Conventional streaked 1D images of the shell motion of the imploding target was recorded together with the time-resolved 2D multi-imaging x-ray streak images of the core shapes on the same x-ray streak camera. Precise comparison of the core dynamics between the experimental and simulation results was performed with an accuracy of 30 ps by fitting the trajectories of the x-ray emission from the imploding shell. {copyright} {ital 1997 American Institute of Physics.}

  13. Auxin Biosynthesis in Maize Kernels1

    PubMed Central

    Glawischnig, Erich; Tomas, Adriana; Eisenreich, Wolfgang; Spiteller, Peter; Bacher, Adelbert; Gierl, Alfons

    2000-01-01

    Auxin biosynthesis was analyzed in a maize (Zea mays) kernel culture system in which the seeds develop under physiological conditions similar to the in vivo situation. This system was modified for precursor feeding experiments. Tryptophan (Trp) is efficiently incorporated into indole-3-acetic acid (IAA) with retention of the 3,3? bond. Conversion of Trp to IAA is not competed by indole. Labeling with the general precursors [U-13C6]glucose and [1,2-13C2]acetate followed by retrobiosynthetic analysis strongly suggest that Trp-dependent IAA synthesis is the predominant route for auxin biosynthesis in the maize kernel. The synthesis of IAA from indole glycerol phosphate and IAA formation via condensation of indole with an acetyl-coenzyme A or phosphoenolpyruvate derived metabolite can be excluded. PMID:10889260

  14. Participatory maize breeding for low nitrogen tolerance

    Microsoft Academic Search

    Altair Toledo Machado; Manlio Silvestre Fernandes

    2001-01-01

    The local maize variety Sol da Manhã has a broad genetic background. It was identified in 1985 in a participatory evaluation\\u000a trial as being suitable for cultivation under low soil fertility conditions in Sol da Manhã, situated in Seropédica, State\\u000a of Rio de Janeiro, Brazil. The variety was then improved for 6 selection cycles by the formal breeding sector at

  15. Fertility Relationships in Maize-Teosinte Hybrids.

    E-print Network

    Rogers, John S. (John Sinclair)

    1950-01-01

    , and to some extent from the other teosinte varieties. 1 BUL LETIN 730 NOVEMBER 1950 Fertility Relationshi ps In Maize-Teosinte Hybrids JOHN S. ROGERS Associate Professor, Department of Agronomy . 2 M AIZE IS A MEMBER of the grass family Gramineae.... Reeves, R. G. and Mangelsdorf, P. C. A proposed taxo- nomic change in the tribe Maydeae (family Gramineae). Amer. Jour. Rot., 29 :815-817. 1942. ...

  16. Ultraviolet Radiation Alters Maize Phyllosphere Bacterial Diversity

    Microsoft Academic Search

    H. Kadivar; A. E. Stapleton

    2003-01-01

    Epiphytic bacteria are subjected to very stressful environments, including UV radiation. Bacterial assemblages on Zea mays (maize) leaves exposure were examined with and without UV-B radiation. Culture-independent molecular techniques were utilized for bacterial identification, diversity analysis and selection of putative UV exposure marker sequences. Few sequences corresponded to previously characterized phyllosphere bacteria. There was a strong tendency toward increased 16S

  17. Maize myosins: Diversity, localization, and function

    Microsoft Academic Search

    Liyun Liu; Juhua Zhou; Thomas C. Pesacreta

    2001-01-01

    This first analysis of monocotyledon myosin genes showed that at least five genes, one of which was probably spliced to yield two isoforms, were expressed in maize (Zea mays L.). The complete coding sequence of ZMM1 was determined, as were most of the sequences of two other myosin cDNAs (ZMM2 and ZMM3). ZMM1 and ZMM2 belonged to myosin class XI

  18. Temperature sensing by primary roots of maize

    NASA Technical Reports Server (NTRS)

    Poff, K. L.

    1990-01-01

    Zea mays L. seedlings, grown on agar plates at 26 degrees C, reoriented the original vertical direction of their primary root when exposed to a thermal gradient applied perpendicular to the gravity vector. The magnitude and direction of curvature can not be explained simply by either a temperature or a humidity effect on root elongation. It is concluded that primary roots of maize sense temperature gradients in addition to sensing the gravitational force.

  19. PLOIDY BARRIER TO ENDOSPERM DEVELOPMENT IN MAIZE

    Microsoft Academic Search

    BOR-YAW LIN

    1984-01-01

    Maize kernels inheriting the indeterminate gametophyte mutant (ig) on the female side had endosperms that ranged in ploidy level from diploid (2x) to nonaploid (9x). In crosses with diploid males, only kernels of the triploid en- dosperm class developed normally. Kernels of the tetraploid endosperm class were half-sized but with well-developed embryos that regularly germinated. Kernels of endosperm composition other

  20. Phenotyping maize for adaptation to drought

    PubMed Central

    Araus, Jose L.; Serret, María D.; Edmeades, Gregory O.

    2012-01-01

    The need of a better adaptation of crops to drought is an issue of increasing urgency. However, enhancing the tolerance of maize has, therefore, proved to be somewhat elusive in terms of plant breeding. In that context, proper phenotyping remains as one of the main factors limiting breeding advance. Topics covered by this review include the conceptual framework for identifying secondary traits associated with yield response to drought and how to measure these secondary traits in practice. PMID:22934056

  1. A guanylyl cyclase-like gene is associated with Gibberella ear rot resistance in maize (Zea mays L.).

    PubMed

    Yuan, J; Liakat Ali, M; Taylor, J; Liu, J; Sun, G; Liu, W; Masilimany, P; Gulati-Sakhuja, A; Pauls, K P

    2008-02-01

    Gibberella ear rot, caused by the fungal pathogen Fusarium graminearum Schwabe, is a serious disease of maize (Zea mays L.) grown in northern climates. The infected maize grain contains toxins that are very harmful to livestock and humans. A maize gene that encodes a putative 267-amino acid guanylyl cyclase-like protein (ZmGC1) was characterized and shown to be associated with resistance to this disease. The putative ZmGC1 amino acid sequence is 53% identical and 65% similar to AtGC1, an Arabidopsis guanylyl cyclase. The Zmgc1 coding sequence is nearly identical in a Gibberella ear rot-resistant line (CO387) and a susceptible line (CG62) but several nucleotide sequence differences were observed in the UTRs and introns of the two alleles. Using a 463 bp probe derived from the CG62 allele of Zmgc1 and a recombinant inbred (RI) mapping population developed from a CG62 x CO387 cross, six Zmgc1 restriction fragment length polymorphism (RFLP) fragments (ER1_1, ER1_2, ER1_3, ER1_4, ER1_5, and ER5_1) were mapped on maize chromosomes 2, 3, 7, and 8. Markers ER1_1 and ER5_1 on chromosomes 7 and 8, respectively, were significantly associated with Gibberella ear rot resistance, each in three different environments. The amount of Zmgc1 transcript in ear tissues increased more quickly and to a greater extent in the resistant genotype compared to the susceptible genotype after inoculation with F. graminearum. Zmgc1 is the first guanylyl cyclase gene characterized in maize and the first gene found to be associated with Gibberella ear rot resistance in this plant. PMID:18074115

  2. Natural maize phenolic acids for control of aflatoxigenic fungi on maize.

    PubMed

    Nesci, A; Gsponer, N; Etcheverry, M

    2007-06-01

    Natural phytochemicals may be an alternative to synthetic chemicals for controlling fungal growth and mycotoxin production in stored maize. A key to progress in this field is to select the best natural maize phytochemicals to be applied in a storage maize ecosystem. This research was undertaken to evaluate the effects of the natural phytochemicals trans-cinnamic acid (CA) and ferulic acid (FA) alone at concentrations of 20 to 30 mM and in 5 combinations on Aspergillus flavus Link and A. parasiticus Speare populations and aflatoxin B(1) production. Studies on Aspergillus population and aflatoxin B(1) production were carried out in maize grain in relation to a water activity a(w) of 0.99, 0.97, 0.95, and 0.93. CA and FA at concentrations of 25 to 30 mM, respectively, and CA-FA mixture T9 (25 + 30 mM) were the treatments most effective at inhibiting A. flavus and A. parasiticus population at all a(w) assayed after 11 d of incubation. At all a(w) values, the mixture CA-FA T9 (25 + 30 mM) completely inhibited (100%) aflatoxin B(1) production by both strains at a(w)= 0.99, 0.97, 0.95, and 0.93. Decreased aflatoxin B(1) levels in comparison with the control were observed with mixtures CA-FA T6 (10 + 25 mM), T7 (20 + 20 mM), and T8 (20 + 30 mM) of both strains in the majority of a(w) assayed. The data show that CA and FA could be considered as effective fungitoxicants for A. flavus and A. parasiticus in maize in the a(w) range 0.99 to 0.93. The information obtained shows promise for controlling aflatoxigenic fungi in stored maize. PMID:17995741

  3. The migration of paraxial and lateral plate mesoderm cells emerging from the late primitive streak is controlled by different Wnt signals

    PubMed Central

    Sweetman, Dylan; Wagstaff, Laura; Cooper, Oliver; Weijer, Cornelis; Münsterberg, Andrea

    2008-01-01

    Background Co-ordinated cell movement is a fundamental feature of developing embryos. Massive cell movements occur during vertebrate gastrulation and during the subsequent extension of the embryonic body axis. These are controlled by cell-cell signalling and a number of pathways have been implicated. Here we use long-term video microscopy in chicken embryos to visualize the migration routes and movement behaviour of mesoderm progenitor cells as they emerge from the primitive streak (PS) between HH stages 7 and 10. Results We observed distinct cell movement behaviours along the length of the streak and determined that this is position dependent with cells responding to environmental cues. The behaviour of cells was altered by exposing embryos or primitive streak explants to cell pellets expressing Wnt3a and Wnt5a, without affecting cell fates, thus implicating these ligands in the regulation of cell movement behaviour. Interestingly younger embryos were not responsive, suggesting that Wnt3a and Wnt5a are specifically involved in the generation of posterior mesoderm, consistent with existing mouse and zebrafish mutants. To investigate which downstream components are involved mutant forms of dishevelled (dsh) and prickle1 (pk1) were electroporated into the primitive streak. These had differential effects on the behaviour of mesoderm progenitors emerging from anterior or posterior regions of the streak, suggesting that multiple Wnt pathways are involved in controlling cell migration during extension of the body axis in amniote embryos. Conclusion We suggest that the distinct behaviours of paraxial and lateral mesoderm precursors are regulated by the opposing actions of Wnt5a and Wnt3a as they leave the primitive streak in neurula stage embryos. Our data suggests that Wnt5a acts via prickle to cause migration of cells from the posterior streak. In the anterior streak, this is antagonised by Wnt3a to generate non-migratory medial mesoderm. PMID:18541012

  4. A model-based approach to preplanting risk assessment for gray leaf spot of maize.

    PubMed

    Paul, P A; Munkvold, G P

    2004-12-01

    ABSTRACT Risk assessment models for gray leaf spot of maize, caused by Cercospora zeae-maydis, were developed using preplanting site and maize genotype data as predictors. Disease severity at the dough/dent plant growth stage was categorized into classes and used as the response variable. Logistic regression and classification and regression tree (CART) modeling approaches were used to predict severity classes as a function of planting date (PD), amount of maize soil surface residue (SR), cropping sequence, genotype maturity and gray leaf spot resistance (GLSR) ratings, and longitude (LON). Models were development using 332 cases collected between 1998 and 2001. Thirty cases collected in 2002 were used to validate the models. Preplanting data showed a strong relationship with late-season gray leaf spot severity classes. The most important predictors were SR, PD, GLSR, and LON. Logistic regression models correctly classified 60 to 70% of the validation cases, whereas the CART models correctly classified 57 to 77% of these cases. Cases misclassified by the CART models were mostly due to overestimation, whereas the logistic regression models tended to misclassify cases by underestimation. Both the CART and logistic regression models have potential as management decision-making tools. Early quantitative assessment of gray leaf spot risk would allow for more sound management decisions being made when warranted. PMID:18943706

  5. Phenolics in maize genotypes differing in susceptibility to Gibberella stalk rot (Fusarium graminearum Schwabe).

    PubMed

    Santiago, Rogelio; Reid, Lana M; Arnason, John T; Zhu, Xiaoyang; Martinez, Noelia; Malvar, Rosa A

    2007-06-27

    The relationship between phenolic compounds and maize pith resistance to Fusarium graminearum, the causal agent of Gibberella stalk rot, was investigated. The phenolic acid profiles in the stalks of six maize inbred lines of varying susceptibility were evaluated from silking to grain maturity. Four different fractions of phenolic compounds were extracted from inoculated and non-inoculated (control) pith tissues: insoluble cell-wall-bound, free, soluble ester-bound, and soluble glycoside-bound phenolics. Analysis by HPLC revealed that p-coumaric acid and ferulic acid were the most abundant compounds in the soluble and cell-wall-bound fractions. The quantity of free, glycoside-bound, and ester-bound phenolics in the pith was lower than the level required for the inhibition of Fusarium growth or mycotoxins production; however, significant negative correlations between diferulic acid contents in the cell walls and disease severity ratings 4 days after inoculation were found. The results indicated that future studies should focus on the levels of diferulic acids during the early infection process. Diferulates may play a role in genotypic resistance of maize to Gibberella stalk rot as preformed barriers to infection. PMID:17547419

  6. Impact of enhanced ultraviolet-B irradiance on maize yield formation and structure: a field evaluation

    NASA Astrophysics Data System (ADS)

    Gao, Wei; Zheng, Youfei; Slusser, James R.; He, Yuhong; Zhang, Ronggang

    2003-11-01

    Stratospheric ozone depletion and enhanced solar ultraviolet-B (UV-B) irradiance may have adverse impacts on the productivity of agricultural crops. Though only a small portion of the total solar electromagnetic spectrum, UV-B irradiance has a disproportionately large photobiological effect, largely because it is readily absorbed by important macromolecules such as proteins and nucleic acids. Numerous investigations have demonstrated that the effect of UV-B enhancements on plants includes a reduction in grain yield, alteration in species competition, susceptibility to disease, and changes in plant structure and pigmentation. Many experiments examining UV-B radiation effects on plants were conducted in growth chambers or greenhouses. It has been questioned if the effect of UV-B radiation on plants can be extrapolated to field responses from indoor studies because of the unnaturally high ratios of UV-B/UV-A and UV-B/PAR in many indoor studies. Field studies on UV-B radiation effect on plants have been recommended in order to use the UV and PAR irradiance provided by natural light. This study found the maize yield formation and yield structural elements responded to enhanced UV-B radiation under field conditions. Enhanced UV-B radiation caused a significant reduction of the dry matter accumulation and the maize grain yield in turn was affected. Analysis of yield structure indicates that the maize yield decreased with increased UV-B radiation and was evidently related to the decreased kernel weight and kernel number per ear.

  7. Proteomic profiling of two maize inbreds during early gibberella ear rot infection.

    PubMed

    Mohammadi, Mohsen; Anoop, Valar; Gleddie, Steve; Harris, Linda J

    2011-09-01

    Fusarium graminearum is the causal agent of gibberella ear rot in maize ears, resulting in yield losses due to mouldy and mycotoxin-contaminated grain. This study represents a global proteomic approach to document the early infection by F. graminearum of two maize inbreds, B73 and CO441, which differ in disease susceptibility. Mock- and F. graminearum-treated developing kernels were sampled 48?h post-inoculation over three field seasons. Infected B73 kernels consistently contained higher concentrations of the mycotoxin deoxynivalenol than the kernels of the more tolerant inbred CO441. A total of 2067 maize proteins were identified in the iTRAQ analysis of extracted kernel proteins at a 99% confidence level. A subset of 878 proteins was identified in at least two biological replicates and exhibited statistically significantly altered expression between treatments and/or the two inbred lines of which 96 proteins exhibited changes in abundance >1.5-fold in at least one of the treatments. Many proteins associated with the defense response were more abundant after infection, including PR-10 (PR, pathogenesis-related), chitinases, xylanase inhibitors, proteinase inhibitors, and a class III peroxidase. Kernels of the tolerant inbred CO441 contained higher levels of these defense-related proteins than B73 kernels even after mock treatment, suggesting that these proteins may provide a basal defense against Fusarium infection in CO441. PMID:21751381

  8. Aflatoxin regulations in a network of global maize trade.

    PubMed

    Wu, Felicia; Guclu, Hasan

    2012-01-01

    Worldwide, food supplies often contain unavoidable contaminants, many of which adversely affect health and hence are subject to regulations of maximum tolerable levels in food. These regulations differ from nation to nation, and may affect patterns of food trade. We soughtto determine whether there is an association between nations' food safety regulations and global food trade patterns, with implications for public health and policymaking. We developed a network model of maize trade around the world. From maize import/export data for 217 nations from 2000-2009, we calculated basic statistics on volumes of trade; then examined how regulations of aflatoxin, a common contaminant of maize, are similar or different between pairs of nations engaging in significant amounts of maize trade. Globally, market segregation appears to occur among clusters of nations. The United States is at the center of one cluster; European countries make up another cluster with hardly any maize trade with the US; and Argentina, Brazil, and China export maize all over the world. Pairs of nations trading large amounts of maize have very similar aflatoxin regulations: nations with strict standards tend to trade maize with each other, while nations with more relaxed standards tend to trade maize with each other. Rarely among the top pairs of maize-trading nations do total aflatoxin standards (standards based on the sum of the levels of aflatoxins B(1), B(2), G(1), and G(2)) differ by more than 5 µg/kg. These results suggest that, globally, separate maize trading communities emerge; and nations tend to trade with other nations that have very similar food safety standards. PMID:23049773

  9. Aflatoxin Regulations in a Network of Global Maize Trade

    PubMed Central

    Wu, Felicia; Guclu, Hasan

    2012-01-01

    Worldwide, food supplies often contain unavoidable contaminants, many of which adversely affect health and hence are subject to regulations of maximum tolerable levels in food. These regulations differ from nation to nation, and may affect patterns of food trade. We soughtto determine whether there is an association between nations' food safety regulations and global food trade patterns, with implications for public health and policymaking. We developed a network model of maize trade around the world. From maize import/export data for 217 nations from 2000–2009, we calculated basic statistics on volumes of trade; then examined how regulations of aflatoxin, a common contaminant of maize, are similar or different between pairs of nations engaging in significant amounts of maize trade. Globally, market segregation appears to occur among clusters of nations. The United States is at the center of one cluster; European countries make up another cluster with hardly any maize trade with the US; and Argentina, Brazil, and China export maize all over the world. Pairs of nations trading large amounts of maize have very similar aflatoxin regulations: nations with strict standards tend to trade maize with each other, while nations with more relaxed standards tend to trade maize with each other. Rarely among the top pairs of maize-trading nations do total aflatoxin standards (standards based on the sum of the levels of aflatoxins B1, B2, G1, and G2) differ by more than 5 µg/kg. These results suggest that, globally, separate maize trading communities emerge; and nations tend to trade with other nations that have very similar food safety standards. PMID:23049773

  10. Aflatoxin control in maize by Trametes versicolor.

    PubMed

    Scarpari, Marzia; Bello, Cristiano; Pietricola, Chiara; Zaccaria, Marco; Bertocchi, Luigi; Angelucci, Alessandra; Ricciardi, Maria Rosaria; Scala, Valeria; Parroni, Alessia; Fabbri, Anna A; Reverberi, Massimo; Zjalic, Slaven; Fanelli, Corrado

    2014-01-01

    Aspergillus flavus is a well-known ubiquitous fungus able to contaminate both in pre- and postharvest period different feed and food commodities. During their growth, these fungi can synthesise aflatoxins, secondary metabolites highly hazardous for animal and human health. The requirement of products with low impact on the environment and on human health, able to control aflatoxin production, has increased. In this work the effect of the basidiomycete Trametes versicolor on the aflatoxin production by A. flavus both in vitro and in maize, was investigated. The goal was to propose an environmental loyal tool for a significant control of aflatoxin production, in order to obtain feedstuffs and feed with a high standard of quality and safety to enhance the wellbeing of dairy cows. The presence of T. versicolor, grown on sugar beet pulp, inhibited the production of aflatoxin B1 in maize by A. flavus. Furthermore, treatment of contaminated maize with culture filtrates of T. versicolor containing ligninolytic enzymes, showed a significant reduction of the content of aflatoxin B1. PMID:25525683

  11. Differential Localization of Antioxidants in Maize Leaves.

    PubMed

    Doulis, A. G.; Debian, N.; Kingston-Smith, A. H.; Foyer, C. H.

    1997-07-01

    The aim of this work was to determine the compartmentation of antioxidants between the bundle-sheath and mesophyll cells of maize (Zea mays L.) leaves. Rapid fractionation of the mesophyll compartment was used to minimize modifications in the antioxidant status and composition due to extraction procedures. The purity of the mesophyll isolates was assessed via the distribution of enzyme and metabolite markers. Ribulose-1,5 bisphosphate and ribulose-1,5-bisphosphate carboxylase/oxygenase were used as bundle-sheath markers and phosphoenolpyruvate carboxylase was used as the mesophyll marker enzyme. Glutathione reductase and dehydroascorbate reductase were almost exclusively localized in the mesophyll tissue, whereas ascorbate, ascorbate peroxidase, and superoxide dismutase were largely absent from the mesophyll fraction. Catalase, reduced glutathione, and monodehydroascorbate reductase were found to be approximately equally distributed between the two cell types. It is interesting that, whereas H2O2 levels were relatively high in maize leaves, this oxidant was largely restricted to the mesophyll compartment. We conclude that the antioxidants in maize leaves are partitioned between the two cell types according to the availability of reducing power and NADPH and that oxidized glutathione and dehydroascorbate produced in the bundle-sheat tissues have to be transported to the mesophyll for re-reduction to their reduced forms. PMID:12223757

  12. Distribution of expansins in graviresponding maize roots

    NASA Technical Reports Server (NTRS)

    Zhang, N.; Hasenstein, K. H.

    2000-01-01

    To test if expansins, wall loosening proteins that disrupt binding between microfibrils and cell wall matrix, participate in the differential elongation of graviresponding roots, Zea mays L. cv. Merit roots were gravistimulated and used for immunolocalization with anti-expansin. Western blots showed cross-reaction with two proteins of maize, one of the same mass as cucumber expansin (29 kDa), the second slightly larger (32 kDa). Maize roots contained mainly the larger protein, but both were found in coleoptiles. The expansin distribution in cucumber roots and hypocotyls was similar to the distribution in maize. Roots showed stronger expansin signals on the expanding convex side than the concave flank as early as 30 min after gravistimulation. Treatment with brefeldin A, a vesicle transport inhibitor, or the auxin transport inhibitor, naphthylphthalamic acid, showed delayed graviresponse and the appearance of differential staining. Our results indicate that expansins may be transported and secreted to cell walls via vesicles and function in wall expansion.

  13. The President's Day cyclone 17-19 February 1979: An analysis of jet streak interactions prior to cyclogenesis

    NASA Technical Reports Server (NTRS)

    Uccellini, L. W.; Kocin, P. J.; Walsh, C. H.

    1981-01-01

    The President's Day cyclone, produced record breaking snowfall along the East Coast of the United States in February 1979. Conventional radiosonde data, SMS GOES infrared imagery and LFM 2 model diagnostics were used to analyze the interaction of upper and lower tropospheric jet streaks prior to cyclogenesis. The analysis reveals that a series of complex scale interactive processes is responsible for the development of the intense cyclone. The evolution of the subsynoptic scale mass and momentum fields prior to and during the period of rapid development of the President's Day cyclone utilizing conventional data and SMS GOES imagery is documented. The interaction between upper and lower tropospheric jet streaks which occurred prior to the onset of cyclogenesis is discussed as well as the possible effects of terrain modified airflow within the precyclogenesis environment. Possible deficiencies in the LFM-2 initial wind fields that could have been responsible, in part, for the poor numerical forecast are examined.

  14. A One-Step Real-Time RT-PCR Assay for the Detection and Quantitation of Sugarcane Streak Mosaic Virus

    PubMed Central

    Fu, Wei-Lin; Sun, Sheng-Ren; Fu, Hua-Ying; Chen, Ru-Kai; Su, Jin-Wei; Gao, San-Ji

    2015-01-01

    Sugarcane mosaic disease is caused by the Sugarcane streak mosaic virus (SCSMV; genus Poacevirus, family Potyviridae) which is common in some Asian countries. Here, we established a protocol of a one-step real-time quantitative reverse transcription PCR (real-time qRT-PCR) using the TaqMan probe for the detection of SCSMV in sugarcane. Primers and probes were designed within the conserved region of the SCSMV coat protein (CP) gene sequences. Standard single-stranded RNA (ssRNA) generated by PCR-based gene transcripts of recombinant pGEM-CP plasmid in vitro and total RNA extracted from SCSMV-infected sugarcane were used as templates of qRT-PCR. We further performed a sensitivity assay to show that the detection limit of the assay was 100 copies of ssRNA and 2?pg of total RNA with good reproducibility. The values obtained were approximately 100-fold more sensitive than those of the conventional RT-PCR. A higher incidence (68.6%) of SCSMV infection was detected by qRT-PCR than that (48.6%) with conventional RT-PCR in samples showing mosaic symptoms. SCSMV-free samples were verified by infection with Sugarcane mosaic virus (SCMV) or Sorghum mosaic virus (SrMV) or a combination of both. The developed qRT-PCR assay may become an alternative molecular tool for an economical, rapid, and efficient detection and quantification of SCSMV. PMID:26185758

  15. Strategies for the Production of Maize-derived Pharmaceuticals using Cytoplasmic Male Sterile Lines: in vitro Tissue Culture/Transformation and Field Breeding Approaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant-made pharmaceuticals (PMPs) offer great promise as efficient and cost-effective products for the treatment of human and animal diseases. Maize seed is known for its large storage capacity and stability of proteins and starches; hence, it is considered an ideal organ for manufacturing recombin...

  16. A second-generation x-ray streak camera with true large format, high dynamic range, and high reliability

    Microsoft Academic Search

    Ke-Xun Sun; William Nishimura; Theodore Perry; Steve Compton

    2005-01-01

    This paper will review the specifications, test and experiment performance features of Bechtel Nevada's Phase 2 X-ray Streak Camera (P2XSC). The P2XSC was developed to meet stringent inertial confinement fusion (ICF) and high energy density (HED) science requirements for experiments at Omega laser facility at Laboratory for Laser Energetics (LLE), and National Ignition Facility (NIF) at Lawrence Livermore National Laboratory

  17. Interaction of Lucerne Transient Streak Virus and the Viroid-like RNA2 of Solanum nodiflorum Mottle Virus

    Microsoft Academic Search

    A. T. Jones; M. A. Mayo

    1983-01-01

    SUMMARY The particles of two serologically unrelated viruses, Solanum nodiflorum mottle (SNMV) and lucerne transient streak (LTSV), contain linear single-stranded RNA-1 (mol. wt. approx. 1.4 x 106), and linear and circular RNA molecules of mol. wt. approx. 1-2 x 105 (RNA-2). SNMV RNA-2 is reported to be part of the virus genome, but LTSV RNA-2 is a satellite-like RNA which

  18. A Multiscale Numerical Study of Hurricane Andrew (1992). Part VI: Small-Scale Inner-Core Structures and Wind Streaks

    Microsoft Academic Search

    M. K. Yau; Yubao Liu; Da-Lin Zhang; Yongsheng Chen

    2004-01-01

    The objectives of Part VI of this series of papers are to (a) simulate the finescale features of Hurricane Andrew (1992) using a cloud-resolving grid length of 2 km, (b) diagnose the formation of small-scale wind streaks, and (c) perform sensitivity experiments of varying surface fluxes on changes in storm inner-core structures and intensity. As compared to observations and a

  19. THEMIS Observations and TES Surface Compositions of Low-Albedo Intracrater Materials and Wind Streaks in Western Arabia Terra

    Microsoft Academic Search

    M. B. Wyatt; H. Y. McSween; P. R. Christensen

    2002-01-01

    High-resolution thermal infrared images (100m\\/pixel) from the Mars Odyssey Thermal Emission Imaging System (THEMIS) are used for thermophysical analyses of low-albedo intracrater materials and wind streaks in Western Arabia Terra and comparisons with Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) derived surface compositions. Atmospherically corrected thermal emissivity data from TES have been used to identify two global-scale spectral surface

  20. Inferring the time resolved core electron temperature from x-ray emission measured by a streak camera

    NASA Astrophysics Data System (ADS)

    Khan, Shahab; Izumi, Niko; Patel, Pravesh; Macphee, Andrew; Ma, Tammy; Cerjan, Charlie; Town, Richard; Bradley, David

    2014-10-01

    The electron temperature (Te) of the hot spot within the core of imploded inertial confinement fusion capsules is an effective indicator of implosion performance. A temporally resolved measurement of Te helps elucidate the mechanisms for hot spot heating and cooling such as alpha-heating and mix. Additionally, comparison with simulations will aid in tuning models to effectively predict implosion performance. The Streaked Polar Instrumentation for Diagnosing Energetic Radiation (SPIDER) is an x-ray streak camera designed to record the x-ray burn history during the stagnation phase. SPIDER accurately reports bang time and burn duration of implosions on the National Ignition Facility (NIF). The addition of several filters of specific materials and thicknesses spread across the spatial axis of the streak camera imager allows for a least square fit of the signal through these filters to a bremsstrahlung hot spot model. The fitted parameters of the model are the Te, opacity, and X-ray yield which is valuable for ablator mix estimates. The details of this calculation and results from several shots on NIF are presented.

  1. Statistical iterative reconstruction for streak artefact reduction when using multidetector CT to image the dento-alveolar structures

    PubMed Central

    Hayakawa, Y; Kober, C

    2014-01-01

    Objectives: When metallic prosthetic appliances and dental fillings exist in the oral cavity, the appearance of metal-induced streak artefacts is not avoidable in CT images. The aim of this study was to develop a method for artefact reduction using the statistical reconstruction on multidetector row CT images. Methods: Adjacent CT images often depict similar anatomical structures. Therefore, reconstructed images with weak artefacts were attempted using projection data of an artefact-free image in a neighbouring thin slice. Images with moderate and strong artefacts were continuously processed in sequence by successive iterative restoration where the projection data was generated from the adjacent reconstructed slice. First, the basic maximum likelihood–expectation maximization algorithm was applied. Next, the ordered subset–expectation maximization algorithm was examined. Alternatively, a small region of interest setting was designated. Finally, the general purpose graphic processing unit machine was applied in both situations. Results: The algorithms reduced the metal-induced streak artefacts on multidetector row CT images when the sequential processing method was applied. The ordered subset–expectation maximization and small region of interest reduced the processing duration without apparent detriments. A general-purpose graphic processing unit realized the high performance. Conclusions: A statistical reconstruction method was applied for the streak artefact reduction. The alternative algorithms applied were effective. Both software and hardware tools, such as ordered subset–expectation maximization, small region of interest and general-purpose graphic processing unit achieved fast artefact correction. PMID:24754471

  2. A robust in-situ warp-correction algorithm for VISAR streak camera data at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Labaria, George R.; Warrick, Abbie L.; Celliers, Peter M.; Kalantar, Daniel H.

    2015-02-01

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is a 192-beam pulsed laser system for high energy density physics experiments. Sophisticated diagnostics have been designed around key performance metrics to achieve ignition. The Velocity Interferometer System for Any Reflector (VISAR) is the primary diagnostic for measuring the timing of shocks induced into an ignition capsule. The VISAR system utilizes three streak cameras; these streak cameras are inherently nonlinear and require warp corrections to remove these nonlinear effects. A detailed calibration procedure has been developed with National Security Technologies (NSTec) and applied to the camera correction analysis in production. However, the camera nonlinearities drift over time affecting the performance of this method. An in-situ fiber array is used to inject a comb of pulses to generate a calibration correction in order to meet the timing accuracy requirements of VISAR. We develop a robust algorithm for the analysis of the comb calibration images to generate the warp correction that is then applied to the data images. Our algorithm utilizes the method of thin-plate splines (TPS) to model the complex nonlinear distortions in the streak camera data. In this paper, we focus on the theory and implementation of the TPS warp-correction algorithm for the use in a production environment.

  3. EXPRESSION OF C4 PHOTOSYNTHETIC ENZYMES IN OAT-MAIZE CHROMOSOME ADDITION LINES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oat-maize addition lines have been successfully generated, and they are available for every maize chromosome, 1 through 10. Addition lines are oat plants (C3 photosynthesis) that include one or more chromosomes from maize (C4 photosynthesis). These oat-maize addition lines and derivative radiation h...

  4. Chemical and sensory qualities of home-level flake maize product

    Microsoft Academic Search

    S. B. Fasoyiro; V. A. Obatolu; O. A. Ashaye; O. O. Oyewole

    2002-01-01

    Maize (Zea mays) is an important staple crop in Nigeria, mostly processed into fermented porridges. Describes an attempt to develop a convenience food from fermented maize. Maize was processed into flakes through home level processing of dry-milling, steeping, sieving, cooking and drying. Three fermented products were formulated by varying the proportions of cooked porridge and fermented maize slurry. The moisture,

  5. Nixtamalized Flour From Quality Protein Maize ( Zea mays L). Optimization of Alkaline Processing

    Microsoft Academic Search

    J. MILÁN-CARRILLO; R. GUTIÉRREZ-DORADO; E. O. CUEVAS-RODRÍGUEZ; J. A. GARZÓN-TIZNADO; C. REYES-MORENO

    2004-01-01

    Quality of maize proteins is poor, they are deficient in the essential amino acids lysine and tryptophan. Recently, in México were successfully developed nutritionally improved 26 new hybrids and cultivars called quality protein maize (QPM) which contain greater amounts of lysine and tryptophan. Alkaline cooking of maize with lime (nixtamalization) is the first step for producing several maize products (masa,

  6. Assessment of wind-induced environmental lodging stress for maize based on GIS

    Microsoft Academic Search

    Chunqiao Mi; Xiaodong Zhang; Shaoming Li; Jianyu Yang; Dehai Zhu; Yang Yang; Zhe Liu

    2011-01-01

    Lodging in maize is one of the major problems in maize production worldwide. This study is to assess environmental lodging stress for maize based on probability analysis of extreme wind event in maize vegetative stage. A total of 687 growing counties in Huang-Huai-Hai Plain, China were chosen as study area. There were 148 meteorology stations with daily extreme wind speed

  7. Constructing a Cytogenetic Map of the Maize Genome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We are developing a pachytene cytogenetic FISH (Fluorescence in situ Hybridization) map of the maize (Zea mays L.) genome using maize marker-selected sorghum BACs (Bacterial Artificial Chromosome) as described by Koumbaris and Bass (2003, Plant J. 35:647). The two main projects are the production of...

  8. Seedling traits of maize as indicators of root lodging

    E-print Network

    Paris-Sud XI, Université de

    Agronomy Seedling traits of maize as indicators of root lodging P Stamp, C Kiel Swiss Federal whether root lodging of maize (Zea mays L) can be predicted at the seedling stage. In the first experiment-leaf stage, the diameter of the primary root was closely and negatively correlated with root lodging

  9. Maize Diversification by Capturing Useful Alleles from Exotic Germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Archeological, carbon-14 dating of maize specimens, and microsatellite evidence has provided strong support for domestication of maize 9,000 - 10,000 years ago from Z. mays ssp. parviglumis (Doebley, 1990) in southern Mexico (Matsuoka et. al., 2002). Since then, early and modern plant breeders...

  10. REGULAR ARTICLE Field decomposition of transgenic Bt maize residue

    E-print Network

    Richner, Heinz

    and plant biomass on the soil ecosystem. Keywords Transgenic Bt corn . Decomposition process . Risk;Introduction Transgenic Bacillus thuringiensis (Bt) maize plants expressing toxins against lepidopteran (Cry1AbREGULAR ARTICLE Field decomposition of transgenic Bt maize residue and the impact on non

  11. The History of Maize and its Current Uses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The history of maize including its origins (both anecdotal from the various Native American viewpoints and scientific from biological and archaeological findings) and how scientists believe maize was domesticated and improved will be conveyed. Current uses (including food, feed, and commercial appli...

  12. A single molecule scaffold for the maize genome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    About 85% of the maize genome consists of highly repetitive Sequences that are interspersed by low copy, gene-coding sequences. The maize community has dealt with this genomic complexity by the Construction of an integrated genetic and physical map (iMap), but this resource alone was not sufficient ...

  13. Original article Degradation of maize stem by two rumen

    E-print Network

    Boyer, Edmond

    was observed. rumen / anaerobic fungi / cellulolytic bacteria / microbial interaction / maize stem degradationOriginal article Degradation of maize stem by two rumen fungal species, Piromyces communis and Caecomyces communis, in pure cultures or in association with cellulolytic bacteria V Roger E Grenet J Jamot

  14. APPLICATION OF HACCP TO CONTROL MYCOTOXINS IN MAIZE BREEDING PROGRAMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize ear rot and associated mycotoxin contamination are serious problems for maize growers around the world. In the U.S. corn-belt severe ear rot and mycotoxin outbreaks occur sporadically while they are serious problems yearly in other regions such as the southeastern U.S. During hybrid selectio...

  15. Temperature responses of tropical maize cultivars selected for broad adaptation

    Microsoft Academic Search

    H. R. Lafitte; G. O. Edmeades; E. C. Johnson

    1997-01-01

    Maize cultivars with broad thermal adaptation may be useful in areas where the crop experiences large fluctuations in temperature, or when a cultivar is targeted for several areas with contrasting temperature regimes. This study evaluated the effects of temperature on development and yield of maize cultivars differing in both adaptation and selection history. Experiments were sown in seven tropical environments

  16. Maize flour fortification in Africa: markets, feasibility, coverage, and costs.

    PubMed

    Fiedler, John L; Afidra, Ronald; Mugambi, Gladys; Tehinse, John; Kabaghe, Gladys; Zulu, Rodah; Lividini, Keith; Smitz, Marc-Francois; Jallier, Vincent; Guyondet, Christophe; Bermudez, Odilia

    2014-04-01

    The economic feasibility of maize flour and maize meal fortification in Kenya, Uganda, and Zambia is assessed using information about the maize milling industry, households' purchases and consumption levels of maize flour, and the incremental cost and estimated price impacts of fortification. Premix costs comprise the overwhelming share of incremental fortification costs and vary by 50% in Kenya and by more than 100% across the three countries. The estimated incremental cost of maize flour fortification per metric ton varies from $3.19 in Zambia to $4.41 in Uganda. Assuming all incremental costs are passed onto the consumer, fortification in Zambia would result in at most a 0.9% increase in the price of maize flour, and would increase annual outlays of the average maize flour-consuming household by 0.2%. The increases for Kenyans and Ugandans would be even less. Although the coverage of maize flour fortification is not likely to be as high as some advocates have predicted, fortification is economically feasible, and would reduce deficiencies of multiple micronutrients, which are significant public health problems in each of these countries. PMID:24102661

  17. MAIZE RACES AND TRAITS IDENTIFIED FROM THE GEM PROJECT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Germplasm Enhancement of Maize Project (GEM) is a cooperative effort of the USDA-ARS, land grant universities, private industry, international, and non-governmental organizations (NGO) organizations to broaden the germplasm base of maize. The project is administered through the USDA-ARS Plant I...

  18. Mutant maize variety containing the glt1-1 allele

    DOEpatents

    Nelson, Oliver E. (Cross Plains, WI); Pan, David (Madison, WI)

    1994-01-01

    A maize plant has in its genome a non-mutable form of a mutant allele designated vitX-8132. The allele is located at a locus designated as glt which conditions kernels having an altered starch characteristic. Maize plants including such a mutant allele produce a starch that does not increase in viscosity on cooling, after heating.

  19. CORRELATION BETWEEN BIOTIC STRESSES AND AFLATOXIN CONTAMINATION IN MAIZE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin, a toxin produced by the fungus Aspergillus flavus, is the most potent carcinogen found in nature. Aflatoxin contamination of maize is a chronic problem in the southern US, where high temperatures, water stress, and insect damage produce conditions conducive to infection of maize by A. fla...

  20. Chromoplast development in a carotenoid mutant of maize

    Microsoft Academic Search

    Björn Walles

    1971-01-01

    Summary The lethal recessive mutantlycopenic in maize is characterized by the synthesis of lycopene instead of the normal carotenoids. At normal conditions of illumination it loses chlorophyll by photo-oxidation. Seedlings of this mutant and of normal maize were grown at light intensities of 25–30 lux and 500–30,000 lux. Their plastid development was studied by electron microscopy.

  1. Can Maize Anthocyanins Function as Resistance Molecules to Corn Earworm?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect herbivory of valuable crops increases the probability of fungal infection in damaged tissues. Mycotoxins produced by some fungi are harmful to livestock and humans. Anthocyanin biosynthesis in maize protects tissues from biotic and abiotic stresses. Constitutive expression of the maize B1 ...

  2. Induction of maize acid phosphatase activities under phosphorus starvation

    Microsoft Academic Search

    Song Joong Yun; Shawn M. Kaeppler

    2001-01-01

    Large variation in phosphorus-(P) acquisition efficiency exists among maize inbred and hybrid genotypes. Acid phosphatases are a type of enzyme that affects P acquisition and P-use efficiency in plants. The objectives of this research were (1) to characterize acid phosphatase activity in maize grown hydroponically under P starvation, and (2) to determine if there is differential induction of acid phosphatases

  3. Maize Centromeres and Knobs (neocentromeres) R. Kelly Dawe

    E-print Network

    Maize Centromeres and Knobs (neocentromeres) R. Kelly Dawe Abstract In most species, the only chromosomal domains that interact with the cytoskeleton are the centromeres. However in maize there are two motile domains: the centromeres and knobs/neocentromeres. Intensive research has been conducted on both

  4. Molecular and Functional Dissection of the Maize B Chromosome Centromere

    E-print Network

    Molecular and Functional Dissection of the Maize B Chromosome Centromere Weiwei Jin,a Jonathan C, Georgia 30602 The centromere of the maize (Zea mays) B chromosome contains several megabases of a B-specific repeat (ZmBs), a 156-bp satellite repeat (CentC), and centromere-specific retrotransposons (CRM elements

  5. IS CATALASE ACTIVITY ASSOCIATED WITH MAIZE RESISTANCE TO ASPERGILLUS FLAVUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Catalase activity was measured in various cob tissues during maize ear development because of its role in maintaining reactive oxygen homeostasis during biotic and abiotic stress. Catalase activity was determined in immature and mature embryos, pericarp, and rachis tissues of maize lines that are re...

  6. RESPONSE OF MAIZE AND WHEAT TO SULFUR DIOXIDE

    EPA Science Inventory

    Four hybrids of maize and seven cultivars of wheat were exposed to relatively low concentrations of sulfur dioxide (0.1 to 0.6 ppm) for up to 100 hours. Maize was found to be tolerant to sulfur dioxide and only minor differences were observed in dry mass, foliar injury, and total...

  7. Isolation and partial characterization of feruloylated oligosaccharides from maize bran

    Microsoft Academic Search

    Luc Saulnier; Jacqueline Vigouroux; Jean-François Thibault

    1995-01-01

    Maize bran contains phenolic acids [? 4% dry matter; mainly ferulic acid (Fe) and also diferulic acid], heteroxylans (? 50%), and cellulose (? 20%), but is devoid of lignin. Treatment of maize pericarp with 0.05 M trifluoroacetic acid at 100°C for 2 h released ?90% of the heteroxylans and ?90% of the ferulic acid and its esters. After fractionation of

  8. Plant physiology Relative efficiency of two zinc sources for maize

    E-print Network

    Paris-Sud XI, Université de

    Plant physiology Relative efficiency of two zinc sources for maize (Zea mays L.) in two calcareous plants in 2 arid calcareous soils of Iran were investigated in a glasshouse study. Plants supplied of ZnEDTA over ZnS04 in terms of growht and Zn utilization by maize in arid region calcareous soils

  9. Nonhydraulic signalling of soil drying in mycorrhizal maize

    Microsoft Academic Search

    Robert M. Augé; Xiangrong Duan; Robert C. Ebel; Ann J. W. Stodola

    1994-01-01

    Our objectives were to (1) verify that nonhydraulic signalling of soil drying can reduce leaf growth of maize, (2) determine if a mycorrhizal influence on such signalling can occur independently of a mycorrhizal effect on leaf phosphorus concentration, plant size or soil drying rate, and (3) determine if leaf phosphorus concentration can affect response to the signalling process. Maize (Zea

  10. Variation of Starch Granule Size in Tropical Maize Germ Plasm

    Microsoft Academic Search

    M. R. CAMPBELL; J. LI; T. G. BERKE; D. V. GLOVER

    Granule size is an important characteristic of starch that can influence its functional and wet-milling extraction properties. Genetic variation for granule size has been found among maize (Zea mays L.) genotypes pos- sessing single gene mutations affecting starch synthesis. In a previous study, 35 tropical and semitropical maize populations were examined for starch thermal properties. The purpose of this study

  11. Mutant maize variety containing the glt1-1 allele

    DOEpatents

    Nelson, O.E.; Pan, D.

    1994-07-19

    A maize plant has in its genome a non-mutable form of a mutant allele designated vitX-8132. The allele is located at a locus designated as glt which conditions kernels having an altered starch characteristic. Maize plants including such a mutant allele produce a starch that does not increase in viscosity on cooling, after heating. 2 figs.

  12. Interaction of F. verticillioides and Talaromyces sp. in maize seeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We conducted studies in maize fields (Illinois, USA, 2013) to observe the interactions of Talaromyces species with fumonisin producing Fusarium verticillioides in corn seeds. Maize ears were inoculated during the milk phase using sterile wooden toothpicks dipped in conidium suspensions, or sterile d...

  13. Pedigree selection for Gibberella ear rot resistance in maize

    Microsoft Academic Search

    Daniel A. Presello; Lana M. Reid; Gail Butler; Diane E. Mather

    2005-01-01

    The pedigree method is often used for developing inbred lines in maize (Zea mays L.). This study was conducted to assess the effectiveness of pedigree selection for improving resistance to Gibberella ear rot in four maize populations. Selection was based on the severity of ear rot symptoms after inoculation with macroconidial suspensions of Fusarium graminearum (Schwabe) into the silk channel

  14. Susceptibility to aflatoxin contamination among maize land races from Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize, the critical staple food for billions of people, was domesticated in Mexico about 9,000 YBP. Today, a great array of maize land races (MLRs) across rural Mexico is harbored in a living library that has been passed among generations since before establishment of the modern state. MLRs have bee...

  15. Entering the second century of maize quantitative genetics

    PubMed Central

    Wallace, J G; Larsson, S J; Buckler, E S

    2014-01-01

    Maize is the most widely grown cereal in the world. In addition to its role in global agriculture, it has also long served as a model organism for genetic research. Maize stands at a genetic crossroads, as it has access to all the tools available for plant genetics but exhibits a genetic architecture more similar to other outcrossing organisms than to self-pollinating crops and model plants. In this review, we summarize recent advances in maize genetics, including the development of powerful populations for genetic mapping and genome-wide association studies (GWAS), and the insights these studies yield on the mechanisms underlying complex maize traits. Most maize traits are controlled by a large number of genes, and linkage analysis of several traits implicates a ‘common gene, rare allele' model of genetic variation where some genes have many individually rare alleles contributing. Most natural alleles exhibit small effect sizes with little-to-no detectable pleiotropy or epistasis. Additionally, many of these genes are locked away in low-recombination regions that encourage the formation of multi-gene blocks that may underlie maize's strong heterotic effect. Domestication left strong marks on the maize genome, and some of the differences in trait architectures may be due to different selective pressures over time. Overall, maize's advantages as a model system make it highly desirable for studying the genetics of outcrossing species, and results from it can provide insight into other such species, including humans. PMID:23462502

  16. Oxidized lipids in the diet accelerate the development of fatty streaks in cholesterol-fed rabbits.

    PubMed

    Staprãns, I; Rapp, J H; Pan, X M; Hardman, D A; Feingold, K R

    1996-04-01

    Studies have indicated that oxidized lipoproteins may play a role in atherosclerosis. We have recently demonstrated that the levels of oxidized lipoproteins in the circulation can be directly correlated to the quantity of oxidized lipids in the diet. The present study tested the hypothesis that dietary oxidized lipids accelerate the development of atherosclerosis. For 12 to 14 weeks, 36 male New Zealand White rabbits were fed a low-cholesterol (0.25%) diet containing either 5% unoxidized corn oil (control diet) or 5% oxidized corn oil (oxidized-lipid diet). Serum cholesterol levels increased to a similar extent in both groups, with the majority of the cholesterol in the beta-migrating very low density lipoprotein (beta-VLDL) fraction. Beta-VLDL from control animals contained 3.86+/- 0.57 versus 9.07 +/- 2.14 nmol conjugated dienes per micromol cholesterol (P<.05) in rabbits fed the oxidized-lipid diet. No difference in oxidized lipid levels was detected in LDL. Most important, feeding a diet rich in oxidized-lipid resulted in a 100% increase in fatty streak lesions in the aorta. Additionally, rabbits that were fed the oxidized-lipid++ diet had a >100% increase in total cholesterol in the pulmonary artery that was primarily due to an increase in cholesteryl ester. Oxidized lipids are frequently present in the typical US diet, and our results suggest that consumption of these foods may be an important risk factor for atherosclerosis. PMID:8624775

  17. Laser Timing Jitter Measurements using a Dual-Sweep Streak Camera at the A0 Photoinjector

    SciTech Connect

    Ruan, J.; Lumpkin, A.H.; Santucci, J.K.; /Fermilab

    2009-04-30

    Excellent phase stability of the drive laser is a critical performance specification of photoinjectors such as Fermilab's A0 photoinjector (A0PI). Previous efforts based on the measurement of the power spectrum of the signal of a fast photodiode illuminated by the mode locked infrared laser pulse component indicated a phase jitter of less than 1.4 ps (technique limited). A recently procured dual sweep plugin unit and existing Hamamatsu C5680 streak camera were used to study the phase stability of the UV laser pulse component. Initial measurements with the synchroscan vertical sweep unit locked to 81.25 MHz showed that the phase slew through the micropulse train and the phase jitter micropulse to micropulse were two key aspects that could be evaluated. The phase slew was much less than 100 fs per micropulse, and the total phase jitter (camera, trigger, and laser) was approximately 300 fs RMS for measurements of 50-micropulse trains. Data on the macropulse phase stability were also obtained. A possible upgrade to achieve better phase stability will be also discussed.

  18. New Experimental Hosts of Tobacco streak virus and Absence of True Seed Transmission in Leguminous Hosts.

    PubMed

    Vemana, K; Jain, R K

    2010-10-01

    Of 70 plant species tested, 50 species were susceptible to Tobacco streak virus (TSV) on sap inoculation. Both localized (necrotic and chlorotic spots) and systemic (necrotic spots, axillary shoot proliferation, stunting, total necrosis and wilt) symptoms are observed by majority of plant species. Eleven new experimental hosts were identified viz., Amaranthus blitum var. oleracea (Chaulai sag), Celosia cristata (Cocks comb), Beta vulgaris var. bengalensis (Palak/Indian spinach), Calendula officinalis (Pot marigold), Chrysanthemum indicum, Cosmos sulphurens (Yellow cosmos), Citrullus lunatus (Watermelon), Lagenaria siceraria (Bottle gourd), Coriandrum sativum (Coriander), Hibiscus subderiffa var. subderiffa (Roselle) and Portulaca oleraceae (Little hogweed). Detected groundnut seed infection with TSV for the first time by Direct antigen coated immunosorbent assay (DAC-ELISA) using whole seed. The seed infection ranged from 18.9 to 28.9% among the seeds collected from naturally infected and sap inoculated groundnut varieties (JL 24, TMV 2, Prasuna, Kadiri 6, Kadiri 9, Anantha and Kadiri 7 Bold) belonging to spanish and virginia types. Further, TSV was detected both in pod shell and seed testa and none of the samples showed the presence of TSV either in cotyledon or embryo. Grow-out and bio-assay tests proved the absence of seed transmission in groundnut and other legume crops. Hence, TSV isolate was not a true seed transmission case under Indian conditions in legumes. PMID:23637490

  19. Improved detection of episomal Banana streak viruses by multiplex immunocapture PCR.

    PubMed

    Le Provost, Grégoire; Iskra-Caruana, Marie-Line; Acina, Isabelle; Teycheney, Pierre-Yves

    2006-10-01

    Banana streak viruses (BSV) are currently the main viral constraint to Musa germplasm movement, genetic improvement and mass propagation. Therefore, it is necessary to develop and implement BSV detection strategies that are both reliable and sensitive, such as PCR-based techniques. Unfortunately, BSV endogenous pararetrovirus sequences (BSV EPRVs) are present in the genome of Musa balbisiana. They interfere with PCR-based detection of episomal BSV in infected banana and plantain, such as immunocapture PCR. Therefore, a multiplex, immunocapture PCR (M-IC-PCR) was developed for the detection of BSV. Musa sequence tagged microsatellite site (STMS) primers were selected and used in combination with BSV species-specific primers in order to monitor possible contamination by Musa genomic DNA, using multiplex PCR. Furthermore, immunocapture conditions were optimized in order to prevent Musa DNA from interfering with episomal BSV DNA during the PCR step. This improved detection method successfully allowed the accurate, specific and sensitive detection of episomal DNA only from distinct BSV species. Its implementation should benefit PCR-based detection of viruses for which homologous sequences are present in the genome of their hosts, including transgenic plants expressing viral sequences. PMID:16857272

  20. Improving the diffraction of full-length human selenomethionyl metavinculin crystals by streak-seeding

    SciTech Connect

    Rangarajan, Erumbi S.; Izard, Tina (Scripps)

    2012-06-28

    Metavinculin is an alternatively spliced isoform of vinculin that has a 68-residue insert in its tail domain (1134 total residues) and is exclusively expressed in cardiac and smooth muscle tissue, where it plays important roles in myocyte adhesion complexes. Mutations in the metavinculin-specific insert are associated with dilated cardiomyopathy (DCM) in man. Crystals of a DCM-associated mutant of full-length selenomethionine-labeled metavinculin grown by hanging-drop vapor diffusion diffracted poorly and were highly sensitive to radiation, preventing the collection of a complete X-ray diffraction data set at the highest possible resolution. Streak-seeding markedly improved the stability, crystal-growth rate and diffraction quality of DCM-associated mutant metavinculin crystals, allowing complete data collection to 3.9 {angstrom} resolution. These crystals belonged to space group P4{sub 3}2{sub 1}2, with two molecules in the asymmetric unit and unit-cell parameters a = b = 170, c = 211 {angstrom}, {alpha} = {beta} = {gamma} = 90{sup o}.

  1. High-resolution mapping of loci conferring resistance to sugarcane mosaic virus in maize using RFLP, SSR, and AFLP markers

    Microsoft Academic Search

    M. L. Xu; A. E. Melchinger; X. C. Xia; T. Lübberstedt

    1999-01-01

    Sugarcane mosaic virus (SCMV) is one of the most important virus diseases of maize in Europe. Genetic analysis on backcross\\u000a five (BC5) progeny derived from the cross FAP1360A (resistant)?×?F7 (susceptible) confirmed that at least two dominant genes,\\u000a Scm1 and Scm2, are required for resistance to SCMV in the progeny of this cross. With the aid of RFLP and SSR marker

  2. Initiation and processing of atp6 , T- urf13 and ORF221 transcripts from mitochondria of T cytoplasm maize

    Microsoft Academic Search

    John C. Kennell; Daryl R. Pring

    1989-01-01

    The mitochondrial gene T-urf13 is implicated in cytoplasmic male sterility and maternal inheritance of susceptibility to disease in T cytoplasm maize. The organization of the T-urf13 region is a consequence of multiple recombinational events, one of which has duplicated a 5 kb region that is 5' to atp6. Transcription initiation and processing sites for atp6 were identified within the 5

  3. Diversity in global maize germplasm: characterization and utilization.

    PubMed

    Prasanna, B M

    2012-11-01

    Maize (Zea mays L.) is not only of worldwide importance as a food, feed and as a source of diverse industrially important products, but is also a model genetic organism with immense genetic diversity. Although it was first domesticated in Mexico, maize landraces are widely found across the continents. Several studies in Mexico and other countries highlighted the genetic variability in the maize germplasm. Applications of molecular markers, particularly in the last two decades, have led to new insights into the patterns of genetic diversity in maize globally, including landraces as well as wild relatives (especially teosintes) in Latin America, helping in tracking the migration routes of maize from the centers of origin, and understanding the fate of genetic diversity during maize domestication. The genome sequencing of B73 (a highly popular US Corn Belt inbred) and Palomero (a popcorn landrace in Mexico) in the recent years are important landmarks in maize research, with significant implications to our understanding of the maize genome organization and evolution. Next-generation sequencing and high-throughput genotyping platforms promise to further revolutionize our understanding of genetic diversity and for designing strategies to utilize the genomic information for maize improvement. However, the major limiting factor to exploit the genetic diversity in crops like maize is no longer genotyping, but high-throughput and precision phenotyping. There is an urgent need to establish a global phenotyping network for comprehensive and efficient characterization of maize germplasm for an array of target traits, particularly for biotic and abiotic stress tolerance and nutritional quality. 'Seeds of Discovery' (SeeD), a novel initiative by CIMMYT with financial support from the Mexican Government for generating international public goods, has initiated intensive exploration of phenotypic and molecular diversity of maize germplasm conserved in the CIMMYT Gene Bank; this is expected to aid in effective identification and use of novel alleles and haplotypes for maize improvement. Multi-institutional efforts are required at the global level to systematically explore the maize germplasm to diversify the genetic base of elite breeding materials, create novel varieties and counter the effects of global climate changes. PMID:23107920

  4. Tritimovirus P1 functions as a suppressor of RNA silencing and an enhancer of disease symptoms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat streak mosaic virus (WSMV) is an eriophyid mite-transmitted virus of the genus Tritimovirus, family Potyviridae. Complete deletion of HC-Pro has no effect on WSMV virulence or disease synergism, suggesting that a different viral protein suppresses post-transcriptional gene silencing (PTGS). PT...

  5. Plant Disease / September 2002 10431043 Perennial Wheat Germ Plasm Lines Resistant to Eyespot, Cephalosporium Stripe,

    E-print Network

    Murray, Timothy D.

    Plant Disease / September 2002 10431043 Perennial Wheat Germ Plasm Lines Resistant to Eyespot, Cephalosporium Stripe, and Wheat Streak Mosaic C. M. Cox, Former Graduate Research Assistant, Department of Plant are needed that are ecologically and economically sustainable. Perennial wheat has the potential to con- vert

  6. Meso-beta scale numerical simulation studies of terrain-induced jet streak mass/momentum perturbations

    NASA Technical Reports Server (NTRS)

    Lin, Yuh-Lang; Kaplan, Michael L.

    1995-01-01

    Mesoscale model simulations provide insight into the complex jet streak adjustments on 11-12 July 1981 that preceded the first of two significant gravity wave events to have been generated over the Rocky Mountains in Montana. Simulations employing a variety of terrain treatments indicate that prior to wave formation, geostrophic adjustment processes modified the structure of the mid-upper tropospheric jet streak by creating secondary jetlets to the southeast of the polar jet streak in proximity to the gravity wave generation region. This simulated restructuring of the mid-upper tropospheric jet streak is the result of a four stage process. During stage 1, the wind adjusts to the mass field as the jet streak exit region propagates into the inflection point between the upstream trough and downstream ridge in the height field. Stage 2 is initiated as the mass field is forced to adjust to the new ageostrophic wind field created during stage 1. Stage 3 is defined by a second geostrophic adjustment process occurring in a similar manner but to the south and east of the adjustment which occurs during stage 1. A low-level mesoscale jetlet is formed during stage 4 in response to the low-level pressure falls that are established during stage 3. The perturbation of this jetlet, caused by orographically-induced adiabatic and diabatic physical processes, is the likely mechanism responsible for the generation of the first and second episode of observed gravity waves. The dynamics responsible for this wave episode are discussed as differential surface sensible heating inducing an orographically-forced mountain-plains solenoid, resulting in the formation of additional mesoscale jetlets and internal gravity waves. Also discussed is how convective latent heating modifies the numerically simulated terrain-induced internal gravity waves, especially their amplitude and phase velocities, which provide better agreement with those wave characteristics observed in nature. Finally, the three-dimensional linear response of a zonally uniform barotropic flow in a vertically unbounded, continuously stratified, Boussinesq atmosphere which is perturbed from geostrophic equilibrium is investigated.

  7. Rumen microbial degradation of the top internode of maize Co125 and maize W401 observed by scanning electron microscopy

    E-print Network

    Paris-Sud XI, Université de

    is a good model to evidence the influence of lignin in cell-wall degradation. When the different tis- suesRumen microbial degradation of the top internode of maize Co125 and maize W401 observed by scanning of the beginning of the appearance of lignin in the cell walls on the microbial rumen degrada- tion. Two lines

  8. THE MAIZE MAPPING PROJECT: COMPREHENSIVE GENETIC, PHYSICAL AND DATABASE RESOURCES FOR MAIZE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Progress in preparing an integrated genetic and physical map of maize is described. The strategy is to fingerprint bacterial artificial chromosome (BAC) fragments and assemble the fragments in a deep-coverage resource, accompanied by pegging with markers to confirm and to intercalate the assembled c...

  9. Similarity of maize and sorghum genomes as revealed by maize RFLP probes

    Microsoft Academic Search

    G. Binelli; L. Gianfranceschi; M. E. Pè; G. Taramino; C. Busso; J. Stenhouse; E. Ottaviano

    1992-01-01

    Densely saturated genetic maps of neutral genetic markers are a prerequisite either for plant breeding programs to improve quantitative traits in crops or for evolutionary studies. cDNA and genomic clones from maize were utilized to initiate the construction of a RFLP linkage map in Sorghum bicolor. To this purpose, an F2 population was produced from starting parental lines IS 18729

  10. Analysis of the Fusarium graminearum species complex from wheat, barley and maize in South Africa provides evidence of species-specific differences in host preference.

    PubMed

    Boutigny, Anne-Laure; Ward, Todd J; Van Coller, Gert J; Flett, Bradley; Lamprecht, Sandra C; O'Donnell, Kerry; Viljoen, Altus

    2011-09-01

    Species identity and trichothecene toxin potential of 560 members of the Fusarium graminearum species complex (FGSC) collected from diseased wheat, barley and maize in South Africa was determined using a microsphere-based multilocus genotyping assay. Although three trichothecene types (3-ADON, 15-ADON and NIV) were represented among these isolates, strains with the 15-ADON type predominated on all three hosts. A significant difference, however, was identified in the composition of FGSC pathogens associated with Gibberella ear rot (GER) of maize as compared to Fusarium head blight (FHB) of wheat or barley (P<0.001). F. graminearum accounted for more than 85% of the FGSC isolates associated with FHB of wheat and barley (N=425), and was also the dominant species among isolates from maize roots (N=35). However, with the exception of a single isolate identified as an interspecific hybrid between Fusariumboothii and F. graminearum, GER of maize (N=100) was exclusively associated with F. boothii. The predominance of F. graminearum among FHB isolates, and the near exclusivity of F. boothii among GER isolates, was observed across all cultivars, collection dates, and provinces sampled. Because these results suggest a difference in host preference among species of the FGSC, we hypothesize that F. graminearum may be less well adapted to infect maize ears than other members of the FGSC. PMID:21601644

  11. Inhibition of non-enzymatic glycation by silk extracts from a Mexican land race and modern inbred lines of maize (Zea mays).

    PubMed

    Farsi, Darius Arthur; Harris, Cory S; Reid, Lana; Bennett, Steffany A L; Haddad, Pierre S; Martineau, Louis C; Arnason, John Thor

    2008-01-01

    Non-enzymatic glycation and the accumulation of advanced glycation end products (AGEs) are associated with various disease states, including complications of diabetes and aging. Secondary metabolites from several plant species are known to inhibit non-enzymatic glycation and the formation of AGEs, including flavonoids found in the style (silk) of Zea mays (maize). Thirteen modern maize inbreds and one land race were tested for in vitro inhibition of non-enzymatic glycation of bovine serum albumin. Many of the tested extracts exhibited inhibitory activity, in particular the newest inbreds, which were bred for resistance to gibberella ear rot (Fusarium graminearum) and common smut (Ustilago maydis). The most active maize genotype (CO441), displaying an IC50 of 9.5 microg/mL, was more effective than aminoguanidine, a known inhibitor of glycation. Zapalote chico, a land race with high maysin content, showed only moderate inhibitory activity compared with the modern maize genotypes. Antiglycation activity was highly correlated with the total phenolic content of silk extracts and mildly correlated with resistance to certain fungal infections. The results identify modern resistant and high phenolic maize inbreds as promising candidates for the development of natural AGE inhibitors for the prevention and treatment of diabetic complications and the degenerative effects of aging. PMID:17724765

  12. Sweet Corn Hybrid Disease Nursery - 2010

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This report summarizes the reactions of 439 sweet corn hybrids to Stewart’s wilt, common rust, maize dwarf mosaic virus, Southern leaf blight, and Northern leaf blight based on their performance in the University of Illinois sweet corn disease nursery in 2010. The reactions of these hybrids to two h...

  13. 2D Optical Streaking for Ultra-Short Electron Beam Diagnostics

    SciTech Connect

    Ding, Y.T.; Huang, Z.; Wang, L.; /SLAC

    2011-12-14

    We propose a novel approach to measure short electron bunch profiles at micrometer level. Low energy electrons generated during beam-gas ionization are simultaneously modulated by the transverse electric field of a circularly-polarized laser, and then they are collected at a downstream screen where the angular modulation is converted to a circular shape. The longitudinal bunch profile is simply represented by the angular distribution of the electrons on the screen. We only need to know the laser wavelength for calibration and there is no phase synchronization problem. Meanwhile the required laser power is also relatively low in this setup. Some simulations examples and experimental consideration of this method are discussed. At Linac Coherent Light Source (LCLS), an S-band RF transverse deflector (TCAV) is used to measure the bunch length with a resolution 10 femtosecond (fs) rms. An X-band deflector (wavelength 2.6cm) is proposed recently to improve the resolution. However, at the low charge operation mode (20pC), the pulse length can be as short as fs. It is very challenging to measure femtosecond and sub-femtosecond level bunch length. One of the methods is switching from RF to {mu}m level wavelength laser to deflect the bunch. A powerful laser ({approx}10s GW) is required to deflect such a high energy beam (GeV) in a wiggler. Synchronization is another difficulty: the jitter between the bunch and the laser can be larger than the laser wavelength, which makes single-shot measurement impossible. To reduce the laser power, we propose to use ionized electrons from high energy electron beam and gas interaction for high energy electron bunch diagnostics. Similarly, the femtosecond X-ray streak camera uses X-ray ionization electrons to measure the X-ray pulse. The electrons generated by beam-gas ionization have low energy (eVs). Therefore, a lower laser power is possible to deflect such low energy electrons. Note that there is no field ionization in our case. To avoid field ionization, which occurs in plasma case, gases species with high field ionization threshold should be considered. For a linear polarized laser, the kick to the ionized electrons depends on the phase of the laser when the electrons are born and the unknown timing jitter between the electron beam and laser beam makes the data analysis very difficult. Here we propose to use a circular polarized laser to do a 2-dimensional (2D) streaking (both x and y) and measure the bunch length from the angular distribution on the screen, where the phase jitter causes only a rotation of the image on the screen without changing of the relative angular distribution. Also we only need to know the laser wavelength for calibration. A similar circular RF deflecting mode was used to measure long bunches. We developed a numerical particle-in-Cell (PIC) code to study the dynamics of ionization electrons with the high energy beam and the laser beam.

  14. Primitive streak mesoderm-like cell lines expressing Pax-3 and Hox gene autoinducing activities.

    PubMed

    Pruitt, S C

    1994-01-01

    Differentiating P19 embryonal carcinoma (EC) cells transiently express an endogenous activity capable of inducing Pax-3 expression in adjacent P19 stem cells (Pruitt, Development 116, 573-583, 1992). In the present study, expression of this activity in mesodermal cell lineages is demonstrated. First, expression of the mesodermal marker Brachyury correlates with expression of Pax-3-inducing activity. Second, the ability of leukemia inhibitory factor (LIF) to block mesoderm differentiation at two different points is demonstrated and correlated with the inhibition of Pax-3-inducing activity. Finally, two mesodermal cell lines that express Pax-3-inducing activity were derived from P19 EC cells. Each of these lines expresses high levels of the mesodermal marker Brachyury and high levels of Oct-3/4 (which is down-regulated at early times during mesoderm differentiation) suggesting that these lines are early mesodermal derivatives. Unlike EC or embryonic stem cell lines, each of the two mesodermal derivatives autoinduces Hox gene expression on aggregation even in the presence of LIF. Following aggregation, anterior-specific genes are expressed more rapidly than more posterior genes. These observations directly demonstrate the ability of murine mesodermal derivatives to autoinduce Hox gene expression in the absence of signals from other cell lineages. Similar to the Pax-3-inducing activity, signals from mesodermal cell lines were sufficient to induce HOX expression in adjacent P19 stem cells in cell mixing assays. These observations are consistent with the previous suggestion (Blum, M., Gaunt, S. J., Cho, K. W. Y., Steinbeisser, H., Blumberg, B., Bittner, D. and De Robertis, E. M. (1992) Cell 69, 1097-1106) that signals responsible for anterior-posterior organizer activity are localized to the anterior primitive streak mesoderm of the mouse embryo. PMID:7907014

  15. Detection, discrimination and discovery of a new Tobacco streak virus strain.

    PubMed

    Dutta, M; Ali, A; Melcher, U

    2015-09-01

    Soybean plants that exhibited symptoms of virus infection were sampled from different counties of Oklahoma. These plants were tested serologically for 15 viruses known to infect soybean plants. Fifty-seven samples that exhibited typical virus-like symptoms did not test positive for any of the 15 viruses used in a dot-immunobinding assay (DIBA). Four samples were pooled and used for next generation sequencing using the 454-Roche protocol. Sequence and phylogenetic analysis of the sequences obtained revealed infection with a distinct strain of Tobacco streak virus (TSV). TSV was one of the 15 viruses initially tested for using DIBA and had tested negative. TSV belongs to the genus Ilarvirus and has been reported as a causal agent of bud blight in soybean crops in Brazil and the United States. Out of 10 reported primer pairs for TSV reverse transcription-polymerase chain reaction (RT-PCR), only two had the potential, based on sequence similarity, to amplify part of the genome of the distinct strain of TSV found in Oklahoma and only one was actually able to amplify the region. In this study, a new primer pair, specific to all known TSV and capable of amplifying the Oklahoma strain (TSV-OK), was designed from a highly conserved region of coat protein (CP) sequences and end-point PCR and quantitative RT-PCR detection methods were developed and their sensitivity assayed. This is the first report of specific primers designed from this highly conserved region in the CP of TSV for detection of TSV. Twenty-three of the 57 DIBA soybean samples that initially tested negative were retested with the new specific end-point PCR method and found positive for TSV infection. PMID:25907471

  16. Physiological Responses of Hard Red Winter Wheat to Infection by Wheat streak mosaic virus.

    PubMed

    Pradhan, Gautam P; Xue, Qingwu; Jessup, Kirk E; Hao, Baozhen; Price, Jacob A; Rush, Charles M

    2015-05-01

    Wheat streak mosaic virus (WSMV) causes significant yield loss in hard red winter wheat in the U.S. Southern High Plains. Despite the prevalence of this pathogen, little is known about the physiological response of wheat to WSMV infection. A 2-year study was initiated to (i) investigate the effect of WSMV, inoculated at different development stages, on shoot and root growth, water use, water use efficiency (WUE), and photosynthesis and (ii) understand the relationships between yield and photosynthetic parameters during WSMV infection. Two greenhouse experiments were conducted with two wheat cultivars mechanically inoculated with WSMV at different developmental stages, from three-leaf to booting. WSMV inoculated early, at three- to five-leaf stage, resulted in a significant reduction in shoot biomass, root dry weight, and yield compared with wheat infected at the jointing and booting stages. However, even when inoculated as late as jointing, WSMV still reduced grain yield by at least 53%. Reduced tillers, shoot biomass, root dry weight, water use, and WUE contributed to yield loss under WSMV infection. However, infection by WSMV did not affect rooting depth and the number of seminal roots but reduced the number of nodal roots. Leaf photosynthetic parameters (chlorophyll [SPAD], net photosynthetic rate [Pn], stomatal conductance [Gs], intercellular CO2 concentration [Ci], and transpiration rate [Tr]) were reduced when infected by WSMV, and early infection reduced parameters more than late infection. Photosynthetic parameters had a linear relationship with grain yield and shoot biomass. The reduced Pn under WSMV infection was mainly in response to decreased Gs, Ci, and SPAD. The results of this study indicated that leaf chlorophyll and gas exchange parameters can be used to quantify WSMV effects on biomass and grain yield in wheat. PMID:25901871

  17. Fluorescence measurement by a streak camera in a single-photon-counting mode.

    PubMed

    Komura, Masayuki; Itoh, Shigeru

    2009-01-01

    We describe here a recently developed fluorescence measurement system that uses a streak camera to detect fluorescence decay in a single photon-counting mode. This system allows for easy measurements of various samples and provides 2D images of fluorescence in the wavelength and time domains. The great advantage of the system is that the data can be handled with ease; furthermore, the data are amenable to detailed analysis. We describe the picosecond kinetics of fluorescence in spinach Photosystem (PS) II particles at 4-77 K as a typical experimental example. Through the global analysis of the data, we have identified a new fluorescence band (F689) in addition to the already established F680, F685, and F695 emission bands. The blue shift of the steady-state fluorescence spectrum upon cooling below 77 K can be interpreted as an increase of the shorter-wavelength fluorescence, especially F689, due to the slowdown of the excitation energy transfer process. The F685 and F695 bands seem to be thermally equilibrated at 77 K but not at 4 K. The simple and efficient photon accumulation feature of the system allows us to measure fluorescence from leaves, solutions, single colonies, and even single cells. The 2D fluorescence images obtained by this system are presented for isolated spinach PS II particles, intact leaves of Arabidopsis thaliana, the PS I super-complex of a marine centric diatom, Chaetoceros gracilis, isolated membranes of a purple photosynthetic bacterium, Acidiphilium rubrum, which contains Zn-BChl a, and a coral that contains a green fluorescent protein and an algal endosymbiont, Zooxanthella. PMID:19568951

  18. Biofuel, land and water: maize, switchgrass or Miscanthus?

    NASA Astrophysics Data System (ADS)

    Zhuang, Qianlai; Qin, Zhangcai; Chen, Min

    2013-03-01

    The productive cellulosic crops switchgrass and Miscanthus are considered as viable biofuel sources. To meet the 2022 national biofuel target mandate, actions must be taken, e.g., maize cultivation must be intensified and expanded, and other biofuel crops (switchgrass and Miscanthus) must be cultivated. This raises questions on the use efficiencies of land and water; to date, the demand on these resources to meet the national biofuel target has rarely been analyzed. Here, we present a data-model assimilation analysis, assuming that maize, switchgrass and Miscanthus will be grown on currently available croplands in the US. Model simulations suggest that maize can produce 3.0-5.4 kiloliters (kl) of ethanol for every hectare of land, depending on the feedstock to ethanol conversion efficiency; Miscanthus has more than twice the biofuel production capacity relative to maize, and switchgrass is the least productive of the three potential sources of ethanol. To meet the biofuel target, about 26.5 million hectares of land and over 90 km3 of water (of evapotranspiration) are needed if maize grain alone is used. If Miscanthus was substituted for maize, the process would save half of the land and one third of the water. With more advanced biofuel conversion technology for Miscanthus, only nine million hectares of land and 45 km3 of water would probably meet the national target. Miscanthus could be a good alternative biofuel crop to maize due to its significantly lower demand for land and water on a per unit of ethanol basis.

  19. Effects of temperature changes on maize production in Mozambique

    USGS Publications Warehouse

    Harrison, L.; Michaelsen, J.; Funk, C.; Husak, G.

    2011-01-01

    We examined intraseasonal changes in maize phenology and heat stress exposure over the 1979-2008 period, using Mozambique meteorological station data and maize growth requirements in a growing degree-day model. Identifying historical effects of warming on maize growth is particularly important in Mozambique because national food security is highly dependent on domestic food production, most of which is grown in already warm to hot environments. Warming temperatures speed plant development, shortening the length of growth periods necessary for optimum plant and grain size. This faster phenological development also alters the timing of maximum plant water demand. In hot growing environments, temperature increases during maize pollination threaten to make midseason crop failure the norm. In addition to creating a harsher thermal environment, we find that early season temperature increases have caused the maize reproductive period to start earlier, increasing the risk of heat and water stress. Declines in time to maize maturation suggest that, independent of effects to water availability, yield potential is becoming increasingly limited by warming itself. Regional variations in effects are a function of the timing and magnitude of temperature increases and growing season characteristics. Continuation of current climatic trends could induce substantial yield losses in some locations. Farmers could avoid some losses through simple changes to planting dates and maize varietal types.

  20. Structure and expression of maize phytochrome family homeologs.

    PubMed Central

    Sheehan, Moira J; Farmer, Phyllis R; Brutnell, Thomas P

    2004-01-01

    To begin the study of phytochrome signaling in maize, we have cloned and characterized the phytochrome gene family from the inbred B73. Through DNA gel blot analysis of maize genomic DNA and BAC library screens, we show that the PhyA, PhyB, and PhyC genes are each duplicated once in the genome of maize. Each gene pair was positioned to homeologous regions of the genome using recombinant inbred mapping populations. These results strongly suggest that the duplication of the phytochrome gene family in maize arose as a consequence of an ancient tetraploidization in the maize ancestral lineage. Furthermore, sequencing of Phy genes directly from BAC clones indicates that there are six functional phytochrome genes in maize. Through Northern gel blot analysis and a semiquantitative reverse transcriptase polymerase chain reaction assay, we determined that all six phytochrome genes are transcribed in several seedling tissues. However, expression from PhyA1, PhyB1, and PhyC1 predominate in all seedling tissues examined. Dark-grown seedlings express higher levels of PhyA and PhyB than do light-grown plants but PhyC genes are expressed at similar levels under light and dark growth conditions. These results are discussed in relation to phytochrome gene regulation in model eudicots and monocots and in light of current genome sequencing efforts in maize. PMID:15280251

  1. Maize (Zea mays L.) genetic factors for preventing fumonisin contamination.

    PubMed

    Butrón, Ana; Santiago, Rogelio; Mansilla, Pedro; Pintos-Varela, Cristina; Ordas, Amando; Malvar, Rosa Ana

    2006-08-01

    Fusarium moniliforme and Fusarium proliferatum are the most frequently isolated fungi from maize (Zea mays L.) in Spain. Both Fusarium species produce toxins potentially dangerous for animals and humans, the fumonisins being the most significant of those toxins. White maize is preferred for human consumption, and extra care should be taken to avoid kernel mycotoxin contamination. The objectives of this study were to identify and quantify kernel infection by Fusarium spp. and contamination by fumonisin on white maize hybrids, to search for white maize sources of resistance to infection by Fusarium spp. and mycotoxin contamination, and to preliminarily study the genetics involved in such resistances. Ten F(1) single crosses derived from a diallel mating design among five white maize inbreds were evaluated in a randomized complete block design with three replications in 2002 at two locations. Fusarium verticilloides and F. proliferatum were detected on kernels of white maize hybrids cultivated in northwestern Spain. No differences in fungal infection were found among maize genotypes, but differences in fumonisin contamination were significant and could be related, in part, to differences in husk tightness. Among the genotypes studied, general combining ability (GCA) effects were the most important for resistance to fumonisin contamination. Inbreds EP10 and EC22 showed the most favorable GCA effects for husk tightness and fumonisin content, and the cross between them, EP10 x EC22, had the most favorable specific combining ability (SCA) effect for husk tightness. Inbreds EP10 and EC22 showed favorable GCA effects for fumonisin contamination and husk tightness, and the cross EP10 x EC22 was the only one with an average fumonisin level below 1 mug/g. Although this should be confirmed with more extensive studies, white maize inbreds developed from white maize landraces could be sources of resistance to fumonisin contamination. PMID:16881725

  2. From many, one: genetic control of prolificacy during maize domestication.

    PubMed

    Wills, David M; Whipple, Clinton J; Takuno, Shohei; Kursel, Lisa E; Shannon, Laura M; Ross-Ibarra, Jeffrey; Doebley, John F

    2013-06-01

    A reduction in number and an increase in size of inflorescences is a common aspect of plant domestication. When maize was domesticated from teosinte, the number and arrangement of ears changed dramatically. Teosinte has long lateral branches that bear multiple small ears at their nodes and tassels at their tips. Maize has much shorter lateral branches that are tipped by a single large ear with no additional ears at the branch nodes. To investigate the genetic basis of this difference in prolificacy (the number of ears on a plant), we performed a genome-wide QTL scan. A large effect QTL for prolificacy (prol1.1) was detected on the short arm of chromosome 1 in a location that has previously been shown to influence multiple domestication traits. We fine-mapped prol1.1 to a 2.7 kb "causative region" upstream of the grassy tillers1 (gt1) gene, which encodes a homeodomain leucine zipper transcription factor. Tissue in situ hybridizations reveal that the maize allele of prol1.1 is associated with up-regulation of gt1 expression in the nodal plexus. Given that maize does not initiate secondary ear buds, the expression of gt1 in the nodal plexus in maize may suppress their initiation. Population genetic analyses indicate positive selection on the maize allele of prol1.1, causing a partial sweep that fixed the maize allele throughout most of domesticated maize. This work shows how a subtle cis-regulatory change in tissue specific gene expression altered plant architecture in a way that improved the harvestability of maize. PMID:23825971

  3. From Many, One: Genetic Control of Prolificacy during Maize Domestication

    PubMed Central

    Wills, David M.; Whipple, Clinton J.; Takuno, Shohei; Kursel, Lisa E.; Shannon, Laura M.; Ross-Ibarra, Jeffrey; Doebley, John F.

    2013-01-01

    A reduction in number and an increase in size of inflorescences is a common aspect of plant domestication. When maize was domesticated from teosinte, the number and arrangement of ears changed dramatically. Teosinte has long lateral branches that bear multiple small ears at their nodes and tassels at their tips. Maize has much shorter lateral branches that are tipped by a single large ear with no additional ears at the branch nodes. To investigate the genetic basis of this difference in prolificacy (the number of ears on a plant), we performed a genome-wide QTL scan. A large effect QTL for prolificacy (prol1.1) was detected on the short arm of chromosome 1 in a location that has previously been shown to influence multiple domestication traits. We fine-mapped prol1.1 to a 2.7 kb “causative region” upstream of the grassy tillers1 (gt1) gene, which encodes a homeodomain leucine zipper transcription factor. Tissue in situ hybridizations reveal that the maize allele of prol1.1 is associated with up-regulation of gt1 expression in the nodal plexus. Given that maize does not initiate secondary ear buds, the expression of gt1 in the nodal plexus in maize may suppress their initiation. Population genetic analyses indicate positive selection on the maize allele of prol1.1, causing a partial sweep that fixed the maize allele throughout most of domesticated maize. This work shows how a subtle cis-regulatory change in tissue specific gene expression altered plant architecture in a way that improved the harvestability of maize. PMID:23825971

  4. Maize food allergy: lipid-transfer proteins, endochitinases, and alpha-zein precursor are relevant maize allergens in double-blind placebo-controlled maize-challenge-positive patients.

    PubMed

    Pastorello, Elide A; Farioli, Laura; Pravettoni, Valerio; Scibilia, Joseph; Conti, Amedeo; Fortunato, Donatella; Borgonovo, Linda; Bonomi, Simona; Primavesi, Laura; Ballmer-Weber, Barbara

    2009-09-01

    Italian patients with maize anaphylaxis have been shown to have IgE toward two major maize allergens: an alpha-amylase inhibitor and a 9-kDa LTP. A complete study on maize food allergens in patients with positive maize double-blind, placebo-controlled food challenge (DBPCFC) is lacking. The objective was to utilize the three maize protein fractions to identify and characterize the most relevant IgE-binding proteins recognized by the sera of Italian and Swiss patients with either a positive maize-DBPCFC or a history of maize-induced anaphylaxis. Osborne's protein fractions of maize were extracted to obtain water-soluble, total zein, and total protein fractions. Protein IgE-binding capacity was investigated by SDS-PAGE immunoblotting using the sera from DBPCFC-positive patients and from patients with maize-induced anaphylaxis. Purified maize LTP was used to inhibit the IgE immunoblotting of the three protein fractions. IgE immunoblotting demonstrated that the 9-kDa LTP was recognized by all the Italian patients and by none of the Swiss patients. Other allergens were: 14-kDa alpha-amylase inhibitor, 30-kDa endochitinases A and -B, 19 kDa zein-beta precursor, and 26 kDa zein-alpha precursor; a newly described allergen, the globulin-2 precursor, identified in the total protein fraction. It is noteworthy that maize LTP and endochitinase were cross-reactive with grape LTP and one grape endochitinase. LTP was found to be the only major allergen in Italian patients with either positive maize challenge or a history of maize-induced anaphylaxis. We have identified other maize allergens in subjects with maize food allergy, as grape cross-reactive endochitinase, however, the clinical significance of these proteins needs to be investigated in larger groups of patients with allergy to these food items. PMID:19669736

  5. Cell Wall Development in Maize Coleoptiles 1

    PubMed Central

    Carpita, Nicholas C.

    1984-01-01

    The physical bases for enhancement of growth rates induced by auxin involve changes in cell wall structure. Changes in the chemical composition of the primary walls during maize (Zea mays L. cv WF9 × Bear 38) coleoptile development were examined to provide a framework to study the nature of auxin action. This report documents that the primary walls of maize cells vary markedly depending on developmental state; polymers synthesized and deposited in the primary wall during cell division are substantially different from those formed during cell elongation. The embryonal coleoptile wall is comprised of mostly glucuronoarabinoxylan (GAX), xyloglucan, and polymers enriched in 5-arabinosyl linkages. During development, both GAX and xyloglucan are synthesized, but the 5-arabinosyls are not. Rapid coleoptile elongation is accompanied by synthesis of a mixed-linked glucan that is nearly absent from the embryonal wall. A GAX highly substituted with mostly terminal arabinofuranosyl units is also synthesized during elongation and, based on pulse-chase studies, exhibits turnover possibly to xylans with less substitution via loss of the arabinosyl and glucuronosyl linkages. Images Fig. 2 PMID:16663799

  6. Adaptation of US maize to temperature variations

    NASA Astrophysics Data System (ADS)

    Butler, Ethan E.; Huybers, Peter

    2013-01-01

    High temperatures are associated with reduced crop yields, and predictions for future warming have raised concerns regarding future productivity and food security. However, the extent to which adaptation can mitigate such heat-related losses remains unclear. Here we empirically demonstrate how maize is locally adapted to hot temperatures across US counties. Using this spatial adaptation as a surrogate for future adaptation, we find that losses to average US maize yields from a 2°C warming would be reduced from 14% to only 6% and that loss in net production is wholly averted. This result does not account for possible changes in temperature variability or water resources, nor does it account for all possible forms of adaptation, but it does show that adaptation is of first-order importance for predicting future changes in yield. Further research should be undertaken regarding the ability to adapt to a changing climate, including analysis of other crops and regions, the application of more sophisticated models of crop development, and field trials employing artificially increased temperature.

  7. IMPACTS OF MAIZE BREEDING RESEARCH AND RECENT SHIFTS IN THE ROLE OF PUBLIC AND PRIVATE SUPPLIERS OF MAIZE SEED TECHNOLOGIES IN EASTERN AND SOUTHERN AFRICA

    Microsoft Academic Search

    R. M. Hassan; M. Mekuria; W. Mwangi

    1999-01-01

    The changing structure of the maize seed industry and the impact of public and private maize breeding research in eastern and southern Africa were analyzed. The results provide evidence of the growing dominance of private seed companies and hybrids as a result of the liberalization of the maize seed industry in the region. Participation of the private sector, however, was

  8. Maize food allergy: lipid-transfer proteins, endochitinases, and alpha-zein precursor are relevant maize allergens in double-blind placebo-controlled maize-challenge-positive patients

    Microsoft Academic Search

    Elide A. Pastorello; Laura Farioli; Valerio Pravettoni; Joseph Scibilia; Amedeo Conti; Donatella Fortunato; Linda Borgonovo; Simona Bonomi; Laura Primavesi; Barbara Ballmer-Weber

    2009-01-01

    Italian patients with maize anaphylaxis have been shown to have IgE toward two major maize allergens: an alpha-amylase inhibitor\\u000a and a 9-kDa LTP. A complete study on maize food allergens in patients with positive maize double-blind, placebo-controlled\\u000a food challenge (DBPCFC) is lacking. The objective was to utilize the three maize protein fractions to identify and characterize\\u000a the most relevant IgE-binding

  9. Subpopulation level variation of banana streak viruses in India and common evolution of banana and sugarcane badnaviruses.

    PubMed

    Sharma, Susheel Kumar; Vignesh Kumar, P; Geetanjali, A Swapna; Pun, Khem Bahadur; Baranwal, Virendra Kumar

    2015-06-01

    Genome sequences of three episomal Banana streak MY virus (BSMYV) isolates sampled from triploid banana hybrids (Chini Champa: AAB; Malbhog: AAB and Monthan: ABB), grown in North-East and South India are reported in this study by sequence-independent improved rolling circle amplification (RCA). RCA coupled with restriction fragment length polymorphism revealed diverse restriction profiles of five BSMYV isolates. Nucleotide substitution rates of BSMYV subpopulation and Banana streak OL virus subpopulation was 7.13 × 10(-3) to 1.59 × 10(-2) and 2.65 × 10(-3) to 5.49 × 10(-3), respectively, for the different coding regions. Analysis of the genetic diversity of banana and sugarcane badnaviruses revealed a total of 32 unique recombination events among banana and sugarcane badnaviruses (inter BSV-SCBV), in addition to the extensive recombination with in banana streak viruses and sugarcane bacilliform viruses (intra-BSV and intra-SCBV). Many unique fragments were shown to contain similar ruminant sequence fragments which indicated the possibility that the two groups of badnaviruses or their ancestors to colonise same host before making the host shift. The distribution of recombination events, hot-spots (intergenic region and C-terminal of ORF3) as well as cold-spots (distributed in ORF3) displayed the mirroring of recombination traces in both group of badnaviruses. These results support the hypothesis of relatedness of banana and sugarcane badnaviruses and the host and geographical shifts that followed the fixation of the species complex appear to be a recent event. PMID:25672291

  10. A compact streak camera for 150 fs time resolved measurement of bright pulses in ultrafast electron diffraction

    NASA Astrophysics Data System (ADS)

    Kassier, G. H.; Haupt, K.; Erasmus, N.; Rohwer, E. G.; von Bergmann, H. M.; Schwoerer, H.; Coelho, S. M. M.; Auret, F. D.

    2010-10-01

    We have developed a compact streak camera suitable for measuring the duration of highly charged subrelativistic femtosecond electron bunches with an energy bandwidth in the order of 0.1%, as frequently used in ultrafast electron diffraction (UED) experiments for the investigation of ultrafast structural dynamics. The device operates in accumulation mode with 50 fs shot-to-shot timing jitter, and at a 30 keV electron energy, the full width at half maximum temporal resolution is 150 fs. Measured durations of pulses from our UED gun agree well with the predictions from the detailed charged particle trajectory simulations.

  11. Rearing the maize weevil, Sitophilus zeamais, on an artificial maize-cassava diet.

    PubMed

    Ojo, James Adebayo; Omoloye, Adebayo Amos

    2012-01-01

    Dry artificial diet pellets prepared with maize, cassava chips, and amino acid supplements (lysine and methionine) were evaluated for mass culture of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), a highly polyphagous pest of many stored grains. Evaluation was done in the laboratory at temperature 26 ± 2 °C, 60-70% RH, 12:12 L:D photoperiod. The artificial diet was compounded from different proportions of maize (M) variety TZPB-SW-R, cassava (C) variety TMS-2110, and amino acid supplements, and was pelletized into 6 mm diameter pellets on which five pairs of one-day-old S. zeamais were bioassayed. The diet M(9)C(1) (90% M and 10% C) was the most suitable diet with comparatively shorter developmental period (34.8 days) and the highest F(1) emergence of progeny (145.4) compared to the control, M(10)C(0) (100% M and 0% C). PMID:22947098

  12. Nutritional evaluation of tortillas and chips form quality protein maize and food grade maize

    E-print Network

    Sproule, Anastasia Marie

    1985-01-01

    and Phipps, 1980), which causes an even greater dependence on cereals in the diet of low-income groups. Therefore, there is a need for a cereal with a higher quality protein source. Normal maize has poor protein quality because of a deficiency of several... of protein in the endosperm than their completely soft opaque-2 counterparts (Pollmer and Phipps, 1980). Also, within the modified kernel, the vitreous fraction has generally more protein than the soft fraction (Pollmer and Phipps, 1980). Vasal (1972...

  13. Cassava virus diseases: biology, epidemiology, and management.

    PubMed

    Legg, James P; Lava Kumar, P; Makeshkumar, T; Tripathi, Leena; Ferguson, Morag; Kanju, Edward; Ntawuruhunga, Pheneas; Cuellar, Wilmer

    2015-01-01

    Cassava (Manihot esculenta Crantz.) is the most important vegetatively propagated food staple in Africa and a prominent industrial crop in Latin America and Asia. Its vegetative propagation through stem cuttings has many advantages, but deleteriously it means that pathogens are passed from one generation to the next and can easily accumulate, threatening cassava production. Cassava-growing continents are characterized by specific suites of viruses that affect cassava and pose particular threats. Of major concern, causing large and increasing economic impact in Africa and Asia are the cassava mosaic geminiviruses that cause cassava mosaic disease in Africa and Asia and cassava brown streak viruses causing cassava brown streak disease in Africa. Latin America, the center of origin and domestication of the crop, hosts a diverse set of virus species, of which the most economically important give rise to cassava frog skin disease syndrome. Here, we review current knowledge on the biology, epidemiology, and control of the most economically important groups of viruses in relation to both farming and cultural practices. Components of virus control strategies examined include: diagnostics and surveillance, prevention and control of infection using phytosanitation, and control of disease through the breeding and promotion of varieties that inhibit virus replication and/or movement. We highlight areas that need further research attention and conclude by examining the likely future global outlook for virus disease management in cassava. PMID:25591878

  14. Preharvest aflatoxin in maize genotypes under inoculation with Aspergillus flavus

    E-print Network

    Mayfield, Kerry L.

    2009-05-15

    conducted through inoculation with a highly concentrated solution of Aspergillus flavus FR: Link spores, a naturally occurring fungus which infects maize and produces a toxic metabolite (aflatoxin) to humans and animals consuming the grain. No commercial...

  15. Determining density of maize canopy. 1: Digitized photography

    NASA Technical Reports Server (NTRS)

    Stoner, E. R.; Baumgardner, M. F.; Swain, P. H.

    1972-01-01

    The relationship between different densities of maize (Zea mays L.) canopies and the energy reflected by these canopies was studied. Field plots were laid out, representing four growth stages of maize, on a dark soil and on a very light colored surface soil. Spectral and spatial data were obtained from color and color infrared photography taken from a vertical distance of 10 m above the maize canopies. Estimates of ground cover were related to field measurements of leaf area index. Ground cover was predicted from leaf area index measurements by a second order equation. Color infrared photography proved helpful in determining the density of maize canopy on dark soils. Color photography was useful for determining canopy density on light colored soils. The near infrared dye layer is the most valuable in canopy density determinations.

  16. Exploring Hormone Crosstalk in Fusarium verticillioidies Infection of Maize 

    E-print Network

    Drab, Dillon

    2013-02-04

    a direct effect on in vitro fungal growth. Available auxin deficient mutants of maize were exploited in a kernel bioassay and colonization was assessed through ergosterol quantification by high-performance liquid chromatography. Collectively, our...

  17. Phenotypic and genotypic characterization of high lysine maize 

    E-print Network

    Bhatnagar, Sandeep

    2006-04-12

    modification. Amino acid levels of inbred lines were significantly correlated with those of hybrids, but with low predictive value. In the third experiment 92 high lysine maize inbreds with different origins [Stiff Stalk, Non Stiff Stalk, Pop 69, temperate (Tx...

  18. Characterization of maize testing locations in eastern and southern Africa

    E-print Network

    Maideni, Francis W.

    2006-08-16

    The region of eastern and southern Africa is very diverse in environments and agronomic practices. The region has one of the highest per capita consumption of maize (Zea mays. L), which is predominantly produced by smallholder farmers. Some...

  19. Preharvest aflatoxin in maize genotypes under inoculation with Aspergillus flavus 

    E-print Network

    Mayfield, Kerry L.

    2009-05-15

    conducted through inoculation with a highly concentrated solution of Aspergillus flavus FR: Link spores, a naturally occurring fungus which infects maize and produces a toxic metabolite (aflatoxin) to humans and animals consuming the grain. No commercial...

  20. Exploring Hormone Crosstalk in Fusarium verticillioidies Infection of Maize

    E-print Network

    Drab, Dillon

    2013-02-04

    . Previously, acs2 acs6, an ethylene biosynthetic mutant of maize has been found to be more resistant to Fusarium infection, colonization, and mycotoxin production. However, the molecular mechanism behind this phenomenon is poorly understood. Hormones...

  1. Original article Ground cover and leaf area index of maize

    E-print Network

    Paris-Sud XI, Université de

    . For both maize (Zea mays L, var Dea) and sugar beet (Beta vul- garis, var Matador), we found the extinction vulgaris, var Matador). Dans les deux cas, on observe une remarquable stabilité du coefficient d

  2. Measuring x-ray burn history with the Streaked Polar Instrumentation for Diagnosing Energetic Radiation (SPIDER) at the National Ignition Facility (NIF)

    NASA Astrophysics Data System (ADS)

    Khan, S. F.; Bell, P. M.; Bradley, D. K.; Burns, S. R.; Celeste, J. R.; Dauffy, L. S.; Eckart, M. J.; Gerhard, M. A.; Hagmann, C.; Headley, D. I.; Holder, J. P.; Izumi, N.; Jones, M. C.; Kellogg, J. W.; Khater, H. Y.; Kimbrough, J. R.; Macphee, A. G.; Opachich, Y. P.; Palmer, N. E.; Petre, R. B.; Porter, J. L.; Shelton, R. T.; Thomas, T. L.; Worden, J. B.

    2012-10-01

    We present a new diagnostic for the National Ignition Facility (NIF) [1,2]. The Streaked Polar Instrumentation for Diagnosing Energetic Radiation (SPIDER) is an x-ray streak camera for use on almost-igniting targets, up to ~1017 neutrons per shot. It measures the x-ray burn history for ignition campaigns with the following requirements: X-Ray Energy 8-30keV, Temporal Resolution 10ps, Absolute Timing Resolution 30ps, Neutron Yield: 1014 to 1017. The features of the design are a heavily shielded instrument enclosure outside the target chamber, remote location of the neutron and EMP sensitive components, a precise laser pulse comb fiducial timing system and fast streaking electronics. SPIDER has been characterized for sweep linearity, dynamic range, temporal and spatial resolution. Preliminary DT implosion data shows the functionality of the instrument and provides an illustration of the method of burn history extraction.

  3. Hairless Streaks in Cattle Implicate TSR2 in Early Hair Follicle Formation

    PubMed Central

    Murgiano, Leonardo; Shirokova, Vera; Welle, Monika Maria; Jagannathan, Vidhya; Plattet, Philippe; Oevermann, Anna; Pienkowska-Schelling, Aldona; Gallo, Daniele; Gentile, Arcangelo; Mikkola, Marja; Drögemüller, Cord

    2015-01-01

    Four related cows showed hairless streaks on various parts of the body with no correlation to the pigmentation pattern. The stripes occurred in a consistent pattern resembling the lines of Blaschko. The non-syndromic hairlessness phenotype observed occurred across three generations of a single family and was compatible with an X-linked mode of inheritance. Linkage analysis and subsequent whole genome sequencing of one affected female identified two perfectly associated non-synonymous sequence variants in the critical interval on bovine chromosome X. Both variants occurred in complete linkage disequilibrium and were absent in more than 3900 controls. An ERCC6L missense mutation was predicted to cause an amino acid substitution of a non-conserved residue. Analysis in mice showed no specific Ercc6l expression pattern related to hair follicle development and therefore ERCC6L was not considered as causative gene. A point mutation at the 5'-splice junction of exon 5 of the TSR2, 20S rRNA accumulation, homolog (S. cerevisiae), gene led to the production of two mutant transcripts, both of which contain a frameshift and generate a premature stop codon predicted to truncate approximately 25% of the protein. Interestingly, in addition to the presence of both physiological TSR2 transcripts, the two mutant transcripts were predominantly detected in the hairless skin of the affected cows. Immunohistochemistry, using an antibody against the N-terminal part of the bovine protein demonstrated the specific expression of the TSR2 protein in the skin and the hair of the affected and the control cows as well as in bovine fetal skin and hair. The RNA hybridization in situ showed that Tsr2 was expressed in pre- and post-natal phases of hair follicle development in mice. Mammalian TSR2 proteins are highly conserved and are known to be broadly expressed, but their precise in vivo functions are poorly understood. Thus, by dissecting a naturally occurring mutation in a domestic animal species, we identified TSR2 as a regulator of hair follicle development. PMID:26203908

  4. The Role of cis Regulatory Evolution in Maize Domestication

    PubMed Central

    Lemmon, Zachary H.; Bukowski, Robert; Sun, Qi; Doebley, John F.

    2014-01-01

    Gene expression differences between divergent lineages caused by modification of cis regulatory elements are thought to be important in evolution. We assayed genome-wide cis and trans regulatory differences between maize and its wild progenitor, teosinte, using deep RNA sequencing in F1 hybrid and parent inbred lines for three tissue types (ear, leaf and stem). Pervasive regulatory variation was observed with approximately 70% of ?17,000 genes showing evidence of regulatory divergence between maize and teosinte. However, many fewer genes (1,079 genes) show consistent cis differences with all sampled maize and teosinte lines. For ?70% of these 1,079 genes, the cis differences are specific to a single tissue. The number of genes with cis regulatory differences is greatest for ear tissue, which underwent a drastic transformation in form during domestication. As expected from the domestication bottleneck, maize possesses less cis regulatory variation than teosinte with this deficit greatest for genes showing maize-teosinte cis regulatory divergence, suggesting selection on cis regulatory differences during domestication. Consistent with selection on cis regulatory elements, genes with cis effects correlated strongly with genes under positive selection during maize domestication and improvement, while genes with trans regulatory effects did not. We observed a directional bias such that genes with cis differences showed higher expression of the maize allele more often than the teosinte allele, suggesting domestication favored up-regulation of gene expression. Finally, this work documents the cis and trans regulatory changes between maize and teosinte in over 17,000 genes for three tissues. PMID:25375861

  5. Fossil-fuel carbon emission control in irrigated maize production

    Microsoft Academic Search

    B. D. Wind; W. W. Wallender

    1997-01-01

    To evaluate optimal management strategies which reduce fossil-fuel carbon emissions, an idealized gross returns objective function was developed for the production of irrigated maize with the inclusion of a disincetive carbon-taxing term. The gross returns objective function is multivariant and optimized through a gradient search procedure. Carbon emissions emanating from maize production stem from the utilization of fossil-fuel energy on

  6. Molecular and biochemical characterization of three lipoxygenases in maize 

    E-print Network

    Nemchenko, Andriy

    2009-06-02

    are most likely localized to chloroplasts. Similar to other known plant LOXs, deduced amino acid sequences of both ZmLOX10 and ZmLOX11 contained residues required for iron binding and enzyme catalytic activity (Prigge et al. 1996): His-559 and His-564... of LOXs and their derivatives in maize (Zea mays) interactions with two economically most important maize fungal pathogens Aspergillus flavus and 8 Fusarium verticillioides. These filamentous fungi colonize corn seed and cause tremendous economic...

  7. Delivery methods for introducing endophytic bacteria into maize

    Microsoft Academic Search

    Wellington Bressan; Marcela T. Borges

    2004-01-01

    The effectiveness of fivemethods for delivery of ten endophyticbacteria into maize stem and root tissues wasstudied in greenhouse conditions at EmbrapaMilho Sorgo, Sete Lagoas, MG, Brazil. Thedelivery methods included seed inoculation,soil drench, foliar spray, pruned-root dip andseed inoculation + soil drench. The bacterialendophytes were previously isolated from maizeplants, and reinoculated and recovered aftertreatments from maize, cv BR201. Each of thefive

  8. Globulin1 gene expression in regenerable Zea mays (maize) callus

    Microsoft Academic Search

    D. R. Duncan; A. L. Kriz; R. Paiva; J. M. Widholm

    2003-01-01

    Since maize callus cultures regenerate plants via somatic embryogenesis, one might expect to find similar proteins in both zygotic embryos and tissue cultures. The 63-kD globulin protein designated GLB1, the expression of which is regulated by abscisic acid (ABA), is one such protein. When maize Type I regenerable callus was exposed for 24 h to 0.1 mM ABA or a

  9. A crop population perspective on maize seed systems in Mexico.

    PubMed

    Dyer, George A; Taylor, J Edward

    2008-01-15

    Improvement of local germplasm through artificial selection is regarded as the main force behind maize evolution and diversity in Mexico, the crop's center of origin. This perspective neglects the larger social context of maize evolution. Using a theoretical approach and Mexico-wide data, we show that farmer-led evolution of maize is largely driven by a technological diffusion and appropriation process that selectively integrates nonlocal germplasm into local seed stocks. Our approach construes farmer practices as events in the life history of seed to build a demographic model. The model shows how random and systematic differences in management combine to structure maize seed populations into subpopulations that can spread or become extinct, in some cases independently of visible agronomic advantages. The process involves continuous population bottlenecks that can lead to diversity loss. Nonlocal germplasm thus might play a critical role in maintaining diversity in individual localities. Empirical estimates show that introduction of nonlocal seed in Central and Southeastern Mexico is rarer than previously thought; prompt replacement further prevents new seed from spreading. Yet introduced seed perceived as valuable diffuses rapidly, contributing variation in the form of type diversity or through introgression into local seed. Maize seed dynamics and evolution are thus part of a complex social process driven by farmers' desire to appropriate the value in maize farming, not always achieved by preserving or improving local seed stocks. PMID:18184814

  10. A crop population perspective on maize seed systems in Mexico

    PubMed Central

    Dyer, George A.; Taylor, J. Edward

    2008-01-01

    Improvement of local germplasm through artificial selection is regarded as the main force behind maize evolution and diversity in Mexico, the crop's center of origin. This perspective neglects the larger social context of maize evolution. Using a theoretical approach and Mexico-wide data, we show that farmer-led evolution of maize is largely driven by a technological diffusion and appropriation process that selectively integrates nonlocal germplasm into local seed stocks. Our approach construes farmer practices as events in the life history of seed to build a demographic model. The model shows how random and systematic differences in management combine to structure maize seed populations into subpopulations that can spread or become extinct, in some cases independently of visible agronomic advantages. The process involves continuous population bottlenecks that can lead to diversity loss. Nonlocal germplasm thus might play a critical role in maintaining diversity in individual localities. Empirical estimates show that introduction of nonlocal seed in Central and Southeastern Mexico is rarer than previously thought; prompt replacement further prevents new seed from spreading. Yet introduced seed perceived as valuable diffuses rapidly, contributing variation in the form of type diversity or through introgression into local seed. Maize seed dynamics and evolution are thus part of a complex social process driven by farmers' desire to appropriate the value in maize farming, not always achieved by preserving or improving local seed stocks. PMID:18184814

  11. Meiotic drive of chromosomal knobs reshaped the maize genome.

    PubMed Central

    Buckler, E S; Phelps-Durr, T L; Buckler, C S; Dawe, R K; Doebley, J F; Holtsford, T P

    1999-01-01

    Meiotic drive is the subversion of meiosis so that particular genes are preferentially transmitted to the progeny. Meiotic drive generally causes the preferential segregation of small regions of the genome; however, in maize we propose that meiotic drive is responsible for the evolution of large repetitive DNA arrays on all chromosomes. A maize meiotic drive locus found on an uncommon form of chromosome 10 [abnormal 10 (Ab10)] may be largely responsible for the evolution of heterochromatic chromosomal knobs, which can confer meiotic drive potential to every maize chromosome. Simulations were used to illustrate the dynamics of this meiotic drive model and suggest knobs might be deleterious in the absence of Ab10. Chromosomal knob data from maize's wild relatives (Zea mays ssp. parviglumis and mexicana) and phylogenetic comparisons demonstrated that the evolution of knob size, frequency, and chromosomal position agreed with the meiotic drive hypothesis. Knob chromosomal position was incompatible with the hypothesis that knob repetitive DNA is neutral or slightly deleterious to the genome. We also show that environmental factors and transposition may play a role in the evolution of knobs. Because knobs occur at multiple locations on all maize chromosomes, the combined effects of meiotic drive and genetic linkage may have reshaped genetic diversity throughout the maize genome in response to the presence of Ab10. Meiotic drive may be a major force of genome evolution, allowing revolutionary changes in genome structure and diversity over short evolutionary periods. PMID:10471723

  12. Water Transfer in an Alfalfa/Maize Association 1

    PubMed Central

    Corak, Steven J.; Blevins, Dale G.; Pallardy, Stephen G.

    1987-01-01

    We investigated the possibility of interspecific water transfer in an alfalfa (Medicago sativa L.) and maize (Zea mays L.) association. An alfalfa plant was grown through two vertically stacked plastic tubes. A 5 centimeter air gap between tubes was bridged by alfalfa roots. Five-week old maize plants with roots confined to the top tube were not watered, while associated alfalfa roots had free access to water in the bottom tube (the ?/+ treatment). Additional treatments included: top and bottom tubes watered (+/+), top and bottom tubes droughted (?/?), and top tube droughted after removal of alfalfa root bridges and routine removal of alfalfa tillers (?*). Predawn leaf water potential of maize in the ?/+ treatment fell to ?1.5 megapascals 13 days after the start of drought; thereafter, predawn and midday potentials were maintained near ?1.9 megapascals. Leaf water potentials of maize in the ?/? and ?* treatments declined steadily; all plants in these treatments were completely desiccated before day 50. High levels of tritium activity were detected in water extracted from both alfalfa and maize leaves after 3H2O was injected into the bottom ?/+ tube at day 70 or later. Maize in the ?/+ treatment was able to survive an otherwise lethal period of drought by utilizing water lost by alfalfa roots. Images Fig. 2 PMID:16665484

  13. Hydrothermal carbonization of anaerobically digested maize silage.

    PubMed

    Mumme, Jan; Eckervogt, Lion; Pielert, Judith; Diakité, Mamadou; Rupp, Fabian; Kern, Jürgen

    2011-10-01

    Hydrochars were prepared by hydrothermal carbonization (HTC) of maize silage previously treated at 55 °C in a two-stage solid-state reactor system. The HTC was carried out in a 1-L stirred pressure reactor with pH regulation by citric acid. The treated silage carbonized at relatively mild conditions (190 °C, 2 h), and the hydrochars showed mainly amorphous macro-size features with a carbon content of 59-79% (ash-free, dry) and a higher heating value of 25-36 MJ kg?¹. Temperature was the main influencing factor. The surface area according to Brunauer-Emmett-Teller (BET) analysis was highest at 190 °C (12.3 m²) g?¹). Based on these results, the hydrochars are potentially interesting for applications such as an alternative fuel or a soil conditioner. PMID:21802284

  14. Regulatory modules controlling maize inflorescence architecture

    PubMed Central

    Eveland, Andrea L.; Goldshmidt, Alexander; Pautler, Michael; Morohashi, Kengo; Liseron-Monfils, Christophe; Lewis, Michael W.; Kumari, Sunita; Hiraga, Susumu; Yang, Fang; Unger-Wallace, Erica; Olson, Andrew; Hake, Sarah; Vollbrecht, Erik; Grotewold, Erich; Ware, Doreen; Jackson, David

    2014-01-01

    Genetic control of branching is a primary determinant of yield, regulating seed number and harvesting ability, yet little is known about the molecular networks that shape grain-bearing inflorescences of cereal crops. Here, we used the maize (Zea mays) inflorescence to investigate gene networks that modulate determinacy, specifically the decision to allow branch growth. We characterized developmental transitions by associating spatiotemporal expression profiles with morphological changes resulting from genetic perturbations that disrupt steps in a pathway controlling branching. Developmental dynamics of genes targeted in vivo by the transcription factor RAMOSA1, a key regulator of determinacy, revealed potential mechanisms for repressing branches in distinct stem cell populations, including interactions with KNOTTED1, a master regulator of stem cell maintenance. Our results uncover discrete developmental modules that function in determining grass-specific morphology and provide a basis for targeted crop improvement and translation to other cereal crops with comparable inflorescence architectures. PMID:24307553

  15. The Genetic Architecture of Maize Stalk Strength

    PubMed Central

    Peiffer, Jason A.; Flint-Garcia, Sherry A.; De Leon, Natalia; McMullen, Michael D.; Kaeppler, Shawn M.; Buckler, Edward S.

    2013-01-01

    Stalk strength is an important trait in maize (Zea mays L.). Strong stalks reduce lodging and maximize harvestable yield. Studies show rind penetrometer resistance (RPR), or the force required to pierce a stalk rind with a spike, is a valid approximation of strength. We measured RPR across 4,692 recombinant inbreds (RILs) comprising the maize nested association mapping (NAM) panel derived from crosses of diverse inbreds to the inbred, B73. An intermated B73×Mo17 family (IBM) of 196 RILs and a panel of 2,453 diverse inbreds from the North Central Regional Plant Introduction Station (NCRPIS) were also evaluated. We measured RPR in three environments. Family-nested QTL were identified by joint-linkage mapping in the NAM panel. We also performed a genome-wide association study (GWAS) and genomic best linear unbiased prediction (GBLUP) in each panel. Broad sense heritability computed on a line means basis was low for RPR. Only 8 of 26 families had a heritability above 0.20. The NCRPIS diversity panel had a heritability of 0.54. Across NAM and IBM families, 18 family-nested QTL and 141 significant GWAS associations were identified for RPR. Numerous weak associations were also found in the NCRPIS diversity panel. However, few were linked to loci involved in phenylpropanoid and cellulose synthesis or vegetative phase transition. Using an identity-by-state (IBS) relationship matrix estimated from 1.6 million single nucleotide polymorphisms (SNPs) and RPR measures from 20% of the NAM panel, genomic prediction by GBLUP explained 64±2% of variation in the remaining RILs. In the NCRPIS diversity panel, an IBS matrix estimated from 681,257 SNPs and RPR measures from 20% of the panel explained 33±3% of variation in the remaining inbreds. These results indicate the high genetic complexity of stalk strength and the potential for genomic prediction to hasten its improvement. PMID:23840585

  16. Unraveling Reciprocal Lipid-Mediated Communication between Maize Seed and Aspergillus flavus 

    E-print Network

    Borrego, Eli James

    2014-07-31

    from maize and Aspergillus flavus within the context of the oxylipin-mediated cross-kingdom crosstalk. Maize wild-type and near-isogenic mutants for several lipoxygenase (LOX) and 12-oxophytodienoate reductases (OPR) related to jasmonic acid...

  17. Molecular characterization of Fusarium globosum strains from South African maize and Japanese wheat

    E-print Network

    Molecular characterization of Fusarium globosum strains from South African maize and Japanese wheat wheat in Japan. Here, multiple analyses revealed that, despite morphological similarities, South African maize and Japanese wheat isolates of the fungus exhibit multiple differences. An amplified fragment

  18. Improving Maize by QTL Mapping, Agronomic Performance and Breeding to Reduce Aflatoxin in Texas 

    E-print Network

    Mayfield, Kerry Lucas

    2012-07-16

    Aflatoxins are potent carcinogens produced by the fungus Aspergillus flavus Link:Fr and are a significant preharvest problem in maize production in Texas, the southern US, and subtropical climates. Several sources of maize germplasm are available...

  19. Estimated Fumonisin Exposure in Guatemala Is Greatest in Consumers of Lowland Maize1,2

    Microsoft Academic Search

    Olga A. Torres; Edwin Palencia; Ligia Lopez de Pratdesaba; Ruben Grajeda; Mario Fuentes; Marcy C. Speer; Alfred H. Merrill Jr; Kerry O'Donnell; Charles W. Bacon; Anthony E. Glenn; Ronald T. Riley

    Fumonisin mycotoxins contaminate maize worldwide. Analysis of maize samples (n ¼ 396) collected from fields in Guatemala from 2000 to 2003 found that lowland maize (,360 m) had significantly more fumonisin B1 than highland maize (.1200 m). For example, 78% of the lowland samples collected at harvest in 2002 contained .0.3 mg\\/g of fumonisin B1, whereas only 2% of the

  20. Crop rotation and nitrogen effects on maize susceptibility to gibberella (Fusarium graminearum) ear rot

    Microsoft Academic Search

    L. M. Reid; X. Zhu; B. L. Ma

    2001-01-01

    An experiment was established in 1992 in eastern Ontario, Canada to determine the effects of crop rotation (continuous maize, soybean-maize and alfalfa-maize) and nitrogen (N) amendment [0, 100 and 200 kg N ha-1 of fertilizer (NH4NO3), and 50 and 100 Mg ha-1 (wet wt.) each of stockpiled and rotted dairy manure] on maize production and soil properties. From 1997 to