bluuebunny/crossref_metadata_2025 huggingface dataset:
MicroRNA-21 regulates the self-renewal of mouse spermatogonial stem cells
Authors: Niu Zhiyv , Goodyear Shaun M. , Rao Shilpa , Wu Xin , Tobias John W. , Avarbock Mary R. , Brinster Ralph L.
Published: July 2011

MicroRNAs (miRs) play a key role in the control of gene expression in a wide array of tissue systems, where their functions include the regulation of self-renewal, cellular differentiation, proliferation, and apoptosis. However, the functional importance of individual miRs in controlling spermatogonial stem cell (SSC) homeostasis has not been investigated. Using high-throughput sequencing, we profiled the expression of miRs in the Thy1
+
testis cell population, which is highly enriched for SSCs, and the Thy1
−
cell population, composed primarily of testis somatic cells. In addition, we profiled the global expression of miRs in cultured germ cells, also enriched for SSCs. Our results demonstrate that miR-21, along with miR-34c, -182, -183, and -146a, are preferentially expressed in the Thy1
+
SSC-enriched population, compared with Thy1
−
somatic cells. Importantly, we demonstrate that transient inhibition of miR-21 in SSC-enriched germ cell cultures increased the number of germ cells undergoing apoptosis and significantly reduced the number of donor-derived colonies of spermatogenesis formed from transplanted treated cells in recipient mouse testes, indicating that miR-21 is important in maintaining the SSC population. Moreover, we show that in SSC-enriched germ cell cultures, miR-21 is regulated by the transcription factor ETV5, known to be critical for SSC self-renewal.
Loss of CD4 T-cell–dependent tolerance to proteins with modified amino acids
Authors: Gauba Varun , Grünewald Jan , Gorney Vanessa , Deaton Lisa M. , Kang Mingchao , Bursulaya Badry , Ou Weijia , Lerner Richard A. , Schmedt Christian , Geierstanger Bernhard H. , Schultz Peter G. , Ramirez-Montagut Teresa
Published: July 2011

The site-specific incorporation of the unnatural amino acidp-nitrophenylalanine (pNO2Phe) into autologous proteins overcomes self-tolerance and induces a long-lasting polyclonal IgG antibody response. To determine the molecular mechanism by which such simple modifications to amino acids are able to induce autoantibodies, we incorporated pNO2Phe, sulfotyrosine (SO3Tyr), and 3-nitrotyrosine (3NO2Tyr) at specific sites in murine TNF-α and EGF. A subset of TNF-α and EGF mutants with these nitrated or sulfated residues is highly immunogenic and induces antibodies against the unaltered native protein. Analysis of the immune response to the TNF-α mutants in different strains of mice that are congenic for the H-2 locus indicates that CD4 T-cell recognition is necessary for autoantibody production. IFN-γ ELISPOT analysis of CD4 T cells isolated from vaccinated mice demonstrates that peptides with mutated residues, but not the wild-type residues, are recognized. Immunization of these peptides revealed that a CD4 repertoire exists for the mutated peptides but is lacking for the wild-type peptides and that the mutated residues are processed, loaded, and presented on the I-Abmolecule. Overall, our results illustrate that, although autoantibodies are generated against the endogenous protein, CD4 cells are activated through a neo-epitope recognition mechanism. Therefore, tolerance is maintained at a CD4 level but is broken at the level of antibody production. Finally, these results suggest that naturally occurring posttranslational modifications such as nitration may play a role in antibody-mediated autoimmune disorders.
Between the common and the differentiated: reflections on the work of the School Curriculum and Assessment Authority on values education
Authors: Haydon Graham
Published: July 2011

This article focuses on the proposals and procedures of the National Forum for Values in Education and the Community in the UK. It critically examines two conflicting strategies. The first of these is that the Qualifications and Curriculum Authority (QCA), to which the Forum reported, should provide general guidance on how each school should work out and seek to implement its own policy on values education, with no further substantive prescription incorporated into the guidance. The second strategy is that they should prescribe both a preferred set of values to be imparted and a preferred method for imparting them. The article examines the QCA framework for action which steers between these two extremes.
Politics, parallels and perennial curriculum questions: the battle over school history in England and the United States
Authors: Foster Stuart J.
Published: July 2011

In both England and the United States history remains among the most controversial subjects in the school curriculum. Indeed, fiercely contested arguments over National Curriculum history in England and national standards for history in the United States graphically illustrate the enormous ideological pressures exerted on the subject in the two cultures. However, although the intense politicization of the disputes in both countries properly suggests some common experiences, the educational context these policies sought to affect are markedly different. In form and substance history teaching in the United States and England has distinctive national characteristics. Nevertheless, attention to debates over the teaching of history on both sides of the Atlantic illuminates the difficulties involved in providing a meaningful history education for young people. Furthermore, the respective national experiences offer opportunities for considered reflection on enduring and universal curriculum questions associated with the teaching of history.
National versus state curriculum standards for history in the United States: where will the debate lead us?
Authors: Doppen Frans H. , Yeager Elizabeth Anne
Published: July 2011

During the past two decades, the debate over a national curriculum has been the subject of much controversy in the United States. However, this debate, part of a much larger debate over the broader goals of public education, has inevitably clashed with the long‐held American notion of local control of schools. The purpose of this article is to present a brief historical overview and identify some issues which continue to feature prominently in the ongoing debate over national and state curriculum standards. The authors focus on curriculum standards for history. A case‐study of this specific debate will reveal some of the major issues which have surfaced in the broader debate.
Understanding integrated curriculum
Authors: Kysilka Marcella L.
Published: July 2011

Integrated curriculum is currently being advocated in the United States to ‘solve’ many of the curriculum problems confronting education. Models of curriculum integration permeate the professional literature, yet there is little consensus as to exactly what is meant by integrated curriculum and how to establish such curricula in the publicly funded schools. The language of curriculum integration is confusing and leads to uncertainty and concern about the potential of integrated curriculum to impact positively on schools. Placing the models on a curriculum continuum will reveal that they range from traditional discipline‐based, objective‐driven, teacher‐controlled models to interest‐based, student exploration. Although historically research supports integrative curriculum, there is a paucity of current research which would support arguments for restructuring the American curriculum in this fashion. Additionally, there is a great deal of resistance to change both from within and outside the educational community to massive curriculum restructuring.
A look at curriculum integration from the bridge
Authors: Gehrke Nathalie J.
Published: July 2011

This article looks at the popularity of curriculum integration in the 1990s in the United States. It offers evidence from national curriculum standards documents, books in print, journal articles, national coalitions and organizations, and curriculum in use to suggest that curriculum integration is experiencing a peak in interest, much like the early era of progressive education, and the open education movement of the 1960s. It further traces the intellectual roots of the current movement and looks at the conceptual differences in the two factions in the curriculum integration movement: the correlated/fused and the core. Different assumptions about the primary source of the curriculum lie at the heart of the split. An extensive reference section offers a sample of the writings on curriculum integration in the 1990s.
The role of subject area, gender, ethnicity and school background in the degree results of Cambridge University undergraduates
Authors: Leman Patrick J.
Published: July 2011

This article examines the relationship between a number of social factors and variations in the class marks awarded to final year undergraduates at the University of Cambridge in 1997 and 1998. Analysis of the categorical data demonstrates that the subject studied, gender and ethnic origin are associated with variations in the marks awarded to undergraduates. Social class and school background were not directly associated with variations in performance. However, a student's school background, ethnic origin, gender and the subject studied interact in complex ways to lead to differences in class marks. The relative influence of these different social variables is discussed. The article concludes that a student's academic performance is linked to aspects of a student's social identity and that these social identities may be created in a range of different social contexts. In this respect, one important source of identity stems from the subject a student studies.
Exploring student‐centred learning in GNVQs: case‐studies of classroom practice
Authors: Yeomans David
Published: July 2011

This article, which is based upon ESRC‐funded research, utilizes two case‐studies to explore the nature of teaching and learning within GNVQs. A model which emphasizes the exertion of student control across different dimensions of learning is used to clarify the meaning of student‐centred learning in the two examples. The discussion of teaching and learning in GNVQs is contextualized within an account of the development of the qualification and a review of research findings which have explored the constraints and opportunities which GNVQs offer for the development of student‐centred learning. The article concludes by suggesting that while there are powerful constraints on student‐centred learning within GNVQs, particularly with regard to assessment, these are mediated in practice by the pedagogical principles, curricular specialisms and institutional locations of the teachers responsible for the courses.
Textual support for primary science teaching?
Authors: Watt Dorothy , Simon Shirley
Published: July 2011

The aim of this study is to explore how the science teaching of five primary teachers (their planning, classroom implementation, assessment and evaluation) relates to their subject knowledge, perceived confidence in teaching, and the way they use published curriculum resource materials. Of the five teachers only one, who did not have a background in science, made systematic use of published curriculum materials. This scheme appears to have enabled her planning and assessment to resemble that of the teacher with a background in science. While planning was well supported by the materials, her classroom teaching shared features with the other teachers who were not science experts, using strategies to keep children's activities within the bounds of her subject knowledge. The features of curriculum materials which seem to have enabled this effective practice to develop are considered to be a clear statement of learning objectives, key science ideas and models of questions for formative assessment. It is proposed that if the national scheme of work produced by the Qualifications and Curriculum Authority is to be as useful to teachers as it could be, LEAs or school science co‐ordinators should make a bridge between classroom practice and the scheme of work's objectives and activity suggestions by developing formative assessment questions to help teachers translate the activities into a form which will more actively involve the children in the important science ideas and processes.
The diversity of poetry: how trainee teachers’ perceptions affect their attitudes to poetry teaching
Authors: Ray Rita
Published: July 2011

In response to a perceived reluctance to engage with poetry on the part of teachers and trainee teachers, a questionnaire was administered to a group of 48 trainees in their second year of training, before they undertook the part of their course dealing with the teaching of poetry. Their responses indicated that they had had a positive experience of poetry during their own primary education but had ceased to enjoy or understand poetry at secondary level. In discussing the responses, attention is drawn to the importance of understanding the difference between poetry as a specialist subject and as a vehicle for teaching other things. The difference between ‘enjoyment’ and ‘appreciation’, as outlined by Wittgenstein, is defined and applied to the study of poetry. Ways of extending trainees’ understanding and ability to teach poetry are explored. It is concluded that in order to get ‘on the inside of the subject they should (a) be allowed to respond freely to poetry at their own level and (b) be initiated into the kind of skills and knowledge which will enable them to identify the progressive features of poetry itself as well as the instrumental aspects of poetry teaching in the primary school.
School‐based curriculum development: the Hong Kong experience
Authors: Chun Lo Yiu
Published: July 2011

The purpose of this article is to analyse the nature of the School‐based Curriculum Project Scheme (SBCPS), which was introduced into the Hong Kong education system in 1988. The aims of the scheme were to promote school‐based curriculum development (SBCD) designed to meet the learning needs of pupils and to encourage teachers to solve curriculum problems. Overall, the article provides insights into the characteristics of the SBCPS which was introduced into a highly centralized context and was initiated through a highly centralized mechanism, and describes how it was implemented into Hong Kong schools. This underlines the need both to view curriculum policies critically and to recognize the impact that the prevailing culture in schools has on attempts at curriculum innovations.
Osteoblast mineralization requires β1 integrin/ICAP-1–dependent fibronectin deposition
Authors: Brunner Molly , Millon-Frémillon Angélique , Chevalier Genevieve , Nakchbandi Inaam A. , Mosher Deane , Block Marc R. , Albigès-Rizo Corinne , Bouvard Daniel
Published: July 2011

The morphogenetic and differentiation events required for bone formation are orchestrated by diffusible and insoluble factors that are localized within the extracellular matrix. In mice, the deletion of ICAP-1, a modulator of β1 integrin activation, leads to severe defects in osteoblast proliferation, differentiation, and mineralization and to a delay in bone formation. Deposition of fibronectin and maturation of fibrillar adhesions, adhesive structures that accompany fibronectin deposition, are impaired upon ICAP-1 loss, as are type I collagen deposition and mineralization. Expression of β1 integrin with a mutated binding site for ICAP-1 recapitulates the ICAP-1–null phenotype. Follow-up experiments demonstrated that ICAP-1 negatively regulates kindlin-2 recruitment onto the β1 integrin cytoplasmic domain, whereas an excess of kindlin-2 binding has a deleterious effect on fibrillar adhesion formation. These results suggest that ICAP-1 works in concert with kindlin-2 to control the dynamics of β1 integrin–containing fibrillar adhesions and, thereby, regulates fibronectin deposition and osteoblast mineralization.
Preferential binding of a kinesin-1 motor to GTP-tubulin–rich microtubules underlies polarized vesicle transport
Authors: Nakata Takao , Niwa Shinsuke , Okada Yasushi , Perez Franck , Hirokawa Nobutaka
Published: July 2011

Polarized transport in neurons is fundamental for the formation of neuronal circuitry. A motor domain–containing truncated KIF5 (a kinesin-1) recognizes axonal microtubules, which are enriched in EB1 binding sites, and selectively accumulates at the tips of axons. However, it remains unknown what cue KIF5 recognizes to result in this selective accumulation. We found that axonal microtubules were preferentially stained by the anti–GTP-tubulin antibody hMB11. Super-resolution microscopy combined with EM immunocytochemistry revealed that hMB11 was localized at KIF5 attachment sites. In addition, EB1, which binds preferentially to guanylyl-methylene-diphosphate (GMPCPP) microtubules in vitro, recognized hMB11 binding sites on axonal microtubules. Further, expression of hMB11 antibody in neurons disrupted the selective accumulation of truncated KIF5 in the axon tips. In vitro studies revealed approximately threefold stronger binding of KIF5 motor head to GMPCPP microtubules than to GDP microtubules. Collectively, these data suggest that the abundance of GTP-tubulin in axonal microtubules may underlie selective KIF5 localization and polarized axonal vesicular transport.
Nuclear translocation of AMPK-α1 potentiates striatal neurodegeneration in Huntington’s disease
Authors: Ju Tz-Chuen , Chen Hui-Mei , Lin Jiun-Tsai , Chang Ching-Pang , Chang Wei-Cheng , Kang Jheng-Jie , Sun Cheng-Pu , Tao Mi-Hua , Tu Pang-Hsien , Chang Chen , Dickson Dennis W. , Chern Yijuang
Published: July 2011

Adenosine monophosphate–activated protein kinase (AMPK) is a major energy sensor that maintains cellular energy homeostasis. Huntington’s disease (HD) is a neurodegenerative disorder caused by the expansion of CAG repeats in the huntingtin (Htt) gene. In this paper, we report that activation of the α1 isoform of AMPK (AMPK-α1) occurred in striatal neurons of humans and mice with HD. Overactivation of AMPK in the striatum caused brain atrophy, facilitated neuronal loss, and increased formation of Htt aggregates in a transgenic mouse model (R6/2) of HD. Such nuclear accumulation of AMPK-α1 was activity dependent. Prevention of nuclear translocation or inactivation of AMPK-α1 ameliorated cell death and down-regulation of Bcl2 caused by mutant Htt (mHtt). Conversely, enhanced expression of Bcl2 protected striatal cells from the toxicity evoked by mHtt and AMPK overactivation. These data demonstrate that aberrant activation of AMPK-α1 in the nuclei of striatal cells represents a new toxic pathway induced by mHtt.
Sensitivity of Carbon Emission Estimates from Indirect Land‐Use Change
Authors: Dumortier Jerome , Hayes Dermot J. , Carriquiry Miguel , Dong Fengxia , Du Xiaodong , Elobeid Amani , Fabiosa Jacinto F. , Tokgoz Simla
Published: July 2011

An agricultural projection and greenhouse gas model are used to assess the impact of global cropland expansion on carbon emissions and the sensitivity of those estimates to modifications in assumptions concerning idle cropland, the degree of refinement in carbon coefficients, market responses, and yield increase. The results indicate that the impact of cropland expansion on carbon emissions is extremely sensitive to model assumptions. This is particularly true with respect to the price‐induced yield response. Given the available knowledge, it is very difficult to narrow the range of reasonable parameter values to tighten the set of results to a level that would allow robust policy conclusions.
The Productivity of Nanobiotechnology Research and Education in U.S. Universities
Authors: Weber William L. , Xia Yin
Published: July 2011

The knowledge production process of thirty universities that participated in nanobiotechnology research during 1990–2005 is estimated by a stochastic directional technology distance function. Knowledge outputs include journal articles, patents, and Ph.D students. The dual elasticity of transformation between knowledge outputs is estimated. An increase in patents reduces the revenue shares of publications and Ph.D students for a majority of the thirty universities. Aggregate university inefficiency has a U shape with a minimum in 1997. Evidence of technological regress is found which indicates that the increased production of patents, publications, and Ph.D students is due to bigger research budgets.
Migratory Responses to Agricultural Risk in Northern Nigeria
Authors: Dillon Andrew , Mueller Valerie , Salau Sheu
Published: July 2011

We investigate the extent that Nigerian households engage in internal migration to ensure against ex ante and ex post agricultural risk due to weather‐related variability and shocks. We use data on the migration patterns of individuals over a twenty‐year period and temperature degree days to proxy agricultural risk. We find suggestive evidence of household response to ex ante risk by sending males to migrate. Robust findings show that males migrate in response to ex post risk. As global climate change increases risk, these results suggest that increased migration could result as households mitigate risk and strain limited resources in Nigerian cities.
Cheap Talk Scripts and Online Choice Experiments: “Looking Beyond the Mean”
Authors: Tonsor Glynn T. , Shupp Robert S.
Published: July 2011

This paper presents the first known assessment of cheap talk effectiveness in a choice experiment conducted online with a focus on the distinction between impacts on stated willingness to pay at the population mean and in targeted sub‐samples. Utilizing a large national survey and split‐sample experimental design, we find cheap talk scripts may not only influence the level of willingness to pay estimated for representative consumers, but also may produce more reliable estimates. The magnitude of the impact that cheap talk has on willingness to pay is found to depend on the evaluated respondent sub‐sample.
Structural Agricultural Land Use Modeling for Spatial Agro‐Environmental Policy Analysis
Authors: Fezzi Carlo , Bateman Ian J.
Published: July 2011

This paper develops a spatially disaggregated, structural econometric model of agricultural land use and production based on the joint multi‐output technology representation introduced by Chambers and Just (1989). Starting from a flexible specification of the farm profit function, we derive land use allocation, input application, crop yield, and livestock intensity equations in a joint and theoretically consistent framework. To account for the presence of censored observations in micro‐level data, the model is estimated as a system of two‐limit Tobit equations via quasi‐maximum likelihood. We present an empirical application using fine‐scale spatial data covering the entirety of England and Wales and including the main economic, policy, and environmental drivers of land use change in the past forty years. A simulation of the effects of diffuse pollution reduction measures illustrates how our approach can be applied for agro‐environmental policy appraisal.
Elevated Activity of Dolichyl Phosphate Mannose Synthase Enhances Biocontrol Abilities of Trichoderma atroviride
Authors: Zembek Patrycja , Perlińska-Lenart Urszula , Brunner Kurt , Reithner Barbara , Palamarczyk Grażyna , Mach Robert L. , Kruszewska Joanna S.
Published: July 2011

Antagonism of Trichoderma spp. against phytopathogenic fungi is widely exploited for biocontrol of plant diseases. A crucial role in the biocontrol mechanism is attributed to cell-wall-degrading enzymes secreted by Trichoderma spp. Therefore, more efficient production and secretion of the enzymes should elevate the biocontrol abilities of Trichoderma spp. Because the majority of secretory hydrolases are glycoproteins, it has been postulated that the posttranslational modification of these proteins could constitute a bottleneck in their production and secretion. Our previous study showed that improvement of O-glycosylation elevated protein secretion by Trichoderma reesei. In this study, we enhanced the biocontrol abilities of T. atroviride P1 against plant pathogens by overexpressing the Saccharomyces cerevisiae DPM1 gene coding for dolichyl phosphate mannose (DPM) synthase, a key enzyme in the O-glycosylation pathway. The transformants we obtained showed doubled DPM synthase activity and, at the same time, significantly elevated cellulolytic activity. They also revealed an improved antifungal activity against the plant pathogen Pythium ultimum.
Variable Expression of the Stagonospora nodorum Effector SnToxA Among Isolates Is Correlated with Levels of Disease in Wheat
Authors: Faris Justin D. , Zhang Zengcui , Rasmussen Jack B. , Friesen Timothy L.
Published: July 2011

Most research on host–pathogen interactions is focused on mechanisms of resistance, but less is known regarding mechanisms of susceptibility. The wheat–Stagonospora nodorum pathosystem involves pathogen-produced effectors, also known as host-selective toxins, that interact with corresponding dominant host genes to cause disease. Recognition of the S. nodorum effectors SnToxA and SnTox2 is mediated by the wheat genes Tsn1 and Snn2, respectively. Here, we inoculated a population of wheat recombinant inbred lines that segregates for Tsn1 and Snn2 with conidia from two S. nodorum isolates, Sn4 and Sn5, which both produce SnToxA and SnTox2 to compare the effects of compatible Tsn1–SnToxA and Snn2–SnTox2 interactions between the two isolates. Genetic analysis revealed that the two interactions contribute equally to disease caused by isolate Sn4 but the Tsn1–SnToxA interaction contributed substantially more to disease conferred by Sn5 than did the Snn2–SnTox2 interaction. Sequence analysis of the SnToxA locus from Sn4 and Sn5 indicated that they were 99.5% identical, with no polymorphisms in the coding region or the predicted promoters. Analysis of transcription levels showed that expression levels of SnToxA peaked at 26 h postinoculation for both isolates but SnToxA expression in Sn5 was more than twice that of Sn4. This work demonstrates that necrotrophic effectors of different isolates can be expressed at different levels in planta, and that higher levels of expression lead to increased levels of disease in the wheat–S. nodorum pathosystem.
Large-Scale Data Integration Reveals Colocalization of Gene Functional Groups with Meta-QTL for Multiple Disease Resistance in Barley
Authors: Schweizer Patrick , Stein Nils
Published: July 2011

Race-nonspecific and durable resistance of plant genotypes to major pathogens is highly relevant for yield stability and sustainable crop production but difficult to handle in practice due to its polygenic inheritance by quantitative trait loci (QTL). As far as the underlying genes are concerned, very little is currently known in the most important crop plants such as the cereals. Here, we integrated publicly available data for barley (Hordeum vulgare subsp. vulgare) in order to detect the most important genomic regions for QTL-mediated resistance to a number of fungal pathogens and localize specific functional groups of genes within these regions. This identified 20 meta-QTL, including eight hot spots for resistance to multiple diseases that were distributed over all chromosomes. At least one meta-QTL region for resistance to the powdery mildew fungus Blumeria graminis was found to be co-linear between barley and wheat, suggesting partial evolutionary conservation. Large-scale genetic mapping revealed that functional groups of barley genes involved in secretory processes and cell-wall reinforcement were significantly over-represented within QTL for resistance to powdery mildew. Overall, the results demonstrate added value resulting from large-scale genetic and genomic data integration and may inform genomic-selection procedures for race-nonspecific and durable disease resistance in barley.
Cytokinin Induction of Root Nodule Primordia in Lotus japonicus Is Regulated by a Mechanism Operating in the Root Cortex
Authors: Heckmann Anne Birgitte , Sandal Niels , Bek Anita Søndergaard , Madsen Lene Heegaard , Jurkiewicz Anna , Nielsen Mette Wibroe , Tirichine Leila , Stougaard Jens
Published: July 2011

Cytokinin plays a central role in the formation of nitrogen-fixing root nodules following inoculation with rhizobia. We show that exogenous cytokinin induces formation of discrete and easily visible nodule primordia in Lotus japonicus roots. The expression of nodulin genes was up-regulated upon cytokinin treatment, suggesting that the genuine nodulation program was indeed activated. This offers a simple approach for dissecting the underlying mechanism. Cytokinin-induced nodule primordia formation was unperturbed in several loss-of-function mutants impaired in epidermal responses to either rhizobial infection, Nod factor application, or both. However, absence of primordia in nsp1, nsp2, and nin mutants showed the requirement for these transcriptional regulators in the cytokinin-mediated activation of the root cortex. Distinguishing the epidermal and cortical responses further, we found that external cytokinin application induced expression of the Nin::GUS reporter gene within the root cortex but not in the root epidermis. Using L. japonicus lhk1-1 and har1 mutants, we demonstrate that discrete activation of root cortical cells by cytokinin depends on the LHK1 cytokinin receptor and is subjected to HAR1-mediated autoregulation.
First Report of ‘Candidatus Phytoplasma asteris’ Associated with Oilseed Rape Phyllody in Poland
Authors: Zwolińska A. , Krawczyk K. , Klejdysz T. , Pospieszny H.
Published: July 2011

Winter oilseed rape (Brassica napus L.) is widely grown in Poland to produce vegetable oil for industrial processing of human and animal feed. In recent years, according to European Union directives on the use of biofuels (Directive 2003/30/EC), the area under oilseed rape cultivation in Poland has dramatically increased to 810,000 ha in 2009 and is still increasing. Morphological deformations of winter oilseed rape indicative of phytoplasma infection have been observed sporadically in Poland since 2000 (3). Plants exhibiting floral virescence, phyllody, as well as auxiliary bud proliferation, reduced leaves, and malformation of siliques were identified during surveys of research fields in Wielkopolska during May and June of 2009 and 2010. To confirm phytoplasma infection of these plants, inflorescence and leaf tissues were collected from nine diseased and three symptomless plants from three different field locations with 1 to 16% disease incidence. Total DNA was extracted from each plant tissue sample with a modified cetyltrimethylammoniumbromide method (2). Samples were analyzed for phytoplasma DNA with a nested PCR assay employing phytoplasma universal rRNA operon primer pair P1/P7 followed by R16F2n/R16R2, using previously described conditions (1). PCR products of 1.8 and 1.2 kb were obtained from all diseased plants only following PCRs with P1/P7 and nested primer pair R16F2n/R16R2, respectively. PCR products were not obtained from symptomless plants. Eight 1.2-kb amplicons were sequenced (GenBank Accession Nos. JN193475 to JN193482). Comparative analysis of the R16F2n/R16R2 rDNA sequences confirmed the phytoplasma origin of the rDNA sequences that shared 100 to 99% identity with Maize bushy stunt phytoplasma (GenBank Accession No. HQ530152), Alfalfa stunt phytoplasma (GenBank Accession No. GU289675), Primula green yellows phytoplasma (GenBank Accession No. HM590623), and other aster yellows group phytoplasmas. A 1.8-kb amplicon of isolate designated RzW14 was sequenced (GenBank Accession No. HM561990) and had 99% identity with Aster yellow group phytoplasmas from Lithuania (GenBank Accession Nos.GU223208 and AY744071). A virtual restriction fragment length polymorphism analysis of the 16S rDNA sequences from the R16F2n/R16R2 amplicons was performed with iPhyClassifier (4). Restriction profile comparisons identified all aster yellows group phytoplasmas as subgroup 16SrI-B strains. To our knowledge, this is the first report of a ‘Candidatus Phytoplasma asteris’-related strain infecting oilseed rape in Poland.

References: (1) I. M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (2) A. C. Padovan et al. Aust. J. Grape Wine Res. 1:25, 1995. (3) M. Starzycki and E. Starzycka. Oilseed Crops 21:399, 2000. (4) Y. Zhao et al. Int. J. Syst. Evol. Microbiol. 59:2582, 2009.
First Report of Tomato leaf curl New Delhi virus Infecting Cucumber in Central Java, Indonesia
Authors: Mizutani T. , Daryono B. S. , Ikegami M. , Natsuaki K. T.
Published: July 2011

Cucumber (Cucumis sativus L.) is an important vegetable in Indonesia. Cucumber plants showing yellowy green mosaic symptoms on leaves were observed in Klaten, Central Java, Indonesia in August 2008. Total DNAs were extracted from symptomatic leaves, and the putative viral genomes were amplified by PCR with the Deng A and B primers (2). The PCR-amplified viral genomic DNA was sequenced. The remaining part of DNA-A was amplified with two primers sets (ToLCNDV-A1F 5′-ACCAACAGGCCGATGAACA-3′ and ToLCNDV-A1R 5′-TTCCCACTATCTTCCTGTGCA-3′; ToLCNDV-A2F 5′-TCGAGTGTGATRAAGAYTGCA-3′ and ToLCNDV-A2R 5′-ACTAACTAAGCATTGCAGCGTC-3′ [R = A and G, Y = C and T]) and sequenced. The remaining part of DNA-B was amplified with two primers sets (ToLCNDV-B1F 5′-ARGAGTTYMCRYYTGTGGA-3′ and ToLCNDV-B1R 5′-TKCWGTYGGTCATGTCGT-3′; ToLCNDV-B2F 5′-TCYGTCAATCKCATGTCGYGT-3′ and ToLCNDV-B2R 5′-CCTTACGCGTATAYTGTYTRGA-3′ [K = G and T, M = A and C, W = A and T]) and sequenced. Full-length DNA-A (2,739 nt; GenBank Accession No. AB613825) and DNA-B (2,690 nt; GenBank Accession No. AB613826) sequences of a bipartite Tomato leaf curl New Delhi virus (ToLCNDV) from Central Java were obtained and they were most similar to the corresponding sequences of both DNA-A and DNA-B of ToLCNDV-[cucumber:Thailand] (DNA-A, GenBank Accession No. AB330079; DNA-B, GenBank Accession No. AB330080) at 95.5 and 91.0% nucleotide identities, respectively. On the basis of high nucleotide sequence identity with ToLCNDV-[cucumber:Thailand] and the demarcation criteria in species identification (3), the virus isolate from the diseased cucumber in Central Java is considered as a variant of ToLCNDV and was accordingly named ToLCNDV-Indonesia[Indonesia:Java:Cucumber:2008] (ToLCNDV-ID[ID:Jav:Cuc:08]). Although the importance of begomovirus diseases on chili pepper (Solanaceae) is currently highly noticed in Indonesia (1), ToLCNDV was newly isolated from cucumber (Cucurbitaceae) in this study. Therefore, farmers in Indonesia should pay more attention to controlling begomovirus vectors, white flies, on Cucurbitaceae. To our knowledge, this is the first report of the natural occurrence of ToLCNDV in Indonesia.

References: (1) P. J. D. Barro et al. Biol. Invas.10:411, 2008. (2) D. Deng et al. Ann. Appl. Biol. 125:327, 1994. (3) C. M. Fauquet et al. Arch. Virol. 153:783, 2008.
Apical Necrosis and Premature Drop of Persian (English) Walnut Fruit Caused by Xanthomonas arboricola pv. juglandis
Authors: Moragrega Concepció , Matias Josep , Aletà Neus , Montesinos Emilio , Rovira Mercé
Published: July 2011

Etiological and epidemiological aspects of apical necrosis of walnut fruit were studied on cultivars Chandler, Franquette, and Hartley in a Spanish walnut orchard during 2007 and 2008. Affected fruit showed brown necrosis beginning at the blossom end of nuts; these symptoms differed from lesions of common blight of walnut (Xanthomonas arboricola pv. juglandis). X. arboricola pv. juglandis was consistently isolated from apical lesions throughout the growing season. Field isolates reproduced symptoms observed in the orchard when inoculated on immature detached walnut fruit in the laboratory. Sporadic occurrence of Fusarium spp. and Alternaria spp., mainly in dropped fruit, was attributed to secondary colonization of apical lesions that were originally caused by X. arboricola pv. juglandis. Apical necrosis and common blight were similar in disease epidemiology and cultivar susceptibility; a major increase in epidemics occurred at initial fruit development, and cvs. Chandler and Hartley were more affected than cv. Franquette. Our results suggest that apical necrosis is a new manifestation of walnut blight characterized by distinct symptoms and severe premature fruit drop.
Detection of Multiple Verticillium Species in Soil Using Density Flotation and Real-Time Polymerase Chain Reaction
Authors: Debode J. , Van Poucke K. , França S. C. , Maes M. , Höfte M. , Heungens K.
Published: July 2011

Wet sieving of soil samples, followed by plating on semi-selective medium and microscopic analysis, is the most commonly used technique to quantify microsclerotia-forming Verticillium species in soil. However, the method is restricted to small samples, does not allow easy differentiation between species, and takes several weeks to complete. This study describes an alternative method to test 100-g soil samples for three Verticillium species (V. tricorpus, V. dahliae, and V. longisporum) using density flotation-based extraction of microsclerotia followed by new real-time polymerase chain reaction (PCR) assays. Primers for these real-time PCR assays were designed to the ribosomal DNA internal transcribed spacer for V. tricorpus and the β-tubulin gene for V. dahliae + V. longisporum and V. longisporum. Tests with artificially and naturally infested soils showed that the new method is reproducible and sensitive (0.1 to 0.5 microsclerotia/g soil), allows differentiation among the three species, and can be completed in one day. The results of the new method and the wet-sieving method were highly correlated for V. tricorpus (R2 = 0.78), but not for V. dahliae/V. longisporum, probably due to the loss of germinability of V. dahliae/V. longisporum microsclerotia during prolonged dry storage of the soil.
Triticum mosaic virus Isolates in the Southern Great Plains
Authors: Fuentes-Bueno Irazema , Price Jacob A. , Rush Charles M. , Seifers Dallas L. , Fellers John P.
Published: July 2011

In 2006, a previously unknown wheat (Triticum aestivum) virus was discovered in Western Kansas and given the name Triticum mosaic virus (TriMV). TriMV has since been found in wheat samples isolated all across the Great Plains. Even though it can infect singularly, TriMV is mostly found with Wheat streak mosaic virus (WSMV) as a co-infection. The potential for TriMV to cause economic loss is significant, but very little is known about the virus. The objective of this study was to survey the TriMV population for genetic variation by nucleotide sequencing of isolates across a geographical region. A secondary objective was to characterize the WSMV isolates that are being co-transmitted with TriMV. Fourteen different TriMV isolations were taken from locations in Texas, Oklahoma, and Kansas, and the coat protein cDNA was sequenced. Thirteen nucleotide differences were found in the TriMV isolates, of which three induce amino acid changes. WSMV isolates had 65 nucleotide changes when compared to WSMV Sydney81. Our results indicate the TriMV virus population has minimal amounts of sequence variation and no singular WSMV genotype is specifically associated with TriMV co-infection. Based on the isolates analyzed, it appears that the field population of TriMV is very homogeneous.
First Report of Cylindrocarpon macrodidymum on Acer palmatum in Virginia
Authors: Dart N. L. , Weeda S. M.
Published: July 2011

In October 2010, containerized Acer palmatum Thunb. trees (‘Red Select’, ‘Viridis’, and ‘Hubb's Red Willow’) with crown cankers and root rot were observed at a central Virginia nursery. Sections of lower stem cankers and rootlets were sampled from 14 trees by surface-sterilizing tissue and plating on V8 juice agar. A species of Cylindrocarpon was isolated from 72% of sampled trees and recovered from 57% of 50 cankers and 74% of 50 sections of symptomatic rootlets. On potato dextrose agar (PDA), macroconidia were cylindrical, straight, and rounded at both ends. Chlamydospores were common and intercalary or terminal in the mycelium. To identify to species, the internal transcribed spacer of ribosomal DNA and partial sequences of the beta tubulin gene were sequenced and compared with published sequences (GenBank Accession Nos. AM419110.1 and AM419109.1), which exactly matched sequences of Cylindrocarpon macrodidymum, a recently described species (1,2). Neighbor-joining analyses using Blast Tree View placed C. macrodidymum and the unknown isolate in a closely related but distinct clade from C. pauciseptatum and C. liriodendri. Species-specific primers also confirmed the isolates to be C. macrodidymum (2). A. palmatum seedlings (generic root stock) were inoculated by placing a colonized PDA plug over 1-cm scalpel incision wounds (n = 12) and wrapping treated sections of stem with Parafilm to prevent desiccation. Twelve root systems were inoculated by mixing a colonized PDA plate with 1 liter of water and drenching the soil of each plant. Twelve wounds and root systems were inoculated with uncolonized PDA for controls. After 4 weeks, inoculated wounded seedlings developed brown lesions extending 1 to 3 cm from incision wounds. Inoculated roots developed root rot. Controls produced no visible symptoms. A Cylindrocarpon sp. was recovered from 85% of surface-sterilized sections of inoculated wounded stem and 100% inoculated symptomatic roots. No Cylindrocarpon sp. was isolated from stem or root controls. To our knowledge, this is the first report of this pathogen on A. palmatum. Other reported hosts include grapevines (Vitis spp.) and apple (Malus spp.) (3). This finding demonstrates the ability of C. macrodidymum to impact an ornamental host and the potential for this pathogen to impact the ornamental nursery industry.

References: (1) S. Alaniz et al. Plant Dis. 93:821, 2009. (2) J. Auger et al. Plant Dis. 91:470, 2007. (3) Y. T. Tewoldemedhin et al. Eur. J. Plant Pathol. 129:637, 2011.
Virulence in Oat Crown Rust (Puccinia coronata f. sp. avenae) in the United States from 2006 through 2009
Authors: Carson M. L.
Published: July 2011

The use of race-specific seedling genes for resistance is the primary means of controlling crown rust of oat (Puccinia coronata f. sp. avenae) in the United States. To better utilize those resistance genes, knowledge of the occurrence and frequency of corresponding virulence in the population of P. coronata f. sp. avenae in the United States is essential. In total, 571 single-pustule isolates of oat crown rust were collected from cultivated and wild oat (Avena sativa and A. fatua, respectively) in the major oat production areas of the United States from 2006 through 2009. They were tested for virulence on seedlings of 31 differential oat lines in the greenhouse. In all, 201 races were found among the 357 isolates from the spring oat region of the north-central United States, and 140 races were found among 214 isolates from the southern winter oat region. The crown rust populations from the winter and spring oat regions were clearly differentiated from one another, differing in the frequency of virulence for 24 of the 31 differentials. Some virulence associations previously reported in the U.S. oat crown rust population were also found in both regions in this survey, even when the dataset was clone corrected. Associations between virulence to the Pc genes were predominately positive in both regions but both positive and negative associations occurred more frequently in the winter oat region, where sexual reproduction does not occur. Some of the virulence diversity in the oat crown rust population in the United States can be related to the deployment of resistance genes in commercial oat cultivars and virulence associations existing in the oat crown rust population. When data from a previous report covering 2001 through 2005 is combined with data reported in this article, the mean virulence of the U.S. populations of crown rust continued to increase from 2001 to 2009. Virulence to Pc38, Pc39, Pc45, Pc48, Pc52, Pc55, Pc56, Pc57, Pc59, Pc62, Pc63, Pc64, Pc68, and Pc96 significantly increased in one or both regions during this time period. No significant declines in virulence frequency were found in either region. Genes for crown rust resistance derived from A. sterilis appear to be as rapidly defeated as has happened to Pc genes from A. sativa. There is an urgent need to find additional sources of effective resistance to P. coronata f. sp. avenae and introgress it into adapted oat cultivars.
Variability for Resistance to Phytophthora nicotianae Within a Collection of Nicotiana rustica Accessions
Authors: Nifong J. M. , Nicholson J. S. , Shew H. D. , Lewis R. S.
Published: July 2011

Black shank, caused by Phytophthora nicotianae, is one of the most important diseases affecting tobacco (Nicotiana tabacum) production worldwide. Many current tobacco cultivars possess immunity to race 0 of this pathogen conferred by introgressed dominant genetic factors. Novel alleles conditioning resistance to alternative races are desired. The objective of this research was to evaluate variability for black shank resistance within a collection of N. rustica germplasm using both soilborne disease nurseries and controlled race-specific (race 0 and race 1) inoculations. Nearly all of the 86 accessions studied exhibited very high resistance to race 0, and many displayed levels of race 1 resistance greater than that exhibited by the resistant flue-cured tobacco check, ‘K 346’. Materials found to be highly resistant to race 0 and race 1 in growth-chamber experiments also had the best survivability in field disease nurseries. N. rustica accessions TR 6, TR 12, TR 16, TR 21, TR 20, TR 48, TR 54, TR 57, and TR 69 could be sources of novel alleles with large effects on black shank resistance, and could have value for burley and flue-cured tobacco breeding.
Exponential and Power-Law Contact Distributions Represent Different Atmospheric Conditions
Authors: Reynolds A. M.
Published: July 2011

It is well known that the dynamics of plant disease epidemics are very sensitive to the functional form of the contact distribution—the probability distribution function for the distance of viable fungal spore movement until deposition. Epidemics can take the form of a constant-velocity travelling wave when the contact distribution is exponentially bounded. Fat-tailed contact distributions, on the other hand, lead to epidemic spreads that accelerate over time. Some empirical data for contact distributions can be well represented by negative exponentials while other data are better represented by fat-tailed inverse power laws. Here we present data from numerical simulations that suggest that negative exponentials and inverse power laws are not competing candidate forms of the contact distribution but are instead representative of different atmospheric conditions. Contact distributions for atmospheric boundary-layers with stabilities ranging from strongly convective (a hot windless day time scenario) to stable stratification (a cold windy night time scenario) but without precipitation events are calculated using well-established state-of-the-art Lagrangian stochastic (particle tracking) dispersal models. Contact distributions are found to be well represented by exponentials for strongly convective conditions; a –3/2 inverse power law for convective boundary-layers with wind shear; and by a –2/3 inverse power law for stably stratified conditions.