A sugar beet chlorophyll a/b binding protein promoter void of G-box like elements confers strong and leaf specific reporter gene expression in transgenic sugar beet

BACKGROUND: Modification of leaf traits in sugar beet requires a strong leaf specific promoter. With such a promoter, expression in taproots can be avoided which may otherwise take away available energy resources for sugar accumulation. RESULTS: Suppression Subtractive Hybridization (SSH) was utilized to generate an enriched and equalized cDNA library for leaf expressed genes from sugar beet. Fourteen cDNA fragments corresponding to thirteen different genes were isolated. Northern blot analysis indicates the desired tissue specificity of these genes. The promoters for two chlorophyll a/b binding protein genes (Bvcab11 and Bvcab12) were isolated, linked to reporter genes, and transformed into sugar beet using promoter reporter gene fusions. Transient and transgenic analysis indicate that both promoters direct leaf specific gene expression. A bioinformatic analysis revealed that the Bvcab11 promoter is void of G-box like regulatory elements with a palindromic ACGT core sequence. The data indicate that the presence of a G-box element is not a prerequisite for leaf specific and light induced gene expression in sugar beet. CONCLUSIONS: This work shows that SSH can be successfully employed for the identification and subsequent isolation of tissue specific sugar beet promoters. These promoters are shown to drive strong leaf specific gene expression in transgenic sugar beet. The application of these promoters for expressing resistance improving genes against foliar diseases is discussed

Behavior Of Spandrel Beams Strengthened With Steel Fibers Under Combined Loading

Anggota konkrit mengalami kilasan diiringi juga dengan lenturan dan ricihan. Sehingga kini, kod amalan reka bentuk anggota-anggota konkrit bertetulang menganggap bahawa kesan kilasan dapat dielakkan dengan selamat disebabkan faktor keselamatan yang tinggi digunakan dalam lenturan dan ricihan. Justeru itu, gabungan beban terhadap anggota-anggota tidak diberi perhatian yang serius. Namun demikian, andaian ini sudah tidak boleh diaplikasi lagi kerana isu kilasan kini merupakan perkara biasa dan memainkan peranan yang signifikan dalam struktur, contohnya rasuk spandrel. Rasuk spandrel atau dikenali juga sebagai rasuk-L, amat bergantung pada perimeter bangunan. Sebarang kegagalan pada rasuk spandrel boleh menjadi serius sehingga mencacatkan papak, sumbungan tiang-rasuk dan tebukan plat rata konkrit. Dengan mencampurkan gentian keluli sebagai bahan tambahan, ia boleh meningkatkan kekuatan kilasan rasuk spandrel di bawah beban gabungan dan prestasi struktur konkrit seperti beban maksimum, kemuluran dan rintangan retak. Gentian keluli boleh merintangi gabungan beban seperti rakap dan tetulang membujur, namun penyelidikan di dalam bidang ini masih samar dan terhad. Lebih-lebih lagi kepentingan menggunakan bertetulang gentian dalam struktur konkrit untuk diaplikasi dalam infrastruktur awam telah meningkat. Oleh yang demikian, pengetahuan sedia ada tentang konkrit gentian keluli sepaiknya digabungjalinkan dalam kod amalan reka bentuk. Eksperimen dijalankan untuk menilai perlakuan rasuk spandrel gentian yang diperkukuh dengan gentian keluli tertakluk pada gabungan kilasan, lenturan dan ricihan. Sejumlah 18 rasuk spandrel disediakan dan diuji dengan dua gabungan beban biasa i.e. kilasan tinggi terhadap nisbah lenturan dan kilasan rendah terhadap nisbah lenturan. Sampel rasuk dibahagikan kepada tiga kumpulan, iaitu rasuk konkrit biasa, spesimen dengan tetulang pengukuh memanjang, dan spesimen dengan tertulang dan rakap. Semua kes dikaji dengan pecahan isipadu gentian keluli 0%, 1%, dan 1.5%. Rasuk konkrit bertetulang gentian mempamerkan prestasi keseluruhan yang baik berbanding dengan rasuk kawalan tanpa gentian. Diperhatikan sumbangan utama daripada gentian keluli ke atas tingkah laku kilasan adalah terhadap keretakan konkrit. Penambahan gentian keluli adalah penting untuk rasuk tanpa tetulang keluli konvensional, penambahan ini terbukti mampu meningkatkan kapasiti semasa kilasan. Di samping itu, analisis berangka melalui kaedah elemen terhingga dilakukan terhadap data eksperimen untuk meramalkan tingkah laku struktur rasuk spandrel. Satu teknik baru diutara untuk mengambilkira kesan gentian keluli dalam elemen konkrit dan kesan titik lembut konkrit dalam mampatan dan tegangan. Kelakuan umum model unsur terhingga yang diwakili plot kilas-piuh dan plot bebanlenturan menunjukkan hubungan yang baik dengan data ujian daripada rasuk kawalan dan rasuk spandrel. Walau bagaimanapun, model unsur terhingga menunjukkan kekukuhan yang tinggi berbanding dengan data ujian dalam julat tidak linear untuk rasuk tanpa tetulang keluli. ________________________________________________________________________________________________________________________ Important concrete members are subjected to significant torsion accompanied by bending and shear. Until recent years, the design codes of reinforced concrete members assumed that the effects of torsion could be safely neglected due to high safety factors for shear and bending moment. Thus, members under combined loading were not treated with serious attention. However, this assumption cannot be applied anymore as torsion issues become common and play a significant role in structural members, such as spandrel beams. The spandrel beam, or the L-beam, lies on the perimeter of buildings. Any failure in spandrel beams can seriously damage slabs, beam-column connections, and punch concrete flat-plates. By incorporating steel fibers, it can enhance torsional behavior of spandrel beam under combined load in addition to the structural performance such as maximum load, ductility and cracking resistance. Steel fibers may provide resistance to combined loading as stirrups and longitudinal bars, this investigation is still scare and limited. Moreover, a worldwide interest in utilizing fiber reinforced concrete structures for civil infrastructure applications has increased. This study presents the advantage of using steel fiber concrete in strengthening spandrel beams under different reinforcement and loading cases. An experimental investigation was conducted to assess the behavior of steel fiber reinforced concrete spandrel beams subjected to combined torsion, bending, and shear. A total of 18 spandrel beams were prepared and tested with two common loading combinations i.e. high torque to bending ratio and low torque to bending ratio. All beams were divided into three groups, namely, plain concrete beams, specimens with longitudinal reinforcing bars and specimens with bars and stirrups. All cases were examined with 0%, 1%, and 1.5% steel fiber volume fractions. Fibrous concrete beams exhibited improved overall torsional performance with respect to the corresponding non-fibrous control beams. The main contribution of steel fibers on the torsional behavior is mainly observed after concrete cracking. The addition of steel fibers was essential to the beams without conventional steel reinforcement since fibers were the only reinforcement and proved capable to provide enhanced torsional moment capacities. Besides, a numerical analysis by finite element method was suggested against the experimental data to predict the structural behavior of spandrel beams. A new technique was presented to incorporate the effects of steel fibers within concrete element and the softening effect of concrete in compression and tension. The general behavior of the finite element model represented by the torque-twist plot and load-deflection plots show good agreement with the test data from the plain and fiber reinforced spandrel beam. However, the finite element models show higher stiffness than the test data in the nonlinear ranges for beams without steel reinforcement

Current status and future opportunities for serial crystallography at MAX IV Laboratory

Over the last decade, serial crystallography, a method to collect complete diffraction datasets from a large number of microcrystals delivered and exposed to an X-ray beam in random orientations at room temperature, has been successfully implemented at X-ray free-electron lasers and synchrotron radiation facility beamlines. This development relies on a growing variety of sample presentation methods, including different fixed target supports, injection methods using gas-dynamic virtual-nozzle injectors and high-viscosity extrusion injectors, and acoustic levitation of droplets, each with unique requirements. In comparison with X-ray free-electron lasers, increased beam time availability makes synchrotron facilities very attractive to perform serial synchrotron X-ray crystallography (SSX) experiments. Within this work, the possibilities to perform SSX at BioMAX, the first macromolecular crystallography beamline at MAX IV Laboratory in Lund, Sweden, are described, together with case studies from the SSX user program: an implementation of a high-viscosity extrusion injector to perform room temperature serial crystallography at BioMAX using two solid supports - silicon nitride membranes (Silson, UK) and XtalTool (Jena Bioscience, Germany). Future perspectives for the dedicated serial crystallography beamline MicroMAX at MAX IV Laboratory, which will provide parallel and intense micrometre-sized X-ray beams, are discussed

Detecting and staging podoconiosis cases in North West Cameroon: positive predictive value of clinical screening of patients by community health workers and researchers

Background The suitability of using clinical assessment to identify patients with podoconiosis in endemic communities has previously been demonstrated. In this study, we explored the feasibility and accuracy of using Community Health Implementers (CHIs) for the large scale clinical screening of the population for podoconiosis in North-west Cameroon. Methods Before a regional podoconiosis mapping, 193 CHIs and 50 health personnel selected from 6 health districts were trained in the clinical diagnosis of the disease. After training, CHIs undertook community screening for podoconiosis patients under health personnel supervision. Identified cases were later re-examined by a research team with experience in the clinical identification of podoconiosis. Results Cases were identified by CHIs with an overall positive predictive value (PPV) of 48.5% [34.1–70%]. They were more accurate in detecting advanced stages of the disease compared to early stages; OR 2.07, 95% CI = 1.15–3.73, p = 0.015 for all advanced stages). Accuracy of detecting cases showed statistically significant differences among health districts (χ2 = 25.30, p = 0.0001). Conclusion Podoconiosis being a stigmatized disease, the use of CHIs who are familiar to the community appears appropriate for identifying cases through clinical diagnosis. However, to improve their effectiveness and accuracy, more training, supervision and support are required. More emphasis must be given in identifying early clinical stages and in health districts with relatively lower PPVs

A hypomorphic Cbx3 allele causes prenatal growth restriction and perinatal energy homeostasis defects

Mammals have three HP1 protein isotypes HP1β (CBX1), HP1γ (CBX3) and HP1α (CBX5) that are encoded by the corresponding genes Cbx1, Cbx3 and Cbx5. Recent work has shown that reduction of CBX3 protein in homozygotes for a hypomorphic allele (Cbx3 hypo) causes a severe postnatal mortality with around 99% of the homozygotes dying before weaning. It is not known what the causes of the postnatal mortality are. Here we show that Cbx3 hypo/hypo conceptuses are significantly reduced in size and the placentas exhibit a haplo-insufficiency. Late gestation Cbx3 hypo/hypo placentas have reduced mRNA transcripts for genes involved in growth regulation, amino acid and glucose transport. Blood vessels within the Cbx3 hypo/hypo placental labyrinth are narrower than wild-type. Newborn Cbx3 hypo/hypo pups are hypoglycemic, the livers are depleted of glycogen reserves and there is almost complete loss of stored lipid in brown adipose tissue (BAT). There is a 10-fold reduction in expression of the BAT-specific Ucp1 gene, whose product is responsible for non-shivering themogenesis. We suggest that it is the small size of the Cbx3 hypo/hypo neonates, a likely consequence of placental growth and transport defects, combined with a possible inability to thermoregulate that causes the severe postnatal mortality

Urban resilience:two diverging interpretations

This paper uses two diverging interpretations of resilience to review and assess current UK policies for urban resilience. Both developed in scientific studies, the first interpretation is based on a mechanistic model of systems that can recover their original state after shocks, and the second is based on an evolutionary model enabling adaptation to disturbances. The literature review demonstrates that at present urban resilience is predominantly associated with the former. By contrast, only few policies and studies are inspired by the latter, although this is better suited to analyse dynamics of urban adaptation and manage cities accordingly. The contribution of this paper to an understanding of urban resilience is therefore twofold. First, an identification of the long-term consequences on the built environment associated with each model is provided, with the mechanical model ultimately hindering adaptation. Second, some approaches to generate effective responses to environmental and societal change are identified. Ultimately, this paper emphasises that the idea of a resilient city is fit for this age characterised by uncertainty, albeit it requires the recognition within planning practice that urban adaptation cannot be attained with current methodologies, and that much can be learned from theories on the resilience of ecosystems.

Alternative splicing of the maize Ac transposase transcript in transgenic sugar beet (Beta vulgaris L.)

The maize Activator/Dissociation (Ac/Ds) transposable element system was introduced into sugar beet. The autonomous Ac and non-autonomous Ds element excise from the T-DNA vector and integrate at novel positions in the sugar beet genome. Ac and Ds excisions generate footprints in the donor T-DNA that support the hairpin model for transposon excision. Two complete integration events into genomic sugar beet DNA were obtained by IPCR. Integration of Ac leads to an eight bp duplication, while integration of Ds in a homologue of a sugar beet flowering locus gene did not induce a duplication. The molecular structure of the target site indicates Ds integration into a double strand break. Analyses of transposase transcription using RT–PCR revealed low amounts of alternatively spliced mRNAs. The fourth intron of the transposase was found to be partially misspliced. Four different splice products were identified. In addition, the second and third exon were found to harbour two and three novel introns, respectively. These utilize each the same splice donor but several alternative splice acceptor sites. Using the SplicePredictor online tool, one of the two introns within exon two is predicted to be efficiently spliced in maize. Most interestingly, splicing of this intron together with the four major introns of Ac would generate a transposase that lacks the DNA binding domain and two of its three nuclear localization signals, but still harbours the dimerization domain

Sources of variation for indoor nitrogen dioxide in rural residences of Ethiopia

<p>Abstract</p> <p>Background</p> <p>Unprocessed biomass fuel is the primary source of indoor air pollution (IAP) in developing countries. The use of biomass fuel has been linked with acute respiratory infections. This study assesses sources of variations associated with the level of indoor nitrogen dioxide (NO₂).</p> <p>Materials and methods</p> <p>This study examines household factors affecting the level of indoor pollution by measuring NO₂. Repeated measurements of NO₂were made using a passive diffusive sampler. A <it>Saltzman </it>colorimetric method using a spectrometer calibrated at 540 nm was employed to analyze the mass of NO₂on the collection filter that was then subjected to a mass transfer equation to calculate the level of NO₂for the 24 hours of sampling duration. Structured questionnaire was used to collect data on fuel use characteristics. Data entry and cleaning was done in EPI INFO version 6.04, while data was analyzed using SPSS version 15.0. Analysis of variance, multiple linear regression and linear mixed model were used to isolate determining factors contributing to the variation of NO₂concentration.</p> <p>Results</p> <p>A total of 17,215 air samples were fully analyzed during the study period. Wood and crop were principal source of household energy. Biomass fuel characteristics were strongly related to indoor NO₂concentration in one-way analysis of variance. There was variation in repeated measurements of indoor NO₂over time. In a linear mixed model regression analysis, highland setting, wet season, cooking, use of fire events at least twice a day, frequency of cooked food items, and interaction between ecology and season were predictors of indoor NO₂concentration. The volume of the housing unit and the presence of kitchen showed little relevance in the level of NO₂concentration.</p> <p>Conclusion</p> <p>Agro-ecology, season, purpose of fire events, frequency of fire activities, frequency of cooking and physical conditions of housing are predictors of NO₂concentration. Improved kitchen conditions and ventilation are highly recommended.</p