5,320 research outputs found
A molecular diagnostic for tropical race 4 of the banana
This study analysed genomic variation of the translation elongation factor 1 (TEF-1) and the intergenic spacer region (IGS) of the nuclear ribosomal operon of Fusarium oxysporum f. sp. cubense (Foc) isolates, from different banana production areas, representing strains within the known races, comprising 20 vegetative compatibility groups
A Detection Method for Tropical Race 4 of the Banana Pathogen Fusarium oxysporum f. sp. cubense
Fusarium oxysporum f. sp. cubense (Foc) is the causal agent of Fusarium wilt, the devastating disease that ruined the ‘Gros Michel’ (AAA)-based banana production in the first half of the 20th century. The occurrence of a new variant in Southeast Asia that overcomes the resistance in Cavendish clones such as ‘Grand Naine’ (AAA) is a major concern to current banana production worldwide. The threat posed by this new variant, called tropical race 4 (TR4), may be overcome by the introduction of resistant cultivars. However, the identification of new resistant sources or breeding for resistance is a long-term effort. Currently, the only option to control the disease is to avoid or reduce the spread of the pathogen by eradication of infected plants and isolation of infested plantations. This requires sensitive and highly specific diagnostics that enable early detection of the pathogen. A two-locus database of DNA sequences, from over 800 different isolates from multiple formae speciales of F. oxysporum, was used to develop a molecular diagnostic tool that specifically detects isolates from the vegetative compatibility group (VCG) 01213, which encompasses the Foc TR4 genotype. This diagnostic tool was able to detect all Foc TR4 isolates tested, while none of the Foc isolates from 19 VCGs other than 01213 showed any reaction. In addition, the developed diagnostic tool was able to detect Foc TR4 when using DNA samples from different tissues of ‘Grand Naine’ plants inoculated with TR4 isolate
Quantitative Analysis of the Publishing Landscape in High-Energy Physics
World-wide collaboration in high-energy physics (HEP) is a tradition which
dates back several decades, with scientific publications mostly coauthored by
scientists from different countries. This coauthorship phenomenon makes it
difficult to identify precisely the ``share'' of each country in HEP scientific
production. One year's worth of HEP scientific articles published in
peer-reviewed journals is analysed and their authors are uniquely assigned to
countries. This method allows the first correct estimation on a ``pro rata''
basis of the share of HEP scientific publishing among several countries and
institutions. The results provide an interesting insight into the geographical
collaborative patterns of the HEP community. The HEP publishing landscape is
further analysed to provide information on the journals favoured by the HEP
community and on the geographical variation of their author bases. These
results provide quantitative input to the ongoing debate on the possible
transition of HEP publishing to an Open Access model.Comment: For a better on-screen viewing experience this paper can also be
obtained at:
http://doc.cern.ch/archive/electronic/cern/preprints/open/open-2006-065.pd
Heterogeneity of wheat endosperm proteolipids (CM proteins)
Proteins extracted with CHCl3-MeOH from wheat endosperm have been fractionated by Sephadex G-100 and the 15 000–20 000 MW range fraction, designated CM protein, has been examined by combined electrofocusing (pH range 5–8) and electrophoresis (pH 3.2) and the heterogeneity of the electrophoretic components has been ascertained. It has been shown by joint mapping and by sequential extraction that CM proteins are extracted by 70% EtOH but not by H2O, although they can be made water-soluble after dialysis against an acid buffer, pH 3.2, 3 M urea, without losing their solubility in CHCl3-MeOH mixtures. It is concluded that CM proteins fit the definition of a Folch—Lees proteolipid. The Triticum aestivum (genomes ABD) map can be reconstructed by mixing T. durum (AB) and Aegilops squarrosa (D). The low intragenomic variability of CM protein is confirmed
Constraining the period of the ringed secondary companion to the young star J1407 with photographic plates
Context. The 16 Myr old star 1SWASP J140747.93-394542.6 (V1400 Cen) underwent
a series of complex eclipses in May 2007, interpreted as the transit of a giant
Hill sphere filling debris ring system around a secondary companion, J1407b. No
other eclipses have since been detected, although other measurements have
constrained but not uniquely determined the orbital period of J1407b. Finding
another eclipse towards J1407 will help determine the orbital period of the
system, the geometry of the proposed ring system and enable planning of further
observations to characterize the material within these putative rings. Aims. We
carry out a search for other eclipses in photometric data of J1407 with the aim
of constraining the orbital period of J1407b. Methods. We present photometry
from archival photographic plates from the Harvard DASCH survey, and Bamberg
and Sonneberg Observatories, in order to place additional constraints on the
orbital period of J1407b by searching for other dimming and eclipse events.
Using a visual inspection of all 387 plates and a period-folding algorithm we
performed a search for other eclipses in these data sets. Results. We find no
other deep eclipses in the data spanning from 1890 to 1990, nor in recent
time-series photometry from 2012-2018. Conclusions. We rule out a large
fraction of putative orbital periods for J1407b from 5 to 20 years. These
limits are still marginally consistent with a large Hill sphere filling ring
system surrounding a brown dwarf companion in a bound elliptical orbit about
J1407. Issues with the stability of any rings combined with the lack of
detection of another eclipse, suggests that J1407b may not be bound to J1407.Comment: 8 pages, 3 tables, 4 figures, accepted for publication in A&A. LaTeX
files of the paper, scripts for the figures, and a minimal working FPA can be
found under https://github.com/robinmentel/Constraining-Period
Anomalous NMR Spin-Lattice Relaxation in SrB_{6} and Ca_{1-x}La_{x}B_{6}
We report the results of {11}B nuclear magnetic resonance (NMR) measurements
of SrB_{6} and Ca_{0.995}La_{0.05}B_{6} below room temperature. Although the
electrical resistivities of these two materials differ substantially, their
{11}B-NMR responses exhibit some strikingly common features. Both materials
exhibit ferromagnetic order, but their {11}B-NMR spectra reveal very small
hyperfine fields at the Boron sites. The spin lattice relaxation T_{1}^{-1}
varies considerably with external field but changes with temperature only below
a few K. We discuss these unusual results by considering various different
scenarios for the electronic structure of these materials.Comment: Accepted for publication in Phys. Rev. B Rapid communication, 4
pages, 3 figures. This manuscript replaces an earlier version and includes
some minor changes in the text and in Fig.
Enzymatic extraction of hydroxycinnamic acids from coffee pulp
Ferulic, caffeic, p-coumaric and chlorogenic acids are classified as hydroxycinnamic acids, presenting anticarcinogenic, anti-inflammatory and antioxidant properties. In this work, enzymatic extraction has been studied in order to extract high value-added products like hydroxycinnamic acids from coffee pulp. A commercial pectinase and enzyme extract produced by Rhizomucor pusillus strain 23aIV in solid-state fermentation using olive oil or coffee pulp (CP) as an inducer of the feruloyl esterase activity were evaluated separately and mixed. The total content (covalently linked and free) of ferulic, caffeic, p-coumaric and chlorogenic acids was 5276 mg per kg of coffee pulp. Distribution was as follows (in %): chlorogenic acid 58.7, caffeic acid 37.6, ferulic acid 2.1 and p-coumaric acid 1.5. Most of the hydroxycinnamic acids were covalently bound to the cell wall (in %): p-coumaric acid 97.2, caffeic acid 94.4, chlorogenic acid 76.9 and ferulic acid 73.4. The content of covalently linked hydroxycinnamic acid was used to calculate the enzyme extraction yield. The maximum carbon dioxide rate for the solid-state fermentation using olive oil as an inducer was higher and it was reached in a short cultivation time. Nevertheless, the feruloyl esterase (FAE) activity (units per mg of protein) obtained in the fermentation using CP as an inducer was 31.8 % higher in comparison with that obtained in the fermentation using olive oil as the inducer. To our knowledge, this is the first report indicating the composition of both esterified and free ferulic, caffeic, p-coumaric and chlorogenic acids in coffee pulp. The highest yield of extraction of hydroxycinnamic acids was obtained by mixing the produced enzyme extract using coffee pulp as an inducer and a commercial pectinase. Extraction yields were as follows (in %): chlorogenic acid 54.4, ferulic acid 19.8, p-coumaric acid 7.2 and caffeic acid 2.3. An important increase in the added value of coffee pulp was mainly due to the extraction of chlorogenic acid
Low-fat dairy consumption and reduced risk of hypertension: the Seguimiento Universidad de Navarra (SUN) cohort
BACKGROUND:
Some observational studies have shown a beneficial effect of dairy consumption on blood pressure, especially in overweight and relatively young (<40 y) persons. However, no results from prospective studies conducted in a free-living population exist that show this association in middle-aged adults.
OBJECTIVE:
The aim of the present study was to assess whether total, low-fat, and whole-fat dairy consumption was associated prospectively with the risk of hypertension.
DESIGN:
This was a prospective study conducted in 5880 university graduates in Spain, aged >20 y in 2000 (mean age: 37 y), free of hypertension and cardiovascular disease at baseline, and followed-up with mailed questionnaires for a median of 27 mo. Dairy consumption was assessed with a previously validated semiquantitative food-frequency questionnaire.
RESULTS:
One hundred eighty new cases of hypertension were identified. The hazard ratio of hypertension between extreme quintiles of low-fat dairy product consumption was 0.46 (95% CI: 0.26, 0.84; P for trend = 0.02) after adjustment for the main known risk factors for hypertension and several dietary factors. No significant association between whole-fat dairy products or total calcium intake and incident hypertension was seen.
CONCLUSION:
In this Mediterranean cohort, low-fat dairy consumption, but not whole-fat dairy consumption, was associated with a lower risk of incident hypertension
Nigrosine staining of wheat endosperm proteolipid patterns on starch gels
We have previously characterized a group of proteolipids from wheat endosperm, designated CM proteins, which are soluble in chloroformmethanol (2:1, v/v) and have a molecular weight lower than 25,000 daltons (1-3). These have been also studied by Redman and Ewart (4). The CM proteins are suitably fractionated into several components by starch gel electrophoresis at pH 3.2 (1). A sensitive staining procedure was required in connection with genetic studies of these proteins because phenotypes had to be ascertained in small endosperm fractions dissected without impairing normal germination and plant development. We report here on Nigrosine staining conditions for CM proteins under which high sensitivity and selectivity are achieve
Laser probing of Cooper-paired trapped atoms
We consider a gas of trapped Cooper-paired fermionic atoms which are
manipulated by laser light. The laser induces a transition from an internal
state with large negative scattering length (superfluid) to one with weaker
interactions (normal gas). We show that the process can be used to detect the
presence of the superconducting order parameter. Also, we propose a direct way
of measuring the size of the gap in the trap. The efficiency and feasibility of
this probing method is investigated in detail in different physical situations.Comment: 9 pages, 8 figure
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