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X.-M. Xu,
D. W. Parry,
P. Nicholson,
M. A. Thomsett, D. Simpson,
S. G. Edwards,
B. M. Cooke,
F. M. Doohan,
S. Monaghan,
A. Moretti,
G. Tocco,
G. Mule,
L. Hornok,
E. Béki,
J. Tatnell,
A. Ritieni
[show abstract]
[hide abstract]
ABSTRACT: Within-field variability in the Fusarium head blight (FHB) and its associated mycotoxins was studied in four European countries.
At each of 14 sites, each FHB pathogen and associated mycotoxins were quantified in 16 quadrat samples at harvest. Overall,
the incidence of quadrat samples with detectable and quantifiable pathogen DNA was significantly lower in the grain than in
the corresponding chaff. Deoxynivalenol (DON) was the most frequently detected toxin in the samples and its accumulation was
most strongly associated with the presence of Fusarium graminearum. Nivalenol (NIV) accumulation was significantly associated only with the presence of F. culmorum. Zearalenone (ZON) accumulation was strongly associated with the presence of all three pathogens (F. graminearum, F. culmorum and F. poae). The levels of both DON and ZON concentrations were positively related to the amount of F. graminearum DNA in the grain or in the chaff. The presence/absence of FHB pathogens within a single quadrat appeared to be independent
of each other. The presence of a particular FHB pathogen and the amount of its DNA, as well as the associated mycotoxin(s),
varied greatly among samples at each site. This study demonstrated the large extent of within-field variability of FHB and
its associated mycotoxins, and the importance of representative sampling in FHB studies.
European Journal of Plant Pathology 04/2012; 120(1):21-34. · 1.41 Impact Factor
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X-M Xu,
P Nicholson,
M A Thomsett, D Simpson,
B M Cooke,
F M Doohan,
J Brennan,
S Monaghan,
A Moretti,
G Mule,
L Hornok,
E Beki,
J Tatnell,
A Ritieni,
S G Edwards
[show abstract]
[hide abstract]
ABSTRACT: ABSTRACT Over 4 years, the environmental conditions and the causal agents of Fusarium head blight (FHB) disease of wheat were determined in field sites in four European countries: Hungary, Ireland, Italy, and the United Kingdom. Polymerase chain reaction-based methods were used to detect each species causing FHB and quantify its DNA (as a measurement of fungal abundance) in the samples. Canonical correspondence analysis (CCA) was used to determine the relationship of the incidence and abundance of each species with weather variables. CCA indicated that little variability in the species prevalence data was explained by the weather variables. In contrast, a greater proportion of variability in abundance data was accounted for by the weather variables. Most samples contained two or more species and statistical analysis suggested that these species tended to coexist at field sites. CCA also indicated that there were differences in the relationships of the prevalence and abundance of the six FHB species with environmental variables. Fusarium poae was associated with relatively drier and warmer conditions, whereas F. graminearum was associated with warmer/humid conditions. F. avenaceum and F. culmorum were both associated with niches of cooler/wet/humid conditions. Two Microdochium species were associated with regions of relatively cool/moderate temperatures and frequent rainfalls of short duration. The results also suggested that environmental conditions differentially affect the infection and colonization processes, and the comparative abundance of the six species.
Phytopathology 02/2008; 98(1):69-78. · 2.80 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Susceptibility of eight commercial European wheat cultivars to fusarium head blight (FHB) disease caused by Fusarium graminearum, F. culmorum, F. poae and Microdochium nivale (formerly known as Fusarium nivale) was compared under controlled environment conditions (16°C). FHB did not differentially affect cultivars in terms of disease symptoms, fungal DNA content of grain or deoxynivalenol (DON) contamination. However, the Hungarian-grown cultivars GK-Othalom and Fatima 2 (of Romanian origin) showed greater type V resistance (yield tolerance) to FHB than did the others. Also, nivalenol was produced by F. poae in these two cultivars and in Italian cultivar Norba, but not in other cultivars. Overall, significant relationships were found between the FHB and seedling blight resistance in vitro of these eight cultivars, but such relationships were generally highly dependent on cultivar, and therefore it is likely that the in vitro test is at best measuring components of FHB resistance and/or genotype-specific resistance components.
Plant Pathology 10/2006; 56(1):55 - 64. · 2.13 Impact Factor
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R E Hartle,
E C Sittler,
F M Neubauer,
R E Johnson,
H T Smith,
F Crary,
D J Mccomas,
D T Young,
A J Coates, D Simpson,
S Bolton,
D Reisenfeld,
K Szego,
J J Berthelier,
A Rymer,
J Vilppola,
J T Steinberg,
N Andre
[show abstract]
[hide abstract]
ABSTRACT: The Cassini plasma spectrometer (CAPS) instrument made measurements of Titan's plasma environment when the Cassini Orbiter flew through the moon's plasma wake October 26, 2004 (flyby TA). Initial CAPS ion and electron measurements from this encounter will be compared with measurements made by the Voyager 1 plasma science instrument (PLS). The comparisons will be used to evaluate previous interpretations and predictions of the Titan plasma environment that have been made using PLS measurements. The plasma wake trajectories of flyby TA and Voyager 1 are similar because they occurred when Titan was near Saturn's local noon. These similarities make possible direct, meaningful comparisons between the various plasma wake measurements. They lead to the following: (A) The light and heavy ions, H + and N + /O + , were observed by PLS in Saturn's magnetosphere in the vicinity of Titan while the higher mass resolution of CAPS yielded H + and H 2 + as the light constituents and O + /CH 4 + as the heavy ions. (B) Finite gyroradius effects were apparent in PLS and CAPS measurements of ambient O + ions as a result of their absorption by Titan's extended atmosphere. (C) The principal pickup ions inferred from both PLS and CAPS measurements are H + , H 2 + , N + , CH 4 + and N 2 + . (D) The inference that heavy pickup ions, observed by PLS, were in narrow beam distributions was empirically established by the CAPS measurements. (E) Slowing down of the ambient plasma due to pickup ion mass loading was observed by both instruments on the anti-Saturn side of Titan. (F) Strong mass loading just outside the ionotail by a heavy ion such as N 2 + is apparent in PLS and CAPS measurements. (G) Except for the expected differences due to the differing trajectories, the magnitudes and structures of the electron densities and temperatures observed by both instruments are similar. The high-energy electron bite-out observed by PLS in the magnetotail is consistent with that observed by CAPS.
Planetary and Space Science 01/2006; 54:1211-1224. · 2.22 Impact Factor
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E. C. Sittler,
N. Andre,
M. Blanc,
A. Coates,
R. E. Johnson,
R. A. Baragiola,
R. E. Hartle,
D. Reisenfeld,
M. Thomsen,
D. Chornay,
M. Shappirio, D. Simpson,
M. Dougherty,
F. Crary,
D. J. McComas,
D. T. Young
[show abstract]
[hide abstract]
ABSTRACT: We will present fluid parameters derived from Cassini Plasma
Spectrometer (CAPS) observations of ions and electrons within Saturn's
inner magnetosphere as presented in Sittler et al. [2005]. From these
parameters one can estimate the ion total flux tube content per L shell,
NL\^2, for protons and water group ions as a function of radial distance
or L shell. When we do this, the calculation shows that the dominant ion
production is confined within the L shells of Dione and Rhea and not
within the vicinity of Enceladus' L shell, L 4, where most of the
neutral oxygen and OH have been observed by Cassini (Esposito et al.,
2005) and HST (Shemansky et al., 1993; Richardson et al., 1998),
respectively. Within the inner most regions of the magnetosphere, the
plasma is very cold and ionization rates due to electron impact are
small so that photoionization may be the only important mechanism for
ion production in the vicinity of Enceladus' L shell. We would argue
that the primary sink for the neutral clouds at L 4 is charge exchange,
which just replaces one ion with another, and therefore does not
contribute to ion production. However, it can contribute to
compositional changes in the plasma with radial distance and/or
redistribution of the plasma in energy space. We will discuss these
issues and how they relate to the sources of neutrals within Saturn's
inner magnetosphere.
1. Sittler et al., GRL, 32, L14S07, 2005. 2. Esposito et al., Science,
307, 1251, 2005. 3. Shemansky et al., Nature, 363, 329, 1993. 4.
Richardson et al., J. Geophys. Res., 103, 20245, 1998.
07/2005; 37:758.
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Xiangming Xu,
D. W. Parry,
P. Nicholson,
M. A. Thomsett, D. Simpson,
S. G. Edwards,
B. M. Cooke,
F. M. Doohan,
J. M. Brennan,
A. Moretti,
G. Tocco,
G. Mule,
L. Hornok,
G. Giczey,
J. Tatnell
[show abstract]
[hide abstract]
ABSTRACT: Two years of field sampling aimed to establish the predominance and association among the fungal pathogens causing Fusarium ear blight (FEB) in four European countries (Hungary, Ireland, Italy and the UK). A PCR-based method was used to detect four Fusarium species and two varieties of Microdochium nivale present in the samples. The prevalence of FEB pathogens differed significantly between countries. Overall, all pathogens were commonly detected in Ireland and to a lesser extent in the UK. In contrast, only two species, F. graminearum and F. poae, were regularly detected in Italy and Hungary. Fusarium culmorum was rarely detected except in Ireland. Log-linear models were used to determine whether there is the independence of the six FEB pathogens at each sampling site. Significant two-pathogen interactions were frequently observed, particularly in harvest samples; all these significant two-pathogen interactions were of the synergistic type, except between F. poae and F. culmorum, and were generally consistent over the 2 years and four countries. Fusarium graminearum and F. poae were least frequently involved in two pathogen interactions but were involved in most of the nine significant three-pathogen interactions. However, only the interaction between F. graminearum, F. avenaceum and F. poae was significant in both years. Potential implications of the present results in FEB management are discussed.
European Journal of Plant Pathology 05/2005; 112(2):143-154. · 1.41 Impact Factor
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Fusarium head scab: Global status and future prospects. 01/1997;
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P Nicholson,
F Doohan,
D Joyce,
HN Rezanoor, D Simpson,
PH Smith,
A Turner,
G Weston,
HJ Dubin,
L Gilchrist,
others
Fusarium head scab: Global status and future prospects. 01/1997;
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Cereal Research Communications 01/1997; 25:477-482. · 0.39 Impact Factor
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Cereal Research Communications 01/1997; 25:477-482. · 0.39 Impact Factor
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Xiangming Xu,
P. Nicholson,
M. A. Thomsett, D. Simpson,
B. M. Cooke,
F. M. Doohan,
J. Brennan,
S. Monaghan,
A. Moretti,
G. Mule,
L. Homok,
E. Beki,
J. Tatnell,
A. Ritieni,
S. G. Edwards
[show abstract]
[hide abstract]
ABSTRACT: Over 4 years, the environmental conditions and the causal agents of Fusarium head blight (FHB) disease of wheat were determined in field sites in four European countries: Hungary, Ireland, Italy, and the United Kingdom. Polymerase chain reaction-based methods were used to detect each species causing FHB and quantify its DNA (as a measurement of fungal abundance) in the samples. Canonical correspondence analysis (CCA) was used to determine the relationship of the incidence and abundance of each species with weather variables. CCA indicated that little variability in the species prevalence data was explained by the weather variables. In contrast, a greater proportion of variability in abundance data was accounted for by the weather variables. Most samples contained two or more species and statistical analysis suggested that these species tended to coexist at field sites. CCA also indicated that there were differences in the relationships of the prevalence and abundance of the six FHB species with environmental variables. Fusarium poae was associated with relatively drier and warmer conditions, whereas F. graminearum was associated with warmer/humid conditions. F. avenaceum and F. culmorum were both associated with niches of cooler/wet/humid conditions. Two Microdochium species were associated with regions of relatively cool/moderate temperatures and frequent rainfalls of short duration. The results also suggested that environmental conditions differentially affect the infection and colonization processes, and the comparative abundance of the six species.
Phytopathology. 98(1):69-78.
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E.C. Sittler,
N. Andre,
M. Blanc,
M. Burger,
R.E. Johnson,
A. Coates,
A. Rymer,
D. Reisenfeld,
M.F. Thomsen,
A. Persoon,
M. Dougherty,
H.T. Smith,
R.A. Baragiola,
R.E. Hartle,
D. Chornay,
M.D. Shappirio, D. Simpson,
D.J. McComas,
D.T. Young
[show abstract]
[hide abstract]
ABSTRACT: Using ion–electron fluid parameters derived from Cassini Plasma Spectrometer (CAPS) observations within Saturn's inner magnetosphere as presented in Sittler et al. [2006a. Cassini observations of Saturn's inner plasmasphere: Saturn orbit insertion results. Planet. Space Sci., 54, 1197–1210], one can estimate the ion total flux tube content, NIONL2, for protons, H+, and water group ions, W+, as a function of radial distance or dipole L shell. In Sittler et al. [2005. Preliminary results on Saturn's inner plasmasphere as observed by Cassini: comparison with Voyager. Geophys. Res. Lett. 32(14), L14S04), it was shown that protons and water group ions dominated the plasmasphere composition. Using the ion–electron fluid parameters as boundary condition for each L shell traversed by the Cassini spacecraft, we self-consistently solve for the ambipolar electric field and the ion distribution along each of those field lines. Temperature anisotropies from Voyager plasma observations are used with (T⊥/T∥)W+∼5 and (T⊥/T∥)H+∼2. The radio and plasma wave science (RPWS) electron density observations from previous publications are used to indirectly confirm usage of the above temperature anisotropies for water group ions and protons. In the case of electrons we assume they are isotropic due to their short scattering time scales. When the above is done, our calculation show NIONL2 for H+ and W+ peaking near Dione's L shell with values similar to that found from Voyager plasma observations. We are able to show that water molecules are the dominant source of ions within Saturn's inner magnetosphere. We estimate the ion production rate SION∼1027 ions/s as function of dipole L using NH+, NW+ and the time scale for ion loss due to radial transport τD and ion–electron recombination τREC. The ion production shows localized peaks near the L shells of Tethys, Dione and Rhea, but not Enceladus. We then estimate the neutral production rate, SW, from our ion production rate, SION, and the time scale for loss of neutrals by ionization, τION, and charge exchange, τCH. The estimated source rate for water molecules shows a pronounced peak near Enceladus’ L shell L∼4, with a value SW∼2×1028 mol/s.
Planetary and Space Science.
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[show abstract]
[hide abstract]
ABSTRACT: Following the infectious salmon anaemia outbreak in Scotland in May 1998, there was a strong interest in evaluating alternatives to sodium hypochlorite for the disinfection of fish farming equipment. Because no information was available, a programme of laboratory testing of several disinfectants against cultured ISA virus was commenced.Cultured ISA virus was grown on permissive cell lines and a stock stored at −80 °C. Disinfectant assays were set up using a procedure similar to that recommended for viruses of higher animals under the UK Animal Health Act (1981). Dilutions of disinfectant at the manufacturer's recommended dose were made in W.H.O. hard water at 4 °C and ISA virus was added for 5 min exposure. Neutralizer was added to inactivate the disinfectant and the samples were dialysed. Residual and starting virus was titrated on SHK-1 cells using a focus-forming assay (FFA). Briefly, cell layers were fixed with acetone, incubated with diluted ISA virus monoclonal antibody 3H6F8, then incubated with diluted goat anti-mouse Ig phosphatase conjugate and bound conjugate visualised with fast red TR/napthol-AS MX stain. Stained foci were counted.Virucidal reductions in titre of >4 log10 focus forming units (ffu)/ml were obtained using the six types of virucide. A virus titre reduction of log10 4 is the approved disinfectant inactivation standard in the UK according to the current DEFRA guideline protocol for disinfectant testing for veterinary viruses. According to this definition six branded disinfectants were found effective for the disinfection of fish farming equipment or fish ova at the manufacturer's recommended dose for 5 min duration.
Aquaculture.
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A Scalone,
R De Luna,
G Oliva,
L Baldi,
G Satta,
G Vesco,
W Mignone,
C Turilli,
R.R Mondesire, D Simpson,
A.R Donoghue,
G.R Frank,
L Gradoni
[show abstract]
[hide abstract]
ABSTRACT: Canine infections with Leishmania infantum are important as a cause of serious disease in the dog and as a reservoir for human visceral leishmaniasis (VL). Accurate diagnosis of canine infections is essential to the veterinary community and for VL surveillance programs. A standardized ELISA using a purified recombinant antigen (rK39) specific to VL was compared to the immunofluorescent antibody test (IFAT) as the standard. The ELISA was developed, optimized and evaluated using sera from 6368 dogs. The standardized ELISA and IFAT results were highly concordant. The timing and pattern of ELISA and IFAT seroconversion in dogs followed prospectively after natural infections were very similar. Antibodies reacting with rK39 were more common in asymptomatic canine infections than reported for subclinical human VL. The rK39 ELISA is a relatively simple and rapid assay for assessing the infection status of dogs, and is an alternative to IFAT, especially when screening large numbers of samples.
Veterinary Parasitology.
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[show abstract]
[hide abstract]
ABSTRACT: Human lymphoblast mutants at the X-linked hprt locus have been examined by Southern blot, Northern blot and DNA sequence analysis. A previous study had shown that approximately a third of the spontaneously-arising mutants and half those induced by formaldehyde showed no alteration in restriction fragment pattern and thus were classified as point mutationns. In this report, Northern blot analysis was used to show that these point mutants fall into 4 categories; normal size and amount of RNA, normal size but reduced amounts, reduced size of RNA or no RNA.Sequence analyses of cDNAs prepared from hprt mRNAs were performed on 1 spontaneous and 7 formaldehyde-induced mutants with normal Northern blots. The spontaneous mutant was caued by an AT→GC transition. 6 of the formaldehyde-induced mutants were base substitutions, all of which occurred at AT base-pairs. There was an apparent hot spot, in that independent mutants were AT→CG transversions at one specific site. The remaining mutant had lost exon 8.
Mutation Research Letters.
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R.E. Hartle,
E.C. Sittler,
F.M. Neubauer,
R.E. Johnson,
H.T. Smith,
F. Crary,
D.J. McComas,
D.T. Young,
A.J. Coates, D. Simpson,
S. Bolton,
D. Reisenfeld,
K. Szego,
J.J. Berthelier,
A. Rymer,
J. Vilppola,
J.T. Steinberg,
N. Andre
[show abstract]
[hide abstract]
ABSTRACT: The Cassini plasma spectrometer (CAPS) instrument made measurements of Titan's plasma environment when the Cassini Orbiter flew through the moon's plasma wake October 26, 2004 (flyby TA). Initial CAPS ion and electron measurements from this encounter will be compared with measurements made by the Voyager 1 plasma science instrument (PLS). The comparisons will be used to evaluate previous interpretations and predictions of the Titan plasma environment that have been made using PLS measurements. The plasma wake trajectories of flyby TA and Voyager 1 are similar because they occurred when Titan was near Saturn's local noon. These similarities make possible direct, meaningful comparisons between the various plasma wake measurements. They lead to the following: (A) The light and heavy ions, H+and N+/O+, were observed by PLS in Saturn's magnetosphere in the vicinity of Titan while the higher mass resolution of CAPS yielded H+ and H2+as the light constituents and O+/CH4+ as the heavy ions. (B) Finite gyroradius effects were apparent in PLS and CAPS measurements of ambient O+ ions as a result of their absorption by Titan's extended atmosphere. (C) The principal pickup ions inferred from both PLS and CAPS measurements are H+, H2+, N+, CH4+ and N2+. (D) The inference that heavy pickup ions, observed by PLS, were in narrow beam distributions was empirically established by the CAPS measurements. (E) Slowing down of the ambient plasma due to pickup ion mass loading was observed by both instruments on the anti-Saturn side of Titan. (F) Strong mass loading just outside the ionotail by a heavy ion such as N2+ is apparent in PLS and CAPS measurements. (G) Except for the expected differences due to the differing trajectories, the magnitudes and structures of the electron densities and temperatures observed by both instruments are similar. The high-energy electron bite-out observed by PLS in the magnetotail is consistent with that observed by CAPS.
Planetary and Space Science.
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[show abstract]
[hide abstract]
ABSTRACT: Right and left hemisphere visual evoked responses from central locations were collected from 10 normal right-handed women in the follicular and luteal phases of their menstrual cycle. Subjects were tested sober and under 3 doses of ethanol. Amplitude and latency characteristics of the N120 and P180 components for each hemispheres were determined. Asymmetry between hemispheres for the various measurements was then calculated. the follicular phase was associated with a significant P180 latency asymmetry under baseline or placebo conditions. Virtually no asymmetry for P180 latency was present in the luteal phase. Ethanol eliminated the follicular P180 latency asymmetry and reduced the amplitude of both N120 and P180 in a dose-related fashion. The latency of the N120 component was prolonged by ethanol in a similar fashion. Interactions between menstrual cycle and ethanol occurred for both amplitude and latency of P180, but only for the response from the left hemisphere. These occurred at low or moderate doses of ethanol and illustrate the need to consider both the biphasic effects of low doses of ethanol and the possibility of lateralization of these effects to one cerebral hemisphere.RésuméLes réposes évoquées visuelles des hémisphères droit et gauche au niveau des localisations centrales ont été obtenues chez 10 femmes normales droitières aux phases folliculinique et lutéïnique de leur cycle menstruel. Les sujets ont été testés en état de sobriété et sous 3 doses d'éthanol. Les caractéristiques d'amplitude et de latence des composantes N120 et P180 ont été mesurées pour chaque hémisphère. L'asymétrie entre les hémisphères a été ensuite calculée pour les différentes mesures. A la phase folliculinique on observe une asymétrie de latence significative du P180 dans des conditions standard et sous placebo. Virtuellement aucune asymétrie de latence du P180 n'est observée à la phase lutéïnique. L'éthanol supprime l'asymétrie de latence du P180 à la période folliculinique et diminue l'amplitude de N120 et P120 d'une manière liée à la dose. La latence de la composante N120 est prolongée par l'éthanol de façon similaire. Des interactions entre le cycle menstruel et l'éthanol surviennent à la fois pour l'amplitude et la latence du P180 mais seulement pour la réponse de l'hémisphère gauche. Celles-ci se produisent pour des doses faibles ou modérées d'éthanol et illustrent le besoin de prendre en considération aussi bien les effets biphasiques des petites doses d'éthanol que la possibilité de latéralisation de ces effets à un hémisphère cérébral.
Electroencephalography and Clinical Neurophysiology.
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X. M. Xu,
D. W. Parry,
P. Nicholson,
M. A. Thomsett, D. Simpson,
S. G. Edwards,
B. M. Cooke,
F. Doohan,
A. van Maanen,
A. Moretti,
G. Tocco,
G. Mule,
L. Hornok,
G. Giczey,
J. Tatnell,
A. Ritieni
[show abstract]
[hide abstract]
ABSTRACT: This paper reports the results of field sampling in 2001 aimed at establishing the relationship between the incidence of Fusarium ear blight (FEB; Fusarium culmorum, F. graminearum [ Gibberella zeae], Microdochium nivale [ Monographella nivalis], F. avenaceum [ Gibberella avenacea] and F. poae), the biomass (DNA) of the associated Fusarium species and the accumulation of related mycotoxins in wheat grains from UK, Irish Republic, Italy and Hungary. The prevalence of Fusarium species as well as the FEB incidence and the resulting mycotoxins varied with the country. For almost all of the sites where mycotoxins (deoxynivalenol [vomitoxin], nivalenol and zearalenone) were detected, the levels were very low and negligible. Deoxynivalenol was the most common toxin detected, while beauvericin, fusaproliferin and enniatins were not detected in any samples. There appears to be no quantitative relationship between the amount of Fusarium DNA and the concentration of mycotoxins in the grain.
Aspects of Applied Biology.
