bluuebunny/crossref_metadata_2025 huggingface dataset:
The spatiotemporal variability of lightning activity in the Himalayan foothills
Authors: Ramesh Kumar P. , Kamra A. K.
Published: November 2012

The spatiotemporal variability of lightning activity in the region of the Himalayan foothills and perpendicular to it has been examined from about 16‐year data from the TRMM satellite. The monthly mean flash rate for the period from 1995 to 2010 is maximum in an arc‐shaped area along the Himalayan foothills and decreases on both the north and south sides of it. Seasonal variation of mean flash rate changes from annual to semiannual as the area shifts from north to south of the Himalayas and the average elevation of area decreases from 5043 m to 219 m. Further, the mean flash rate is higher in the afternoon and lower from midnight to midday. In the Himalayan foothills, the mean flash rate is highly correlated with surface temperature but poorly correlated with the convective available potential energy (CAPE). Lightning flashes occurring in the high‐altitude regions, as compared to the low‐altitude regions, are less energetic but more frequent. The empirical orthogonal function (EOF) analysis has been applied to three different data sets of flash rates, surface temperature, and CAPE in the 18.75°N–36°N and 68.75°E–93.75°E area for the period of 1995–2010 to examine the relationship between these parameters in terms of seasonal variations in this region. Spatial distributions of the first mode of flash rate and CAPE and of the first and second modes of surface temperature indicate that the Himalayan range exerts a strong effect on the flash rate distributions in this region. However, while the first mode of spatial distribution of flash rate is in phase with the surface temperature, the time series of CAPE and flash rate are out of phase for the first mode but in phase for their second modes. This result amounts to that 65% of variability in CAPE cannot be associated with the changes in flash rate but 22% of CAPE variability can be associated with changes in flash rate. Higher values of flash rate in the Himalayan foothills are suggested to be associated with the diurnal cycle of a mountain breeze front. Relative roles of convective activities due to solar heating of land, orography of the region, and the synoptic convective systems embedded in monsoon current are discussed to explain the results.
Implementation of the Quasi‐equilibrium Tropical Circulation Model 2 (QTCM2): Global simulations and convection sensitivity to free tropospheric moisture
Authors: Lintner Benjamin R. , Bellon Gilles , Sobel Adam H. , Kim Daehyun , Neelin J. David
Published: November 2012

The implementation of the Quasi‐equilibrium Tropical Circulation Model 2 (QTCM2), an intermediate level complexity model, is described. Following the approach of Sobel and Neelin (2006), an explicit, prognostic atmospheric boundary layer (ABL) of fixed depth is added to a free troposphere (FT) containing one baroclinic and one barotropic mode. QTCM2 is shown to simulate reasonable climatologies of temperature, moisture, winds, and precipitation, albeit with only modest improvements relative to the predecessor single vertical mode version, QTCM1. The addition of an ABL increases the sharpness of horizontal precipitation and moisture gradients, and the separation of the moisture profile into ABL and FT components allows investigation into the separate roles of these two components in modulating deep convection. Model sensitivity to various convection parameters is explored, with contrasting precipitation responses often seen within the cores of convecting regions and along their margins.
Seepage flow with free surface in fracture networks
Authors: Jiang Qinghui , Yao Chi , Ye Zuyang , Zhou Chuangbing
Published: November 2012

Key Points

PDE formulation of a free‐surface seepage problem on the entire fracture network

Variational inequality (VI) formulation for unconfined seepage problem

The numerical solution procedure based on the discrete VI formulation
Assessing preferential flow by simultaneously injecting nanoparticle and chemical tracers
Authors: Subramanian S. K. , Li Yan , Cathles L. M.
Published: November 2012

Key Points

Diagnose short circuited flow

Use of nanoparticles as tracers

Diffusion into stagnant zones
Intravenous HOE-642 Reduces Brain Edema and Na Uptake in the Rat Permanent Middle Cerebral Artery Occlusion Model of Stroke: Evidence for Participation of the Blood–Brain Barrier Na/H Exchanger
Authors: O'Donnell Martha E , Chen Yi-Je , Lam Tina I , Taylor Kelleen C , Walton Jeffrey H , Anderson Steven E
Published: November 2012

Cerebral edema forms in the early hours of ischemic stroke by processes involving increased transport of Na and Cl from blood into brain across an intact blood–brain barrier (BBB). Our previous studies provided evidence that the BBB Na–K–Cl cotransporter is stimulated by the ischemic factors hypoxia, aglycemia, and arginine vasopressin (AVP), and that inhibition of the cotransporter by intravenous bumetanide greatly reduces edema and infarct in rats subjected to permanent middle cerebral artery occlusion (pMCAO). More recently, we showed that BBB Na/H exchanger activity is also stimulated by hypoxia, aglycemia, and AVP. The present study was conducted to further investigate the possibility that a BBB Na/H exchanger also participates in edema formation during ischemic stroke. Sprague-Dawley rats were subjected to pMCAO and then brain edema and Na content assessed by magnetic resonance imaging diffusion-weighed imaging and magnetic resonance spectroscopy Na spectroscopy, respectively, for up to 210 minutes. We found that intravenous administration of the specific Na/H exchange inhibitor HOE-642 significantly decreased brain Na uptake and reduced cerebral edema, brain swelling, and infarct volume. These findings support the hypothesis that edema formation and brain Na uptake during the early hours of cerebral ischemia involve BBB Na/H exchanger activity as well as Na–K–Cl cotransporter activity.
In Vivo Imaging of Dopaminergic Neurotransmission after Transient Focal Ischemia in Rats
Authors: Martín Abraham , Gómez-Vallejo Vanessa , Sebastián Eneko San , Padró Daniel , Markuerkiaga Irati , Llarena Irantzu , Llop Jordi
Published: November 2012

The precise biologic mechanisms involved in functional recovery processes in response to stroke such as dopaminergic neurotransmission are still largely unknown. For this purpose, we performed in parallel in vivo magnetic resonance imaging and positron emission tomography (PET) with [18F]fluorodeoxyglucose ([18F]FDG) and [11C]raclopride at 1, 3, 7, 14, 21, and 28 days after middle cerebral artery occlusion in rats. In the ischemic territory, PET [18F]FDG showed a initial decrease in cerebral metabolism followed by a time-dependent recovery to quasi-normal values at day 14 after ischemia. The PET with [11C]raclopride, a ligand for dopamine D2 receptor, showed a sustained binding during the first week after ischemia that declined dramatically from day 14 to day 28. Interestingly, a slight increase in [11C]raclopride binding was observed at days 1 to 3 followed by the uppermost binding at day 7 in the contralateral territory. Likewise, in vitro autoradiography using [3H]raclopride confirmed these in vivo results. Finally, the neurologic test showed major neurologic impairment at day 1 followed by a recovery of the cerebral function at day 28 after cerebral ischemia. Taken together, these results might suggest that dopamine D2 receptor changes in the contralateral hemisphere could have a key role in functional recovery after cerebral ischemia.
Hyperforin Attenuates Brain Damage Induced by Transient Middle Cerebral Artery Occlusion (MCAO) in Rats via Inhibition of TRPC6 Channels Degradation
Authors: Lin Yun , Zhang Jian-Cheng , Fu Jun , Chen Fang , Wang Jie , Wu Zhi-Lin , Yuan Shi-Ying
Published: November 2012

Hyperforin, a lipophilic constituent of medicinal herb St John's wort, has been identified as the main active ingredient of St John's wort extract for antidepressant action by experimental and clinical studies. Hyperforin is currently known to activate transient receptor potential canonical (subtype) 6 (TRPC6) channel, increase the phosphorylated CREB (p-CREB), and has N-methyl-D-aspartate receptor-antagonistic effect that convert potential neuroprotective effects in vitro. However, the protective effects of hyperforin on ischemic stroke in vivo remain controversial and its neuroprotective mechanisms are still unclear. This study was designed to examine the effects of intracerebroventricular (ICV) injection of hyperforin on transient focal cerebral ischemia in rats. Hyperforin, when applied immediately after middle cerebral artery occlusion (MCAO) onset, significantly reduced infarct volumes and apoptotic cells, and also increased neurologic scores at 24 hours after reperfusion accompanied by elevated TRPC6 and p-CREB activity and decreased SBDP145 activity. When MEK or CaMKIV activity was specifically inhibited, the neuroprotective effect of hyperforin was attenuated, and we observed a correlated decrease in CREB activity. In conclusion, our results clearly showed that ICV injection of hyperforin immediately after MCAO onset blocked calpain-mediated TRPC6 channels degradation, and then to stimulate the Ras/MEK/ERK and CaMKIV pathways that converge on CREB activation, contributed to neuroprotection.
Assessment of Leptomeningeal Collaterals Using Dynamic CT Angiography in Patients with Acute Ischemic Stroke
Authors: Menon Bijoy K , O'Brien Billy , Bivard Andrew , Spratt Neil J , Demchuk Andrew M , Miteff Ferdinand , Lu Xuewen , Levi Christopher , Parsons Mark W
Published: November 2012

Whole-brain dynamic time-resolved computed tomography angiography (CTA) is a technique developed on the new 320-detector row CT scanner capable of generating time-resolved cerebral angiograms from skull base to vertex. Unlike a conventional cerebral angiogram, this technique visualizes pial arterial filling in all vascular territories, thereby providing additional hemodynamic information. Ours was a retrospective study of consecutive patients with ischemic stroke and M1 middle cerebral artery +/– intracranial internal carotid artery occlusions presenting to our center from June 2010 and undergoing dynamic time-resolved CTA and perfusion CT within 6 hours of symptom onset. Leptomeningeal collateral status was assessed by determining relative prominence of pial arteries in the ischemic region, rate and extent of retrograde flow, and various topographical patterns of pial arterial filling. Twenty-five patients were included in the study. We demonstrate the existence of the following novel properties of leptomeningeal collaterals in humans: (a) posterior (posterior cerebral artery (PCA)–MCA) dominant collateralization, (b) intra-territorial ‘within MCA region’ leptomeningeal collaterals, and (c) significant variability in size, extent, and retrograde filling time in pial arteries. We also describe a simple and reliable collateral grading template that, for the first time on dynamic CTA, incorporates back-filling time as well as size and extent of collateral filling.
Ras-guanine-nucleotide-releasing factors 1 and 2 interact with PLCγ at focal adhesions to enable IL-1-induced Ca2+ signalling, ERK activation and MMP-3 expression
Authors: Wang Qin , Siminovitch Katherine A. , Downey Gregory P. , McCulloch Christopher A.
Published: November 2012

IL (interleukin)-1 signalling in anchorage-dependent cells involves focal-adhesion-restricted and Ca2+-dependent Ras and ERK (extracellular-signal-regulated kinase) activation that leads to MMP (matrix metalloproteinase) release and extracellular matrix remodelling. Ras activity is regulated, in part, by the Ca2+-responsive Ras GRFs (guanine-nucleotide-releasing factors) 1 and 2, but the mechanisms that link and localize IL-1-induced Ca2+ signalling to focal adhesions are not defined. In the present study we characterized the role of Ras-GRF1/2 in Ca2+ and Ras→ERK signalling after IL-1 stimulation. By immunoprecipitation we found that Ras-GRF1/2 associates with PLCγ1 (phospholipase Cγ1). This association enables PLCγ1 recruitment to focal adhesions and is required for Ras signalling, ERK activation and MMP-3 release downstream of IL-1 stimulation. Depletion of PLCγ1 by siRNA (small interfering RNA) abolished IL-1-induced Ras activation and MMP-3 expression. Buffering of cytosolic Ca2+ reduced Ras interactions with Ras-GRF1/2 and blocked MMP-3 release. The results of the present study show that, in addition to their functions as Ras-exchange factors, Ras-GRF1 and -GRF2 may act as adaptors that bind PLCγ1 and restrict Ca2+ signalling to the vicinity of focal adhesions, indicating a new role for these GRFs that is required for IL-1 induction of the Ras→ERK pathway and MMP-3 expression.
Reduction of Methicillin-ResistantStaphylococcus aureusInfection among Veterans in Atlanta
Authors: Stenehjem Edward , Stafford Cortney , Rimland David
Published: November 2012

Objective.

Describe local changes in the incidence of community-onset and hospital-onset methicillin-resistantStaphylococcus aureus(MRSA) infection and evaluate the impact of MRSA active surveillance on hospital-onset infection.

Design.

Observational study using prospectively collected data.

Setting.

Atlanta Veterans Affairs Medical Center (AVAMC).

Patients.

All patients seen at the AVAMC over an 8-year period with clinically and microbiologically proven MRSA infection.

Methods.

All clinical cultures positive for MRSA were prospectively identified, and corresponding clinical data were reviewed. MRSA infections were classified into standard clinical and epidemiologic categories. The Veterans Health Administration implemented the MRSA directive in October 2007, which required active surveillance cultures in acute care settings.

Results.

The incidence of community-onset MRSA infection peaked in 2007 at 5.45 MRSA infections per 1,000 veterans and decreased to 3.14 infections per 1,000 veterans in 2011 (P< .001 for trend). Clinical and epidemiologic categories of MRSA infections did not change throughout the study period. The prevalence of nasal MRSA colonization among veterans admitted to AVAMC decreased from 15.8% in 2007 to 11.2% in 2011 (P<.001 for trend). The rate of intensive care unit (ICU)-related hospital-onset MRSA infection decreased from October 2005 through March 2007, before the MRSA directive. Rates of ICU-related hospital-onset MRSA infection remained stable after the implementation of active surveillance cultures. No change was observed in rates of non-ICU-related hospital-onset MRSA infection.

Conclusions.

Our study of the AVAMC population over an 8-year period shows a consistent trend of reduction in the incidence of MRSA infection in both the community and healthcare settings. The etiology of this reduction is most likely multifactorial.
Optical emission spectroscopy study in the VUV–VIS regimes of a developing low-temperature plasma in nitrogen gas
Authors: Fierro A , Laity G , Neuber A
Published: November 2012

The mechanisms leading to the development of an atmospheric low temperature plasma along a surface under pulsed conditions is of current interest. In the early plasma phase, high energy photons are a contributing factor to the process of generating electron avalanches resulting in surface flashover. Since only photons in the vacuum ultraviolet (VUV) regime are energetic enough to cause step-ionization or direct ionization of atmospheric gases, an experiment has been set up to enable observations of photons with wavelengths shorter than 200 nm while still allowing observation up to 800 nm. A spectrum simulation software package has been developed to allow for temperature analysis on the developing plasma in the VUV region. Observations below 200 nm revealed a Boltzmann distributed excited state population corresponding to a temperature of 3.1 eV. Time-resolved emission spectroscopy measurements of the entire electrode region during the streamer phase of breakdown demonstrate the presence of molecular nitrogen emission lines from the second positive system. Further photomultiplier tube measurements of the spark phase showed a rapid decrease in intensity of the second positive system compared to that of a representative atomic emission line in the VUV regime. This emission dominates the ultraviolet–visible (UV–VIS) spectrum during the initial phases of breakdown with little detection of other sources of emission during this phase.
Comparison of a hybrid model to a global model of atmospheric pressure radio-frequency capacitive discharges
Authors: Lazzaroni C , Lieberman M A , Lichtenberg A J , Chabert P
Published: November 2012

A one-dimensional hybrid analytical–numerical global model of atmospheric pressure radio-frequency (rf) driven capacitive discharges, previously developed, is compared with a basic global model. A helium feed gas with small admixtures of oxygen is studied. For the hybrid model, the electrical characteristics are calculated analytically as a current-driven homogeneous discharge. The electron power balance is solved analytically to determine a time-varying Maxwellian electron temperature, which oscillates on the rf timescale. Averaging over the rf period yields effective rate coefficients for gas phase activated processes. For the basic global model, the electron temperature is constant in time and the sheath physics is neglected. For both models, the particle balance relations for all species are integrated numerically to determine the equilibrium discharge parameters. Variations of discharge parameters with composition and rf power are determined and compared. The rate coefficients for electron-activated processes are strongly temperature dependent, leading to significantly larger neutral and charged particle densities for the hybrid model. For small devices, finite sheath widths limit the operating regimes to low O2 fractions. This is captured by the hybrid model but cannot be predicted from the basic global model.
Corrigendum: Quantifying dielectrophoretic nanoparticle response to amplitude modulated input signal
Authors: Bakewell D J , Chichenkov A
Published: November 2012

The full text of this article is available in the PDF provided.
Optimized tokamak power exhaust with double radiative feedback in ASDEX Upgrade
Authors: Kallenbach A. , Bernert M. , Eich T. , Fuchs J.C. , Giannone L. , Herrmann A. , Schweinzer J. , Treutterer W.
Published: November 2012

A double radiative feedback technique has been developed on the ASDEX Upgrade tokamak for optimization of power exhaust with a standard vertical target divertor. The main chamber radiation is measured in real time by a subset of three foil bolometer channels and controlled by argon injection in the outer midplane. The target heat flux is in addition controlled by nitrogen injection in the divertor private flux region using either a thermoelectric sensor or the scaled divertor radiation obtained by a bolometer channel in the outer divertor. No negative interference of the two radiation controllers has been observed so far. The combination of main chamber and divertor radiative cooling extends the operational space of a standard divertor configuration towards high values of P/R. P
heat/R = 14 MW m−1 has been achieved so far with nitrogen seeding alone as well as with combined N + Ar injection, with the time-averaged divertor peak heat flux below 5 MW m−2. Good plasma performance can be maintained under these conditions, namely H
98(y,2) = 1 and β
N = 3.
Effect of Cooking on Lignans Content in Whole‐Grain Pasta Made with Different Cereals and Other Seeds
Authors: Durazzo Alessandra , Azzini Elena , Turfani Valeria , Polito Angela , Maiani Giuseppe , Carcea Marina
Published: November 2012

Lignans are of increasing interest because of their potential anticarcinogenic, antioxidant, estrogenic, and antiestrogenic activities. In this work, mixed‐cereal pastas manufactured by adding 60% whole‐grain flours of different cereals (wheat, oat, rye, barley, and rice) to durum wheat semolina, a multigrain pasta with different grains (cereals, legumes, and flaxseed), and a traditional industrial durum wheat semolina were analyzed for their lignans content both in the raw and in the cooked state, ready for consumption. For raw mixed‐cereal pastas, total lignans were within the range 94.91–485.62 μg/100 g d.w. After cooking, total lignans losses of about 35.5, 18.31, and 5.46% were observed respectively in oat‐, rye‐, and rice‐added pastas, whereas increases of 5.74 and 13.62% were observed in barley‐added and whole durum wheat pastas. Interesting results were obtained for the multigrain pasta: the raw product exhibited a total lignans content of 9,686.17 ± 287.03 μg/100 g d.w., and the major contribution was given by secoisolariciresinol. This highest total lignans value resulted from its rich and varied composition in seeds of different origin, legumes, and flaxseed in particular. Our findings showed that mixed‐cereal and multigrain pastas can be considered a good source of lignans. The effect of cooking was not the same for each product, and it depended on the different lignans profile of each grain, on the different chemical structure of each lignan, and on the nature of the food matrix.
Nitric Oxide as a Mediator for Defense Responses
Authors: Bellin Diana , Asai Shuta , Delledonne Massimo , Yoshioka Hirofumi
Published: November 2012

Sequential recognition of invading microbes and rapid induction of plant immune responses comprise at least two recognition systems. Early basal defenses are initiated by pathogen-associated molecular patterns and pattern recognition receptors (PRR) in the plasma membrane. Pathogens produce effectors to suppress defense but plants, in turn, can sense such effectors by dominant plant resistance (R) gene products. Plant PRR and R proteins modulate signaling networks for defense responses that rely on rapid production of reactive nitrogen species (RNS) and reactive oxygen species (ROS). Recent research has shown that nitric oxide (NO) mainly mediates biological function through chemical reactions between locally controlled accumulation of RNS and proteins leading to potential alteration of protein function. Many proteins specifically regulated by NO and participating in signaling during plant defense response have been identified, highlighting the physiological relevance of these modifications in plant immunity. ROS function independently or in cooperation with NO during defense, modulating the RNS signaling functions through the entire process. This review provides an overview of current knowledge about regulatory mechanisms for NO burst and signaling, and crosstalk with ROS in response to pathogen attack.
Population Genetic Structures of Puccinia striiformis in Ningxia and Gansu Provinces of China
Authors: Liang Junmin , Wan Qiong , Luo Yong , Ma Zhanhong
Published: November 2012

Wheat stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici, is one of the most destructive plant diseases in China. Gansu and Ningxia Provinces are considered to be the key areas for over-summering of this pathogen in China. In this study, 283 P. striiformis f. sp. tritici isolates were collected in these two provinces. Amplified fragment length polymorphism (AFLP) was used to analyze the population genetics and to infer the chance of population exchanges between different geographic locations and seasons. The genotypic diversity of the Gansu population (0.514) was slightly higher than that of the Ningxia population (0.489). The occurrence of frequent population exchanges between these two regions was observed, showing that 40 AFLP genotypes were shared by the populations of the two provinces. Gene flow between these two regions in autumn and spring subpopulations was also detected. The genotype distribution in three populations of Ningxia from opposite sides of the Liupan Mountains revealed possible significant effects of the mountains on limiting gene flow and population exchange. Phylogenetic analysis confirmed the possibility of recombination in some of the studied subpopulations in both provinces.
Analysis of Genetic and Molecular Identity Among Field Isolates of the Rice Blast Fungus with an International Differential System, Rep-PCR, and DNA Sequencing
Authors: Xing Junjie , Jia Yulin , Correll James C. , Lee Fleet N. , Cartwright Richard , Cao Mengliang , Yuan Longping
Published: November 2012

The Pi-ta gene deployed in southern U.S. rice germplasm is effective in preventing the infection by strains of Magnaporthe oryzae isolates that carry the avirulence (AVR) gene AVR-Pita1. In the present study, 169 isolates from rice (Oryza sativa) cultivars, with and without Pi-ta, were analyzed for their genetic identity using an international differential system, repetitive element-based polymerase chain reaction (Rep-PCR), and sequence analysis of PCR products of AVR-Pita1. These isolates belong to the races IA1, IB1, IB17, IC1, and IC17 of M. oryzae. These isolates were further classified into 15 distinct groups by Rep-PCR. There was a predominant group within each race. Pathogenicity assays on ‘Katy’ (Pi-ta) and ‘M202’ (pi-ta) rice determined that IC1 was virulent to Katy and M202; IB17, IC17, and most of IA1 and IB1 were avirulent to Katy and virulent to M202, suggesting that the Pi-ta gene in Katy is responsible for preventing infection by these isolates. Consistently, AVR-Pita1 was not amplified from 28 virulent isolates. One AVR-Pita1 allele was amplified by AVR-Pita1-specific primers in 78 avirulent isolates. Interestingly, different AVR-Pita1 alleles were found in each of the 12 avirulent isolates, as determined by DNA sequencing. Sequence analysis of 90 PCR products revealed 10 AVR-Pita1 haplotypes, 4 of which were new. In total, 12 amino acid changes were identified in the new variants when compared with the first described AVR-Pita sequence (AF207841). The finding of isolates with altered AVR-Pita1 from rice cultivars with and without Pi-ta suggests that these virulent isolates were adapted to the field environments in the southern United States. Further research will be needed to verify this prediction.
Identification, Virulence, and Distribution of Two Biovars ofPseudomonas syringaepv.actinidiaein New Zealand
Authors: Vanneste J. L. , Yu J. , Cornish D. A. , Tanner D. J. , Windner R. , Chapman J. R. , Taylor R. K. , Mackay J. F. , Dowlut S.
Published: November 2012

Pseudomonas syringae pv. actinidiae, the causal agent of bacterial canker of kiwifruit, was detected for the first time in New Zealand in November 2010. Only in Bay of Plenty, one of the four regions where this pathogen had been detected, did symptoms evolve beyond leaf spots, resulting in cane die-back, wilting of canes, and canker, sometimes leading to death of the vine. Molecular analysis (cts haplotype and BOX-polymerase chain reaction [PCR] electrophoretic pattern) of strains isolated from different regions of New Zealand revealed that two biovars could be distinguished. They have been called biovar 3 and biovar 4 to differentiate them from strains from Japan (biovar 1) or Korea (biovar 2), which have a different cts haplotype or a different BOX-PCR pattern. Biovars 3 and 4 displayed different degrees of virulence, as measured by their ability to cause leaf spots on young, potted kiwifruit plants. Biovar 3, which has also been present in Italy since 2008 and in France, was found in the Bay of Plenty, where cane diebacks were observed. In contrast, no symptoms other than leaf spots have been observed in orchards where strains of biovar 4 have been isolated. We report the distribution and the disease progression of biovars 3 and 4 in New Zealand.
First Report of Seedling Blight of Watermelon Caused by Acidovorax citrulli Transmitted from Rootstock of Pumpkin in China
Authors: Tian Y. L. , Zhao Y. Q. , Hu B. S. , Liu F. Q.
Published: November 2012

Bacterial fruit blotch (BFB) is a devastating disease caused by Acidovorax citrulli, which was first observed in the United States in 1988 (3). A. citrulli can cause severe infection on a wide range of cucurbits, including watermelon, cantaloupe, and pumpkin. Cotyledon symptoms are brown, angular, necrotic spots or large necrotic lesions. The disease is seedborne, so seeds usually serve as the primary inoculum source for BFB outbreaks (2). In July 2012, seedling blight was observed by local farmers from Anhui province in China on watermelon seedlings grafted to pumpkin rootstocks; lesions were morphologically similar to those caused by A. citrulli. Presence of A. citrulli was detected in symptomatic samples by using species-specific primers BX-L1/BX-S-R2 (1). The seed company claimed seeds of watermelon (cv. Changfeng) were certified free of bacterial fruit blotch, but pumpkin seeds (cv. Kangkuxianfeng-1) had not been tested for A. citrulli. For investigating the inoculum source, the remaining seeds of watermelon (cv. Changfeng) and pumpkin (cv. Kangkuxianfeng-1) for seedling production were collected from the farmer and processed for pathogen extraction as described by Walcott and Gitaitis (2). Two microliters of seed wash was used as template for PCR using primers BX-L1/BX-S-R2 (1). The experiment was conducted three times. A 279-bp DNA fragment was consistently amplified by PCR from seed wash of pumpkin seeds, but not from the seed wash of watermelon seeds. Three Acidovorax-like strains (A1, A2, and A3) were isolated from pumpkin seed wash using TWZ semi-selective medium (0.5% peptone, 0.025% CaCl2, 1% Tween-80, 50 mg/liter berberine, 50 mg/liter cycloheximide, 50 mg/liter 2,3,5-triphenyltetrazolium chloride). PCR was performed on the 16S rDNA gene from isolate strain A1, A2, and A3 (1,492 bp; GenBank Accession Nos. JX875533, JX875534, and JX875535) with primers rp1/fd2 (4), and PCR products were sequenced. Results of sequence analysis showed the sequences of strains A1, A2, and A3 were 99% identical to that of the type strain of A. citrulli AAC00-1 (NC_008752). Pathogencity was confirmed by injection of pumpkin cotyledons with bacterial suspensions of each isolate. Collected pumpkin seeds (n = 100 seeds) and watermelon seeds (n = 100 seeds) were planted in plastic pots containing sterilized field soil at room temperature to detect A. citrulli by a wet chamber growing out test. Eight days later, brown, angular, necrotic spots or wilt developed in pumpkin seedlings, but no symptoms were noted on the watermelon seedlings. To our knowledge, this is the first report of A. citrulli causing watermelon seedling blight transmitted from pumpkin seeds by grafting in China.

References: (1) O. Bahar et al. Plant Pathol. 57:754, 2008. (2) R. R. Walcott and R. D. Gitaitis. Plant Dis. 84:470, 2000. (3) G. C. Wall et al. Phytopathology 78:1605, 1988. (4) W. G. Weisburg et al. J. Bacteriol. 173:697, 1991.
First Report of Impatiens Downy Mildew Caused by Plasmopara obducens in Kentucky
Authors: Ward N. A. , Dixon E. , Amsden B.
Published: November 2012

Impatiens downy mildew (Plasmopara obducens (J. Schröt.) J. Schröt. (syn Peronospora obducens) was first reported in the United States in 2004, but widespread outbreaks were observed throughout North America in 2011 (5). In June 2012, symptoms, including severe defoliation while plants retained upright stems, were observed on approximately 100 landscape impatiens (Impatiens walleriana Hook.f.) in Franklin County in central Kentucky. All plants in the landscape were affected. Plants were primarily defoliated and remaining leaves were stunted, mottled, and chlorotic with edges curled downward; no flowers were present. Under examination with a dissecting microscope, white downy fungal growth was observed. Closer examination confirmed that the growth consisted of colorless sporangiophores that were mainly unbranched, straight, and rigid (1,3). Sporangiophores consisted of apical branches attached at right angles to main axes, ranging from 67.2 to 89.9 μm long (1). Sporangia were ovoid and hyaline, measuring 11.2 to 13.3 μm × 8.2 to 10.7 μm (3). No oospores were observed. Pathogenicity tests were performed by inoculating 20 to 40 leaves on three plants each of the cvs. Dazzler and Super Elfin with suspensions of 1 × 105 sporangiophores per ml in sterile distilled water. Sporangia were obtained by washing infected leaves with sterile distilled water, and inoculations were completed by spraying leaves until runoff. Plants sprayed with sterile water served as controls. Plants were covered with black plastic bags for 48 h and then maintained under fluorescent lights for 10 days at room temperature (22 to 25°C). Sporangiophores were recovered from inoculated plants after 10 days, and morphology matched original inoculum; symptoms included chlorotic, downward curling leaves with sporulation on the undersides. Non-inoculated plants did not develop symptoms after 21 days. Molecular identification of the pathogen was conducted using three leaves from one plant from each cultivar. PCR was conducted by amplifying the large ribosomal subunit DNA using primers NL-1 and NL-4 (2). Amplicons of 762 to 691 bp were produced from diseased plant tissue that contained visible sporangiophores, and the bands were extracted from the gel and purified. Sequence results confirmed 100% similarity to accessions from Florida (GenBank Accession No. JX217746.1) and Ohio (JX142134.1) and 99% similarity to amplicons reported from Serbia (HQ246451.1) and UK (AY587558.1). This is believed to be the first report of downy mildew infecting impatiens in Kentucky.

References: (1) O. Constantinescu. Mycologia 83:473, 1991. (2) W. Maier et al. Can. J. Bot 81:12, 2003. (3) P. A. Saccardo. Syllogue Fungorum 7:242, 1888. (4) S. N. Wegulo et al. Plant Dis. 88:909, 2004.
Nitrogen Fertilization of the Host Plant Influences Production and Pathogenicity of Botrytis cinerea Secondary Inoculum
Authors: Abro Manzoor Ali , Lecompte François , Bryone Florian , Nicot Philippe C.
Published: November 2012

The influence of nitrogen (N) nutrition on a plant's susceptibility to Botrytis spp. and other pathogens is well documented. However, little is known of possible effects on sporulation of the pathogen on diseased tissue and on the pathogenicity of resulting secondary inoculum. To address this question, sporulation by two strains of Botrytis cinerea was quantified on tomato plants produced under different N irrigation regimes with inputs of NO3– at 0.5 to 45 mmol liter–1 (mM). Sporulation decreased significantly (P < 0.05) with increasing N fertilization up to NO3– at 15 to 30 mM. The secondary inoculum was collected and used to inoculate pruning wounds on tomato plants produced under a standard fertilization regime. Pathogenicity of the spores was significantly influenced by the nutritional status of their production substrate. Disease severity was highest with spores produced on plants with very low or very high N fertilization (NO3– at 0.5 or 30 mM). It was lowest for inoculum from plants with moderate levels of N fertilization. These results suggest that it may be possible to find an optimum level of N fertilization to reduce the production of secondary inoculum and its pathogenicity to tomato.
The genome of the pear (Pyrus bretschneideri Rehd.)
Authors: Wu Jun , Wang Zhiwen , Shi Zebin , Zhang Shu , Ming Ray , Zhu Shilin , Khan M. Awais , Tao Shutian , Korban Schuyler S. , Wang Hao , Chen Nancy J. , Nishio Takeshi , Xu Xun , Cong Lin , Qi Kaijie , Huang Xiaosan , Wang Yingtao , Zhao Xiang , Wu Juyou , Deng Cao , Gou Caiyun , Zhou Weili , Yin Hao , Qin Gaihua , Sha Yuhui , Tao Ye , Chen Hui , Yang Yanan , Song Yue , Zhan Dongliang , Wang Juan , Li Leiting , Dai Meisong , Gu Chao , Wang Yuezhi , Shi Daihu , Wang Xiaowei , Zhang Huping , Zeng Liang , Zheng Danman , Wang Chunlei , Chen Maoshan , Wang Guangbiao , Xie Lin , Sovero Valpuri , Sha Shoufeng , Huang Wenjiang , Zhang Shujun , Zhang Mingyue , Sun Jiangmei , Xu Linlin , Li Yuan , Liu Xing , Li Qingsong , Shen Jiahui , Wang Junyi , Paull Robert E. , Bennetzen Jeffrey L. , Wang Jun , Zhang Shaoling
Published: November 2012

The draft genome of the pear (Pyrus bretschneideri) using a combination of BAC-by-BAC and next-generation sequencing is reported. A 512.0-Mb sequence corresponding to 97.1% of the estimated genome size of this highly heterozygous species is assembled with 194× coverage. High-density genetic maps comprising 2005 SNP markers anchored 75.5% of the sequence to all 17 chromosomes. The pear genome encodes 42,812 protein-coding genes, and of these, ∼28.5% encode multiple isoforms. Repetitive sequences of 271.9 Mb in length, accounting for 53.1% of the pear genome, are identified. Simulation of eudicots to the ancestor of Rosaceae has reconstructed nine ancestral chromosomes. Pear and apple diverged from each other ∼5.4–21.5 million years ago, and a recent whole-genome duplication (WGD) event must have occurred 30–45 MYA prior to their divergence, but following divergence from strawberry. When compared with the apple genome sequence, size differences between the apple and pear genomes are confirmed mainly due to the presence of repetitive sequences predominantly contributed by transposable elements (TEs), while genic regions are similar in both species. Genes critical for self-incompatibility, lignified stone cells (a unique feature of pear fruit), sorbitol metabolism, and volatile compounds of fruit have also been identified. Multiple candidate SFB genes appear as tandem repeats in the S-locus region of pear; while lignin synthesis-related gene family expansion and highly expressed gene families of HCT, C3′H, and CCOMT contribute to high accumulation of both G-lignin and S-lignin. Moreover, alpha-linolenic acid metabolism is a key pathway for aroma in pear fruit.
Identification and Characterization of the Missing Pyrimidine Reductase in the Plant Riboflavin Biosynthesis Pathway
Authors: Hasnain Ghulam , Frelin Océane , Roje Sanja , Ellens Kenneth W. , Ali Kashif , Guan Jiahn-Chou , Garrett Timothy J. , de Crécy-Lagard Valérie , Gregory Jesse F. , McCarty Donald R. , Hanson Andrew D.
Published: November 2012

Riboflavin (vitamin B2) is the precursor of the flavin coenzymes flavin mononucleotide and flavin adenine dinucleotide. In Escherichia coli and other bacteria, sequential deamination and reduction steps in riboflavin biosynthesis are catalyzed by RibD, a bifunctional protein with distinct pyrimidine deaminase and reductase domains. Plants have two diverged RibD homologs, PyrD and PyrR; PyrR proteins have an extra carboxyl-terminal domain (COG3236) of unknown function. Arabidopsis (Arabidopsis thaliana) PyrD (encoded by At4g20960) is known to be a monofunctional pyrimidine deaminase, but no pyrimidine reductase has been identified. Bioinformatic analyses indicated that plant PyrR proteins have a catalytically competent reductase domain but lack essential zinc-binding residues in the deaminase domain, and that the Arabidopsis PyrR gene (At3g47390) is coexpressed with riboflavin synthesis genes. These observations imply that PyrR is a pyrimidine reductase without deaminase activity. Consistent with this inference, Arabidopsis or maize (Zea mays) PyrR (At3g47390 or GRMZM2G090068) restored riboflavin prototrophy to an E. coli ribD deletant strain when coexpressed with the corresponding PyrD protein (At4g20960 or GRMZM2G320099) but not when expressed alone; the COG3236 domain was unnecessary for complementing activity. Furthermore, recombinant maize PyrR mediated NAD(P)H-dependent pyrimidine reduction in vitro. Import assays with pea (Pisum sativum) chloroplasts showed that PyrR and PyrD are taken up and proteolytically processed. Ablation of the maize PyrR gene caused early seed lethality. These data argue that PyrR is the missing plant pyrimidine reductase, that it is plastid localized, and that it is essential. The role of the COG3236 domain remains mysterious; no evidence was obtained for the possibility that it catalyzes the dephosphorylation that follows pyrimidine reduction.
Staying tuned: grasshoppers from noisy roadside habitats produce courtship signals with elevated frequency components
Authors: Lampe Ulrike , Schmoll Tim , Franzke Alexandra , Reinhold Klaus
Published: November 2012

Anthropogenic noise is known to affect acoustic signal production in birds, frogs and mammals. These animals use different mechanisms to adjust their signals to elevated background noise levels (increase in signal amplitude, shift to higher frequencies, etc.). Previous studies have concentrated on behaviourally plastic changes in signal production as a result of elevated background noise levels. To our knowledge, long‐term effects of anthropogenic noise on signal production have not yet been investigated. Moreover, strategies of invertebrate species to ensure acoustic signal transmission under anthropogenic noise have not been examined, so far.

We tested whether and how male Chorthippus biguttulus grasshoppers from noisy roadside habitats may adjust acoustic courtship signals to elevated background noise levels, compared with conspecifics from quiet control habitats. In this species, sexually selected male courtship signals serve to attract potential mating partners, which make the undisturbed transmission of signals in habitats with increased background noise levels crucial for male reproductive success.

Compared to males from control populations, males from roadside habitats produced songs with a significantly higher local frequency maximum under standardized, quiet recording conditions. This local frequency maximum (in the range of c. 6–9 kHz) overlaps with low‐frequent road noise that has the potential to degrade or mask this part of the signals' frequency spectrum.

To our knowledge, this is the first evidence that insects from noisy habitats produce different acoustic signals than conspecifics from quiet habitats, possibly using a more permanent mechanism for signal adjustment than behavioural plasticity, which was found in different bird species adjusting to high background noise levels. Such an effect of anthropogenic noise has not been shown for any invertebrate species before, and our results suggest that similar strategies to avoid degradation or masking by noise (i.e. increase in carrier frequency) are used over a wide range of taxa, including both, vertebrates and invertebrates.
Suicide and Psychiatrist's Liability in Italian Law Cases
Authors: Terranova Claudio , Sartore Daniela
Published: November 2012

The aim of the study is to analyze the factors that are most frequently associated with a verdict of guilty delivered to the psychiatrist in cases of a patient's suicide in Italian law. Twenty‐six sentences (1975–2009) were analyzed according to the claim of malpractice, patient characteristics, circumstances of the suicide, and reasons for the court's judgment. The court held the psychiatrist guilty in 12 cases, considering that the act of suicide was predictable and could have been avoided. Predictability was mainly related to errors in surveillance (7 cases), therapy (1 case), or both (2 cases). An error in diagnosis was considered to be related to the patient's death in two cases. Analysis of medical behavior considered to be erroneous and associated with a verdict of guilty provides an opportunity to discuss the topics relevant not only to practicing psychiatrists but also to experts assessing medical liability in cases of patient suicide.
Does insider trading explain price run‐up ahead of takeover announcements?
Authors: Aspris Angelo , Foley Sean , Frino Alex
Published: November 2012

This study empirically examines the impact of changes in substantial shareholdings ahead of 450 Australian takeover offers between the years 2000 and 2009. Previous studies have attributed a significant proportion of the price run‐up effect in takeover targets to insider‐trading behaviour. This study examines the contribution of a broad range of public information sources that are known to typically generate market anticipation, including the acquisition of toeholds ahead of takeover announcements. Our findings show no significant pre‐bid run‐up for takeover targets after considering these sources. We conclude from these results that previous findings attributing pre‐bid share price run‐up to illegal insider trading may overstate the existence of such conduct.
Seasonal flight activity, phenology and physiological status of the major establishment pests of Eucalyptus nitens plantations, Heteronyx dimidiata and H. crinitus (Coleoptera: Scarabaeidae: Melolonthinae)
Authors: Walker Paul W , Allen Geoff R
Published: November 2012

Heteronyx dimidiata and H. crinitus are significant pests of young Eucalyptus spp. plantations in Tasmania, but little is known about their biology. Adult beetles feeding on the leaves and developing leaf buds of young seedlings can severely affect their growth and form or even kill them. Yellow‐vaned funnel traps were used to monitor the flight activity of Heteronyx in a commercial plantation over 3 years. Visual searches were also conducted to determine the incidence of inactive beetles in the soil underneath trees and the presence of active beetles on leaves. Over 12 000 H. dimidiata and 1300 H. crinitus were collected during the study. The pattern of trap captures was similar in both species with over 90% of beetles being caught in spring and low numbers being caught throughout summer and autumn. High numbers of H. dimidiata were found in the soil surrounding the roots of Eucalyptus nitens seedlings, but very few larvae were present, indicating that oviposition occurs outside these plantations. Trap data suggest that spring flight activity is principally due to the emergence of overwintering adult beetles and that newly eclosed beetles typically invade plantations during late summer/autumn. Spring trap captures were strongly male biased, suggesting a scramble mating system where males were more active as they competitively searched for females. Over 65% of the variation in H. dimidiata activity in spring was accounted for by levels of solar radiation and wind. Females mated up to three times and ovarian development usually commenced in spring. The incidence of food in the crop was highest during autumn/winter, but the presence of fat in the abdomen was similar throughout the year. The use of yellow‐vaned funnel traps to monitor the flight activity of diurnally active Heteronyx species in commercial Eucalyptus spp. plantations is recommended.
Responses to Varroa destructor and Nosema ceranae by several commercial strains of Australian and North American honeybees (Hymenoptera: Apidae)
Authors: Rinderer Thomas E , Oldroyd Benjamin P , Frake Amanda M , de Guzman Lilia I , Bourgeois Lelania
Published: November 2012

The potential impact of varroa (Varroa destructor, Anderson & Trueman) on Australian beekeeping and agriculture depends in part on the levels of resistance to this parasite expressed by Australian commercial honeybees (Apis mellifera). The responses of seven lines of Australian honeybees to V. destructor were compared with the responses of a stock of Italian honeybees from the United States known for its susceptibility to V. destructor and two stocks known for their resistance to V. destructor, Russian honeybees (RHB) and a stock expressing the varroa sensitive hygiene trait (VSH). The experiment began in May with uniform colonies having uniform infestation of V. destructor. V. destructor infestations measured as the percentage of adult bees infested in the Australian lines and the Italian stock rose from less than 10% in August to over 25% in October. From August to November, 44% of both the Australian and Italian colonies died while strongly exhibiting symptoms of parasitic mite syndrome. In contrast, RHB and VSH colonies displayed comparative resistance to V. destructor. Their infestation rates rose from about 5% in August to 10% (RHB) and 14% (VSH) in October. Likely, some of this increase resulted from invasion pressure by mites from the dying Australian and Italian colonies. During the August to November period, 4.4% of the RHB and 14.3% of the VSH colonies died. In comparisons of the seven Australian lines, only nonsignificant and trivial differences were found for infestation and mortality rates. All Australian lines were highly susceptible to V. destructor. Additionally, evaluations of rates of Nosema ceranae infections were made throughout the course of the experiment. Although high levels of infection were found across all stocks and lines, no stock or line exhibited an adverse effect from N. ceranae infection.