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Search Results: 1 - 10 of 472320 matches for " Eric A. Schmelz "
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A rapid biosensor-based method for quantification of free and glucose-conjugated salicylic acid
Christopher T DeFraia, Eric A Schmelz, Zhonglin Mou
Plant Methods , 2008, DOI: 10.1186/1746-4811-4-28
Abstract: On the basis of the original biosensor-based method, we optimized extraction and quantification. SAG content was determined by treating crude extracts with β-glucosidase, then measuring the released free SA with the biosensor. β-glucosidase treatment released more SA in acetate buffer extract than in Luria-Bertani (LB) extract, while enzymatic hydrolysis in either solution released more free SA than acid hydrolysis. The biosensor-based method detected higher amounts of SA in pathogen-infected plants than did a GC/MS-based method. SA quantification of control and pathogen-treated wild-type and sid2 (SA induction-deficient) plants demonstrated the efficacy of the method described. Using the methods detailed here, we were able to detect as little as 0.28 μg SA/g FW. Samples typically had a standard deviation of up to 25% of the mean.The ability of Acinetobacter sp. ADPWH_lux to detect SA in a complex mixture, combined with the enzymatic hydrolysis of SAG in crude extract, allowed the development of a simple, rapid, and inexpensive method to simultaneously measure free and glucose-conjugated SA. This approach is amenable to a high-throughput format, which would further reduce the cost and time required for biosensor-based SA quantification. Possible applications of this approach include characterization of enzymes involved in SA metabolism, analysis of temporal changes in SA levels, and isolation of mutants with aberrant SA accumulation.The plant signal molecule salicylic acid (SA) has been shown to play a role in several physiological processes, including heat production, flowering, germination and pathogen resistance [1-5]. In the last two decades, its role in pathogen resistance has been studied extensively [6,7]. Treatment with SA confers resistance to a variety of biotrophic pathogens [5,8], and pathogen infection causes the accumulation of SA [9,10]. SA can be glucosylated to form SAG (2-O-β-D-glucosylsalicylic acid), which serves as a biologically inert reservoir
Spatial Patterns of Aflatoxin Levels in Relation to Ear-Feeding Insect Damage in Pre-Harvest Corn
Xinzhi Ni,Jeffrey P. Wilson,G. David Buntin,Baozhu Guo,Matthew D. Krakowsky,R. Dewey Lee,Ted E. Cottrell,Brian T. Scully,Alisa Huffaker,Eric A. Schmelz
Toxins , 2011, DOI: 10.3390/toxins3070920
Abstract: Key impediments to increased corn yield and quality in the southeastern US coastal plain region are damage by ear-feeding insects and aflatoxin contamination caused by infection of Aspergillus flavus. Key ear-feeding insects are corn earworm, Helicoverpa zea, fall armyworm, Spodoptera frugiperda, maize weevil, Sitophilus zeamais, and brown stink bug, Euschistus servus. In 2006 and 2007, aflatoxin contamination and insect damage were sampled before harvest in three 0.4-hectare corn fields using a grid sampling method. The feeding damage by each of ear/kernel-feeding insects (i.e., corn earworm/fall armyworm damage on the silk/cob, and discoloration of corn kernels by stink bugs), and maize weevil population were assessed at each grid point with five ears. The spatial distribution pattern of aflatoxin contamination was also assessed using the corn samples collected at each sampling point. Aflatoxin level was correlated to the number of maize weevils and stink bug-discolored kernels, but not closely correlated to either husk coverage or corn earworm damage. Contour maps of the maize weevil populations, stink bug-damaged kernels, and aflatoxin levels exhibited an aggregated distribution pattern with a strong edge effect on all three parameters. The separation of silk- and cob-feeding insects from kernel-feeding insects, as well as chewing (i.e., the corn earworm and maize weevil) and piercing-sucking insects (i.e., the stink bugs) and their damage in relation to aflatoxin accumulation is economically important. Both theoretic and applied ramifications of this study were discussed by proposing a hypothesis on the underlying mechanisms of the aggregated distribution patterns and strong edge effect of insect damage and aflatoxin contamination, and by discussing possible management tactics for aflatoxin reduction by proper management of kernel-feeding insects. Future directions on basic and applied research related to aflatoxin contamination are also discussed.
European Corn Borer (Ostrinia nubilalis) Induced Responses Enhance Susceptibility in Maize
Nicole J. Dafoe, James D. Thomas, Paul D. Shirk, Michelle E. Legaspi, Martha M. Vaughan, Alisa Huffaker, Peter E. Teal, Eric A. Schmelz
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0073394
Abstract: Herbivore-induced plant responses have been widely described following attack on leaves; however, less attention has been paid to analogous local processes that occur in stems. Early studies of maize (Zea mays) responses to stem boring by European corn borer (ECB, Ostrinia nubilalis) larvae revealed the presence of inducible acidic diterpenoid phytoalexins, termed kauralexins, and increases in the benzoxazinoid 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3?-one-glucose(HDMBOA-Glc) after 24 h of herbivory. Despite these rapidly activated defenses, larval growth was not altered in short-term feeding assays. Unexpectedly, ECB growth significantly improved in assays using stem tissue preconditioned by 48 h of larval tunneling. Correspondingly, measures of total soluble protein increased over 2.6-fold in these challenged tissues and were accompanied by elevated levels of sucrose and free linoleic acid. While microarray analyses revealed up-regulation of over 1100 transcripts, fewer individual protein increases were demonstrable. Consistent with induced endoreduplication, both wounding and ECB stem attack resulted in similar significant expansion of the nucleus, nucleolus and levels of extractable DNA from challenged tissues. While many of these responses are triggered by wounding alone, biochemical changes further enhanced in response to ECB may be due to larval secreted effectors. Unlike other Lepidoptera examined, ECB excrete exceedingly high levels of the auxin indole-3-acetic acid (IAA) in their frass which is likely to contact and contaminate the surrounding feeding tunnel. Stem exposure to a metabolically stable auxin, such as 2,4-dichlorophenoxyacetic acid (2,4-D), promoted significant protein accumulation above wounding alone. As a future testable hypothesis, we propose that ECB-associated IAA may function as a candidate herbivore effector promoting the increased nutritional content of maize stems.
Atmospheric Imaging Assembly Response Functions: Solving the Fe VIII Problems with Hinode EIS Bright Point Data
Joan T. Schmelz,Benjamin S. Jenkins,Jason A. Kimble
Physics , 2013, DOI: 10.1007/s11207-012-0208-1
Abstract: The Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory is a state-of-the-art imager with the potential to do unprecedented time-dependent multi-thermal analysis at every pixel on scales short compared to the radiative and conductive cooling times. Recent results, however, have identified missing spectral lines in the CHIANTI atomic physics data base, which is used to construct the instrument response functions. We have done differential emission measure analysis using simultaneous AIA and Hinode/EIS observations of six X-ray bright points. Our results not only support the conclusion that CHIANTI is incomplete near 131 angstroms, but more importantly, suggest that the peak temperature of the Fe VIII emissivity/response is likely to be closer to log T = 5.8 than to the current value of log T = 5.7. Using a revised emissivity/response calculation for Fe VIII, we find that the observed AIA 131-angstrom flux can be underestimated by about 1.25, which is smaller than previous comparisons.
Intra-Abdominal Fat Depots Represent Distinct Immunomodulatory Microenvironments: A Murine Model
Courtney A. Cohen, Amanda A. Shea, C. Lynn Heffron, Eva M. Schmelz, Paul C. Roberts
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0066477
Abstract: White adipose tissue (WAT) is a multi-faceted endocrine organ involved in energy storage, metabolism, immune function and disease pathogenesis. In contrast to subcutaneous fat, visceral fat (V-WAT) has been associated with numerous diseases and metabolic disorders, indicating specific functions related to anatomical location. Although visceral depots are often used interchangeably in V-WAT-associated disease studies, there has been a recent subdivision of V-WAT into “true visceral” and non-visceral intra-abdominal compartments. These were associated with distinct physiological roles, illustrating a need for depot-specific information. Here, we use FACS analysis to comparatively characterize the leukocyte and progenitor populations in the stromal vascular fraction (SVF) of peritoneal serous fluid (PSF), parametrial (pmWAT), retroperitoneal (rpWAT), and omental (omWAT) adipose tissue from seven-month old C57BL/6 female mice. We found significant differences in SVF composition between all four microenvironments. PSF SVF was comprised almost entirely of CD45+ leukocytes (>99%), while omWAT contained less, but still almost two-fold more leukocytes than pmWAT and rpWAT (75%, 38% and 38% respectively; p<0.01). PmWAT was composed primarily of macrophages, whereas rpWAT more closely resembled omWAT, denoted by high levels of B1 B-cell and monocyte populations. Further, omWAT harbored significantly higher proportions of T-cells than the other tissues, consistent with its role as a secondary lymphoid organ. These SVF changes were also reflected in the gene expression profiles of the respective tissues. Thus, intra-abdominal fat pads represent independent immunomodulatory microenvironments and should be evaluated as distinct entities with unique contributions to physiological and pathological processes.
The Effects of Parathyroid Hormone Applied at Different Regimes on the Trochanteric Region of the Femur in Ovariectomized Rat Model of Osteoporosis
M. Tezval,A. Banhardt,S. Sehmisch,L. Kolios,U. Schmelz,K. M. Stuermer,E. K. Stuermer
Journal of Osteoporosis , 2011, DOI: 10.4061/2011/363617
Abstract: This study aims to investigate the effects of two application frequencies of parathyroid hormone on the trochanteric region of rat femur. Forty-three-month-old female Sprague-Dawley rats were divided into 4 groups (=10/group). Three groups were ovariectomized, and 8 weeks later they were administered the following treatments (5 weeks): soy-free diet (OVX), subcutaneously injected PTH (0.040 mg/kg) 5 days a week (PTH 5x/w), subcutaneously injected PTH (0.040 mg/kg) every 2 days (PTH e2d), and a sham group. The values of the biomechanical and histomorphometric parameters showed higher results in 5x/w animals in comparison to the OVX and PTH 2ed groups. The ratio between bone diameter/marrow diameter (B.Dm/Ma.Dm) in subtrochanteric cross sections did not show any significant differences between PTH 5x/w and PTH e2d. The increased bone formation rate was observed under PTH treatment in both groups mainly at the endosteal side. The endosteum seems here to be one of the targets of PTH with an accelerate bone formation and a pronounced filling-in of intracortical cavities with higher intensity for the PTH 5x/w in comparison to PTH e2d rats.
Benefits from ecological study methods to taxonomy of enchytraeids in southern Mata Atlantica
Schmelz, Rüdiger Maria;Pe?a, Rut Maria Collado de la;R?mbke, J?rg;
Pesquisa Agropecuária Brasileira , 2009, DOI: 10.1590/S0100-204X2009000800009
Abstract: the objective of this work was to determine how taxonomy benefited from the ecological quantitative and site-based sampling methods in enchytraeids studies. enchytraeids (small relatives of earthworms) were sampled in different phases of rain forest regeneration in the southern mata atlantica in paraná, brazil. the research combined ecological and taxonomic work, because enchytraeids are poorly studied and difficult to identify, and many new species were expected. the provision of large numbers of specimens enabled the test of species diagnoses by investigating the ranges of character variations in a larger series of specimens. simplified species diagnoses adapted to the local conditions that allowed the identification of all specimens, juveniles included, were developed. key characters and character states are presented for the three genera: achaeta, hemienchytraeus and guaranidrilus. among several new species, a rare species, possibly a remnant of the autochthonous forest fauna, was found and described.
The Effects of Parathyroid Hormone Applied at Different Regimes on the Trochanteric Region of the Femur in Ovariectomized Rat Model of Osteoporosis
M. Tezval,A. Banhardt,S. Sehmisch,L. Kolios,U. Schmelz,K. M. Stuermer,E. K. Stuermer
Journal of Osteoporosis , 2011, DOI: 10.4061/2011/363617
Abstract: This study aims to investigate the effects of two application frequencies of parathyroid hormone on the trochanteric region of rat femur. Forty-three-month-old female Sprague-Dawley rats were divided into 4 groups ( /group). Three groups were ovariectomized, and 8 weeks later they were administered the following treatments (5 weeks): soy-free diet (OVX), subcutaneously injected PTH (0.040?mg/kg) 5 days a week (PTH 5x/w), subcutaneously injected PTH (0.040?mg/kg) every 2 days (PTH e2d), and a sham group. The values of the biomechanical and histomorphometric parameters showed higher results in 5x/w animals in comparison to the OVX and PTH 2ed groups. The ratio between bone diameter/marrow diameter (B.Dm/Ma.Dm) in subtrochanteric cross sections did not show any significant differences between PTH 5x/w and PTH e2d. The increased bone formation rate was observed under PTH treatment in both groups mainly at the endosteal side. The endosteum seems here to be one of the targets of PTH with an accelerate bone formation and a pronounced filling-in of intracortical cavities with higher intensity for the PTH 5x/w in comparison to PTH e2d rats. 1. Introduction In the last decade, the parathyroid hormone (PTH) has become more important as a possible alternative for the treatment of postmenopausal osteoporosis. Most of the studies with PTH have focused mainly on the dose-dependent effects of this hormone or its combination with other drugs [1–4]. Since researchers found that the intermittent substitution of PTH, in contrast to its continuous application, was able to prevent postmenopausal bone loss, the question has been which application frequency would deliver the best anabolic result [5]? The time interval between the anabolic und catabolic effects of intermittent application of PTH (“anabolic window”) is the key to respond and to understand such behavior of this hormone. In addition, another unanswered question is how PTH affects different skeletal sites like the wrist, proximal tibia, vertebral bodies and, especially, proximal femur. It is known that the trochanteric fracture of the femur is one of the most common fracture types in menopausal women. Therefore, investigations of the strength of this skeletal site after treatment with antiosteoporotic agents seem to be important and have a high clinical relevance [6]. Such investigations, however, are rare because of the difficulty in producing a reliable trochanteric fracture in animal models [7]. The ovariectomized (OVX) rat is a well-proven animal model for osteoporosis studies [8, 9]. There are many
Patchy worm-like micelles: solution structure studied by small-angle neutron scattering
S. Rosenfeldt,F. Luedel,C. Schulreich,T. Hellweg,A. Radulescu,J. Schmelz,H. Schmalz,L. Harnau
Physics , 2012, DOI: 10.1039/c2cp41231d
Abstract: Triblock terpolymers exhibit a rich self-organization behavior including the formation of fascinating cylindrical core-shell structures with a phase separated corona. After crystallization-induced self-assembly of polystryrene-(block)-polyethylene-(block)-poly(methyl methacrylate) triblock terpolymers (abbreviated as SEMs = Styrene-Ethylene-Methacrylates) from solution, worm-like core-shell micelles with a patchy corona of polystryrene and poly(methyl methacrylate) were observed by transmission electron microscopy. However, the solution structure is still a matter of debate. Here, we present a method to distinguish in-situ between a Janus-type (two faced) and a patchy (multiple compartments) configuration of the corona. To discriminate between both models the scattering intensity must be determined mainly by one corona compartment. Contrast variation in small-angle neutron scattering enables us to focus on one compartment of the SEMs. The results validate the existence of the patchy structure also in solution.
Hinode X-Ray Telescope Detection of Hot Emission from Quiescent Active Regions: A Nanoflare Signature?
J. T. Schmelz,S. H. Saar,E. E. DeLuca,L. Golub,V. L. Kashyap,M. A. Weber,J. A. Klimchuk
Physics , 2009, DOI: 10.1088/0004-637X/693/2/L131
Abstract: The X-Ray Telescope (XRT) on the Japanese/USA/UK {\it Hinode (Solar-B)} spacecraft has detected emission from a quiescent active region core that is consistent with nanoflare heating. The fluxes from 10 broadband X-ray filters and filter combinations were used to constructed Differential Emission Measure (DEM) curves. In addition to the expected active region peak at Log T = 6.3-6.5, we find a high-temperature component with significant emission measure at Log T $>$ 7.0. This emission measure is weak compared to the main peak -- the DEM is down by almost three orders of magnitude -- which accounts of the fact that it has not been observed with earlier instruments. It is also consistent with spectra of quiescent active regions: no Fe XIX lines are observed in a CHIANTI synthetic spectrum generated using the XRT DEM distribution. The DEM result is successfully reproduced with a simple two-component nanoflare model.
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