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991.
Grossi-de-Sa MF Quezado de Magalhaes M Silva MS Silva SM Dias SC Nakasu EY Brunetta PS Oliveira GR Neto OB Sampaio de Oliveira R Soares LH Ayub MA Siqueira HA Figueira EL 《Journal of biochemistry and molecular biology》2007,40(5):773-782
Different isolates of the soil bacterium Bacillus thuringiensis produce multiple crystal (Cry) proteins toxic to a variety of insects, nematodes and protozoans. These insecticidal Cry toxins are known to be active against specific insect orders, being harmless to mammals, birds, amphibians, and reptiles. Due to these characteristics, genes encoding several Cry toxins have been engineered in order to be expressed by a variety of crop plants to control insectpests. The cotton boll weevil, Anthonomus grandis, and the fall armyworm, Spodoptera frugiperda, are the major economically devastating pests of cotton crop in Brazil, causing severe losses, mainly due to their endophytic habit, which results in damages to the cotton boll and floral bud structures. A cry1Ia-type gene, designated cry1Ia12, was isolated and cloned from the Bt S811 strain. Nucleotide sequencing of the cry1Ia12 gene revealed an open reading frame of 2160 bp, encoding a protein of 719 amino acid residues in length, with a predicted molecular mass of 81 kDa. The amino acid sequence of Cry1Ia12 is 99% identical to the known Cry1Ia proteins and differs from them only in one or two amino acid residues positioned along the three domains involved in the insecticidal activity of the toxin. The recombinant Cry1Ia12 protein, corresponding to the cry1Ia12 gene expressed in Escherichia coli cells, showed moderate toxicity towards first instar larvae of both cotton boll weevil and fall armyworm. The highest concentration of the recombinant Cry1Ia12 tested to achieve the maximum toxicities against cotton boll weevil larvae and fall armyworm larvae were 230 microg/mL and 5 microg/mL, respectively. The herein demonstrated insecticidal activity of the recombinant Cry1Ia12 toxin against cotton boll weevil and fall armyworm larvae opens promising perspectives for the genetic engineering of cotton crop resistant to both these devastating pests in Brazil. 相似文献
992.
Kriechbaumer V Park WJ Piotrowski M Meeley RB Gierl A Glawischnig E 《Journal of experimental botany》2007,58(15-16):4225-4233
The auxin indole-3-acetic acid (IAA), which is essential for plant growth and development, is suggested to be synthesized via several redundant pathways. In maize (Zea mays), the nitrilase ZmNIT2 is expressed in auxin-synthesizing tissues and efficiently hydrolyses indole-3-acetonitrile to IAA. Zmnit2 transposon insertion mutants were compromised in root growth in young seedlings and sensitivity to indole-3-acetonitrile, and accumulated lower quantities of IAA conjugates in kernels and root tips, suggesting a substantial contribution of ZmNIT2 to total IAA biosynthesis in maize. An additional enzymatic function, turnover of beta-cyanoalanine, is acquired when ZmNIT2 forms heteromers with the homologue ZmNIT1. In plants carrying an insertion mutation in either nitrilase gene this activity was strongly reduced. A dual role for ZmNIT2 in auxin biosynthesis and in cyanide detoxification as a heteromer with ZmNIT1 is therefore proposed. 相似文献
993.
The ability to encode rules and to detect rule-violating events outside the focus of attention is vital for adaptive behavior. Our brain recordings reveal that violations of abstract auditory rules are processed even when the sounds are unattended. When subjects performed a task related to the sounds but not to the rule, rule violations impaired task performance and activated a network involving supratemporal, parietal and frontal areas although none of the subjects acquired explicit knowledge of the rule or became aware of rule violations. When subjects tried to behaviorally detect rule violations, the brain's automatic violation detection facilitated intentional detection. This shows the brain's capacity for abstraction - an important cognitive function necessary to model the world. Our study provides the first evidence for the task-independence (i.e. automaticity) of this ability to encode abstract rules and for its immediate consequences for subsequent mental processes. 相似文献
994.
Erich J Baker Guan N Lin Huadong Liu Ravi Kosuri 《Source code for biology and medicine》2007,2(1):1-11
Background
Advances in Internet technologies have allowed life science researchers to reach beyond the lab-centric research paradigm to create distributed collaborations. Of the existing technologies that support distributed collaborations, there are currently none that simultaneously support data storage and computation as a shared network resource, enabling computational burden to be wholly removed from participating clients. Software using computation-enable logistical networking components of the Internet Backplane Protocol provides a suitable means to accomplish these tasks. Here, we demonstrate software that enables this approach by distributing both the FASTA algorithm and appropriate data sets within the framework of a wide area network. 相似文献995.
Erni P Windhab EJ Gunde R Graber M Pfister B Parker A Fischer P 《Biomacromolecules》2007,8(11):3458-3466
Acacia gum is a hybrid polyelectrolyte containing both protein and polysaccharide subunits. We study the interfacial rheology of its adsorption layers at the oil/water interface and compare it with adsorbed layers of hydrophobically modified starch, which for economic and political reasons is often used as a substitute for Acacia gum in technological applications. Both the shear and the dilatational rheological responses of the interfaces are considered. In dilatational experiments, the viscoelastic response of the starch derivative is just slightly weaker than that for Acacia gum, whereas we found pronounced differences in shear flow: The interfaces covered with the plant gum flow like a rigid, solidlike material with large storage moduli and a linear viscoelastic regime limited to small shear deformations, above which we observe apparent yielding behavior. In contrast, the films formed by hydrophobically modified starch are predominantly viscous, and the shear moduli are only weakly dependent on the deformation. Concerning their most important technological use as emulsion stabilizers, the dynamic interfacial responses imply not only distinct interfacial dynamics but also different stabilizing mechanisms for these two biopolymers. 相似文献
996.
Loewy EH 《MedGenMed : Medscape general medicine》2007,9(1):7
The ritual of taking an oath upon graduating from medical school is, with a few exceptions, a routine requirement for graduation. Albeit that many students believe that they have taken the Hippocratic Oath, this is virtually never the case. Very often students themselves write many of these oaths, and taking such an oath impresses the student as well as the public, who are potential patients. It sketches the ethically proper way for physicians to treat their patients. Such an oath is meaningful only when it is not coerced but in reality sketches the physicians' obligations toward patients, society, and each other. The question and problem of a coerced oath are discussed. It is concluded that students when first entering medical school know that such an oath will be a requirement for graduation, and because much of the time the persons taking the oath are writing it, I believe that coercion is not a factor. It is an unfortunate fact that throughout the nation students who are known to behave in ethically inappropriate ways are nevertheless allowed to graduate. Possible ways of addressing this troubling situation are discussed. Equally troublesome is the fact that we who administer the oath as well as the students who swear to it are aware that the system of medical care makes it extremely difficult and at times impossible to truly adhere to the full implications of this oath. According to the oath, physicians (in virtually all formulations) swear that social standing (and by implication economic factors) will not change the way in which patients are treated. This becomes impossible when uninsured patients are sent away at the front desk long before the physician can interact with them. Furthermore, the current fact that physicians often are confronted with not doing what they consider a necessary test (or prescribe what they think would be the best medication) raises the problem of either lying or suggesting to the patient that he/she do so--a fact that in the long run cannot help but damage the physician's veracity and the trust which patients put in their physicians. That virtually all codes of the American Medical Association (AMA) as well as the various specialties insist that physicians work toward universal access is stressed. 相似文献
997.
Lara M. Wurster Ronak N. Shah Fabian Placzek Simon Kretschmer Michael Niederleithner Laurin Ginner Jason Ensher Michael P. Minneman Erich E. Hoover Hans Zappe Wolfgang Drexler Rainer A. Leitgeb alar Ataman 《Journal of biophotonics》2019,12(4)
A forward imaging endoscope for optical coherence tomography angiography (OCTA) featuring a piezoelectric fiber scanner is presented. Imaging is performed with an optical coherence tomography (OCT) system incorporating an akinetic light source with a center wavelength of 1300 nm, bandwidth of 90 nm and A‐line rate of 173 kHz. The endoscope operates in contact mode to avoid motion artifacts, in particular, beneficial for OCTA measurements, and achieves a transversal resolution of 12 μm in air at a rigid probe size of 4 mm in diameter and 11.3 mm in length. A spiral scan pattern is generated at a scanning frequency of 360 Hz to sample a maximum field of view of 1.3 mm. OCT images of a human finger as well as visualization of microvasculature of the human palm are presented both in two and three dimensions. The combination of morphological tissue contrast with qualitative dynamic blood flow information within this endoscopic imaging approach potentially enables improved early diagnostic capabilities of internal organs for diseases such as bladder cancer. 相似文献
998.
999.
Native and exotic plant cover vary inversely along a climate gradient 11 years following stand‐replacing wildfire in a dry coniferous forest,Oregon, USA 下载免费PDF全文
Community re‐assembly following future disturbances will often occur under warmer and more moisture‐limited conditions than when current communities assembled. Because the establishment stage is regularly the most sensitive to climate and competition, the trajectory of recovery from disturbance in a changing environment is uncertain, but has important consequences for future ecosystem functioning. To better understand how ongoing warming and rising moisture limitation may affect recovery, we studied native and exotic plant composition 11 years following complete stand‐replacing wildfire in a dry coniferous forest spanning a large gradient in climatic moisture deficit (CMD) from warm and dry low elevation sites to relatively cool and moist higher elevations sites. We then projected future precipitation, temperature and CMD at our study locations for four scenarios selected to encompass a broad range of possible future conditions for the region. Native perennials dominated relatively cool and moist sites 11 years after wildfire, but were very sparse at the warmest and driest (high CMD) sites, particularly when combined with high topographic sun exposure. In contrast, exotic species (primarily annual grasses) were dominant or co‐dominant at the warmest and driest sites, especially with high topographic sun exposure. All future scenarios projected increasing temperature and CMD in coming decades (e.g., from 4.5% to 29.5% higher CMD by the 2080's compared to the 1971–2000 average), even in scenarios where growing season (May‐September) precipitation increased. These results suggest increasing temperatures and moisture limitation could facilitate longer term (over a decade) transitions toward exotic‐dominated communities after severe wildfire when a suitable exotic seed source is present. 相似文献
1000.