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排序方式: 共有207条查询结果,搜索用时 15 毫秒
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Shira D. Gordon Nestor Sandoval Valerio Mazzoni Rodrigo Krugner 《Entomologia Experimentalis et Applicata》2017,164(1):27-34
Animal communication is a complex behavior that is influenced by abiotic and biotic factors of the environment. Glassy‐winged sharpshooters (GWSS), Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), primarily use vibrational signaling for courtship communication. Because GWSS is a major pest, transmitting the plant pathogenic bacterium Xylella fastidiosa Wells et al., interruption of communication is a possible avenue for control. Playback of white noise, pre‐recorded female signals, and artificial female noise (continuously overlapping female signals) significantly reduced mating of GWSS when compared to silent control mating trials. Furthermore, to begin to determine the mechanism underlying playback control, female signaling activity was recorded in the presence of stimuli. In response to playback of female signals, females signaled (duet‐like) more often than females tested in the absence of playback. After the first playback, almost two‐thirds of females signaled a response within 3 s. Additionally, one‐third of the females signaled within 1 s after cessation of white noise, and significantly more in the time periods following noise termination. Results highlight how GWSS responds to differing competitive disturbances in the environment and lays important ground work that possibly could be used to develop pesticide‐free control methods. 相似文献
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Khersonsky O Röthlisberger D Wollacott AM Murphy P Dym O Albeck S Kiss G Houk KN Baker D Tawfik DS 《Journal of molecular biology》2011,407(3):391-1021
Although de novo computational enzyme design has been shown to be feasible, the field is still in its infancy: the kinetic parameters of designed enzymes are still orders of magnitude lower than those of naturally occurring ones. Nonetheless, designed enzymes can be improved by directed evolution, as recently exemplified for the designed Kemp eliminase KE07. Random mutagenesis and screening resulted in variants with > 200-fold higher catalytic efficiency and provided insights about features missing in the designed enzyme. Here we describe the optimization of KE70, another designed Kemp eliminase. Amino acid substitutions predicted to improve catalysis in design calculations involving extensive backbone sampling were individually tested. Those proven beneficial were combinatorially incorporated into the originally designed KE70 along with random mutations, and the resulting libraries were screened for improved eliminase activity. Nine rounds of mutation and selection resulted in > 400-fold improvement in the catalytic efficiency of the original KE70 design, reflected in both higher kcat values and lower Km values, with the best variants exhibiting kcat/Km values of > 5 × 104 s− 1 M− 1. The optimized KE70 variants were characterized structurally and biochemically, providing insights into the origins of the improvements in catalysis. Three primary contributions were identified: first, the reshaping of the active-site cavity to achieve tighter substrate binding; second, the fine-tuning of electrostatics around the catalytic His-Asp dyad; and, third, the stabilization of the active-site dyad in a conformation optimal for catalysis. 相似文献
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Shira D. Gordon Joseph C. Jackson Stephen M. Rogers James F. C. Windmill 《Proceedings. Biological sciences / The Royal Society》2014,281(1795)
Locusts display a striking form of phenotypic plasticity, developing into either a lone-living solitarious phase or a swarming gregarious phase depending on population density. The two phases differ extensively in appearance, behaviour and physiology. We found that solitarious and gregarious locusts have clear differences in their hearing, both in their tympanal and neuronal responses. We identified significant differences in the shape of the tympana that may be responsible for the variations in hearing between locust phases. We measured the nanometre mechanical responses of the ear''s tympanal membrane to sound, finding that solitarious animals exhibit greater displacement. Finally, neural experiments signified that solitarious locusts have a relatively stronger response to high frequencies. The enhanced response to high-frequency sounds in the nocturnally flying solitarious locusts suggests greater investment in detecting the ultrasonic echolocation calls of bats, to which they are more vulnerable than diurnally active gregarious locusts. This study highlights the importance of epigenetic effects set forth during development and begins to identify how animals are equipped to match their immediate environmental needs. 相似文献
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Zehava Grossman Jonathan M. Schapiro Itzchak Levy Daniel Elbirt Michal Chowers Klaris Riesenberg Karen Olstein-Pops Eduardo Shahar Valery Istomin Ilan Asher Bat-Sheva Gottessman Yonat Shemer Hila Elinav Gamal Hassoun Shira Rosenberg Diana Averbuch Keren Machleb-Guri Zipi Kra-Oz Sara Radian-Sade Hagit Rudich Daniela Ram Shlomo Maayan Nancy Agmon-Levin Zev Sthoeger 《PloS one》2014,9(1)
Background
Analysis of potentially different impact of Lopinavir/Ritonavir (LPV/r) on non-B subtypes is confounded by dissimilarities in the conditions existing in different countries. We retrospectively compared its impact on populations infected with subtypes B and C in Israel, where patients infected with different subtypes receive the same treatment.Methods
Clinical and demographic data were reported by physicians. Resistance was tested after treatment failure. Statistical analyses were conducted using SPSS.Results
607 LPV/r treated patients (365 male) were included. 139 had HIV subtype B, 391 C, and 77 other subtypes. At study end 429 (71%) were receiving LPV/r. No significant differences in PI treatment history and in median viral-load (VL) at treatment initiation and termination existed between subtypes. MSM discontinued LPV/r more often than others even when the virologic outcome was good (p = 0.001). VL was below detection level in 81% of patients for whom LPV/r was first PI and in 67% when it was second (P = 0.001). Median VL decrease from baseline was 1.9±0.1 logs and was not significantly associated with subtype. Median CD4 increase was: 162 and 92cells/µl, respectively, for patients receiving LPV/r as first and second PI (P = 0.001), and 175 and 98, respectively, for subtypes B and C (P<0.001). Only 52 (22%) of 237 patients genotyped while under LPV/r were fully resistant to the drug; 12(5%) were partially resistant. In48%, population sequencing did not reveal resistance to any drug notwithstanding the virologic failure. No difference was found in the rates of resistance development between B and C (p = 0.16).Conclusions
Treatment with LPV/r appeared efficient and tolerable in both subtypes, B and C, but CD4 recovery was significantly better in virologically suppressed subtype-B patients. In both subtypes, LPV/r was more beneficial when given as first PI. Mostly, reasons other than resistance development caused discontinuation of treatment. 相似文献27.
Shira Weingarten-Gabbay Susan Klaeger Siranush Sarkizova Leah R. Pearlman Da-Yuan Chen Kathleen M.E. Gallagher Matthew R. Bauer Hannah B. Taylor W. Augustine Dunn Christina Tarr John Sidney Suzanna Rachimi Hasahn L. Conway Katelin Katsis Yuntong Wang Del Leistritz-Edwards Melissa R. Durkin Christopher H. Tomkins-Tinch Pardis C. Sabeti 《Cell》2021,184(15):3962-3980.e17
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Naama Lang-Yona Alla Alster David Cummings Zohar Freiman Ruth Kaplan-Levy Achsa Lupu Nechama Malinsky-Rushansky Shira Ninio Assaf Sukenik Yehudith Viner-Mozzini Tamar Zohary 《Journal of phycology》2023,59(1):97-110
With climate change and re-oligotrophication of lakes due to restoration efforts, the relative importance of benthic cyanobacteria is increasing, but they are much less studied than their planktonic counterparts. Following a major water level rise event that inundated massive reed stands in Lake Kinneret, Israel, we discovered the appearance of a vast abundance of Gloeotrichia pisum (cyanobacteria). This provided an opportunity to investigate the biology and ecology of a benthic epiphytic colonial cyanobacterium, proliferating under altered environmental conditions, with possible toxin production potential and as a model for an invasive epiphyte. The species was identified by its typical morphology, and by sequencing its 16S rRNA gene and the intragenic space. We report on the abundance and spatial distribution of the detected colonies, their morphological characteristics, and pigment composition. High phycoerythrin content provides a brownish color and supports growth at low light levels. Genomic community composition analysis revealed that G. pisum colonies host a diverse microbial community of microalgae, cyanobacteria, bacteria, and archaea with a conserved and characteristic taxonomic composition. The Synechococcales order showed high relative abundance in the colony, as well as other prokaryotes producing secondary metabolites, such as the rhodopsin producer Pseudorhodobacter. The microbial consortium in the colonies performed nitrogen fixation. The diazotroph's phylogenetic relations were demonstrated. Tests for the presence of cyanotoxins (microcystin and cylindrospermopsin) proved negative. This study is the first documentation of this genus in Israel, providing insights into the invasive nature of G. pisum and the ecological implications of its appearance in a lake ecosystem. 相似文献
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