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Abstract The whitefly Bemisia tabaci harbors Portiera aleyrodidarum, an obligatory symbiotic bacterium, as well as several secondary symbionts, including Rickettsia, Hamiltonella, Wolbachia, Arsenophonus, Cardinium and Fritschea, the function of which is unknown. In Israel, Rickettsia is found in both the B and Q of B. tabaci biotypes, and while all other secondary symbionts are located in the bacteriomes, Rickettsia can occupy most of the body cavity of the insect. We tested whether Rickettsia influences the biology of B. tabaci and found that exposing a Rickettsia‐containing population to increasing temperatures significantly increases its tolerance to heat shock that reached 40°C, compared to a Rickettsia‐free population. This increase in tolerance to heat shock was not associated with specific induction of heat‐shock protein gene expression; however, it was associated with reduction in Rickettsia numbers as was assessed by quantitative real‐time polymerase chain reaction and fluorescence in situ hybridization analyses. To assess the causes for thermotolerance when Rickettsia is reduced, we tested whether its presence is associated with the induction of genes required for thermotolerance. We found that under normal 25°C rearing temperature, genes associated with response to stress such as cytoskeleton genes are induced in the Rickettsia‐containing population. Thus, the presence of Rickettsia in B. tabaci under normal conditions induces the expression of genes required for thermotolerance that under high temperatures indirectly lead to this tolerance. 相似文献
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The spatiotemporal dynamics of elementary Ca(2+) release events, such as "blips" and "puffs" shapes the hierarchal Ca(2+) signaling in many cell types. Despite being the building blocks of Ca(2+) patterning, the mechanism responsible for the observed properties of puffs, especially their termination is incompletely understood. In this paper, we employ a data-driven approach to gain insights into the complex dynamics of blips and puffs. We use a model of inositol 1,4,5-trisphosphate (IP(3)) receptor (IP(3)R) derived directly from single channel patch clamp data taken at 10 μM concentration of IP(3) to simulate calcium puffs. We first reproduce recent observations regarding puffs and blips and then investigate the mechanism of puff termination. Our model suggests that during a puff, IP(3)R s proceed around a loop through kinetic states from "rest" to "open" to "inhibited" and back to "rest". A puff terminates because of self-inhibition. Based on our simulations, we rule out the endoplasmic reticulum (ER) Ca(2+) depletion as a possible cause for puff termination. The data-driven approach also enables us to estimate the current through a single IP(3)R and the peak Ca(2+) concentration near the channel pore. 相似文献
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Zi-Feng Jiang Fangfang Xia Kipp W. Johnson Elizabeth Bartom Jigyasa H. Tuteja Rick Stevens Robert L. Grossman Marina Brumin Kevin P. White Murad Ghanim 《Journal of bacteriology》2012,194(23):6678-6679
“Candidatus Portiera aleyrodidarum” is the obligate primary endosymbiotic bacterium of whiteflies, including the sweet potato whitefly Bemisia tabaci, and provides essential nutrients to its host. Here we report two complete genome sequences of this bacterium from the B and Q biotypes of B. tabaci. 相似文献
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A. Konjević Ž. Milovac S. Kontsedalov S. Kanakala M. Ghanim 《Journal of Applied Entomology》2018,142(6):627-631
The whitefly Bemisia tabaci (Gennadius) is a cosmopolitan insect pest and causes great damage to many agricultural crops by direct feeding, and transmitting many plant viruses causing disastrous effects. The global distribution of B. tabaci was previously investigated, but so far, it has not been confirmed in Serbia. Sampling conducted on plants at three localities in Serbia revealed the presence of three whitefly species, one is B. tabaci Mediterranean (MED) species, a quarantine pest. Additionally, Trialeurodes vaporariorum Westwood and an Aleurodes sp. that was not identified to the species level were also confirmed. The last two are common and widespread species in Serbia. Whitefly collections were made from cabbage, kale and oilseed rape plants (Brassica oleracea, B. oleracea var. sabauda, B. napus, respectively) grown in the field, on sunflower (Helianthus annuus) grown in the greenhouse and on potted hibiscus (Hibiscus sp.) and poinsettia (Euphorbia pulcherrima) plants grown indoors. DNA sequence analysis from a portion of the Cytochrome Oxidase I gene (COI) revealed the presence of B. tabaci MED species, which is considered to be a very important pest worldwide and has been reported from neighbouring countries, however, not yet from Serbia. Bemisia tabaci MED is recorded here for the first time in Serbia. This first interception suggests its introduction with ornamentals grown indoors, with no outdoor reports and that it is not yet spread. This report is an important alert for local authorities to take the necessary steps in monitoring and preventing its possible expansion. 相似文献
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Zi-Feng Jiang Fangfang Xia Kipp W. Johnson Christopher D. Brown Elizabeth Bartom Jigyasa H. Tuteja Rick Stevens Robert L. Grossman Marina Brumin Kevin P. White Murad Ghanim 《Applied and environmental microbiology》2013,79(5):1757-1759
“Candidatus Portiera aleyrodidarum” is the primary endosymbiont of whiteflies. We report two complete genome sequences of this bacterium from the worldwide invasive B and Q biotypes of the whitefly Bemisia tabaci. Differences in the two genome sequences may add insights into the complex differences in the biology of both biotypes. 相似文献
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John R. CressmanJr. Ghanim Ullah Jokubas Ziburkus Steven J. Schiff Ernest Barreto 《Journal of computational neuroscience》2009,26(2):159-170
In these companion papers, we study how the interrelated dynamics of sodium and potassium affect the excitability of neurons,
the occurrence of seizures, and the stability of persistent states of activity. In this first paper, we construct a mathematical
model consisting of a single conductance-based neuron together with intra- and extracellular ion concentration dynamics. We
formulate a reduction of this model that permits a detailed bifurcation analysis, and show that the reduced model is a reasonable
approximation of the full model. We find that competition between intrinsic neuronal currents, sodium-potassium pumps, glia,
and diffusion can produce very slow and large-amplitude oscillations in ion concentrations similar to what is seen physiologically
in seizures. Using the reduced model, we identify the dynamical mechanisms that give rise to these phenomena. These models
reveal several experimentally testable predictions. Our work emphasizes the critical role of ion concentration homeostasis
in the proper functioning of neurons, and points to important fundamental processes that may underlie pathological states
such as epilepsy.
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John R. Cressman Jr.Email: |
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Identification and Localization of a Rickettsia sp. in Bemisia tabaci (Homoptera: Aleyrodidae) 总被引:1,自引:0,他引:1 下载免费PDF全文
Yuval Gottlieb Murad Ghanim Elad Chiel Dan Gerling Vitaly Portnoy Shimon Steinberg Galil Tzuri A. Rami Horowitz Eduard Belausov Neta Mozes-Daube Svetlana Kontsedalov Moshe Gershon Shunit Gal Nurit Katzir Einat Zchori-Fein 《Applied microbiology》2006,72(5):3646-3652
Whiteflies (Homoptera: Aleyrodidae) are sap-sucking insects that harbor “Candidatus Portiera aleyrodidarum,” an obligatory symbiotic bacterium which is housed in a special organ called the bacteriome. These insects are also home for a diverse facultative microbial community which may include Hamiltonella, Arsenophonus, Fritchea, Wolbachia, and Cardinium spp. In this study, the bacteria associated with a B biotype of the sweet potato whitefly Bemisia tabaci were characterized using molecular fingerprinting techniques, and a Rickettsia sp. was detected for the first time in this insect family. Rickettsia sp. distribution, transmission and localization were studied using PCR and fluorescence in situ hybridizations (FISH). Rickettsia was found in all 20 Israeli B. tabaci populations screened but not in all individuals within each population. A FISH analysis of B. tabaci eggs, nymphs, and adults revealed a unique concentration of Rickettsia around the gut and follicle cells, as well as a random distribution in the hemolymph. We postulate that the Rickettsia enters the oocyte together with the bacteriocytes, leaves these symbiont-housing cells when the egg is laid, multiplies and spreads throughout the egg during embryogenesis and, subsequently, disperses throughout the body of the hatching nymph, excluding the bacteriomes. Although the role Rickettsia plays in the biology of the whitefly is currently unknown, the vertical transmission on the one hand and the partial within-population infection on the other suggest a phenotype that is advantageous under certain conditions but may be deleterious enough to prevent fixation under others. 相似文献