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21.
Jonathan C. Erickson María Herrera Mauricio Bustamante Aristide Shingiro Thomas Bowen 《PloS one》2015,10(8)
Swarms of insects instrumented with wireless electronic backpacks have previously been proposed for potential use in search and rescue operations. Before deploying such biobot swarms, an effective long-term neural-electric stimulus interface must be established, and the locomotion response to various stimuli quantified. To this end, we studied a variety of pulse types (mono- vs. bipolar; voltage- vs. current-controlled) and shapes (amplitude, frequency, duration) to parameters that are most effective for evoking locomotion along a desired path in the Madagascar hissing cockroach (G. portentosa) in response to antennal and cercal stimulation. We identified bipolar, 2 V, 50 Hz, 0.5 s voltage controlled pulses as being optimal for evoking forward motion and turns in the expected contraversive direction without habituation in ≈50% of test subjects, a substantial increase over ≈10% success rates previously reported. Larger amplitudes for voltage (1–4 V) and current (50–150 μA) pulses generally evoked larger forward walking (15.6–25.6 cm; 3.9–5.6 cm/s) but smaller concomitant turning responses (149 to 80.0 deg; 62.8 to 41.2 deg/s). Thus, the radius of curvature of the initial turn-then-run locomotor response (≈10–25 cm) could be controlled in a graded manner by varying the stimulus amplitude. These findings could be used to help optimize stimulus protocols for swarms of cockroach biobots navigating unknown terrain. 相似文献
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Valeria Catena Francesca De Nicola Frauke Goeman Simona Iezzi Cristina Sorino Maurilio Ponzoni Gianluca Bossi Vincenzo Federico Francesca La Rosa Maria Rosaria Ricciardi Elena Lesma Paolo D'Onorio De Meo Tiziana Castrignanò Maria Teresa Petrucci Francesco Pisani Marta Chesi P Leif Bergsagel Aristide Floridi Giovanni Tonon Claudio Passananti Giovanni Blandino Maurizio Fanciulli 《The EMBO journal》2015,34(9):1214-1230
Mammalian target of rapamycin (mTOR) is a key protein kinase that regulates cell growth, metabolism, and autophagy to maintain cellular homeostasis. Its activity is inhibited by adverse conditions, including nutrient limitation, hypoxia, and DNA damage. In this study, we demonstrate that Che‐1, a RNA polymerase II‐binding protein activated by the DNA damage response, inhibits mTOR activity in response to stress conditions. We found that, under stress, Che‐1 induces the expression of two important mTOR inhibitors, Redd1 and Deptor, and that this activity is required for sustaining stress‐induced autophagy. Strikingly, Che‐1 expression correlates with the progression of multiple myeloma and is required for cell growth and survival, a malignancy characterized by high autophagy response. 相似文献
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Brooke W. Bullington Myung Hee Lee Jane Mlingi Ndalloh Paul Christine Aristide Emily Fontana Eric R. Littmann Crispin Mukerebe Peter Shigella Philibert Kashangaki Samuel E. Kalluvya Claudia J. de Dood Govert J. van Dam Paul L.A.M. Corstjens Daniel W. Fitzgerald Eric G. Pamer Jennifer A. Downs 《The ISME journal》2021,15(5):1539
Schistosome infection is recognized as a potentially modifiable risk factor for HIV in women by the World Health Organization. Alterations in cervicovaginal bacteria have been associated with HIV acquisition and have not been studied in schistosome infection. We collected cervical swabs from Tanzanian women with and without S. mansoni and S. haematobium to determine effects on cervicovaginal microbiota. Infected women were treated, and follow-up swabs were collected after 3 months. 16S rRNA sequencing was performed on DNA extracted from swabs. We compared 39 women with S. mansoni with 52 uninfected controls, and 16 with S. haematobium with 27 controls. S. mansoni-infected women had increased abundance of Peptostreptococcus (p = 0.026) and presence of Prevotella timonesis (p = 0.048) compared to controls. High-intensity S. haematobium infection was associated with more diverse cervicovaginal bacterial communities than uninfected controls (p = 0.0159). High-intensity S. mansoni infection showed a similar trend (p = 0.154). At follow-up, we observed increased alpha diversity in S. mansoni (2.53 vs. 1.72, p = 0.022) and S. haematobium (2.05 vs. 1.12, p = 0.066) infection groups compared to controls. Modifications in cervicovaginal microbiota, particularly increased diversity and abundance of taxa associated with bacterial vaginosis and HIV (Peptostreptococcus, Prevotella), were associated with schistosome infection. 相似文献
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Kyle M. Douglass Nicklaus A. Sparrow Marga Bott Cristina Fernandez‐Valle Aristide Dogariu 《Journal of biophotonics》2013,6(5):387-392
Schwann cell motility was observed on laminin‐coated quartz cylinders with different curvatures over an 18 hour period. A new analysis based on difference images helped to determine the minimal radius of curvature, 46 μm, which restricted motility along the cylinder axis. The migration speed, measured by calculating differences between successive images in the time series, ranged between 0.3 to 0.8 μm per minute and is similar to previously reported rates for Schwann cells. Difference images provide a rapid and simple method for the analysis of cell motility on large populations of cells. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Maria Grazia Di Certo Enrico M Batassa Ida Casella Annalucia Serafino Aristide Floridi Claudio Passananti Paola Molinari Elisabetta Mattei 《BMC cell biology》2008,9(1):56
Background
Chimeric proteins obtained by the fusion of a G protein-coupled receptor (GPCR) sequence to the N-terminus of the G protein α-subunit have been extensively used to investigate several aspects of GPCR signalling. Although both the receptor and the G protein generally maintain a fully functional state in such polypeptides, original observations made using a chimera between the β2-adrenergic receptor (β2AR) and Gαs indicated that the fusion to the α-subunit resulted in a marked reduction of receptor desensitization and down-regulation. To further investigate this phenomenon, we have compared the rates of internalization and recycling between wild-type and Gαs-fused β2AR. 相似文献28.
Yverlin Z Pruvot Lily-Arison René de Roland Gilbert Razafimanjato Marius PH Rakotondratsima Aristide Andrianarimisa Russell Thorstrom 《Ostrich》2018,89(2):109-115
We studied the nesting biology and food habits of the endangered and endemic Sakalava Rail Amaurornis olivieri from July to November 2015 in the Mandrozo Protected Area, western Madagascar. Three nesting pairs were observed and their nests were constructed in a dense mat of reeds Phragmites mauritianus and averaged 56.7 ± 15.3 cm above the water (n = 3 nests). Nests were built by both adults and it took 3 d on average to complete a nest (n = 2 nests). Thirteen matings were observed and lasted 4.1 s on average (n = 2 pairs). Average clutch size was three eggs (n = 2 nests). Both sexes incubated; the incubation period was 15–17 d (n = 2 nests). Both male and female participated in brooding and feeding the young, which remained for 3 d in the nest and became independent of their parents at 45 d of age. Based on 194 identified food items, the Sakalava Rail’s diet was composed of invertebrates: spiders (53.1%), insects (32%), crustaceans (10.8%) and molluscs (4.1%). The home ranges of two radio-tagged individuals were 0.95 and 1.98 ha. 相似文献
29.
Liron Boyman Aristide?C. Chikando George?S.B. Williams Ramzi?J. Khairallah Sarah Kettlewell Christopher?W. Ward Godfrey?L. Smith Joseph?P.Y. Kao W.?Jonathan Lederer 《Biophysical journal》2014,107(6):1289-1301
Existing theory suggests that mitochondria act as significant, dynamic buffers of cytosolic calcium ([Ca2+]i) in heart. These buffers can remove up to one-third of the Ca2+ that enters the cytosol during the [Ca2+]i transients that underlie contractions. However, few quantitative experiments have been presented to test this hypothesis. Here, we investigate the influence of Ca2+ movement across the inner mitochondrial membrane during both subcellular and global cellular cytosolic Ca2+ signals (i.e., Ca2+ sparks and [Ca2+]i transients, respectively) in isolated rat cardiomyocytes. By rapidly turning off the mitochondria using depolarization of the inner mitochondrial membrane potential (ΔΨm), the role of the mitochondria in buffering cytosolic Ca2+ signals was investigated. We show here that rapid loss of ΔΨm leads to no significant changes in cytosolic Ca2+ signals. Second, we make direct measurements of mitochondrial [Ca2+] ([Ca2+]m) using a mitochondrially targeted Ca2+ probe (MityCam) and these data suggest that [Ca2+]m is near the [Ca2+]i level (∼100 nM) under quiescent conditions. These two findings indicate that although the mitochondrial matrix is fully buffer-capable under quiescent conditions, it does not function as a significant dynamic buffer during physiological Ca2+ signaling. Finally, quantitative analysis using a computational model of mitochondrial Ca2+ cycling suggests that mitochondrial Ca2+ uptake would need to be at least ∼100-fold greater than the current estimates of Ca2+ influx for mitochondria to influence measurably cytosolic [Ca2+] signals under physiological conditions. Combined, these experiments and computational investigations show that mitochondrial Ca2+ uptake does not significantly alter cytosolic Ca2+ signals under normal conditions and indicates that mitochondria do not act as important dynamic buffers of [Ca2+]i under physiological conditions in heart. 相似文献
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Papanicolaou KN Khairallah RJ Ngoh GA Chikando A Luptak I O'Shea KM Riley DD Lugus JJ Colucci WS Lederer WJ Stanley WC Walsh K 《Molecular and cellular biology》2011,31(6):1309-1328
Mitofusin-2 (Mfn-2) is a dynamin-like protein that is involved in the rearrangement of the outer mitochondrial membrane. Research using various experimental systems has shown that Mfn-2 is a mediator of mitochondrial fusion, an evolutionarily conserved process responsible for the surveillance of mitochondrial homeostasis. Here, we find that cardiac myocyte mitochondria lacking Mfn-2 are pleiomorphic and have the propensity to become enlarged. Consistent with an underlying mild mitochondrial dysfunction, Mfn-2-deficient mice display modest cardiac hypertrophy accompanied by slight functional deterioration. The absence of Mfn-2 is associated with a marked delay in mitochondrial permeability transition downstream of Ca(2+) stimulation or due to local generation of reactive oxygen species (ROS). Consequently, Mfn-2-deficient adult cardiomyocytes are protected from a number of cell death-inducing stimuli and Mfn-2 knockout hearts display better recovery following reperfusion injury. We conclude that in cardiac myocytes, Mfn-2 controls mitochondrial morphogenesis and serves to predispose cells to mitochondrial permeability transition and to trigger cell death. 相似文献