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1.
M. L. Getchell B. Zielinski J. A. DeSimone T. V. Getchell 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1987,160(2):155-168
Topical application of the odorants guaiacol (10(-3) mol/l, 1-30 min) and 2-isobutyl-3-methoxypyrazine (IBMP, 10(-5)-10(-3) mol/l, 15 min) caused time- and concentration-dependent reductions in the secretory granule content of acinar cells of the superficial Bowman's glands (sBG) and moderate to extensive vacuolation in acinar cells of sBG and deep olfactory glands (dG). Topical application of 9.8 mg/ml scopolamine 10 min before 10(-4) mol/l IBMP significantly reduced the amount of secretory granule depletion from sBG compared to that seen with IBMP alone and resulted in less extensive vacuolation in sBG and dG acinar cells. The i.p. injection of 42 mg/kg propranolol 10 min before topical application of 10(-4) mol/l IBMP had no effect on the action of IBMP. Guaiacol and IBMP also had time- and concentration-dependent effects on the secretory activity of sustentacular cells in the olfactory epithelium. The protrusion of secretory material into the mucociliary matrix that covers the epithelial surface and vacuolation within the secretory material resulted from odorant application. Scopolamine and propranolol had no effects on the action of IBMP on sustentacular cell secretory activity. When applied in the vapor phase, guaiacol elicited action potentials recorded from individual olfactory receptor neurons; the impulse frequency was concentration-dependent and showed tonic and phasic components when the duration of stimulation was varied. Low to moderate concentrations of IBMP delivered in the vapor phase evoked monophasic negative slow voltage transients recorded from the surface of the olfactory mucosa. The amplitudes of these transients increased with increasing stimulus concentrations. Higher concentrations or longer stimulus durations evoked longer-latency positive-voltage generating processes and negative afterpotentials. The properties of the electrophysiological responses to both odorants were characteristic of responses evoked by a wide variety of 'typical' odorants. 相似文献
2.
Sugar-activated ion transport in canine lingual epithelium. Implications for sugar taste transduction 总被引:2,自引:1,他引:1
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There is good evidence indicating that ion-transport pathways in the apical regions of lingual epithelial cells, including taste bud cells, may play a role in salt taste reception. In this article, we present evidence that, in the case of the dog, there also exists a sugar-activated ion-transport pathway that is linked to sugar taste transduction. Evidence was drawn from two parallel lines of experiments: (a) ion-transport studies on the isolated canine lingual epithelium, and (b) recordings from the canine chorda tympani. The results in vitro showed that both mono- and disaccharides in the mucosal bath stimulate a dose-dependent increase in the short-circuit current over the concentration range coincident with mammalian sugar taste responses. Transepithelial current evoked by glucose, fructose, or sucrose in either 30 mM NaCl or in Krebs-Henseleit buffer (K-H) was partially blocked by amiloride. Among current carriers activated by saccharides, the current response was greater with Na than with K. Ion flux measurements in K-H during stimulation with 3-O-methylglucose showed that the sugar-evoked current was due to an increase in the Na influx. Ouabain or amiloride reduced the sugar-evoked Na influx without effect on sugar transport as measured with tritiated 3-O-methylglucose. Amiloride inhibited the canine chorda tympani response to 0.5 M NaCl by 70-80% and the response to 0.5 M KCl by approximately 40%. This agreed with the percent inhibition by amiloride of the short-circuit current supported in vitro by NaCl and KCl. Amiloride also partially inhibited the chorda tympani responses to sucrose and to fructose. The results indicate that in the dog: (a) the ion transporter subserving Na taste also subserves part of the response to K, and (b) a sugar-activated, Na-preferring ion-transport system is one mechanism mediating sugar taste transduction. Results in the literature indicate a similar sweet taste mechanism for humans. 相似文献
3.
S Mierson G L Heck S K DeSimone T U Biber J A DeSimone 《Biochimica et biophysica acta》1985,816(2):283-293
Ion transport across the lingual epithelium has been implicated as an early event in gustatory transduction. The fluxes of isotopically labelled Na+ and Cl- were measured across isolated canine dorsal lingual epithelium under short-circuit conditions. The epithelium actively absorbs Na+ and to a lesser extent actively secretes Cl-. Under symmetrical conditions with Krebs-Henseleit buffer on both sides, (1) Na+ absorption accounts for 46% of the short-circuit current (Isc); (2) there are two transcellular Na+ pathways, one amiloride-sensitive and one amiloride-insensitive; (3) ouabain, added to the serosal solution, inhibits both Isc and active Na+ absorption. When hyperosmotic (0.25 M) NaCl is placed in the mucosal bath, both Isc and Na+ absorption increase; net Na+ absorption is at least as much as Isc. Ion substitution studies indicate that the tissue may transport a variety of larger ions, though not as effectively as Na+ and Cl-. Thus we have shown that the lingual epithelium, like other epithelia of the gastrointestinal tract, actively transports ions. However, it is unusual both in its response to hyperosmotic solutions and in the variety of ions that support a transepithelial short-circuit current. Since sodium ion transport under hyperosmotic conditions has been shown to correlate well with the gustatory neural response, the variety of ions transported may likewise indicate a wider role for transport in taste transduction. 相似文献
4.
Cellular Concentrations and Uniformity of Cell-Type Accumulation of Two Lea Proteins in Cotton Embryos 总被引:18,自引:0,他引:18
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The levels and cell-type distribution of late embryogenesis abundant (Lea) proteins D-7 and D-113 have been determined in mature cotton embryos by immunochemical methods. The two proteins were expressed in and purified from Escherichia coli and utilized for antibody production in rabbits. The antiserum to each protein was found to interact with all members of each protein family in cotton extracts by protein gel blotting. Using these antibodies in quantitative "rocket" immunoelectrophoreses, D-7 proteins were found to accumulate to ~8 x 1015 molecules per embryo, which is equivalent to ~109 molecules per "average cell." D-113 proteins accumulate to ~1016 molecules per embryo, which equates to ~1.3 x 109 molecules per average cell. These values calculate to concentrations of about 226 and 283 [mu]M, respectively, in the cell aqueous phase immediately prior to seed desiccation. In immunocytochemical studies using the fluorophor rhodamine linked to the secondary antibody, both proteins appeared to be evenly present in the cytosol of all cell types present in the embryo, including both cotyledon and axis epidermal cells. Thus, their function does not appear related to unique functions of specific cell or tissue types. The very high molar concentrations of the two proteins, coupled with their unusual predicted structure and their cytosol location, would seem to reduce the number of their conceivable functions. 相似文献
5.
The ratio of total globin alpha to beta chain synthesis was determined in reticulocytes isolated from the blood of the members of a black family, some of whom had sickle cell trait with low blood HbS concentrations (25-30%). The results support the hypothesis that sickle cell trait individuals with low HbS concentrations also carry a gene for alpha-thalassemia. 相似文献
6.
Sandra A. DeSimone 《Restoration Ecology》2013,21(2):149-152
Researchers reexamining the relationship between restoration science and practice report a continuing scientist‐practitioner gap. As a land manager with scientific training, I offer my perspective of the chasm and describe a restoration practice infused with as much science as the realities of limited budget and time allow. The coastal sage scrub (CSS) restoration project at Starr Ranch, a 1,585 ha Audubon preserve in southern California, combines non‐chemical invasive species control, restoration, and applied research. Our practices evolve from modified scientific approaches and the scientific literature. Results from experiments with non‐optimum replication (on effects of seed rates, soil tamping, and timing of planting) nonetheless had value for management decisions. A critical practice came from academic research that encouraged cost‐effective passive restoration. Our passive restoration monitoring data showed 28–100% total native cover after 3–5 years. Another published study found that restoration success in semiarid regions is dependent on rainfall, a finding vital for understanding active restoration monitoring results that showed a range of 0–88% total native cover at the end of the first season. Work progresses through a combination of applied research, a watchful eye on the scientific literature, and “ecological intuition” informed by the scientific literature and our own findings. I suggest that it is less critical for academic scientists to address the basic questions on technique that are helpful to land managers but rather advocate practitioner training in methods to test alternative strategies and long‐term monitoring. 相似文献
7.
Scott H Robertson Chris K Smith Anna L Langhans Sara E McLinden Matthew A Oberhardt Karoly R Jakab Bette Dzamba Douglas W DeSimone Jason A Papin Shayn M Peirce 《BMC systems biology》2007,1(1):46-15
Background
Tissue morphogenesis is a complex process whereby tissue structures self-assemble by the aggregate behaviors of independently acting cells responding to both intracellular and extracellular cues in their environment. During embryonic development, morphogenesis is particularly important for organizing cells into tissues, and although key regulatory events of this process are well studied in isolation, a number of important systems-level questions remain unanswered. This is due, in part, to a lack of integrative tools that enable the coupling of biological phenomena across spatial and temporal scales. Here, we present a new computational framework that integrates intracellular signaling information with multi-cell behaviors in the context of a spatially heterogeneous tissue environment. 相似文献8.
Ippolito Alberto DeSimone Antonio Deshpande Vikram S. 《Biomechanics and modeling in mechanobiology》2022,21(4):1043-1065
Biomechanics and Modeling in Mechanobiology - Adherent cells seeded on substrates spread and evolve their morphology while simultaneously displaying motility. Phenomena such as contact guidance,... 相似文献
9.
Antonetta B.C. Buskermolen Hamsini Suresh Siamak S. Shishvan Andrea Vigliotti Antonio DeSimone Nicholas A. Kurniawan Carlijn V.C. Bouten Vikram S. Deshpande 《Biophysical journal》2019,116(10):1994-2008
Contact guidance—the widely known phenomenon of cell alignment induced by anisotropic environmental features—is an essential step in the organization of adherent cells, but the mechanisms by which cells achieve this orientational ordering remain unclear. Here, we seeded myofibroblasts on substrates micropatterned with stripes of fibronectin and observed that contact guidance emerges at stripe widths much greater than the cell size. To understand the origins of this surprising observation, we combined morphometric analysis of cells and their subcellular components with a, to our knowledge, novel statistical framework for modeling nonthermal fluctuations of living cells. This modeling framework is shown to predict not only the trends but also the statistical variability of a wide range of biological observables, including cell (and nucleus) shapes, sizes, and orientations, as well as stress-fiber arrangements within the cells with remarkable fidelity with a single set of cell parameters. By comparing observations and theory, we identified two regimes of contact guidance: 1) guidance on stripe widths smaller than the cell size (w ≤ 160 μm), which is accompanied by biochemical changes within the cells, including increasing stress-fiber polarization and cell elongation; and 2) entropic guidance on larger stripe widths, which is governed by fluctuations in the cell morphology. Overall, our findings suggest an entropy-mediated mechanism for contact guidance associated with the tendency of cells to maximize their morphological entropy through shape fluctuations. 相似文献
10.
Thymosin beta4 (Tbeta4), a 5 kDa polypeptide, is a member of the beta-thymosin family. It acts as the principal intracellular G-actin sequestering peptide and exhibits extracellular functions in angiogenesis and wound healing. The N-terminus of Tbeta4 contains a bioactive tetrapeptide, acSDKP, a negative regulator of hematopoietic stem-cell proliferation. Here, we show that both peptides inhibit mast-cell proliferation over the concentration range of 10(-6) to 10(-17) M with the maximum effect of both at 10(-14) M. Both Tbeta4 and acSDKP caused dysplastic mast-cell nuclei that were confirmed by DAPI fluorescent staining. Flow-cytometric analysis of ploidy revealed that the dysplastic nuclei were not multinucleated, but fragmented nuclei in G2 growth arrest. We could further demonstrate that 10(-8) or 10(-14) M Tbeta4 or acSDKP induce mast-cell degranulation. A concentration of 10(-8) M Tbeta4 or acSDKP caused 57 or 89% degranulation, respectively. A number of tryptic fragments of Tbeta4 were assayed beside intact Tbeta4 and the tetrapeptide, and found to be inactive. 相似文献