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Different Signals (different + signal)
Terms modified by Different Signals Selected AbstractsCharacterization of the electrical performance of different signal via geometriesMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2006Sedig S. Agili Abstract Several signal via geometries are analyzed for across and through transmission by varying the drill-hole diameter, ratio of the pad and antipad diameters to drill-hole diameter, and number of ground planes. Time- and frequency-domain results showing impedance-, insertion-, and return-loss trends, which are useful for designing via geometries for high-speed transmission, are obtained. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 315,320, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21336 [source] Regulation of glucose transporter 4 traffic by energy deprivation from mitochondrial compromiseACTA PHYSIOLOGICA, Issue 1 2009A. Klip Abstract Skeletal muscle is the major store and consumer of fatty acids and glucose. Glucose enters muscle through glucose transporter 4 (GLUT4). Upon insufficient oxygen availability or energy compromise, aerobic metabolism of glucose and fatty aids cannot proceed, and muscle cells rely on anaerobic metabolism of glucose to restore cellular energy status. An increase in glucose uptake into muscle is a key response to stimuli requiring rapid energy supply. This chapter analyses the mechanisms of the adaptive regulation of glucose transport that rescue muscle cells from mitochondrial uncoupling. Under these conditions, the initial drop in ATP recovers rapidly, through a compensatory increase in glucose uptake. This adaptive response involves AMPK activation by the initial ATP drop, which elevates cell surface GLUT4 and glucose uptake. The gain in surface GLUT4 involves different signals and routes of intracellular traffic compared with those engaged by insulin. The hormone increases GLUT4 exocytosis through phosphatidylinositol 3-kinase and Akt, whereas energy stress retards GLUT4 endocytosis through AMPK and calcium inputs. Given that energy stress is a component of muscle contraction, and that contraction activates AMPK and raises cytosolic calcium, we hypothesize that the increase in glucose uptake during contraction may also involve a reduction in GLUT4 endocytosis. [source] Sustained MAPK activation is dependent on continual NGF receptor regenerationDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2004Dongru Qiu It still remains intriguing how signal specificity is achieved when different signals are relayed by the common intracellular signal transduction pathways. A well documented example for signal specificity determination is found in rat phaeochromocytoma PC12 cells where epidermal growth factor (EGF) stimulation produces a transient mitogen-activated protein kinase (MAPK) activation and leads to cell proliferation while nerve growth factor (NGF) initiates a sustained MAPK activation and induces cell differentiation. In this simulation, we demonstrated that NGF-induced sustained MAPK activation may mainly depend on continual regeneration of NGF receptors and that the presence of a small pool of surface receptors is enough to maintain a sustained MAPK activation. On the other hand, MAPK activation is not significantly sensitive to the half-life of internalized receptors and the levels of NGF-specific MAPK phosphatase MAP kinase phosphatase-3 (MKP-3), though cytoplasmic persistence of internalized NGF-bound receptors and the MKP-3 dependent feedback control also contribute to the sustaining of MAPK activation. These results are consistent with the recent experimental evidence that persistent tyrosine receptor kinase A (TrkA) activity is necessary to maintain transcription in the differentiating PC12 cells (Chang et al. 2003) and a sustained Src kinase activity is detected in response to NGF stimulation (Gatti 2003). It is suggested that sustained or transient MAPK activation induced by different growth factor and neurotrophins, which is crucial to their signaling specificity, could be satisfactorily accounted for by their specific receptor turnover kinetics rather than by the activation of specific downstream signaling cascades. [source] MCE-electrochemical detection for following interactions of ssDNA and dsDNA with methylene blueELECTROPHORESIS, Issue 11 2009Mario Castaño-Álvarez Abstract The interaction between the organic dye, methylene blue and DNA has been studied by MCE with electrochemical detection. Interaction produces two different signals, one corresponding to free methylene blue and other, for the complex methylene blue,DNA. The hybridization between a ssDNA and a complementary sequence, specific to the severe acute respiratory syndrome virus, has been performed and studied in a thermoplastic olefin polymer of amorphous structure CE-microchip with an end-channel gold wire detector. Moreover, studies with a longer dsDNA, an expression vector involved in the transitory or stable expression in mammals cells, pFLAG-CMV4, has also been performed. [source] Osmoadaptation in bacteria and archaea: common principles and differencesENVIRONMENTAL MICROBIOLOGY, Issue 12 2001Markus Roeßler The availability of water is the most important prerequisite for life of any living cell, and exposure of cells to hypersaline conditions always threatens the cells with a drastic loss of water. To re-establish the essential turgor pressure, cells increase the water activity of their cytoplasm by accumulation of compatible solutes, either by synthesis or by uptake. The ability to respond to increasing osmolality is well conserved in all three lines of descent and, here, we compare the osmoadaptive strategies of Bacteria and Archaea. The temporal sequence of events after an osmotic upshock will be discussed, with a focus on the most rapid response, notably the mechanisms of transport activation at the protein level, and different signals for osmolality will be compared. The spectrum of compatible solutes used by different organisms is rather diverse and a comparison of ,bacterial' and ,archaeal' compatible solutes will be given. [source] Intramembrane-sensing histidine kinases: a new family of cell envelope stress sensors in Firmicutes bacteriaFEMS MICROBIOLOGY LETTERS, Issue 2 2006Thorsten Mascher Abstract Two-component signal-transducing systems (TCS) consist of a histidine kinase (HK) that senses a specific environmental stimulus, and a cognate response regulator (RR) that mediates the cellular response. Most HK are membrane-anchored proteins harboring two domains: An extracytoplasmic input and a cytoplasmic transmitter (or kinase) domain, separated by transmembrane helices that are crucial for the intramolecular information flow. In contrast to the cytoplasmic domain, the input domain is highly variable, reflecting the plethora of different signals sensed. Intramembrane-sensing HK (IM-HK) are characterized by their short input domain, consisting solely of two putative transmembane helices. They lack an extracytoplasmic domain, indicative for a sensing process at or from within the membrane interface. Most proteins sharing this domain architecture are found in Firmicutes bacteria. Two major groups can be differentiated based on sequence similarity and genomic context: (1) BceS-like IM-HK that are functionally and genetically linked to ABC transporters, and (2) LiaS-like IM-HK, as part of three-component systems. Most IM-HK sense cell envelope stress, and identified target genes are often involved in maintaining cell envelope integrity, mediating antibiotic resistance, or detoxification processes. Therefore, IM-HK seem to constitute an important mechanism of cell envelope stress response in low G+C Gram-positive bacteria. [source] Cautious response of inexperienced birds to conventional signal of stronger threatJOURNAL OF AVIAN BIOLOGY, Issue 6 2007Tomasz S. Osiejuk Several studies demonstrated that bird song functions as a first line of territorial defence. The efficiency of deterring rivals depends strongly on the strategy of singing used (e.g. alternating/overlapping singing, singing with low/high rate, matching song type of a rival or singing different type). Causes of between males variation during countersinging are still not fully understood, especially when different signals have similar production costs and their meaning is assigned by arbitrary convention (conventional signalling). We tested whether an oscine bird with small repertoire size, the ortolan bunting Emberiza hortulana, differentiate strategy of responding to song of an intruder in relation to its age and threat value of signals. We performed playback experiments to measure response of second year (SY) and after second year (ASY) males to a song of low (eventual variety singing) and high (immediate variety singing) threat value. We found substantial differences in response to playback, which were related both to the type of stimuli used and age of responding males. Both SY and ASY males gave more calls than songs in response to immediate variety playback, which suggest stronger vocal response to the signal of higher threat value. Approaching loudspeaker was similar for both age classes when lower threat value signal was played back, while simultaneously SY males clearly avoided approaching loudspeaker when stronger threat values signal was played back. We conclude that ortolan bunting differentiate response to signal of different threat value and that the strength of response depends on the age of a male. This study provides experimental evidence that age of receiver affects its response to a territorial intruder. It also demonstrates that observed in many studies variation in response to playback may be an effect of age differences between males, which rarely is controlled. [source] Biofeedback experiments with a submaximal jaw closing forceJOURNAL OF ORAL REHABILITATION, Issue 9 2002H. A. JAKSTAT Temporomandibular disorders are often accompanied with pain in the elevator muscles such as Mm. Masseterici and Mm. Temporales. In most experiments measurement of the closing force of these muscles was conducted with maximum bite force using EMG-devices. The experiments presented here were conducted using visual or audible biofeedback using force transducers. Visual feedback was presented on a computer screen using geometrical graphics. Audible feedback used two different signals, the frequency of these audio signals was modulated. The force was chosen between 5 and 30 N, which is near the forces actually used for chewing, but far less than maximum clenching force. The persons chosen for the experiments were divided into two groups: A group of younger persons did not wear any removable dentures, a group of older persons was wearing a total prosthesis of the upper and lower jaw. The results were processed statistically and graphically. The goal for the persons conducting the experiments was to select a closing force as near as possible to the given force which was shown using the biofeedback. The actual force used by the person was also shown. There were no statistically significant differences in the results using 5, 10 or 30 N as given force. Results showed that older edentulous patients can modulate the chewing force not as exactly as younger persons. Especially when using low closing forces (5 N) the edentulous persons showed less exactness in reaching the given closing force. The results of the experiments may be used to develop a test to determine the capability of older patients to perform exact closing (and chewing) movements. [source] Reactive oxygen signaling and abiotic stressPHYSIOLOGIA PLANTARUM, Issue 3 2008Gad Miller Reactive oxygen species (ROS) play a dual role in plant biology acting on the one hand as important signal transduction molecules and on the other as toxic by-products of aerobic metabolism that accumulate in cells during different stress conditions. Because of their toxicity as well as their important signaling role, the level of ROS in cells is tightly controlled by a vast network of genes termed the ,ROS gene network'. Using mutants deficient in key ROS-scavenging enzymes, we have defined a signaling pathway that is activated in cells in response to ROS accumulation. Interestingly, many of the key players in this pathway, including different zinc finger proteins and WRKY transcription factors, are also central regulators of abiotic stress responses involved in temperature, salinity and osmotic stresses. Here, we describe our recent findings and discuss how ROS integrate different signals originating from different cellular compartments during abiotic stress. [source] The Effect of Irradiance on Carboxylating/Decarboxylating Enzymes and Fumarase Activities in Mesembryanthemum crystallinum L. Exposed to Salinity StressPLANT BIOLOGY, Issue 1 2001Z. Miszalski Abstract: In Mesembryanthemum crystallinum plants, treated for 9 days with 0.4 M NaCl at low light intensities (80 - 90 or 95 - 100 ,E m -2 s -1; , = 400 - 700 nm), no day/night malate level differences (,malate) were detected. At high light (385 - 400 ,E m -2 s -1) strong stimulation of PEPC activity, accompanied by a ,malate of 11.3 mM, demonstrated the presence of CAM metabolism. This indicates that, to evolve day/night differences in malate concentration, high light is required. Salt treatment at low light induces and increases the activity of NAD- and NADP-malic enzymes by as much as 3.7- and 3.9-fold, while at high light these values reach 6.4- and 17.7-fold, respectively. The induction of activity of both malic enzymes and PEPC (phospoenolpyruvate carboxylase) take place before ,malate is detectable. An increase in SOD (superoxide dismutase) was observed in plants cultivated at high light in both control and salt-treated plants. However, in salt-treated plants this effect was more pronounced. Carboxylating and decarboxylating enzymes seem to be induced by a combination of different signals, i.e., salt and light intensity. Plants performing CAM, after the decrease of activity of both the decarboxylating enzymes at the beginning of the light period, showed an increase in these enzymes in darkness when the malate pool reaches higher levels. In CAM plants the activity of fumarase (Krebs cycle) is much lower than that in C3 plants. The role of mitochondria in CAM plants is discussed. [source] Relationship between sexual interactions and the timing of the fertile phase in captive female Japanese macaques (Macaca fuscata)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 10 2009Cécile Garcia Abstract Japanese macaques live in multi-male/multi-female social groups in which competition between males, female mate choice, and alternative male mating strategies are important determinants of mating and reproductive success. However, the extent to which adult males rely on female behavior to make their mating decisions as well as the effect of social rank on mating success are not clear as results are inconclusive, varying from study to study. In this study, we combined behavioral and endocrine data of 14 female Japanese macaques to examine the relationship between ovarian cycle phase and frequency of sexual behaviors, and to investigate how social rank influences sexual behavior in this species. We found that there was no increase in female proceptive behaviors during the fertile phase of the ovarian cycle, suggesting that female behaviors did not clearly signal the probability of conception. In spite of that, the frequencies of ejaculatory copulations were highest during this phase, indicating that the attractivity of females increased significantly during the period with higher probability of conception. Males, and especially the highest ranking male, were able to discriminate females nearing ovulation and to concentrate their mating effort, implying that the timing of ovulation was not concealed from them. The , male seemed able to monopolize most female matings, which is probably due in part to the low number of females simultaneously ovulating and to the limited number of inconspicuous places that the lower ranking males have to mate with females and avoid , male aggression. All together, these results suggest that different males may have access to different signals of ovulation and/or are differentially restrained as to how they can act on that information. The exact nature of the estrogen-related cues males use to recognize female reproductive status, and to what extent males use them warrants further investigation. Am. J. Primatol. 71:868,879, 2009. © 2009 Wiley-Liss, Inc. [source] Distinct roles of BMP receptors Type IA and IB in osteo-/chondrogenic differentiation in mesenchymal progenitors (C3H10T1/2)BIOFACTORS, Issue 2 2004Christian Kaps Abstract The functional roles of BMP type IA and IB receptors mediating differentiation into the osteogenic and chondrogenic lineage were investigated in the mesenchymal progenitor line C3H10T1/2 in vitro. The capacity of type IA and IB BMP receptors was assessed by the forced expression of the wild-type (wtBMPR-IA or IB) and of the kinase-deficient, dominant-negative form (dnBMPR-IA or -IB) in parental C3H10T1/2 progenitors as well as in C3H10T1/2 progenitors which recombinantly express BMP2 (C3H10T1/2-BMP2) or GDF5 (C3H10T1/2-GDF5). Consistent with the higher endogenous expression rate of BMPR-IA in comparison with BMPR-IB, BMPR-IA plays the dominant role in BMP2-mediated osteo-/chondrogenic development. BMPR-IB moderately influences osteogenic and hardly chondrogenic development. BMPR-IB seems to be unable to efficiently activate downstream signaling pathways upon forced expression. However, a mutation conferring constitutive activity to the BMPR-IB receptor indicates that this receptor possesses the capacity to activate downstream signaling cascades. These results suggest that in mesenchymal progenitors C3H10T1/2 BMPR-IA is responsible for the initiation of the osteogenic as well as chondrogenic development and that BMPR-IA and -IB receptor pathways are well separated in this mesenchymal progenitor line and may not substitute each other. In addition this indicates that type IB and IA BMP receptors may transmit different signals during the specification and differentiation of mesenchymal lineages. [source] Inhibitory effect of c-Met mutants on the formation of branching tubules by a porcine aortic endothelial cell lineCANCER SCIENCE, Issue 12 2006Marino Maemura The association of hepatocyte growth factor (HGF) with its high-affinity receptor (c-Met) has been shown to induce mitogenesis, motogenesis and morphogenesis in a variety of cell types. Various point mutations in c-Met have been identified in hereditary and sporadic papillary renal carcinomas as well as in other carcinomas. In the present study, we examined the effects of c-Met point mutations on the morphology of a porcine aortic endothelial (PAE) cell line. When cultured in three-dimensional collagen gel, PAE cells formed branching tubule structures, and HGF treatment caused breakdown of the structures and induced a scattered morphology. The exogenous expression of c-Met point mutants inhibited the formation of tubules. HGF treatment induced the formation of tubules by PAE cells expressing some c-Met mutants, but it induced the scattering of PAE cells expressing other c-Met mutants. The presence of a low concentration of a mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) inhibitor cancelled the inhibitory effect of the c-Met point mutations on the formation of tubules. These results suggest that c-Met point mutations affect the extracellular signal-regulated kinase (ERK) signaling required for the formation of tubules by PAE cells, and HGF binding changes the conformation of c-Met mutants, leading to the different signals required for formation of tubules and cell scattering. (Cancer Sci 2006; 97: 1343,1350) [source] | |||||||||||||