Journal articles: 'TRPL'

1

Revuelta, J. L., and M. Jayaram. "Phycomyces blakesleeanus TRP1 gene: organization and functional complementation in Escherichia coli and Saccharomyces cerevisiae." Molecular and Cellular Biology 7, no. 8 (August 1987): 2664–70. http://dx.doi.org/10.1128/mcb.7.8.2664-2670.1987.

Full text

Abstract:

We have cloned the gene encoding the TRPF and TRPC functions of Phycomyces blakesleeanus by complementation of the corresponding activities of Escherichia coli. TRPF also complemented a trpl mutation in Saccharomyces cerevisiae. As in other filamentous fungi, such as Neurospora and Aspergillus spp., the P. blakesleeanus TRPF and TRPC formed part of a trifunctional polypeptide encoded by a single gene (called TRP1). Transcription of TRP1 in P. blakesleeanus did not appear to be regulated by light or by the nutritional status of the culture. The information on the structure and organization of a P. blakesleeanus gene derived from these studies should be useful in devising molecular genetic strategies to analyze the sensory physiology of this organism.

APA, Harvard, Vancouver, ISO, and other styles

2

Revuelta, J. L., and M. Jayaram. "Phycomyces blakesleeanus TRP1 gene: organization and functional complementation in Escherichia coli and Saccharomyces cerevisiae." Molecular and Cellular Biology 7, no. 8 (August 1987): 2664–70. http://dx.doi.org/10.1128/mcb.7.8.2664.

Full text

Abstract:

We have cloned the gene encoding the TRPF and TRPC functions of Phycomyces blakesleeanus by complementation of the corresponding activities of Escherichia coli. TRPF also complemented a trpl mutation in Saccharomyces cerevisiae. As in other filamentous fungi, such as Neurospora and Aspergillus spp., the P. blakesleeanus TRPF and TRPC formed part of a trifunctional polypeptide encoded by a single gene (called TRP1). Transcription of TRP1 in P. blakesleeanus did not appear to be regulated by light or by the nutritional status of the culture. The information on the structure and organization of a P. blakesleeanus gene derived from these studies should be useful in devising molecular genetic strategies to analyze the sensory physiology of this organism.

APA, Harvard, Vancouver, ISO, and other styles

3

Parnas, Moshe, Ben Katz, and Baruch Minke. "Open Channel Block by Ca2+ Underlies the Voltage Dependence of Drosophila TRPL Channel." Journal of General Physiology 129, no. 1 (December 26, 2006): 17–28. http://dx.doi.org/10.1085/jgp.200609659.

Full text

Abstract:

The light-activated channels of Drosophila photoreceptors transient receptor potential (TRP) and TRP-like (TRPL) show voltage-dependent conductance during illumination. Recent studies implied that mammalian members of the TRP family, which belong to the TRPV and TRPM subfamilies, are intrinsically voltage-gated channels. However, it is unclear whether the Drosophila TRPs, which belong to the TRPC subfamily, share the same voltage-dependent gating mechanism. Exploring the voltage dependence of Drosophila TRPL expressed in S2 cells, we found that the voltage dependence of this channel is not an intrinsic property since it became linear upon removal of divalent cations. We further found that Ca2+ blocked TRPL in a voltage-dependent manner by an open channel block mechanism, which determines the frequency of channel openings and constitutes the sole parameter that underlies its voltage dependence. Whole cell recordings from a Drosophila mutant expressing only TRPL indicated that Ca2+ block also accounts for the voltage dependence of the native TRPL channels. The open channel block by Ca2+ that we characterized is a useful mechanism to improve the signal to noise ratio of the response to intense light when virtually all the large conductance TRPL channels are blocked and only the low conductance TRP channels with lower Ca2+ affinity are active.

APA, Harvard, Vancouver, ISO, and other styles

4

Melior, Hendrik, Siqi Li, Ramakanth Madhugiri, Maximilian Stötzel, Saina Azarderakhsh, Susanne Barth-Weber, Kathrin Baumgardt, John Ziebuhr, and Elena Evguenieva-Hackenberg. "Transcription attenuation-derived small RNA rnTrpL regulates tryptophan biosynthesis gene expression in trans." Nucleic Acids Research 47, no. 12 (April 17, 2019): 6396–410. http://dx.doi.org/10.1093/nar/gkz274.

Full text

Abstract:

Abstract Ribosome-mediated transcription attenuation is a basic posttranscriptional regulation mechanism in bacteria. Liberated attenuator RNAs arising in this process are generally considered nonfunctional. In Sinorhizobium meliloti, the tryptophan (Trp) biosynthesis genes are organized into three operons, trpE(G), ppiD-trpDC-moaC-moeA, and trpFBA-accD-folC, of which only the first one, trpE(G), contains a short ORF (trpL) in the 5′-UTR and is regulated by transcription attenuation. Under conditions of Trp sufficiency, transcription is terminated between trpL and trpE(G), and a small attenuator RNA, rnTrpL, is produced. Here, we show that rnTrpL base-pairs with trpD and destabilizes the polycistronic trpDC mRNA, indicating rnTrpL-mediated downregulation of the trpDC operon in trans. Although all three trp operons are regulated in response to Trp availability, only in the two operons trpE(G) and trpDC the Trp-mediated regulation is controlled by rnTrpL. Together, our data show that the trp attenuator coordinates trpE(G) and trpDC expression posttranscriptionally by two fundamentally different mechanisms: ribosome-mediated transcription attenuation in cis and base-pairing in trans. Also, we present evidence that rnTrpL-mediated regulation of trpDC genes expression in trans is conserved in Agrobacterium and Bradyrhizobium, suggesting that the small attenuator RNAs may have additional conserved functions in the control of bacterial gene expression.

APA, Harvard, Vancouver, ISO, and other styles

5

Vassort, Guy, and Julio Alvarez. "Transient receptor potential: a large family of new channels of which several are involved in cardiac arrhythmiaThis article is one of a selection of papers from the NATO Advanced Research Workshop on Translational Knowledge for Heart Health (published in part 1 of a 2-part Special Issue)." Canadian Journal of Physiology and Pharmacology 87, no. 2 (February 2009): 100–107. http://dx.doi.org/10.1139/y08-112.

Full text

Abstract:

The transient receptor potential (TRP) family of ion channels comprises more than 50 cation-permeable channels expressed throughout the animal kingdom. TRPs can be grouped into 7 main subfamilies according to structural homology: the TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPP (polycystin), TRPML (mucolipin), TRPA (ankyrin), and TRPN (NO mechanopotential). During the past 20 years, the cloning and characterization after reexpression of most members of these cation channels have led to a plethora of data and more recently to some understanding of their roles in various cells and tissues. Specifically in the heart, TRPs are known to be involved in various diseases, including hypertrophy, heart failure, and arrhythmia. The later part of this review focuses on the potential contribution of TRPs to cardiac rhythm and their potential proarrhythmic effects. Furthermore, several neurotransmitters that activate the formation of diacylglycerol could modulate cardiac rhythm or, like ATP, induce arrhythmia.

APA, Harvard, Vancouver, ISO, and other styles

6

Paradkar, Ashish S., Leo C. Vining, and Colin Stuttard. "Characterization of tryptophan-requiring auxotrophs of Streptomyces venezuelae ISP5230." Canadian Journal of Microbiology 37, no. 5 (May 1, 1991): 333–38. http://dx.doi.org/10.1139/m91-054.

Full text

Abstract:

The growth supplement requirements in minimal medium, the identity of metabolic intermediates accumulated, and the activity of tryptophan biosynfhetic enzymes detectable in cell extracts allowed the trp mutations in 10 auxotrophic strains of Streptomyces venezuelae ISP5230 to be determined. Three strains contained lesions in the trpA and two in the trpB subunits of tryptophan synthetase; two other strains were either double (trpA, trpB) mutants or contained a polar mutation in one of the subunit genes. Two strains with trpC mutations and one with a trpD mutation were also identified. When considered with information about the relative location of the auxotrophic markers obtained in this and earlier studies, the results indicated that trpA, trpB, and trpC are clustered near hisA and hisB, while trpD is in a separate position near nicB. The arrangement resembles that of the comparable genes in Streptomyces coelicolor A3(2). Key words: tryptophan auxotrophs, Streptomyces venezuelae, mutation loci, tryptophan biosynthesis genes.

APA, Harvard, Vancouver, ISO, and other styles

7

Sharma, Deep, Rekha Rana, and Kiran Thakur. "A REVIEW ON ROLE OF TRPV CATION CHANNELS." Journal of Biomedical and Pharmaceutical Research 10, no. 2 (March 30, 2021): 32–51. http://dx.doi.org/10.32553/jbpr.v10i2.857.

Full text

Abstract:

The mammalian branch of the Transient Receptor Potential (TRP) superfamily of cation channels consists of 28 members. They can be subdivided in six main subfamilies: the TRPC (‘Canonical’), TRPV (‘Vanilloid’), TRPM (‘Melastatin’), TRPP (‘Polycystin’), TRPML (‘Mucolipin’) and the TRPA (‘Ankyrin’) group. The TRPV subfamily comprises channels that are critically involved in nociception and thermo-sensing (TRPV1, TRPV2, TRPV3, TRPV4) as well as highly Ca2+ selective channels involved in Ca2+ absorption/ reabsorption in mammals (TRPV5, TRPV6). In this review we summarize fundamental physiological properties of all TRPV members in the light of various cellular functions of these channels and their significance in the various diseases.

APA, Harvard, Vancouver, ISO, and other styles

8

Walker, Rebecca L., Joseph R. Hume, and Burton Horowitz. "Differential expression and alternative splicing of TRP channel genes in smooth muscles." American Journal of Physiology-Cell Physiology 280, no. 5 (May 1, 2001): C1184—C1192. http://dx.doi.org/10.1152/ajpcell.2001.280.5.c1184.

Full text

Abstract:

Nonselective cation channels (NSCC) are targets of excitatory agonists in smooth muscle, representing the nonselective cation current I cat. Na+ influx through NSCC causes depolarizations and activates voltage-dependent Ca2+ channels, resulting in contraction. The molecular identity of I cat in smooth muscle has not been elucidated; however, products of the transient receptor potential (TRP) genes have characteristics similar to native I cat. We have determined the levels of TRP transcriptional expression in several murine and canine gastrointestinal and vascular smooth muscles and have analyzed the alternative processing of these transcripts. Of the seven TRP gene family members, transcripts for TRP4, TRP6, and TRP7 were detected in all murine and canine smooth muscle cell preparations. TRP3 was detected only in canine renal artery smooth muscle cells. The full-length cDNAs for TRP4, TRP6, and TRP7, as well as one splice variant of TRP4 and two splice variants of TRP7, were cloned from murine colonic smooth muscle. Quantitative RT-PCR determined the relative amounts of TRP4, TRP6, and TRP7 transcripts, as well as that of the splice variants, in several murine smooth muscles. TRP4 is the most highly expressed, while TRP6 and TRP7 are expressed at a lower level in the same tissues. Splice variants for TRP7, deleted for exons encoding amino acids including transmembrane segment S1, predominated in murine smooth muscles, while the full-length form of the transcript was expressed in canine smooth muscles.

APA, Harvard, Vancouver, ISO, and other styles

9

LAN, Ling, Helen BRERETON, and J. Greg BARRITT. "The role of calmodulin-binding sites in the regulation of the Drosophila TRPL cation channel expressed in Xenopus laevis oocytes by Ca2+, inositol 1,4,5-trisphosphate and GTP-binding proteins." Biochemical Journal 330, no. 3 (March 15, 1998): 1149–58. http://dx.doi.org/10.1042/bj3301149.

Full text

Abstract:

The roles of calmodulin-binding sites in the regulation by Ca2+, inositol 1,4,5-trisphosphate (InsP3) and GTP-binding regulatory proteins (G-proteins) of the Drosophila melanogaster TRPL (transient-receptor-potential-like) non-specific Ca2+ channel were investigated. Wild-type TRPL protein and two mutant forms, TRPL (W713G) and TRPL (W814G), in which a key tryptophan residue in each of the two putative calmodulin-binding sites (Sites 1 and 2, respectively) was replaced by glycine, were expressed heterologously in Xenopuslaevis oocytes. Immunofluorescence studies indicated that the expressed TRPL, TRPL (W713G) and TRPL (W814G) proteins are located at the plasma membrane. TRPL oocytes (oocytes injected with trpl cRNA) and TRPL (W814G) oocytes [oocytes injected with trpl (W814G) cRNA] exhibited substantially greater rates of basal (constitutive) Ca2+ inflow (measured using fluo-3 and the Ca2+ add-back protocol) than mock-injected oocytes (mock oocytes). In TRPL (W713G) oocytes, this difference was abolished. In TRPL and TRPL (W814G) [oocytes injected with trpl (W713G) cRNA], but not in TRPL (W713G) oocytes, basal Ca2+ inflow was inhibited by W13, an inhibitor of calmodulin action. Calmodulin (3 μM intracellular) inhibited basal Ca2+ inflow in TRPL but not in TRPL (W713G) or TRPL (W814G) oocytes. Staurosporin, an inhibitor of protein kinase C (PKC), inhibited, while PMA (an activator of PKC) stimulated, basal Ca2+ inflow in TRPL oocytes. In oocytes incubated in the presence of PMA (to suppress Ca2+ inflow through endogenous receptor-activated Ca2+ channels), the InsP3-induced stimulation of Ca2+ inflow through TRPL channels was more clearly evident than in oocytes incubated in the absence of PMA. InsP3 caused a significant stimulation of Mn2+ inflow in TRPL but not in mock oocytes. Rates of InsP3-stimulated Ca2+ inflow through the TRPL, TRPL (W713G) and TRPL (W814G) channels were similar. The ability of GTPγS to stimulate Ca2+ inflow through TRPL channels was inhibited by 50% in TRPL (W713G) oocytes but was unaffected in TRPL (W814G) oocytes. It is concluded that, in the environment of the Xenopus oocyte, the Drosophila TRPL channel is activated by (a) interaction with Ca2+/calmodulin at calmodulin-binding Site 1; (b) PKC; (c) InsP3 in a process that does not involve Ca2+ and calmodulin; and (d) a trimeric G-protein(s) through both a Ca2+/calmodulin-dependent and a Ca2+/calmodulin-independent mechanism.

APA, Harvard, Vancouver, ISO, and other styles

10

Melior, Hendrik, Siqi Li, Maximilian Stötzel, Sandra Maaß, Rubina Schütz, Saina Azarderakhsh, Aleksei Shevkoplias, et al. "Reprograming of sRNA target specificity by the leader peptide peTrpL in response to antibiotic exposure." Nucleic Acids Research 49, no. 5 (February 22, 2021): 2894–915. http://dx.doi.org/10.1093/nar/gkab093.

Full text

Abstract:

Abstract Trans-acting regulatory RNAs have the capacity to base pair with more mRNAs than generally detected under defined conditions, raising the possibility that sRNA target specificities vary depending on the specific metabolic or environmental conditions. In Sinorhizobium meliloti, the sRNA rnTrpL is derived from a tryptophan (Trp) transcription attenuator located upstream of the Trp biosynthesis gene trpE(G). The sRNA rnTrpL contains a small ORF, trpL, encoding the 14-aa leader peptide peTrpL. If Trp is available, efficient trpL translation causes transcription termination and liberation of rnTrpL, which subsequently acts to downregulate the trpDC operon, while peTrpL is known to have a Trp-independent role in posttranscriptional regulation of antibiotic resistance mechanisms. Here, we show that tetracycline (Tc) causes rnTrpL accumulation independently of Trp availability. In the presence of Tc, rnTrpL and peTrpL act collectively to destabilize rplUrpmA mRNA encoding ribosomal proteins L21 and L27. The three molecules, rnTrpL, peTrpL, and rplUrpmA mRNA, form an antibiotic-dependent ribonucleoprotein complex (ARNP). In vitro reconstitution of this ARNP in the presence of competing trpD and rplU transcripts revealed that peTrpL and Tc cause a shift of rnTrpL specificity towards rplU, suggesting that sRNA target prioritization may be readjusted in response to changing environmental conditions.

APA, Harvard, Vancouver, ISO, and other styles

11

ESTACION, Mark, William G. SINKINS, and William P. SCHILLING. "Stimulation of Drosophila TrpL by capacitative Ca2+ entry." Biochemical Journal 341, no. 1 (June 24, 1999): 41–49. http://dx.doi.org/10.1042/bj3410041.

Full text

Abstract:

Trp-like protein (TrpL, where Trp is transient receptor-potential protein) of Drosophila, a non-selective cation channel activated in photoreceptor cells by a phospholipase C-dependent mechanism, is thought to be a prototypical receptor-activated channel. Our previous studies showed that TrpL channels are not activated by depletion of internal Ca2+ stores when expressed in Sf9 cells. Using fura-2 to measure cation influx via TrpL, and cell-attached patch recordings to monitor TrpL single-channel activity directly, we have found a thapsigargin-induced increase in TrpL activity in the presence of extracellular bivalent cations, with Ca2+ > Sr2+ Ba2+. The increase in TrpL channel activity was blocked by concentrations of La3+ that completely inhibited endogenous capacitative Ca2+ entry (CCE), but have no effect on TrpL, suggesting that TrpL exhibits trans-stimulation by cation entry via CCE. TrpL has two putative calmodulin (CaM)-binding domains, designated CBS-1 and CBS-2. To determine which site may be required for stimulation of TrpL by the cytosolic free Ca2+ concentration ([Ca2+]i), a chimaeric construct was created in which the C-terminal domain of TrpL containing CBS-2 was attached to human TrpC1, a short homologue of Trp that is not activated by depletion of internal Ca2+ stores or by a rise in [Ca2+]i. This gain-of-function mutant, designated TrpC1-TrpL, exhibited trans-stimulation by Ca2+ entry via CCE. Examination of CaM binding in gel-overlay experiments showed that TrpL and the TrpC1-TrpL chimaera bound CaM, but TrpC1 or a truncated version of TrpL lacking CBS-2 did not. These results suggest that only CBS-2 binds CaM in native TrpL and that the C-terminal domain containing this site is important for trans-stimulation of TrpL by CCE.

APA, Harvard, Vancouver, ISO, and other styles

12

Delgado, Ricardo, and Juan Bacigalupo. "Unitary Recordings of TRP and TRPL Channels From Isolated Drosophila Retinal Photoreceptor Rhabdomeres: Activation by Light and Lipids." Journal of Neurophysiology 101, no. 5 (May 2009): 2372–79. http://dx.doi.org/10.1152/jn.90578.2008.

Full text

Abstract:

Transient receptor potential (TRP) channels play key roles in sensory transduction. The TRP family founding members, the Drosophila light-dependent channels, were previously studied under voltage clamp, but had not been characterized in intact rhabdomeres at single-channel level. We report patch-clamp recordings from intact isolated photoreceptors of wt and mutant flies lacking TRP ( trp 343), TRPL ( trpl 302), or both channels ( trp 313 ; trpl 302). Unitary currents were activated by light in rhabdomere-attached patches. In excised rhabdomeral patches, the channels were directly activated by molecules implicated in phototransduction, such as diacylglycerol and polyunsaturated fatty acids. Currents recorded from trpl photoreceptors are blocked by external Ca2+, Mg2+ (1 mM), and La3+ (20 μM), whereas those from trp photoreceptors are not. Rhabdomeric patches lacked voltage-dependent activity. Patches from trp;trpl mutants were devoid of channels. These characteristics match the macroscopic conductances, suggesting that the unitary currents from Drosophila trpl and trp photoreceptors correspond to TRP and TRPL.

APA, Harvard, Vancouver, ISO, and other styles

13

Dong, Y., D. L. Kunze, L. Vaca, and W. P. Schilling. "Ins(1,4,5)P3 activates Drosophila cation channel Trpl in recombinant baculovirus-infected Sf9 insect cells." American Journal of Physiology-Cell Physiology 269, no. 5 (November 1, 1995): C1332—C1339. http://dx.doi.org/10.1152/ajpcell.1995.269.5.c1332.

Full text

Abstract:

The trp-like (trpl) gene product (Trpl) is thought to form a nonselective cation channel important for signal transduction in Drosophila photoreceptor cells. This channel may be the insect homologue of mammalian channels involved in Ca2+ signal transduction. To determine the mechanism of receptor-mediated activation of Trpl, whole cell membrane currents were examined in Sf9 insect cells after infection with recombinant baculovirus. Stimulation by bradykinin increased whole cell Trpl currents three- to fivefold. Similar activation of Trpl was observed by inclusion of D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] in the pipette solution during whole cell recordings. These currents were 1) not seen in noninfected cells or in cells expressing only the B2 receptor, 2) mimicked by D-myo-inositol 2,4,5-trisphosphate, and 3-deoxy-3-fluoro-D-myo-inositol 1,4,5-trisphosphate, 3) not seen with D-myo-inositol 1,4-bisphosphate or D-myo-inositol 1,3,4,5-tetrakisphosphate, and 4) blocked by heparin, but not by de-N-sulfated heparin. In contrast, Trpl currents were unaffected by thapsigargin. These results demonstrate that the Trpl cation channel is activated by Ins(1,4,5)P3 in a heparin-sensitive fashion. Regulation of channel activity by Ins(1,4,5)P3 may occur by a number of mechanisms, including direct binding of Ins(1,4,5)P3 to the Trpl channel or direct physical interaction between the Ins(1,4,5)P3 receptor/Ca(2+)-release channel of the endoplasmic reticulum and the Trpl protein.

APA, Harvard, Vancouver, ISO, and other styles

14

Zhang, Lin, Ning Li, Buddhi Dayananda, Lihu Wang, Huimin Chen, and Yunpeng Cao. "Genome-Wide Identification and Phylogenetic Analysis of TRP Gene Family Members in Saurian." Animals 12, no. 24 (December 19, 2022): 3593. http://dx.doi.org/10.3390/ani12243593.

Full text

Abstract:

The transient receptor potential plays a critical role in the sensory nervous systems of vertebrates in response to various mechanisms and stimuli, such as environmental temperature. We studied the physiological adaptive evolution of the TRP gene in the saurian family and performed a comprehensive analysis to identify the evolution of the thermo-TRPs channels. All 251 putative TRPs were divided into 6 subfamilies, except TRPN, from the 8 saurian genomes. Multiple characteristics of these genes were analyzed. The results showed that the most conserved proteins of TRP box 1 were located in motif 1, and those of TRP box 2 were located in motif 10. The TRPA and TRPV in saurian tend to be one cluster, as a sister cluster with TRPC, and the TRPM is the root of group I. The TRPM, TRPV, and TRPP were clustered into two clades, and TRPP were organized into TRP PKD1-like and PKD2-like. Segmental duplications mainly occurred in the TRPM subfamily, and tandem duplications only occurred in the TRPV subfamily. There were 15 sites to be under positive selection for TRPA1 and TRPV2 genes. In summary, gene structure, chromosomal location, gene duplication, synteny analysis, and selective pressure at the molecular level provided some new evidence for genetic adaptation to the environment. This result provides a basis for identifying and classifying TRP genes and contributes to further elucidating their potential function in thermal sensors.

APA, Harvard, Vancouver, ISO, and other styles

15

LAN, Ling, Michael J. BAWDEN, Amanda M. AULD, and Greg J. BARRITT. "Expression of Drosophila trpl cRNA in Xenopus laevis oocytes leads to the appearance of a Ca2+ channel activated by Ca2+ and calmodulin, and by guanosine 5′[γ-thio]triphosphate." Biochemical Journal 316, no. 3 (June 15, 1996): 793–803. http://dx.doi.org/10.1042/bj3160793.

Full text

Abstract:

The effects of expression of the Drosophila melanogaster Trpl protein, which is thought to encode a putative Ca2+ channel [Phillips, Bull and Kelly (1992) Neuron 8, 631–642], on divalent cation inflow in Xenopus laevis oocytes were investigated. The addition of extracellular Ca2+ ([Ca2+]o) to oocytes injected with trpl cRNA and to mock-injected controls, both loaded with the fluorescent Ca2+ indicator fluo-3, induced a rapid initial and a slower sustained rate of increase in fluorescence, which were designated the initial and sustained rates of Ca2+ inflow respectively. Compared with mock-injected oocytes, trpl-cRNA-injected oocytes exhibited a higher resting cytoplasmic free Ca2+ concentration ([Ca2+]i), and higher initial and sustained rates of Ca2+ inflow in the basal (no agonist) states. The basal rate of Ca2+ inflow in trpl-cRNA-injected oocytes increased with (1) an increase in the time elapsed between injection of trpl cRNA and the measurement of Ca2+ inflow, (2) an increase in the amount of trpl cRNA injected and (3) an increase in [Ca2+]o. Gd3+ inhibited the trpl cRNA-induced basal rate of Ca2+ inflow, with a concentration of approx. 5 μM Gd3+ giving half-maximal inhibition. Expression of trpl cRNA also caused an increase in the basal rate of Mn2+ inflow. The increases in resting [Ca2+]i and in the basal rate of Ca2+ inflow induced by expression of trpl cRNA were inhibited by the calmodulin inhibitors W13, calmodazolium and peptide (281–309) of (Ca2+ and calmodulin)-dependent protein kinase II. A low concentration of exogenous calmodulin (introduced by microinjection) activated, and a higher concentration inhibited, the trpl cRNA-induced increase in basal rate of Ca2+ inflow. The action of the high concentration of exogenous calmodulin was reversed by W13 and calmodazolium. When rates of Ca2+ inflow in trpl-cRNA-injected oocytes were compared with those in mock-injected oocytes, the guanosine 5´-[β-thio]diphosphate-stimulated rate was greater, the onset of thapsigargin-stimulated initial rate somewhat delayed and the inositol 1,4,5-trisphosphate-stimulated initial rate markedly inhibited. It is concluded that (1) the divalent cation channel activity of the Drosophila Trpl protein can be detected in Xenopus oocytes; (2) in the environment of the Xenopus oocyte the Trpl channel admits some Mn2+ as well as Ca2+, is activated by cytoplasmic free Ca2+ (through endogenous calmodulin) and by a trimeric GTP-binding regulatory protein, but does not appear to be activated by depletion of Ca2+ in the endoplasmic reticulum; and (3) expression of the Trpl protein inhibits the process by which the release of Ca2+ from intracellular stores activates endogenous store-activated Ca2+ channels.

APA, Harvard, Vancouver, ISO, and other styles

16

Kunze, D. L., W. G. Sinkins, L. Vaca, and W. P. Schilling. "Properties of single Drosophila Trpl channels expressed in Sf9 insect cells." American Journal of Physiology-Cell Physiology 272, no. 1 (January 1, 1997): C27—C34. http://dx.doi.org/10.1152/ajpcell.1997.272.1.c27.

Full text

Abstract:

The transient receptor potential (trp)-like (trpl) gene is thought to encode an ion channel important for signal transduction in Drosophila photoreceptor cells. Consistent with this hypothesis, heterologous expression of the trpl-encoded protein (Trpl) is associated with the appearance of an outwardly rectifying, nonselective cation current. In the present study, single channels were recorded in cell-attached, inside-out, and outside-out membrane patches from Sf9 insect cells infected with recombinant baculovirus-containing trpl cDNA under control of the polyhedrin promoter. The single-channel current-voltage relationship was linear from -100 to +80 mV with a slope conductance of 89-110 pS. The probability of opening was voltage sensitive, increasing at positive potentials contributing to the outwardly rectifying properties of the whole cell currents. The single channels 1) were never observed in Sf9 cells infected with recombinant baculovirus containing the B2 bradykinin receptor cDNA or in noninfected Sf9 cells; 2) appear at the same time postinfection as the Trpl whole cell current; 3) were nonselective with respect to Na+, Ca2+, and Ba2+; 4) were blocked by 1-2 mM La3+ and Gd3+ (but not 10 microM); and 5) were blocked by 4-8 mM Mg2+. The single Trpl channel activity increased spontaneously with time after patch formation, and the activity was further increased by application of bradykinin to cells expressing both the B2 bradykinin receptor and the Trpl protein. These results suggest that this single-channel activity reflects expression of the Trpl protein and provides conclusive evidence that trpl encodes a nonselective cation channel consistent with its proposed role in Drosophila phototransduction.

APA, Harvard, Vancouver, ISO, and other styles

17

Rhodes-Mordov, Elisheva, Tal Brandwine-Shemmer, Rachel Zaguri, Rita Gutorov, Maximilian Peters, and Baruch Minke. "Diacylglycerol Activates the Drosophila Light Sensitive Channel TRPL Expressed in HEK Cells." International Journal of Molecular Sciences 24, no. 7 (March 27, 2023): 6289. http://dx.doi.org/10.3390/ijms24076289.

Full text

Abstract:

Physiological activation by light of the Drosophila TRP and TRP-like (TRPL) channels requires the activation of phospholipase Cβ (PLC). The hydrolysis of phosphatidylinositol 4,5, bisphosphate (PIP2) by PLC is a crucial step in the still-unclear light activation, while the generation of Diacylglycerol (DAG) by PLC seems to be involved. In this study, we re-examined the ability of a DAG analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG) to activate the TRPL channels expressed in HEK cells. Unlike previous studies, we added OAG into the cytosol via a patch-clamp pipette and observed robust activation of the expressed TRPL channels. However, TRPL channel activation was much slower than the physiologically activated TRPL by light. Therefore, we used a picosecond-fast optically activated DAG analogue, OptoDArG. Inactive OptoDArG was added into the intracellular solution with the patch-clamp pipette, and it slowly accumulated on the surface membrane of the recorded HEK cell in the dark. A fast application of intense UV light to the recorded cell resulted in a robust and relatively fast TRPL-dependent current that was greatly accelerated by the constitutively active TRPLF557I pore-region mutation. However, this current of the mutant channel was still considerably slower than the native light-induced TRPL current, suggesting that DAG alone is not sufficient for TRPL channel activation under physiological conditions.

APA, Harvard, Vancouver, ISO, and other styles

18

Hu, Y., and W. P. Schilling. "Receptor-mediated activation of recombinant Trpl expressed in Sf9 insect cells." Biochemical Journal 305, no. 2 (January 15, 1995): 605–11. http://dx.doi.org/10.1042/bj3050605.

Full text

Abstract:

The Drosophila proteins, Trp and Trpl, are suggested to be cation channels responsible for depolarization of the receptor potential associated with stimulation of insect photoreceptor cells by light. Consistent with this hypothesis, we recently showed that recombinant Trpl forms Ca(2+)- and Ba(2+)-permeable non-selective cation channels when expressed in Sf9 cells using the baculovirus expression vector. As Trpl may be activated in the photoreceptor cell after stimulation of phospholipase C, we hypothesized that a similar regulation of recombinant Trpl may be observed in the Sf9 cell after activation of heterologous membrane receptors linked to Ca(2+)-signal-transduction pathways. To test this hypothesis, Ca2+ signalling was examined in Fura-2-loaded Sf9 cells infected with baculovirus containing cDNA for the M5 muscarinic receptor alone (M5 cells) or in cells co-infected with both M5 and Trpl-containing baculoviruses (M5-Trpl cells). Addition of carbachol (100 microM) to M5 cells produced an increase in cytosolic free Ca2+ concentration ([Ca2+]i) (mean +/- S.D.; n = 17) from 101 +/- 20 to 762 +/- 178 nM which declined to a sustained elevated level of 384 +/- 102 nM after 3 min. The sustained component was eliminated by removal of extracellular Ca2+ or by addition of La3+ or Gd3+ (10 microM). In M5-Trpl cells, basal [Ca2+]i increased as a function of time after infection. To evaluate the contribution of Ca2+ influx to the overall profile observed, Ba2+, a Ca2+ surrogate that is not a substrate for the Ca2+ pump, was used. The increase in basal [Ca2+]i seen in M5-Trpl cells was associated with an increase in basal Ba2+ influx. Addition of carbachol to M5-Trpl cells at 30-36 h after infection produced a large increase in [Ca2+]i to a sustained value of 677 +/- 143 nM. This change in [Ca2+]i was (1) blocked by atropine, (2) attenuated in the absence of extracellular Ca2+, and (3) relatively insensitive to La3+, but blocked by Gd3+ in the 0.1-1 mM range. In the presence of 10 microM Gd3+ to block the endogenous-receptor-mediated Ca(2+)-influx in M5-Trpl cells. In sharp contrast increase in Ba2+ influx in M5-Trpl cells. In sharp contrast, neither Ca2+ nor Ba2+ influx through Trpl was affected by thapsigargin, a selective inhibitor of the endoplasmic reticulum Ca(2+)-ATPase pump.(ABSTRACT TRUNCATED AT 400 WORDS)

APA, Harvard, Vancouver, ISO, and other styles

19

Josi, Ahmat. "Perancangan sistem informasi prodi Teknologi Rekayasa Perangkat Lunak (TRPL)." JATISI (Jurnal Teknik Informatika dan Sistem Informasi) 9, no. 3 (September 14, 2022): 2664–75. http://dx.doi.org/10.35957/jatisi.v9i3.1510.

Full text

Abstract:

Prodi Teknologi Rekayasa Perangkat Lunak (TRPL) Politeknik Manufaktur Negeri Bangka Belitung (Polmanbabel), merupakan salah satu program studi yang bergerak dibidang IT. Saat ini prodi TRPL belum mempunyai sistem informasi khusus untuk penyebaran informasi, dan media arsip, sehingga mempersulit masyarakat untuk menemukan informasi terkait dengan prodi TRPL, untuk mengatasi hal tersebut diperlukan sebuah media yang bisa membantu Prodi Teknologi Rekayasa Perangkat Lunak (TRPL) dalam mempublikasikan informasi khusus prodi TRPL. Salah satu media yang bisa membantu untuk penyebaran informasi sekaligus arsip prodi ialah media sistem informasi. Sistem Informasi merupakan susunan dan kumpulan yang terdiri dari perangkat keras, perangkat lunak dan tenaga pelaksanaannya yang bekerja dalam sebuah proses berurutan dan secara bersama-sama saling berkaitan antara satu dan lainnya untuk menghasilkan sebuah produk. Untuk membangun sebuah sistem informasi dapat dilakukan melalui beberapa metode antara lain metode waterfall, SLDC dan web engenering. web engineering (rekayasa web) adalah suatu metode rekayasa perangkat lunak yang digunakan untuk pengembangan sistem ataupun aplikasi berbasis web

APA, Harvard, Vancouver, ISO, and other styles

20

Schopf, Krystina, Thomas K. Smylla, and Armin Huber. "Immunocytochemical Labeling of Rhabdomeric Proteins inDrosophilaPhotoreceptor Cells Is Compromised by a Light-dependent Technical Artifact." Journal of Histochemistry & Cytochemistry 67, no. 10 (June 27, 2019): 745–57. http://dx.doi.org/10.1369/0022155419859870.

Full text

Abstract:

Drosophila photoreceptor cells are employed as a model system for studying membrane protein transport. Phototransduction proteins like rhodopsin and the light-activated TRPL ion channel are transported within the photoreceptor cell, and they change their subcellular distribution in a light-dependent way. Investigating the transport mechanisms for rhodopsin and ion channels requires accurate histochemical methods for protein localization. By using immunocytochemistry the light-triggered translocation of TRPL has been described as a two-stage process. In stage 1, TRPL accumulates at the rhabdomere base and the adjacent stalk membrane a few minutes after onset of illumination and is internalized in stage 2 by endocytosis after prolonged light exposure. Here, we show that a commonly observed crescent shaped antibody labeling pattern suggesting a fast translocation of rhodopsin, TRP, and TRPL to the rhabdomere base is a light-dependent antibody staining artifact. This artifact is most probably caused by the profound structural changes in the microvillar membranes of rhabdomeres that result from activation of the signaling cascade. By using alternative labeling methods, either eGFP-tags or the self-labeling SNAP-tag, we show that light activation of TRPL transport indeed results in fast changes of the TRPL distribution in the rhabdomere but not in the way described previously.

APA, Harvard, Vancouver, ISO, and other styles

21

Vaca, L., W. G. Sinkins, Y. Hu, D. L. Kunze, and W. P. Schilling. "Activation of recombinant trp by thapsigargin in Sf9 insect cells." American Journal of Physiology-Cell Physiology 267, no. 5 (November 1, 1994): C1501—C1505. http://dx.doi.org/10.1152/ajpcell.1994.267.5.c1501.

Full text

Abstract:

The mammalian protein responsible for Ca2+ release-activated current (Icrac) may be homologous to the Drosophila protein designated trp. Thus the activity of trp, and another Drosophila protein designated trp-like or trpl, may be linked to depletion of the internal Ca2+ store via the so-called capacitative Ca2+ entry mechanism. To test this hypothesis, the effect of thapsigargin, a selective inhibitor of the endoplasmic reticulum Ca2+ pump, on trp- and trpl-induced whole cell membrane current was determined using the baculovirus Sf9 insect cell expression system. The results demonstrate that trp and trpl form Ca(2+)-permeable cation channels. The trpl encodes a nonselective cation channel that is constitutively active under basal nonstimulated conditions and is unaffected by thapsigargin, whereas trp is more selective for Ca2+ than Na+ and is activated by depletion of the internal Ca2+ store. Although evaluation of cation selectivity suggests that trp is not identical to the channel responsible for Icrac, these channels must share some structural feature(s) since both are activated by thapsigargin. A unique proline-rich region in the COOH-terminal tail of trp, which is absent in trpl, may be necessary for capacitative Ca2+ entry.

APA, Harvard, Vancouver, ISO, and other styles

22

Xu, X. Z. Shawn, Fred Chien, Alice Butler, Larry Salkoff, and Craig Montell. "TRPγ, a Drosophila TRP–Related Subunit, Forms a Regulated Cation Channel with TRPL." Neuron 26, no. 3 (June 2000): 647–57. http://dx.doi.org/10.1016/s0896-6273(00)81201-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Santoni, Giorgio, Federica Maggi, Maria Beatrice Morelli, Matteo Santoni, and Oliviero Marinelli. "Transient Receptor Potential Cation Channels in Cancer Therapy." Medical Sciences 7, no. 12 (November 30, 2019): 108. http://dx.doi.org/10.3390/medsci7120108.

Full text

Abstract:

In mammals, the transient receptor potential (TRP) channels family consists of six different families, namely TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPML (mucolipin), TRPP (polycystin), and TRPA (ankyrin), that are strictly connected with cancer cell proliferation, differentiation, cell death, angiogenesis, migration, and invasion. Changes in TRP channels’ expression and function have been found to regulate cell proliferation and resistance or sensitivity of cancer cells to apoptotic-induced cell death, resulting in cancer-promoting effects or resistance to chemotherapy treatments. This review summarizes the data reported so far on the effect of targeting TRP channels in different types of cancer by using multiple TRP-specific agonists, antagonists alone, or in combination with classic chemotherapeutic agents, microRNA specifically targeting the TRP channels, and so forth, and the in vitro and in vivo feasibility evaluated in experimental models and in cancer patients. Considerable efforts have been made to fight cancer cells, and therapies targeting TRP channels seem to be the most promising strategy. However, more in-depth investigations are required to completely understand the role of TRP channels in cancer in order to design new, more specific, and valuable pharmacological tools.

APA, Harvard, Vancouver, ISO, and other styles

24

OHNO, N., and X. M. WEN. "TIME-RESOLVED PHOTOLUMINESCENCE OF EXCITONS IN HgI2." International Journal of Modern Physics B 15, no. 28n30 (December 10, 2001): 3920–23. http://dx.doi.org/10.1142/s0217979201009001.

Full text

Abstract:

The time-resolved photoluminescence (TRPL) of red HgI 2 single crystal has been measured to determine the carrier lifetimes and to reveal the energy relaxation of excitons. Sharp near-bandgap luminescence lines due to free and bound excitons are observed at 530 nm, and a broad luminescence band appears at 630 nm at low temperatures. TRPL experiments of the near-bandgap luminescence have revealed that the luminescence comprise fast (30 to 200 ps) and slow (100 to 400 ps) decay components, showing several relaxation processes in free and bound exciton annihilation. TRPL of the broad band at 630 nm has shown that the luminescence is ascribed to the radiative recombination of donor-acceptor (DA) pairs.

APA, Harvard, Vancouver, ISO, and other styles

25

Holewa, Paweł, Jakub Jasiński, Artem Shikin, Elizaveta Lebedkina, Aleksander Maryński, Marcin Syperek, and Elizaveta Semenova. "Optical Properties of Site-Selectively Grown InAs/InP Quantum Dots with Predefined Positioning by Block Copolymer Lithography." Materials 14, no. 2 (January 14, 2021): 391. http://dx.doi.org/10.3390/ma14020391.

Full text

Abstract:

The InAs/InP quantum dots (QDs) are investigated by time-integrated (PL) and time-resolved photoluminescence (TRPL) experiments. The QDs are fabricated site-selectively by droplet epitaxy technique using block copolymer lithography. The estimated QDs surface density is ∼1.5 × 1010 cm−2. The PL emission at T=300 K is centered at 1.5 μm. Below T=250 K, the PL spectrum shows a fine structure consisting of emission modes attributed to the multimodal QDs size distribution. Temperature-dependent PL reveals negligible carrier transfer among QDs, suggesting good carrier confinement confirmed by theoretical calculations and the TRPL experiment. The PL intensity quench and related energies imply the presence of carrier losses among InP barrier states before carrier capture by QD states. The TRPL experiment highlighted the role of the carrier reservoir in InP. The elongation of PL rise time with temperature imply inefficient carrier capture from the reservoir to QDs. The TRPL experiment at T=15 K reveals the existence of two PL decay components with strong dispersion across the emission spectrum. The decay times dispersion is attributed to different electron-hole confinement regimes for the studied QDs within their broad distribution affected by the size and chemical content inhomogeneities.

APA, Harvard, Vancouver, ISO, and other styles

26

ZHANG, Zongming, Yufang TANG, and Michael Xi ZHU. "Increased inwardly rectifying potassium currents in HEK-293 cells expressing murine transient receptor potential 4." Biochemical Journal 354, no. 3 (March 8, 2001): 717–25. http://dx.doi.org/10.1042/bj3540717.

Full text

Abstract:

Drosophila transient receptor potential (Trp) and its mammalian homologues are postulated to form capacitative Ca2+ entry or store-operated channels. Here we show that expression of murine Trp4 in HEK 293 cells also leads to an increase in inwardly rectifying K+ currents. No similar increase was found in cell lines expressing Trp1, Trp3 or Trp6. Consistent with typical characteristics of inward rectifiers, the K+ currents in Trp4-expressing cells were blocked by low millimolar concentrations of Cs+ and Ba2+, but not by 1.2mM Ca2+, and were only slightly inhibited by 5mM tetraethylammonium. Single channel recordings of excised inside-out patches revealed the presence of two conducting states of 51pS and 94pS in Trp4-expressing cells. The outward current in the excised patches was blocked by 1mM spermine, but not by 1mM Mg2+. How Trp4 expression causes the increase in the K+ currents is not known. We propose that Trp4 either participates in the formation of a novel K+ channel or up-regulates the expression or activity of endogenous inwardly rectifying K+ channels.

APA, Harvard, Vancouver, ISO, and other styles

27

LAST, ROBERT L., and GERALD R. FINK. "Tryptophan-Requiring Mutants of the Plant Arabidopsis thaliana." Science 240, no. 4850 (April 15, 1988): 305–10. http://dx.doi.org/10.1126/science.240.4850.305.

Full text

Abstract:

Although amino acid auxotrophs are among the most frequently isolated mutations in microorganisms, no mutants that require amino acids have been isolated at the whole plant level. Tryptophan-requiring mutants of the cruciferous plant Arabidopsis thaliana have now been isolated by selecting for resistance to 5-methylanthranilic acid. The tryptophan requirement of one mutant, trpl-1, results from a defect in the second step of the tryptophan pathway catalyzed by anthranilate phosphoribosyl transferase. Mutant trpl-1 plants are highly fluorescent and aromatic because they accumulate anthranilic acid and anthranilate β-glucoside. Plants homozygous for the trpl-1 mutation exhibit a syndrome of morphological defects suggestive of a defect in the biosynthesis, metabolism, or localization of a tryptophan derivative such as auxin. All of these morphological phenotypes cosegregate with the tryptophan requirement as a simple Mendelian recessive trait.

APA, Harvard, Vancouver, ISO, and other styles

28

Montell, Craig. "New Light on TRP and TRPL." Molecular Pharmacology 52, no. 5 (November 1, 1997): 755–63. http://dx.doi.org/10.1124/mol.52.5.755.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Gutorov, Rita, Ben Katz, Elisheva Rhodes-Mordov, Rachel Zaguri, Tal Brandwine-Shemmer, and Baruch Minke. "The Role of Membrane Lipids in Light-Activation of Drosophila TRP Channels." Biomolecules 12, no. 3 (February 28, 2022): 382. http://dx.doi.org/10.3390/biom12030382.

Full text

Abstract:

Transient Receptor Potential (TRP) channels constitute a large superfamily of polymodal channel proteins with diverse roles in many physiological and sensory systems that function both as ionotropic and metabotropic receptors. From the early days of TRP channel discovery, membrane lipids were suggested to play a fundamental role in channel activation and regulation. A prominent example is the Drosophila TRP and TRP-like (TRPL) channels, which are predominantly expressed in the visual system of Drosophila. Light activation of the TRP and TRPL channels, the founding members of the TRP channel superfamily, requires activation of phospholipase Cβ (PLC), which hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into Diacylglycerol (DAG) and Inositol 1, 4,5-trisphosphate (IP3). However, the events required for channel gating downstream of PLC activation are still under debate and led to several hypotheses regarding the mechanisms by which lipids gate the channels. Despite many efforts, compelling evidence of the involvement of DAG accumulation, PIP2 depletion or IP3-mediated Ca2+ release in light activation of the TRP/TRPL channels are still lacking. Exogeneous application of poly unsaturated fatty acids (PUFAs), a product of DAG hydrolysis was demonstrated as an efficient way to activate the Drosophila TRP/TRPL channels. However, compelling evidence for the involvement of PUFAs in physiological light-activation of the TRP/TRPL channels is still lacking. Light-induced mechanical force generation was measured in photoreceptor cells prior to channel opening. This mechanical force depends on PLC activity, suggesting that the enzymatic activity of PLC converting PIP2 into DAG generates membrane tension, leading to mechanical gating of the channels. In this review, we will present the roles of membrane lipids in light activation of Drosophila TRP channels and present the many advantages of this model system in the exploration of TRP channel activation under physiological conditions.

APA, Harvard, Vancouver, ISO, and other styles

30

Tsai, Ming Kwen, Yueh Chien Lee, Chia Chih Huang, Sheng Yao Hu, Kwong Kau Tiong, and Bo Yao Hong. "Luminescence Mechanism of ZnWO₄ Nanopowder Synthesized by Microwave-Assisted Heating." Applied Mechanics and Materials 470 (December 2013): 44–47. http://dx.doi.org/10.4028/www.scientific.net/amm.470.44.

Full text

Abstract:

The luminescence investigations on the calcinated zinc tungstate nanopowder (ZnWO4 NP) synthesized by microwave-assisted synthesis are presented using photoluminescence (PL) and time-resolved photoluminescence (TRPL) analyses. The X-ray diffraction (XRD) patterns exhibit that the significant wolframite structure of ZnWO4 NP can be detected at calcination temperatures above 300 °C. The 12 K PL and TRPL results demonstrated that the deformation of WO6 octahedra is responsible for the low-energy side of PL spectra and dominate the red-shifted PL spectra with increasing calcination temperatures.

APA, Harvard, Vancouver, ISO, and other styles

31

Chen, Cheng, Zhi Ren Qiu, Xiang Ping Shu, Zeng Cheng Li, Jian Ping Liu, and Zhe Chuan Feng. "Temperature and Time-Resolved Dependence of Photoluminescence in InGaN Quantum Dots." Advanced Materials Research 750-752 (August 2013): 927–30. http://dx.doi.org/10.4028/www.scientific.net/amr.750-752.927.

Full text

Abstract:

Temperature dependence of photoluminescence (PL) and time resolved photoluminescence (TRPL) were obtained by two experimental systems. The relative intensity and peak position of PL show S-shift variation with increasing temperature, which may result from temperature induce carriers redistribution. Fast decay time and slow decay time were fitted by double exponential function from decay curves of TRPL at different emission energy, and the decreasing trend of both fast decay and slow decay time with increasing photon energy is attributed to various channels of recombination in shallow and deep localized states.

APA, Harvard, Vancouver, ISO, and other styles

32

WARR, Coral G., and Leonard E. KELLY. "Identification and characterization of two distinct calmodulin-binding sites in the Trpl ion-channel protein of Drosophila melanogaster." Biochemical Journal 314, no. 2 (March 1, 1996): 497–503. http://dx.doi.org/10.1042/bj3140497.

Full text

Abstract:

Two putative light-sensitive ion channels have been isolated from Drosophila, encoded by the transient-receptor-potential (trp) and transient-receptor-potential-like (trpl) genes. The cDNA encoding the Trpl protein was initially isolated on the basis that the expressed protein binds calmodulin. Using both fusion proteins and a synthetic peptide, we now show that two calmodulin-binding sites are present in the C-terminal domain of the Trpl protein, CBS-1 and CBS-2. CBS-1 binds calmodulin in a Ca2+-dependent fashion, requiring Ca2+ concentrations above 0.3–0.5 μM for calmodulin binding. In contrast, CBS-2 binds the Ca2+-free form of calmodulin, with dissociation occurring at Ca2+ concentrations between 5 and 25 μM. Phosphorylation of a serine residue within a peptide encompassing CBS-1 by cyclic AMP-dependent protein kinase (PKA) abolishes calmodulin binding, and phosphorylation of the adjacent serine by protein kinase C appears to modulate this phosphorylation by PKA. Interpretation of these findings provides a novel model for ion-channel gating and modulation in response to changing levels of intracellular Ca2+.

APA, Harvard, Vancouver, ISO, and other styles

33

Saari, Paulus, Andrew S. French, Päivi H. Torkkeli, Hongxia Liu, Esa-Ville Immonen, and Roman V. Frolov. "Distinct roles of light-activated channels TRP and TRPL in photoreceptors of Periplaneta americana." Journal of General Physiology 149, no. 4 (March 10, 2017): 455–64. http://dx.doi.org/10.1085/jgp.201611737.

Full text

Abstract:

Electrophysiological studies in Drosophila melanogaster and Periplaneta americana have found that the receptor current in their microvillar photoreceptors is generated by two light-activated cationic channels, TRP (transient receptor potential) and TRPL (TRP-like), each having distinct properties. However, the relative contribution of the two channel types to sensory information coding by photoreceptors remains unclear. We recently showed that, in contrast to the diurnal Drosophila in which TRP is the principal phototransduction channel, photoreceptors of the nocturnal P. americana strongly depend on TRPL. Here, we perform a functional analysis, using patch-clamp and intracellular recordings, of P. americana photoreceptors after RNA interference to knock down TRP (TRPkd) and TRPL (TRPLkd). Several functional properties were changed in both knockdown phenotypes: cell membrane capacitance was reduced 1.7-fold, light sensitivity was greatly reduced, and amplitudes of sustained light-induced currents and voltage responses decreased more than twofold over the entire range of light intensities. The information rate (IR) was tested using a Gaussian white-noise modulated light stimulus and was lower in TRPkd photoreceptors (28 ± 21 bits/s) than in controls (52 ± 13 bits/s) because of high levels of bump noise. In contrast, although signal amplitudes were smaller than in controls, the mean IR of TRPLkd photoreceptors was unchanged at 54 ± 29 bits/s1 because of proportionally lower noise. We conclude that TRPL channels provide high-gain/high-noise transduction, suitable for vision in dim light, whereas transduction by TRP channels is relatively low-gain/low-noise and allows better information transfer in bright light.

APA, Harvard, Vancouver, ISO, and other styles

34

Scott, Kristin, and Charles Zuker. "TRP, TRPL and trouble in photoreceptor cells." Current Opinion in Neurobiology 8, no. 3 (June 1998): 383–88. http://dx.doi.org/10.1016/s0959-4388(98)80065-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Kuo, Ting Wei, Ling Min Kong, Zhe Chuan Feng, Wei Liu, Soo Jin Chua, and Ying Sheng Huang. "Photoluminescence Properties of InGaN/GaN Multiple Quantum Well Light Emitting Diodes by Metalorganic Chemical Vapor Deposition." Advanced Materials Research 306-307 (August 2011): 1133–37. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.1133.

Full text

Abstract:

Luminescence properties of blue emission InGaN/GaN multiple quantum well (MQW) light emitting diodes (LEDs), grown on sapphire substrates by metal organic chemical vapor deposition (MOCVD), were studied by time-resolved photoluminescence (TRPL) spectroscopic technique. Samples involved have similar basic structures of three QWs but different well-composition and barrier/well dimensions. TRPL results show that PL intensity and decay time increase with the number of QWs and the indium composition. Correlation of physical properties with crystalline perfection open the way for optimized designs of InGaN MQW LED, with controlled the indium composition and QW numbers.

APA, Harvard, Vancouver, ISO, and other styles

36

Péan, Emmanuel V., Stoichko Dimitrov, Catherine S. De Castro, and Matthew L. Davies. "Interpreting time-resolved photoluminescence of perovskite materials." Physical Chemistry Chemical Physics 22, no. 48 (2020): 28345–58. http://dx.doi.org/10.1039/d0cp04950f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

DWANDARU, W. S. B., A. L. FADLI, E. K. SARI, and ISNAENI. "CDOTS AND CDOTS/S SYNTHESIS FROM NAM-NAM FRUIT (CYNOMETRA CAULIFLORA L.) VIA FRYING METHOD USING COOKING OIL." Digest Journal of Nanomaterials and Biostructures 15, no. 2 (April 2020): 555–60. http://dx.doi.org/10.15251/djnb.2020.152.555.

Full text

Abstract:

This research aims to synthesis carbon-dots (Cdots) and carbon dots/sulphur (Cdots/S) from nam-nam fruit via oil based frying method and to characterize the samples using UVVis spectroscopy, PL, XRD, and TRPL. The UV-Vis result upon the Cdots sample shows absorbance peaks at 242 nm and 268 nm, whereas Cdots/S sample shows absorbance peaks at 228 nm and 268 nm. The PL characterization shows green luminescence with peak intensities at 497.87 nm and 498.79 nm for Cdots and Cdot/S, respectively. TRPL results show the electrons decay lifetime duration of Cdots and Cdots/S, i.e.: 2.46 ns and 1.71 ns, respectively

APA, Harvard, Vancouver, ISO, and other styles

38

Nilius, Bernd, Grzegorz Owsianik, Thomas Voets, and John A. Peters. "Transient Receptor Potential Cation Channels in Disease." Physiological Reviews 87, no. 1 (January 2007): 165–217. http://dx.doi.org/10.1152/physrev.00021.2006.

Full text

Abstract:

The transient receptor potential (TRP) superfamily consists of a large number of cation channels that are mostly permeable to both monovalent and divalent cations. The 28 mammalian TRP channels can be subdivided into six main subfamilies: the TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPP (polycystin), TRPML (mucolipin), and the TRPA (ankyrin) groups. TRP channels are expressed in almost every tissue and cell type and play an important role in the regulation of various cell functions. Currently, significant scientific effort is being devoted to understanding the physiology of TRP channels and their relationship to human diseases. At this point, only a few channelopathies in which defects in TRP genes are the direct cause of cellular dysfunction have been identified. In addition, mapping of TRP genes to susceptible chromosome regions (e.g., translocations, breakpoint intervals, increased frequency of polymorphisms) has been considered suggestive of the involvement of these channels in hereditary diseases. Moreover, strong indications of the involvement of TRP channels in several diseases come from correlations between levels of channel expression and disease symptoms. Finally, TRP channels are involved in some systemic diseases due to their role as targets for irritants, inflammation products, and xenobiotic toxins. The analysis of transgenic models allows further extrapolations of TRP channel deficiency to human physiology and disease. In this review, we provide an overview of the impact of TRP channels on the pathogenesis of several diseases and identify several TRPs for which a causal pathogenic role might be anticipated.

APA, Harvard, Vancouver, ISO, and other styles

39

Xiao, Zijie, Tingting Tao, Jingting Shu, Wei Dang, Shusheng Pan, and Wei Zhang. "Charge Carrier Recombination Dynamics in MAPb(Br1−yIy)3 Single Crystals." Crystals 12, no. 10 (October 9, 2022): 1425. http://dx.doi.org/10.3390/cryst12101425.

Full text

Abstract:

Studying the carrier recombination process in MAPb(Br1−yIy)3 single crystals (SCs) is important for its application in the optoelectronic field. In this work, a series of MAPb(Br1−yIy)3 SCs with varied Br/I compositions have been studied. Steady-state photoluminescence (PL) spectra, time-resolved photoluminescence (TRPL) spectra and time-resolved microwave photoconductivity (TRMC) were used to understand the radiative and non-radiative recombination processes of MAPb(Br1−yIy)3 SCs. By comparing the dynamics of TRPL and TRMC, we conclude that the dynamics of TRPL is dominated by the electron trapping process, which is in accordance with the fast decay component of TRMC kinetics, whereas the slower decay component in TRMC is dominated by the hole trapping process. Moreover, we find both the electron and hole trapping rates in mixed-halide perovskite MAPb(Br1−yIy)3 (0 < y < 1) SCs are higher than that of mono-halide perovskite MAPbBr3 SCs and MAPbI3 SCs. This suggests mixed-halide crystals could introduce additional electron and hole trapping densities, which could be related to the fluctuation of Br/I compositions in the crystals. This work is helpful for understanding carrier recombination process in mixed-halide perovskite SCs.

APA, Harvard, Vancouver, ISO, and other styles

40

Yuan, Long, and Libai Huang. "Exciton dynamics and annihilation in WS2 2D semiconductors." Nanoscale 7, no. 16 (2015): 7402–8. http://dx.doi.org/10.1039/c5nr00383k.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

ESTACION, Mark, William G. SINKINS, and William P. SCHILLING. "Stimulation of Drosophila TrpL by capacitative Ca2+ entry." Biochemical Journal 341, no. 1 (July 1, 1999): 41. http://dx.doi.org/10.1042/0264-6021:3410041.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

WRABACK, MICHAEL, GREGORY A. GARRETT, ANAND V. SAMPATH, and PAUL H. SHEN. "UNDERSTANDING ULTRAVIOLET EMITTER PERFORMANCE USING INTENSITY DEPENDENT TIME-RESOLVED PHOTOLUMINESCENCE." International Journal of High Speed Electronics and Systems 17, no. 01 (March 2007): 179–88. http://dx.doi.org/10.1142/s0129156407004400.

Full text

Abstract:

Time-resolved photoluminescence studies of nitride semiconductors and ultraviolet light emitters comprised of these materials are performed as a function of pump intensity as a means of understanding and evaluating device performance. Comparison of time-resolved photoluminescence (TRPL) on UV LED wafers prior to fabrication with subsequent device testing indicate that the best performance is attained from active regions that exhibit both reduced nonradiative recombination due to saturation of traps associated with point and extended defects and concomitant lowering of radiative lifetime with increasing carrier density. Similar behavior is observed in optically pumped UV lasers. Temperature and intensity dependent TRPL measurements on a new material, AlGaN containing nanoscale compositional inhomogeneities (NCI), show that it inherently combines inhibition of nonradiative recombination with reduction of radiative lifetime, providing a potentially higher efficiency UV emitter active region.

APA, Harvard, Vancouver, ISO, and other styles

43

Gandan, Shumithira, Lucas L. G. Pinel, Juan S. D. Morales, Jo Shien Ng, Chee Hing Tan, and Tomasz Ochalski. "Recombination processes in MBE grown Al_0.85Ga_0.15As_0.56Sb_0.44." AIP Advances 13, no. 4 (April 1, 2023): 045010. http://dx.doi.org/10.1063/5.0145051.

Full text

Abstract:

Quaternary AlGaAsSb alloys have exhibited low excess noise characteristics as gain regions in avalanche photodiodes. In this work, optical spectroscopy techniques are used to demonstrate the recombination dynamics in molecular beam epitaxy grown Al0.85Ga0.15As0.56Sb0.44 with temperature variation. Photoluminescence (PL) measurements at 8–50 K show that the bandgap varies from 1.547 to 1.527 eV. The radiative recombination processes in the alloy were found to be dictated by the complexities of antimony (Sb) incorporation during the growth. Time-resolved PL (TRPL) measurements show a change in initial carrier lifetimes of ∼3.5 µs at 8 K to ∼1 µs at 30 K. The knowledge of carrier dynamics from optical characterization methods such as PL and TRPL can be employed to contribute to shorter feedback loops for improvement of alloy fabrication in addition to enhancing growth processes.

APA, Harvard, Vancouver, ISO, and other styles

44

Yi, Jun, Xueying Ge, Exian Liu, Tong Cai, Chujun Zhao, Shuangchun Wen, Hugo Sanabria, Ou Chen, Apparao M. Rao, and Jianbo Gao. "The correlation between phase transition and photoluminescence properties of CsPbX3 (X = Cl, Br, I) perovskite nanocrystals." Nanoscale Advances 2, no. 10 (2020): 4390–94. http://dx.doi.org/10.1039/d0na00545b.

Full text

Abstract:

We report a correlation between the structural phase transition of CsPbX₃ (X = Cl, Br, I) nanocrystals (NCs) and their temperature dependent steady-state photoluminescence (PL) and time-resolved PL (TRPL).

APA, Harvard, Vancouver, ISO, and other styles

45

WENG, GUO-EN, BAO-PING ZHANG, MING-MING LIANG, XUE-QIN LV, JIANG-YONG ZHANG, LEI-YING YING, ZHI REN QIU, et al. "OPTICAL PROPERTIES AND CARRIER DYNAMICS IN ASYMMETRIC COUPLED InGaN MULTIPLE QUANTUM WELLS." Functional Materials Letters 06, no. 02 (April 2013): 1350021. http://dx.doi.org/10.1142/s1793604713500215.

Full text

Abstract:

Optical properties and carrier dynamics of InGaN/GaN asymmetric coupled quantum wells (ACQWs) are studied by excitation-power-dependent photoluminescence (PL), photoreflectance (PR) and time-resolved PL (TRPL) experiments. Under weak excitations, only the emission from the widest well is observed due to the tunneling from narrower to wider wells. Under strong excitations, the carrier distribution becomes more uniform and an enhanced emission from the mid well (2.5 nm well) is observed. Dependence of the PL intensity on excitation power is well explained by a rate equation model. The energy levels in the ACQW structure are clearly revealed by PR measurements and are in good agreement with calculations. Our results indicate that the enhanced emission from the mid well is ascribed to "reverse tunneling" from 3.0 to 2.5 nm well, which is confirmed by TRPL experiments.

APA, Harvard, Vancouver, ISO, and other styles

46

Žurauskienė, N., S. Ašmontas, A. Dargys, J. Kundrotas, G. Janssen, E. Goovaerts, Stanislovas Marcinkevičius, Paul M. Koenraad, J. H. Wolter, and R. P. Leon. "Semiconductor Nanostructures for Infrared Applications." Solid State Phenomena 99-100 (July 2004): 99–108. http://dx.doi.org/10.4028/www.scientific.net/ssp.99-100.99.

Full text

Abstract:

We present the results of time-resolved photoluminescence (TRPL) and optically detected microwave resonance (ODMR) spectroscopy investigations of semiconductor quantum dots and quantum wells. The ODMR spectra of InAs/GaAs QDs were detected via modulation of the total intensity of the QDs emission induced by 95 GHz microwave excitation and exciton fine structure was studied. Very long life times (up to 10 ns) of photoexcited carriers were observed in this system using TRPL at low temperatures and excitation intensities promising higher responsitivity of such QDs for quantum dot infrared photodetector development. The effects of proton and alpha particles irradiation on carrier dynamics were investigated on different InGaAs/GaAs, InAlAs/AlGaAs and GaAs/AlGaAs QD and QW systems. The obtained results demonstrated that carrier lifetimes in the QDs are much less affected by proton irradiation than that in QWs. A strong influence of irradiation on the PL intensity was observed in multiple QWs after high-energy alpha particles irradiation.

APA, Harvard, Vancouver, ISO, and other styles

47

Patel, Anshuman, and Devesh Jinwala. "A Trust-Integrated RPL Protocol to Detect Blackhole Attack in Internet of Things." International Journal of Information Security and Privacy 15, no. 4 (October 2021): 1–17. http://dx.doi.org/10.4018/ijisp.2021100101.

Full text

Abstract:

Internet of things (IoT) offers communication between user-to-machine and machine-to-machine. Due to their inherent characteristics of open medium, very dynamic topology, lack of infrastructure and lack of centralized management authority, IoT present serious vulnerabilities to security attacks. The routing protocol for low-power and lossy networks (RPL) does not have an inherent mechanism to detect routing attacks. Popular among these IoT attacks is blackhole attack. An attacker can exploit the routing system of RPL to launch blackhole attack against an IoT network. To secure IoT networks from blackhole attack, trust-integrated RPL protocol (TRPL) is proposed and implemented. The trust system is embedded in the RPL protocol to detect and isolate a blackhole attack while optimizing network performance. The trust is calculated from successful interaction between two nodes. The calculated trust value is considered in parent selection. TRPL demonstrates its superior performance over the standard RPL protocol and existing techniques in the detection and isolation of blackhole attacks.

APA, Harvard, Vancouver, ISO, and other styles

48

Wei, Yi, Ahmed Fadil, and Hai Yan Ou. "Localized Surface Plasmon on 6H SiC with Ag Nanoparticles." Materials Science Forum 897 (May 2017): 634–37. http://dx.doi.org/10.4028/www.scientific.net/msf.897.634.

Full text

Abstract:

Silver (Ag) nanoparticles (NPs) were deposited on the surface of bulk Nitrogen-Boron co-doped 6H silicon carbide (SiC), and the Ag NPs were observed to induce localized surface plasmons (LSP) resonances on the SiC substrate, which was expected to improve the internal quantum efficiency (IQE) of the emissions of the donor-acceptor pairs of the SiC substrate. Room-temperature measurements of photoluminescence (PL), transmittance and time-resolved photoluminescence (TRPL) were applied to characterize the LSP resonances. Through the finite-difference time-domain (FDTD) simulation of the LSP resonance of an Ag nanoparticle on the SiC substrate, it is predicted that when the diameter of the cross section on the xy plane of the Ag nanoparticle is greater than 225 nm, the LSP starts to enhance the PL intensity. With implementation of a 3rd order exponential decay fitting model to the TRPL results, it is found that the average minority carrier lifetime of the SiC substrate decreased.

APA, Harvard, Vancouver, ISO, and other styles

49

WACHTER, S., DAL DON, M. BALDAUF, M. SCHMIDT, E. KURTZ, C. KLINGSHIRN, H. KALT, D. LITVINOV, and D. GERTHSEN. "INTER - ISLAND TRANSPORT IN CdSe/ZnSe QUANTUM HETEROSTRUCTURES." International Journal of Modern Physics B 15, no. 28n30 (December 10, 2001): 3584–87. http://dx.doi.org/10.1142/s0217979201008202.

Full text

Abstract:

We report on localization dynamics of excitons in ensembles of self–organized CdSe islands embedded in ZnSe. The experimental methods employed are temperature–dependent, spatially resolved photoluminescence (μ–PL), spatially integrated PL (macro-PL), as well as time–resolved PL (TRPL). We observe the well known non–monotonous shift of the PL maximum with temperature caused by redistribution of the excitons amongst the islands. The measured shift is compared with the exact shift of the bandgap deduced from μ–PL measurements and found to depend strongly on island size and distribution. These transport processes are recovered in the temporal evolution of the PL. The decaytime of the spectrally integrated PL reaches its maximum at exactly the same temperature at which the redhift of the macro–PL turns into a blueshift. In TRPL the PL–spectrum consists of two contributions. We put the emission on the high energy side down to excited states in the islands.

APA, Harvard, Vancouver, ISO, and other styles

50

Mackenzie, Chris, Adrian E. Simmons, and Samuel Kaplan. "Multiple Chromosomes in Bacteria: The Yin and Yang of trp Gene Localization in Rhodobacter sphaeroides 2.4.1." Genetics 153, no. 2 (October 1, 1999): 525–38. http://dx.doi.org/10.1093/genetics/153.2.525.

Full text

Abstract:

Abstract The existence of multiple chromosomes in bacteria has been known for some time. Yet the extent of functional solidarity between different chromosomes remains unknown. To examine this question, we have surveyed the well-described genes of the tryptophan biosynthetic pathway in the multichromosomal photosynthetic eubacterium Rhodobacter sphaeroides 2.4.1. The genome of this organism was mutagenized using Tn5, and strains that were auxotrophic for tryptophan (Trp-) were isolated. Pulsed-field gel mapping indicated that Tn5 insertions in both the large (3 Mb CI) and the small (0.9 Mb CII) chromosomes created a Trp- phenotype. Sequencing the DNA flanking the sites of the Tn5 insertions indicated that the genes trpE-yibQ-trpGDC were at a locus on CI, while genes trpF-aroR-trpB were at locus on CII. Unexpectedly, trpA was not found downstream of trpB. Instead, it was placed on the CI physical map at a locus 1.23 Mb away from trpE-yibQ-trpGDC. To relate the context of the R. sphaeroides trp genes to those of other bacteria, the DNA regions surrounding the trp genes on both chromosomes were sequenced. Of particular significance was the finding that rpsA1, which encodes ribosomal protein S1, and cmkA, which encodes cytidylate monophosphate kinase, were on CII. These genes are considered essential for translation and chromosome replication, respectively. Southern blotting suggested that the trp genes and rpsA1 exist in single copy within the genome. To date, this topological organization of the trp “operon” is unique within a bacterial genome. When taken with the finding that CII encodes essential housekeeping functions, the overall impression is one of close regulatory and functional integration between these chromosomes.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'TRPL'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles