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991.
Takenori Miyamoto Diego Restrepo Edward J. Cragoe Jr. John H. Teeter 《The Journal of membrane biology》1992,127(3):173-183
Summary Olfactory receptor neurons enzymatically dissociated from channel catfish olfactory epithelium were depolarized transiently following dialysis of IP3 or cAMP (added to the patch pipette) into the cytoplasm. Voltage and current responses to IP3 were blocked by ruthenium red, a blocker of an IP3-gated Ca2+-release channel in sarcoplasmic reticulum. In contrast, the responses to cAMP were not blocked by extracellularly applied ruthenium red, nor by l-cis-diltiazem or amiloride and two of its derivatives. The current elicited by cytoplasmic IP3 in neurons under voltage clamp displayed a voltage dependence different from that of the cAMP response which showed marked outward rectification. A sustained depolarization was caused by increased cytoplasmic IP3 or cAMP when the buffering capacity for Ca2+ of the pipette solution was increased, when extracellular Ca2+ was removed or after addition of 20–200 nm charibdotoxin to the bathing solution, indicating that the repolarization was caused by an increase in [Ca
i
] that opened Ca2+-activated K+ channels. The results suggest that different conductances modulated by either IP3 or cAMP are involved in mediating olfactory transduction in catfish olfactory receptor neurons and that Ca2+-activated K+ channels contribute to the termination of the IP3 and cAMP responses.Abbreviations ATP
adenosine 5-triphosphate
- BAPTA
(bis-(o-aminophenoxy)-ethane-N-N-N-N)-tetraacetic acid
- cAMP
adenosine cyclic 3,5-monophosphate
- cGMP
guanosine cyclic 3,5-monophosphate
- CTX
charybdotoxin
- DCB
3,4-dichlorobenzamil
- EDTA
ethylenediaminetetraacetic acid
- EGTA
ethylenglycol-bis-(b-aminoethyl)-N-N-N-N-tetraacetic acid
- HEPES
N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid
- IP3
inositol-1,4,5-triphosphate
- NMDG
N-methyl-d-glucamine
We would like to thank the Tanabe Seiyaku Co., Ltd., for their gift of l-cis-diltiazem. This work was supported by National Institutes of Health grants DC00566 and BRSG S07RR05825. 相似文献
992.
Overproduction of cis-Vaccenic Acid and Altered Temperature Control of Fatty Acid Synthesis in a Mutant of Escherichia coli 总被引:6,自引:4,他引:2 下载免费PDF全文
Diego de Mendoza Jeffrey L. Garwin John E. Cronan Jr. 《Journal of bacteriology》1982,151(3):1608-1611
A mutant of Escherichia coli has been characterized which overproduces cis-vaccenic acid in the temperature range of 30 to 42°C. The mutational lesion acts within the fatty acid biosynthetic pathway rather than at the level of fatty acid incorporation into phospholipid. 相似文献
993.
Mariela Bollini Juan José Casal Diego E. Alvarez Lucía Boiani Mercedes González Hugo Cerecetto Ana María Bruno 《Bioorganic & medicinal chemistry》2009,17(4):1437-1444
A series of novel benzoimidazo and N-aryl-5-oxo-imidazo[1,2-b]isoquinoline-10-carbothioamides was developed. All the compounds were evaluated for their in vitro action against the epimastigote form of Trypanosoma cruzi. Four of them showed higher activity than Nifurtimox. Their unspecific cytotoxicity was evaluated using HeLa and L6 cells, being non-toxic at concentrations at least 15 and 200 times higher than that of T. cruzi IC50. To gain insight into the mechanism of action, their DNA binding properties and reactivity with glutathione were studied, and QSAR study was performed. 相似文献
994.
Diego A. Sampietro Melina A. Sgariglia Jos R. Sobern Emma N. Quiroga Marta A. Vattuone 《Environmental and Experimental Botany》2007,60(3):495-503
Previous studies suggested that allelochemicals from sugarcane straw may suppress the growth of arrowleaf sida (Sida rhombifolia L.). A study was conducted to establish: (1) the direct or indirect role of the organic molecules from sugarcane straw leachate on the growth suppression of arrowleaf sida and (2) if leachate phytotoxins induce proline accumulation in arrowleaf sida tissues as an adaptative response to a water or an oxidative stress. Inhibition of root elongation was the primary effect of sugarcane straw leachate on arrowleaf sida grown in unsterile soil. Addition of activated charcoal to unsterile soil before incorporation of straw leachate reduced the inhibition in root growth suggesting a direct participation of organic molecules in leachate phytotoxicity on arrowleaf sida. Inorganic straw constituents did not inhibit root growth while microbial activity increased leachate phytotoxicity. Soil chemical analysis suggested a direct action of organic molecules in leachate phytotoxicity rather than variations in macro and micronutrients or nutrient microbial immobilization. Straw leachate induced proline accumulation in roots and cotyledons of arrowleaf sida. Proline increase was related with oxidative stress in the roots but not in the cotyledons. Our results indicate a direct action of organic compounds from sugarcane straw and/or their microbial transformation products on root growth of arrowleaf sida. These substances induced proline accumulation in roots mainly as consequence of an oxidative stress while water stress may be the main cause of high proline content in the cotyledons. Although the observed responses could be due to phenolic compounds, the involvement of organic molecules with other chemical nature could not be excluded. 相似文献
995.
Priscila Farias Tempaku Juliana Ramirez Arruda Diego Robles Mazzotti Bruno S. B. Gonçalves Mário Pedrazzoli Lia Bittencourt 《Chronobiology international》2017,34(4):504-510
The circadian system coordinates internal events in a daily schedule to make sure that the body systems are synchronized to environmental time and internal cues. One important behavioral aspect of the circadian system is the chronotype. It is usually assessed through subjective questionnaires, being the Horne-Ostberg Morningness–Eveningness Questionnaire (MEQ) one of the most used. It classifies individuals into three major categories: morning, evening, and intermediate types. Recently, it has been hypothesized the existence of a fourth chronotype, the bimodal type, through an algorithm derived from the MEQ responses. Bimodals answer as morning-types in some questions, and as evening-types in others, resulting in an intermediate total score. To better characterize this phenotype, the present study aimed to detect and characterize the frequency of the bimodal chronotype in the EPISONO, a large population-based cohort, as well as to verify the association between bimodality and sleep parameters and genetic variation in the PER3 gene. Of the 1,042 individuals who participated of the EPISONO, 857 had MEQ filled correctly. We found that 16% of our sample were bimodal types. We observed that bimodal individuals were significantly younger and had lower body mass index. The association between PER3 VNTR genotype and gender with bimodal chronotype was not significant. However, we found an association between bimodality and Epworth Sleepiness Scale (EES) and apnea-hypopnea index (AHI). We did not find a statistically significant difference between bimodals and intermediate non-bimodals for the studied variables. Lastly, it was observed that the most significant predictors for bimodal chronotype were female gender, AHI, and EES. In conclusion, the present work provides more evidence that the bimodal type might have to be considered when classifying chronotype and its association with young age and sleepiness may be due to the influence of social and environmental factors. 相似文献
996.
Laura Moreno Javier Párraga Abraham Galán Nuria Cabedo Jaime Primo Diego Cortes 《Bioorganic & medicinal chemistry》2012,20(22):6589-6597
The attractive structure of the pyrroloisoquinoline moiety, together with its potential antimicrobial activity, encouraged us to prepare six 8-substituted and seven 8,9-disubstituted-1,2,3,5,6,10b-hexahydropyrrolo[2,1-a]isoquinolin-3-ones in a few steps with good yields. We applied a convenient methodology via double intramolecular cyclization conducted by a Bischler-Napieralski cyclodehydration-imine reduction sequence, which is widely employed in the synthesis of isoquinoline alkaloids. Therefore, we synthesized three series of these pyrrolo[2,1-a]isoquinolin-3-ones characterized by the substituent at the 8-position or 8,9-positions of the aromatic ring: (a) different side chains are attached to an 8-OH group (series 1); (b) a chlorine atom is attached to the 8-position (series 2); and (c) 8- and 9-carbons are bearing an identical group (series 3). The compounds bearing a benzylic moiety at the 8-position, for example, 8-benzyloxy-pyrrolo[2,1-a]isoquinolin-3-one (1a) and 8-(4-fluorobenzyloxy)-pyrrolo[2,1-a]isoquinolin-3-one (1e), as well as, a 8-chloro-9-methoxy moiety including the 8-chloro-9-methoxy-pyrrolo[2,1-a]isoquinolin-3-one (2a), provided the most fungicide and bactericide agents, respectively. 相似文献
997.
Blaustein M Pelisch F Tanos T Muñoz MJ Wengier D Quadrana L Sanford JR Muschietti JP Kornblihtt AR Cáceres JF Coso OA Srebrow A 《Nature structural & molecular biology》2005,12(12):1037-1044
Serine/arginine-rich (SR) proteins are important regulators of mRNA splicing. Several postsplicing activities have been described for a subset of shuttling SR proteins, including regulation of mRNA export and translation. Using the fibronectin gene to study the links between signal-transduction pathways and SR protein activity, we show that growth factors not only modify the alternative splicing pattern of the fibronectin gene but also alter translation of reporter messenger RNAs in an SR protein-dependent fashion, providing two coregulated levels of isoform-specific amplification. These effects are inhibited by specific small interfering RNAs against SR proteins and are mediated by the AKT kinase, which elicits opposite effects to those evoked by overexpressing SR protein kinases Clk and SRPK. These results show how SR protein activity is modified in response to extracellular stimulation, leading to a concerted regulation of splicing and translation. 相似文献
998.
The Norian portion of the Costa dei Frascari succession (Matese Mountains, northern Campania) provides an example of a calcareous algae association dominated by the family Pseudoudoteaceae; subordinately, Gymnocodiaceae and Dasycladaceae also occur. The present study deals with the record of Garwoodia maxima
Dragastan, Garwoodia toomeyi
Dragastan, Pseudoudotea magna Dragastan et al., Jabrianella sp., and Asterocalculus heraki Sokac and Grgasovic, from the open-lagoon carbonate deposits which were referred to the portion of the Norian below the Triasina hantkeni Zone.Riassunto. Vengono presentati i risultati di uno studio sistematico condotto sulle alghe calcaree del Norico dei Monti del Matese (Campania settentrionale), per la prima volta segnalate in Italia. La ricca associazione è composta da prevalenti pseudoudoteacee e precisamente: Garwoodia maxima, Garwoodia toomeji, Pseudoudotea magna, Jabrianella sp., oltre a Asterocalculus heraki, Heteroporella zankli e
Probolocuspis espakhensis, recentemente attribuito alle Dasycladales da Senowbari-Daryan and Majidifard. I campioni analizzati provengono dalla porzione inferiore della successione della Costa dei Frascari (versante meridionale dei Monti del Matese) i cui 160 m basali sono costituiti da prevalenti calcari granulo-sostenuti e da rare intercalazioni di calcari fango-sostenuti, talora loferitici, spesso dolomitizzati e stromatolitici. Labbondanza di antozoi, chetetidi, gasteropodi di grandi dimensioni e, in particolare, di resti di echinodermi indica che tali sedimenti si sono deposti in un ambiente di open-lagoon caratterizzato da continui scambi con il mare aperto che garantivano condizioni di salinità e ossigenazione delle acque idonee a questo tipo di organismi. In base allassociazione micropaleontologica e considerata lassenza di Triasina hantkeni
e di Griphoporella curvata, la cui comparsa avviene a circa 160 m dalla base della successione, questi sedimenti sono stati riferiti alla porzione di Norico sottostante la Zona a
Triasina hantkeni (sensu Marcoux et al. 1993). 相似文献
999.
Spermine accumulation under salt stress 总被引:11,自引:0,他引:11
Polyamines have long been recognized to be linked to stress situations, and it is generally accepted that they have protective characteristics. However, little is known about their physiological relevance in plants subjected to long-term salt stress. In order to precise their importance, two rice (Oryza sativa) cultivars differing in their salt tolerance were salinized for 7, 14 and 21 days. The activities of some of the enzymes involved in polyamine metabolism, free polyamines and proline contents were evaluated. Arginine decarboxylase and S-adenosyl-L-methionine decarboxylase activities were reduced in both cultivars as a consequence of salt treatment. However, spermidine synthase activity was reduced in the salt tolerant cultivar (var Giza) but not in the salt sensitive (var El Paso), while no polyamine oxidase activity was detected. During the salinization period, putrescine and spermidine levels decreased in both cultivars, although less dramatically in Giza. Simultaneously, spermine accumulations occur in both varieties, while proline accumulation was major in the sensitive one. However, spermine accumulation induced by treatment with spermidine synthase inhibitor cyclohexylamine, determined no reduction in leaf injury associated with salt stress in both cultivars. The data presented suggest that spermine accumulation is not a salt tolerance trait. 相似文献
1000.
Mammalian circadian rhythms are generated by a hypothalamic suprachiasmatic nuclei (SCN) clock. Light pulses synchronize body rhythms by inducing phase delays during the early night and phase advances during the late night. Phosphorylation events are known to be involved in circadian phase shifting, both for delays and advances. Pharmacological inhibition of the cGMP-dependent kinase (cGK) or Ca2+/calmodulin-dependent kinase (CaMK), or of neuronal nitric oxide synthase (nNOS) blocks the circadian responses to light in vivo. Light pulses administered during the subjective night, but not during the day, induce rapid phosphorylation of both p-CAMKII and p-nNOS (specifically phosphorylated by CaMKII). CaMKII inhibitors block light-induced nNOS activity and phosphorylation, suggesting a direct pathway between both enzymes. Furthermore, SCN cGMP exhibits diurnal and circadian rhythms with maximal values during the day or subjective day. This variation of cGMP levels appears to be related to temporal changes in phosphodiesterase (PDE) activity and not to guanylyl cyclase (GC) activity. Light pulses increase SCN cGMP levels at circadian time (CT) 18 (when light causes phase advances of rhythms) but not at CT 14 (the time for light-induced phase delays). cGK II is expressed in the hamster SCN and also exhibits circadian changes in its levels, peaking during the day. Light pulses increase cGK activity at CT 18 but not at CT 14. In addition, cGK and GC inhibition by KT-5823 and ODQ significantly attenuated light-induced phase shifts at CT 18. This inhibition did not change c-Fos expression SCN but affected the expression of the clock gene per in the SCN. These results suggest a signal transduction pathway responsible for light-induced phase advances of the circadian clock which could be summarized as follows: Glu-Ca2+-CaMKII-nNOS-GC-cGMP-cGK-->-->clock genes. This pathway offers a signaling window that allows peering into the circadian clock machinery in order to decipher its temporal cogs and wheels. 相似文献