排序方式: 共有13条查询结果,搜索用时 31 毫秒
1.
Stephanie R. Dukovcic Janine R. Hutchison Janine E. Trempy 《Journal of applied toxicology : JAT》2010,30(6):574-581
Toxicant sensing technology has evolved to include biological sensors, such as cell‐based biosensors, which rely on viable cells to convey a measurable physiological signal. Chromatophores are a class of pigment cells that have been investigated as cell‐based biosensors. We report the characterization of Oncorhynchus tshawytscha melanophores and describe the melanophore pigment response to neurotransmitters in terms of pigment area occupied. Compared with the previously described model, Betta splendens erythrophores, O. tshawytscha melanophores responded similarly, indicating that pigment responses are biologically conserved between these two species. Additionally, melanophores responded to mercuric chloride and sodium arsenite, similar to B. splendens erythrophores, suggesting that melanophores can be used as detectors for environmental toxicants. This report highlights the potential of O. tshawytscha melanophores to be used as cell‐based biosensors to address environmental toxicity, and warrants a continued investigation to strengthen this technology and its applications. 相似文献
2.
David Sugden David J. Davies Peter J. Garratt Robert Jones Stefan Vonhoff 《European journal of pharmacology》1995,287(3):239-243
Melatonin, a hormone secreted by the pineal gland, can act on the central circadian oscillator in the suprachiasmatic nucleus of the hypothalamus. It has been proposed that melatonin or its analogues may be useful in restoring disturbed circadian rhythms in jet-lag, shift-work and some blind subjects, and as sleep-promoting agents. In the present study, the (−)- and (+)-enantiomers of N-acetyl-4-aminomethyl-6-methoxy-9-methyl-1,2,3,4-tetrahydrocarbazole (AMMTC) were separated and tested. The affinity of the enantiomers at the specific 2-[125I]iodomelatonin binding site in chick brain membranes was compared in competition assays, and their biological activity in a specific melatonin receptor bioassay, aggregation of pigment granules in Xenopus laevis melanophores. The (−)-enantiomer of AMMTC was 130-fold and 230-fold more potent than the (+)-enantiomer in competition radioligand binding assays and melanophores, respectively. Both enantiomers are melatonin receptor agonists; (−)-AMMTC is slightly more potent than melatonin itself. As the tetrahydrocarbazole nucleus holds the C-3 amido side-chain of AMMTC in a restricted conformation, the analogues will be useful in modelling the melatonin receptor binding site. 相似文献
3.
Gerald W. Eagleson Roel A. van der Heijden Eric W. Roubos Bruce G. Jenks 《General and comparative endocrinology》2010,168(2):302-306
The periodic albino of Xenopus laevis displays a transitory presence of black melanin pigment in the embryo but looses this during tadpole development. This mutation, involving a recessive allele, affects melanogenesis in dermal melanophore pigment cells. It has been suggested that the mutation is intrinsic to the melanophore cell itself or, alternatively, reflects malfunction in the neuroendocrine system that regulates melanophore cell function. This latter system, involving pituitary melanotrope cells which produces α-melanophore stimulating hormone (α-MSH), is responsible for stimulating the production and dispersion of melanin pigment in dermal melanophores. The purpose of the present study was to determine to which degree the albinism is intrinsic to the melanophore or involves neuroendocrine malfunction. Experiments involved transplantation of presumptive melanophores from wild-type to albino embryos, and vice versa, immunocytochemical analysis of the albino neuroendocrine system and the creation of wild-type/albino parabiotic animals to determine if the neuroendocrine system of the albino can support melanotrope cell function. We show that the albino has a functional neuroendocrine system and conclude that the defect in the albino primarily affects the melanophore cell, possibly rendering it incapable of responding to α-MSH. It is also apparent from our results that in later stages of development the cellular environment of the melanotrope cell does become important to its development, but the nature of the critical cellular factors involved remains to be determined. 相似文献
4.
5.
The release of melanophore stimulating hormone (MSH) from the pars intermedia of the amphibian Xenopus laevis is regulated by multiple factors of hypothalamic origin. The aim of this study was to determine if potential secretagogues function through a direct action on the melanotrope cell. For this purpose an in vitro superfusion system containing isolated melanotropes (cell suspension) was utilized. The viability of the cells in suspension was tested by examining their ability to synthesize, process and release pro-opiomelanocortin (POMC) related peptides. All biosynthetic functions appeared normal, with the exception that the isolated melanotropes are unable to N-terminally acetylate MSH. Release of immunoreactive-MSH from these cells was shown to be Ca2+-dependent and high K+ stimulated release. Both the neurotransmitters dopamine and γ-aminobuiyric acid (GABA), which are thought to be physiologically important MSH-release inhibiting factors, were shown to inhibit MSH release from isolated melanotropes. Dopamine appeared to function through a dopamine D2 type receptor mechanism while for GABA, both a GABAa and GABAb receptor mechanism are involved. 相似文献
6.
Huang J Rebello SS Rosenberg LA Kaneko M Sakurama T Lucchesi BR 《European journal of pharmacology》1999,380(2-3):203-213
A cDNA clone coding for the guinea pig leukotriene B4 (BLT) receptor has been isolated from a lung cDNA library. The guinea pig BLT receptor has an open reading frame corresponding to 348 amino acids and shares 73% and 70% identity with human and mouse BLT receptors, respectively. Scatchard analysis of membranes prepared from guinea pig and human BLT receptor-transfected human embryonic kidney (HEK) 293 EBNA (Epstein–Bar Virus Nuclear Antigen) cells showed that both receptors displayed high affinity for leukotriene B4 (Kd value of 0.4 nM) and were expressed at high levels (Bmax values ranging from 9 to 12 pmol/mg protein). The rank order of potency for leukotrienes and related analogs in competition for [3H]leukotriene B4 specific binding at the recombinant guinea pig BLT receptor is leukotriene B4>20-OH-leukotriene B4>12(R)-HETE ((5Z,8Z,10E,12(R)14Z)-12-hydroxyeicosatetraen-1-oic acid)>12(S)-HETE ((5Z,8Z,10E,12(S)14Z)-12-Hydroxyeicosatetraen-1-oic acid)>20-COOH-leukotriene B4>U75302 (6-(6-(3-hydroxy-1E,5Z-undecadienyl)-2-pyridinyl)-1,5-hexanediol)leukotriene C4=leukotriene D4=leukotriene E4. For the human receptor the rank order of 12(S)-HETE, 20-COOH-leukotriene B4 and U75302 was reversed. Xenopus melanophore and HEK aequorin-based reporter gene assays were used to demonstrate that the guinea pig and human BLT receptors can couple to both the cAMP inhibitory and intracellular Ca2+ mobilization signaling pathways. However, in the case of the aequorin-expressing HEK cells (designated AEQ17-293) transfected with either the guinea pig or human BLT receptor, expression of G16 was required to achieve a robust Ca2+ driven response. Leukotriene B4 was a potent agonist in functional assays of both the guinea pig and human BLT receptors. U-75302 a leukotriene B4 analogue which possesses both agonistic and antagonistic properties behaved as a full agonist of the guinea pig and human BLT receptors in AEQ17-293 cells and not as an antagonist. The recombinant guinea pig BLT receptor will permit the comparison of the intrinsic potencies of leukotriene B4 receptor antagonists used in guinea pig in vivo models of allergic and inflammatory disorders. 相似文献
7.
人表皮和真皮细胞在多种应激刺激下可产生许多促黑因子和炎症介质,在局部形成自分泌、旁分泌网络而发挥机体调节作用。本文着重从氧化应激和热应激方面综合了近年来的相关因子和介质的研究报道,为进一步研究色素沉着性疾病提供思路。 相似文献
8.
目的 观察斑马鱼鳍和鳞片色素细胞的组成、分布及形态特征.方法 应用光学显微镜对AB品系斑马鱼鳍和鳞片色素细胞的显微结构进行观察.结果 斑马鱼鳍上分布有黑色素细胞和黄色素细胞,未观察到虹彩细胞.根据色素细胞的分布规律,将斑马鱼鳍分为有、无斑马鱼条纹两类.鳞片中分布有黑色素细胞、黄色素细胞和虹彩细胞.黑色素细胞较大,形态上主要分为呈树突状、颜色较浅、体积较大的I类黑色素细胞和呈团状、颜色较深、个体较小的Ⅱ类黑色素细胞.黄色素细胞个体最小,呈黄色或者橙黄色.虹彩细胞较长呈长棒状或梭形,数量最少.结论 斑马鱼体表有黑色素细胞、黄色素细胞和虹彩细胞三种类型色素细胞,但鳍和鳞片在色素细胞组成和分布上存在着差异,鳞片中色素细胞的种类和形态特征较鳍中色素细胞更丰富. 相似文献
9.
Objective: Sequencing of mouse Tbx2 gene and observing the expression of Tbx2 gene in normal and malignant melanophore. Methods:
The PCR products of Tbx2 cDNA were cloned into pUC18 vector and sequenced. The normal and malignant melanocytes were used
to extract total RNA. The expression of Tbx2 gene was detected by RT-PCR. Results: The Tbx2 genome is composed of seven exons
and six introns. No expression of Tbx2 gene in the normal melanocytes was noted, but all malignant melanocytes showed expression
of Tbx2 gene. Conclusion: The observation showed the analysis of the genomic structure of mouse Tbx2. Tbx2 plays a critical
role during the development of the malignant melanophore. 相似文献
10.
Yves Boie Rino Stocco Nicole Sawyer Gillian M. Greig Stacia Kargman Deborah M. Slipetz Gary P. O'Neill Takao Shimizu Takehiko Yokomizo Kathleen M. Metters Mark Abramovitz 《European journal of pharmacology》1999,380(2-3)
A cDNA clone coding for the guinea pig leukotriene B4 (BLT) receptor has been isolated from a lung cDNA library. The guinea pig BLT receptor has an open reading frame corresponding to 348 amino acids and shares 73% and 70% identity with human and mouse BLT receptors, respectively. Scatchard analysis of membranes prepared from guinea pig and human BLT receptor-transfected human embryonic kidney (HEK) 293 EBNA (Epstein–Bar Virus Nuclear Antigen) cells showed that both receptors displayed high affinity for leukotriene B4 (Kd value of 0.4 nM) and were expressed at high levels (Bmax values ranging from 9 to 12 pmol/mg protein). The rank order of potency for leukotrienes and related analogs in competition for [3H]leukotriene B4 specific binding at the recombinant guinea pig BLT receptor is leukotriene B4>20-OH-leukotriene B4>12(R)-HETE ((5Z,8Z,10E,12(R)14Z)-12-hydroxyeicosatetraen-1-oic acid)>12(S)-HETE ((5Z,8Z,10E,12(S)14Z)-12-Hydroxyeicosatetraen-1-oic acid)>20-COOH-leukotriene B4>U75302 (6-(6-(3-hydroxy-1E,5Z-undecadienyl)-2-pyridinyl)-1,5-hexanediol)leukotriene C4=leukotriene D4=leukotriene E4. For the human receptor the rank order of 12(S)-HETE, 20-COOH-leukotriene B4 and U75302 was reversed. Xenopus melanophore and HEK aequorin-based reporter gene assays were used to demonstrate that the guinea pig and human BLT receptors can couple to both the cAMP inhibitory and intracellular Ca2+ mobilization signaling pathways. However, in the case of the aequorin-expressing HEK cells (designated AEQ17-293) transfected with either the guinea pig or human BLT receptor, expression of Gα16 was required to achieve a robust Ca2+ driven response. Leukotriene B4 was a potent agonist in functional assays of both the guinea pig and human BLT receptors. U-75302 a leukotriene B4 analogue which possesses both agonistic and antagonistic properties behaved as a full agonist of the guinea pig and human BLT receptors in AEQ17-293 cells and not as an antagonist. The recombinant guinea pig BLT receptor will permit the comparison of the intrinsic potencies of leukotriene B4 receptor antagonists used in guinea pig in vivo models of allergic and inflammatory disorders. 相似文献