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1.
NADPH2 and ATP competitively inhibit sweet potato glucose 6-phosphatedehydrogenase with NADP and glucose 6-phosphate (G6P), respectively.At pH 8.0, a Lineweaver-Burk plot of the reciprocal rate againstreciprocal G6P concentration was concave downwards in the presenceand absence of ATP, whereas a double reciprocal plot followedthe Michaelis-Menten relationship at pH 7.0, irrespective ofthe presence of ATP. Many of the other metabolic intermediatestested had no effects on the enzyme reaction.
1 This paper constitutes Part 96 of the Phytopathological Chemistryof Sweet Potato with Black Rot and Injury.
2 Present address: Institute of Applied Microbiology, Universityof Tokyo Bunkyo-ku, Tokyo 113. (Received October 20, 1971; ) 相似文献
2.
3.
Tetyana Denysenko Luisa Gennero Carola Juenemann Isabella Morra Paolo Masperi Vincenzo Ceroni Antonella Pragliola Antonio Ponzetto Antonio Melcarne 《Cell biochemistry and function》2014,32(2):164-176
Glioblastomas (GBMs) are the most lethal primary brain tumours. Increasing evidence shows that brain tumours contain the population of stem cells, so‐called cancer stem cells (CSCs). Stem cell marker CD133 was reported to identify CSC population in GBM. Further studies have indicated that CD133 negative cells exhibiting similar properties and are able to initiate the tumour, self‐renew and undergo multilineage differentiation. GBM is a highly heterogeneous tumour and may contain different stem cell populations with different functional properties. We characterized five GBM cell lines, established from surgical samples, according to the marker expression, proliferation and differentiation potential. CD133 positive cell lines showed increased proliferation rate in neurosphere condition and marked differentiation potential towards neuronal lineages. Whereas two cell lines low‐expressing CD133 marker showed mesenchymal properties in vitro, that is high proliferation rate in serum condition and differentiation in mesenchymal cell types. Further, we compared therapy resistance capacity of GBM cell lines treated with hydroxyurea. Our results suggest that CSC concept is more complex than it was believed before, and CD133 could not define entire stem cell population within GBM. At least two different subtypes of GBM CSCs exist, which may have different biological characteristics and imply different therapeutic strategies. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
4.
Behavioral endocrinology of male rats with periodic sexual contacts with exclusive or varied females
G T Taylor D Komitowski S Muto J Weiss 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1989,192(3):236-241
Sexual contact keys a profound series of acute and chronic changes in males that, presumably, are orchestrated by acute pulsatile release of hormones. An experimental paradigm is reported in which male rats were paired periodically with either the same or different estrous females to receive identical amounts of copulatory experiences. Results confirmed the hypothesis that exposure to an unfamiliar female would induce a different endocrine response which would be reflected in various androgen-sensitive systems. The "successively polygynous" males showed more sexual behavior than "monogamous" males, and their respective females solicited the males differently, as well. Circulating levels of testosterone were higher immediately after sexual contact with an unfamiliar than with a familiar female partner. There were no differences in testosterone titers among the groups when the animals were killed at either 2 or 7 weeks after the final copulatory experiences. Yet, necropsies at 2 weeks postcopulation revealed that primary and secondary sex structures from polygynous males clearly were larger. Differences between the two experimental groups were reduced after 7 weeks of sexual rest, yet, polygnous males continued to show a different structural profile than the other groups. Conclusions were that males may experience greater activation of androgen-sensitive behavior and physiology following qualitatively different sexual contacts. 相似文献
5.
In the proximal end of the navicular fossa, the stratified columnar epithelium lining the spongy part of the urethra abruptly changes into the stratified squamous one, presenting a sharp demarcation. It is considered that the junction between these 2 epithelia corresponds to the former site of the junction of the entoderm and ectoderm. The width of the microridges in the distal part of the navicular fossa was about doubled compared to that in the proximal part. It is suggested that the epithelium in the distal part is keratinized, while that in the proximal part is nonkeratinized. 相似文献
6.
Giovanni Savettieri Rosa Guarneri Giuseppe Salemi Vincenzo La Bella Donatella Ferraro Salvatore Scondotto Federico Piccoli 《Neurochemical research》1990,15(8):773-776
[3H]Flunitrazepam (FNZ) binding to cortical neurons from fetal rat brain was investigated in vitro. The use of a synthetic medium specific for neurons made it possible to plot a developmental curve of3H-FNZ binding in an almost pure neuronal culture. Detectable specific binding was present in vitro at time 0 (that is, the 16th gestational day). A progressive increase of binding, due to an increment in the number of recognition sites, was observed on the subsequent days. The affinity of the specific binding sites to3H-FNZ was enhanced by the addition of exogenous GABA, whereas the density was not affected. 相似文献
7.
Vincenzo Carelli Antonio Casini Alessandro Finazzi-Agro Felice Liberatore Silvano Tortorella 《Free radical research》1988,4(6):397-402
The nicotinamide adenine dinucleotide dimers (NAD)2 obtained by electrochemical reduction of NAD+ are oxidized by adriamycin in anaerobic photocatalyzed reaction yielding NAD+ and 7-deoxyadriamyci-none. Under the same conditions NADH is not oxidized. 相似文献
8.
Pierpaolo Correale Antonio Procopio Luigi Celio Michele Caraglia Geppino Genua Vincenzo Coppola Stefano Pepe Nicola Normanno Immacolata Vecchio Giovannella Palmieri Stefania Montagnani Pierosandro Tagliaferri Angelo Raffaele Bianco 《Cancer immunology, immunotherapy : CII》1992,34(4):272-278
Summary Human melanoma cells are sensitive to the lytic activity of natural killer (NK) and lymphokine-activated killer (LAK) cells in vitro. The events resulting in tumour cell killing by lymphocytic effectors have not been completely clarified, and the same target cell determinants regulating responsiveness to immune cytolysis have not yet been identified. Indeed, changes in the differentiative status of leukemia cells as well as in the expression of major histocompatibility complex (MHC) antigens have been described to modulate sensitivity to cytotoxic effectors; moreover surface expression of adhesion factors or extracellular matrix proteins by the cancer cells can promote the activation of the cytolytic effectors and has been described to correlate with tumour cell sensitivity to cytolytic cells. We reasoned that treatment with differentiation inducers could modulate melanoma cell sensitivity to NK and LAK cells. The present study demonstrates that human melanoma GLL-19 cells, when treated with the phorbol diester phorbol 12-myristate 13-acetate (PMA) in vitro, undergo growth inhibition and neuron-like differentiation. Moreover PMA treatment induces an evident inhibition of GLL-19 cell sensitivity to NK- and LAK-mediated cytotoxicity. GLL-19 cells express constitutively MHC class I antigens. PMA treatment, however, does not modify the expression of MHC class I and class II DR antigens in human melanoma GLL-19 cells. We have finally evaluated the effects of PMA on the expression at the cell surface of adhesion factors such as ICAM-1, and extracellular matrix proteins such as collagen IV, laminin and fibronectin; we have also studied the expression of the integrin vitronectin receptor, a membrane receptor for adhesive proteins. While adhesion factors and extracellular matrix proteins appear to play an important role in the interaction between immune effector and tumour target, it can be supposed that the modulation of such membrane-associated proteins or glycoproteins induces NK and LAK resistance in cancer cells. We indeed found that PMA treatment induced in GLL-19 a marked reduction of membrane expression of collagen IV and ICAM-1; moreover PMA reduced the cell membrane expression of the integrin vitronectin receptor. On the other hand, membrane expression of fibronectin and laminin was not affected by PMA. These data indicate that the acquisition of a NK- and LAK-resistant phenotype by GLL-19 cells occurs together with cell differentiation, down-regulation of membrane expression of collagen IV, ICAM-1 and vitronectin receptor, but in the absence of changes in MHC antigens.This work has been supported by the Italian Association for Cancer Research (A. I. R. C.) and by Istituto Superiore di Sanità, Italy-USA joint program on New Therapies on Neoplasia. 相似文献
9.
Solubilization and reconstitution of ca pump from corn leaf plasma membrane 总被引:1,自引:0,他引:1 下载免费PDF全文
The Ca2+ transport system of corn (Zea mays) leaf plasma membrane is composed of Ca2+ pump and Ca2+/H+ antiporter driven by H+ gradient imposed by a H+ pump (M Kasai, S Muto [1990] J Membr Biol 114: 133-142). It is necessary for characterization of these Ca2+ transporters to establish the procedure for their solubilization, isolation, and reconstitution into liposomes. We attempted to solubilize and reconstitute the Ca2+ pump in the present study. A nonionic detergent octaethyleneglycol monododecyl ether (C12E8) was the most effective detergent for a series of extraction and functional reconstitution of the Ca2+ pump among seven detergents examined. This was judged from activities of ATP-dependent 45Ca2+ uptake into liposomes reconstituted with the respective detergent-extract of the plasma membrane by the detergent dilution method. C12E8-extract of the plasma membrane was subjected to high performance liquid chromatography using a DEAE anion exchange column. Ca2+-ATPase was separated from VO43−-sensitive Mg2+-ATPase. These ATPases were separately reconstituted into liposomes, and their ATP-dependent Ca2+ uptake was measured. The liposomes reconstituted with the Ca2+-ATPase, but not with the VO43−-sensitive Mg2+-ATPase, showed ATP-dependent Ca2+ uptake. Nigericin-induced pH gradient (acid inside) caused only a little Ca2+ uptake into liposomes reconstituted with the Ca2+-ATPase, suggesting that the Ca2+/H+ antiporter was not present in the preparation. These results indicate that the Ca2+-ATPase actually functions as Ca2+ pump in the corn leaf plasma membrane. 相似文献