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981.
Bratsos I Bergamo A Sava G Gianferrara T Zangrando E Alessio E 《Journal of inorganic biochemistry》2008,102(4):606-617
We performed extensive studies on the kinetics of hydrolysis of a series of Ru(II)-dmso complexes containing dicarboxylate ligands, such as oxalate, malonate, succinate and 1,1-cyclobutane dicarboxylate (cbdc), derived from anticancer-active Ru(II)-dmso-Cl precursors. The in vitro antitumor activity of those compounds in comparison with their chloride precursors was evaluated against two tumor cell lines, the human KB oral carcinoma and the murine B16-F10 melanoma. The aim of this study was to assess how the nature of the anionic ligands (i.e. dicarboxylates vs. chlorides) affects the chemical behavior and the in vitro antitumor activity of Ru(II)-dmso complexes. Among the tested compounds only one complex, the dimer [fac-Ru(dmso-S)(3)(H(2)O)(mu-cbdc)](2) (5), exhibited moderate activity against both cell lines. Interestingly, this compound is the most kinetically stable in aqueous solution among those investigated. Despite the moderate in vitro activity, in an in vivo test, complex 5 exhibited no activity against both the primary tumor growth and the formation of spontaneous metastases on the MCa mammary carcinoma model. 相似文献
982.
Kowalik-Jankowska T Biega L Kuczer M Konopińska D 《Journal of inorganic biochemistry》2008,102(8):1615-1622
The stoichiometry, stability constants and solution structure of the complexes formed in the reaction of copper(II) with hexapeptide NPTNLH, i.e. the Neobelliera Bullata Trypsin Modulating Oostatic Factor (Neb-TMOF), and its analogues DPTNLH, Ac-NPTNLH and Ac-DPTNLH have been determined by potentiometric, UV-visible, CD and EPR spectroscopic methods. Upon raising pH for Ac-NPTNLH and Ac-DPTNLH peptides, copper(II) coordination starts from the imidazole nitrogen of the His6; afterwards three deprotonated amide nitrogens are progressively involved in metal ions coordination. In a wide pH range of 4.5-8.5 for the NPTNLH and DPTNLH ligands the CuL complex dominates with the imidazole nitrogen of His6 coordinated to form a macrochelate. The N-terminal amino group of the NPTNLH and DPTNLH peptides takes part in the coordination of the metal ion in the CuL, CuH−1L and CuH−2L complexes. However, at pH above 9 the CuH−3L complex with the {NIm, 3N−} coordination mode is formed. For the CuH−2L complex the spectroscopic data clearly indicate the 4N {NH2, CO or COO−, 2N−, NIm} bonding mode with the axial coordination of the N-terminal amine group to the metal ion. 相似文献
983.
Ramírez-Benítez JE Chee-González L Hernandez-Sotomayor SM 《Journal of inorganic biochemistry》2008,102(8):1631-1637
The primary Al-tolerance mechanism in plants involves exudation and/or accumulation of specific organic acid species, which form non-phytotoxic complexes with Al3+ under physiological conditions. An evaluation was done of the role of organic acids in the tolerance mechanism of a cell suspension line of coffee Coffea arabica that exhibits Al-tolerance (LAMt) but for which the metabolic tolerance mechanism remains unknown. Significant differences existed in malate dehydrogenase and citrate synthase activities (key enzymes in organic acids metabolism) between protein extracts (day 7 of culture cycle) of the L2 (Al-sensitive) and LAMt (Al-tolerant) cells when cell suspensions were treated with 100 μM AlCl3. HPLC analysis showed that the suspension cells of both lines exudate malate when incubated in a minimal solution but that exudation was not enhanced by treatment with AlCl3 (100 μM). This is the first study demonstrating that plant Al-tolerance may be associated with down-regulation of malate dehydrogenase and citrate synthase activities. 相似文献
984.
A new method for the identification of Enterococcus species has been developed. It combines PCR amplification of sodA gene and 16S-23S intergenic spacer region with restriction enzyme digestion followed by a melting curve analysis of the restriction fragments (MCARF). All strains analyzed were correctly identified by MCARF. This method was proved to be a reliable enterococcal identification tool. 相似文献
985.
Eliane Gonalves-de-Freitas Fabrício Barreto Teresa Fernanda Sgarbosa Gomes Percilia Cardoso Giaquinto 《Applied animal behaviour science》2008,112(1-2):187-195
Nile tilapia social position (Oreochromis niloticus) can be mediated by multiple channels, including chemical communication. Absence of chemical cues in the environment prevents hierarchical settlement among pairs, and enhances time spent in confrontations. The aim of this study was to test the effect of continuously renewed water flow on the establishment of hierarchical dominance in Nile tilapia juveniles. In this condition, a high frequency of attacks and disruption on hierarchical stability were expected because chemical cues for hierarchy maintenance could be washed out. After 3 days in isolation, the fish were paired by standard size but not by sex, and submitted to two conditions: continuously renewed water flow (RENEWED, n = 7) and non-renewed water flow (NONRENEWED, n = 8). The paired fish were placed in an aquarium (40 cm × 30 cm × 40 cm) for 3 h; four 10-min sessions were video-recorded: the first, immediately after the fish were paired and the others 1, 2, and 3 h after pairing. Hierarchy was identified by a dominance index (DI = given attacks/received + given attacks) for each fish. The hierarchical stability was achieved by analyzing the difference between dominant DI and subordinate DI (DI-D). Hierarchy was established in both groups after second session because the DI was significantly higher for one fish of the pair. The frequency of attacks of the dominant fish in RENEWED and NONRENEWED conditions was similar in all observation sessions. The attack frequency by subordinate fish was also similar during the first three sessions (2-h pairing). However, the frequency of attacks by subordinate fish in the RENEWED condition was higher than in the NONRENEWED situation at the fourth observation session (means ± S.E.: RENEWED = 2.83 ± 0.94 × 10 min−1 and NONRENEWED = 0.25 ± 0.16 × 10 min−1; Mann–Whitney, p = 0.04). At this point, a significant reduction of the DI-D was observed (means ± S.E.: RENEWED = 0.70 ± 0.11 and NONRENEWED = 1,00 ± 0.002; Mann–Whitney, p = 0.04). The changes in DI-D were related to more frequent attacks by the subordinated fish in renewed water flow. According to our results, the unsteady agonistic interaction under renewed water flow leads to social instability. Thus, continuous water renewing can wash out relevant chemical substances and therefore disturb the dominance recognition by subordinate fish. 相似文献
986.
987.
D'Archivio M Scazzocchio B Filesi C Varì R Maggiorella MT Sernicola L Santangelo C Giovannini C Masella R 《FEBS letters》2008,582(15):2291-2298
The effect of oxLDL on CD36 expression has been assessed in preadipocytes induced to differentiate. Novel evidence is provided that oxLDL induce a peroxisome proliferator-activated receptor gamma-independent CD36 overexpression, by up-regulating nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2). The nuclear translocation of Nrf2 appeared to depend on PKC pathway activation. In adipocytes, the CD36 up-regulation may indicate a compensation mechanism to meet the demand of excess oxLDL and oxidised lipids in blood, reducing the risk of atherogenesis. Besides strengthening the hypothesis that oxLDL can contribute to the onset of insulin-resistance, data herein presented highlight the significance of oxLDL-induced CD36 overexpression within the cellular defence response. 相似文献
988.
Bellon SF Kaplan-Lefko P Yang Y Zhang Y Moriguchi J Rex K Johnson CW Rose PE Long AM O'Connor AB Gu Y Coxon A Kim TS Tasker A Burgess TL Dussault I 《The Journal of biological chemistry》2008,283(5):2675-2683
c-Met is a receptor tyrosine kinase often deregulated in human cancers, thus making it an attractive drug target. One mechanism by which c-Met deregulation leads to cancer is through gain-of-function mutations. Therefore, small molecules capable of targeting these mutations could offer therapeutic benefits for affected patients. SU11274 was recently described and reported to inhibit the activity of the wild-type and some mutant forms of c-Met, whereas other mutants are resistant to inhibition. We identified a novel series of c-Met small molecule inhibitors that are active against multiple mutants previously identified in hereditary papillary renal cell carcinoma patients. AM7 is active against wild-type c-Met as well as several mutants, inhibits c-Met-mediated signaling in MKN-45 and U-87 MG cells, and inhibits tumor growth in these two models grown as xenografts. The crystal structures of AM7 and SU11274 bound to unphosphorylated c-Met have been determined. The AM7 structure reveals a novel binding mode compared with other published c-Met inhibitors and SU11274. The molecule binds the kinase linker and then extends into a new hydrophobic binding site. This binding site is created by a significant movement of the C-helix and so represents an inactive conformation of the c-Met kinase. Thus, our results demonstrate that it is possible to identify and design inhibitors that will likely be active against mutants found in different cancers. 相似文献
989.
990.
Laura Yáñez-Espinosa Teresa Terrazas Guillermo Angeles 《Trees - Structure and Function》2008,22(1):77-86
Growth and physiological response of woody plants to flooding have been analyzed in detail; however, relatively few studies
have been oriented towards the effects of water immersion on cambial activity and wood and bark anatomy of trees that are
growing in prolonged flooding conditions. These studies are important to understand the possible effects of predicted sea
level rising in mangroves as a consequence of global warming. We studied five species growing in a mangrove forest, sampling
three to six trees of each species, in sites that have the longest flooding period. Differences in bark appearance and phloem
structure between the submerged stem portion and the portion of the stem above the water surface exist in all species. Although
aerenchyma formation and stem hypertrophy are the most common events related to flooding, each type of tissue responded differently.
Annona glabra L., Laguncularia racemosa (L.) Gaertn f. and Hibiscus
tiliaceus L. developed rythidome. Avicennia germinans (L.) Stearn developed rythidome only in the submerged stem portion. Phyllanthus
elsiae Urb., developed one periderm in both stem portions. Species that developed rythidome also developed aerenchyma between periderms
and in the phellem. H. tiliaceus and P.
elsiae, showed the highest values for anatomical phloem and periderm characters below water surface, while an inverse tendency was
observed in A. glabra and L. racemosa, suggesting that prolonged flooding modifies vascular cambium and phellogen differently. Results indicate that sea level
rising would affect distribution of the species according to their specific flooding tolerance. 相似文献