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301.
Maria Filek Maria Zembala Helinä Hartikainen Zbigniew Miszalski Andrzej Kornaś Renata Wietecka-Posłuszny Paweł Walas 《Plant Cell, Tissue and Organ Culture》2009,96(1):19-28
The aim of the work was to recognize the effect of cadmium (Cd) and selenium (Se) onto properties of plastid lipid membranes.
Plastids were isolated from wheat calli cultured during 2 weeks on Murashige–Skoog media with presence/absence of 2,4-dichlorophenoxyacetic
acid. Plastids obtained in presence of 2,4-D represented an earlier developmental stage in comparison to those, got in absence
of 2,4-D, which reached a pre-chloroplast stage. The studied metals were introduced to culture media separately (2 μM Na2SeO4 or 800 μM CdCl2) or together (Se + Cd). The changes of following properties of plastid envelope membrane caused by both metals were measured:
composition of main lipid fractions, their fatty acid saturation, membrane fluidity, lipid peroxidation and membrane zeta
potential. Results of experiments led to the conclusion that galactolipid component plays a predominant role in modification
of plastid membrane properties responding to Cd and Se addition. It was shown that galactolipid protecting reaction to Cd
toxic action can consists in increased plastid envelope membrane stiffness. The presence of hormone (2,4-D) and Se did not
counterbalance Cd toxic effects (at least under concentration level applied in the experiments). Se applied separately can
probably stimulate plastid/chloroplast transformation in wheat cells by increasing a galactolipid unsaturation degree. The
zeta potentials seem to be important physicochemical parameter in determination of properties of membranes exposed to metal
stress conditions. 相似文献
302.
A V Maksimenko M B Gottikh V Helin Z A Shabarova C Malvy 《Nucleosides & nucleotides》1999,18(9):2071-2091
The influence of the secondary structure of oligonucleotides having a natural phosphodiester backbone on their ability to interact with DNA and RNA targets and on their resistance to the nucleolytic digestion is investigated. Oligonucleotides having hairpin, looped and snail-like structure are found to be much more stable to nuclease degradation in different biological media and inside cells than the linear ones. The structured oligonucleotides can also hybridise with their DNA and RNA targets. 相似文献
303.
Lyudmila Krassikova Boxi Zhang Divya Nagarajan Andr Lima Queiroz Merve Kacal Evangelos Samakidis Helin Vakifahmetoglu-Norberg Erik Norberg 《Cell death and differentiation》2021,28(3):1091
Cancer cells undergo complex metabolic alterations. The mechanisms underlying the tuning of cancer metabolism are under active investigation. Here, we identify the uncharacterized deubiquitinase JOSD2 as a positive regulator of cancer cell proliferation by displaying comprehensive effects on glucose catabolism. We found that JOSD2 directly controls a metabolic enzyme complex that includes Aldolase A, Phosphofructokinase-1 and Phosphoglycerate dehydrogenase, in vitro and in vivo. Further, JOSD2 expression, but not a catalytically inactive mutant, deubiquitinates and stabilizes the enzyme complex, thereby enhancing their activities and the glycolytic rate. This represents a selective JOSD2 feature that is not shared among other Machado–Joseph disease DUBs or observed in nontransformed cells. JOSD2 deficiency displays cytostatic effects and reduces glycolysis in a broad spectrum of tumor cells of distinct origin and its expression correlates with poor prognosis in non-small cell lung cancer. Overall, our study provides evidence for a previously unknown biological mechanism in which JOSD2 integrates glucose and serine metabolism with potential therapeutic implications.Subject terms: Cancer metabolism, Lung cancer 相似文献
304.
Natunen Jari; Seppo Antti; Helin Jari; Reinhold Bruce B.; Rabina Jarkko; Costello Catherine E.; Renkonen Ossi 《Glycobiology》1997,7(5):711-718
A novel saccharide was synthesized by incubating globo-N-tetraose,GalNAcß13Gal 相似文献
305.
Regulation of oxidative metabolism by interferon-gamma during human monocyte to macrophage differentiation 总被引:1,自引:0,他引:1
The capacity of human peripheral blood monocytes to generate highly reactive oxygen-derived molecules was studied during differentiation of the cells to macrophages in vitro. The effect of semipurified native interferon gamma (IFN gamma) on the differentiation-associated production of active oxygen intermediates was assessed by continuous exposure of the cells to IFN gamma or by adding it to the cultures at different stages of in vitro differentiation. Chemiluminescence (CL) response, triggered by opsonised zymosan, was highest in fresh isolated monocytes and fell constantly during a two-week culture. IFN gamma had little effect on CL. Generation of intracellular O2- was determined by the reduction of nitroblue tetrazolium (NBT). Zymosan-induced NBT reduction increased slightly during monocyte to macrophage differentiation and was further enhanced by continuous presence of IFN gamma. Hydrogen peroxide (H2O2) release, triggered by phorbol myristate acetate (PMA), was low in monocytes, increased slightly, reaching a maximum on day 3, and declined thereafter. H2O2 secretion was greatly enhanced by the presence of IFN gamma and remained raised for at least 14 d. When added at intervals to spontaneously matured monocytes, IFN gamma had only modest and transient effects on the generation of intracellular O2- and H2O2. It is concluded that IFN gamma seems so to modulate human mononuclear phagocyte differentiation that they maintain or increase their oxidative metabolic capacity. 相似文献
306.
5-Aminolevulinic acid (ALA), a precursor of porphyrin synthesis, increased the production of various porphyrin compounds in Candida guilliermondii cells. Metalloporphyrins and protoporphyrin IX (PPIX) were predominantly accumulated, respectively, at ALA concentrations of 0.2-0.4 mM and at those higher than 1.5 mM. 2,2;-Dipyridyl which complexed with bivalent metals significantly increased the content of endogenous PPIX even at ALA concentrations lower than 0.5 mM. Under these conditions, the yeast sensitivity to photodynamic effect of visible light (400-600 nm) dramatically increased due to photosensitization by endogenous PPIX. 相似文献
307.
We have refined to 2.3 A resolution two muconate cycloisomerase (MCIase) variant structures, F329I and I54V, that differ from each other and from wild-type in their activity toward cis,cis-muconate (CCM) and substituted CCMs. The working and free R-factors for F329I are 17.4/21.6% and for I54V, 17.6/22.3% with good stereochemistry. Except for the mutated residue, there are no significant changes in structure. To understand the differences in enzymatic properties we docked substituted CCMs and CCM into the active sites of the variants and wild type. The extra space the mutations create appears to account for most of the enzymatic differences. The lack of other structural changes explains why, although structurally equivalent changes occur in chloromuconate cycloisomerase (CMCIase), the changes in themselves do not convert a MCIase into a dehalogenating CMCIase. Reanalysis of the CMCIase structure revealed only one general acid/base, K169. The structural implication is that, in 2-chloro-CCM conversion by CMCIase, the lactone ring of 5-chloromuconolactone rotates before dehalogenation to bring the acidic C4 proton next to K169. Therefore, K169 alone performs both required protonation and deprotonation steps, the first at C5 as in MCIase, and the second, after ring rotation, at C4. This distinguishes CMCIase from alpha/beta barrel isomerases and racemases, which use two different bases. 相似文献