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111.
Jacek Turyn Magdalena Stojek Julian Swierczynski 《Molecular and cellular biochemistry》2010,345(1-2):181-188
Successful treatment of obesity and related diseases by chronic food restriction requires the understanding of the effect of such nutritional therapy on the expression of genes which have been implicated to be involved in some diseases associated with obesity. The purpose of this study was to examine the effect of chronic food restriction and chronic food restriction/refeeding on lipogenic enzymes, especially the expression of genes encoding the stearoyl-CoA desaturase 1 (Scd1) and elongase6 (Elovl6) in rat liver and adipose tissue. We found that both chronic food restriction and chronic food restriction/refeeding caused increased expression of the Scd1 and Elovl6 genes in both the liver and adipose tissue. The increase was more pronounced in case of chronic food restriction/refeeding (several-fold increase) than that in chronic food restriction alone (two to threefold increase). Essentially, similar results were obtained when the expression of fatty acid synthase, acetyl-CoA carboxylase, ATP-citrate lyase, and malic enzyme genes was studied. Moreover, we found that chronic food restriction and short-term fasting exert opposite effects on the expression of lipogenic enzymes genes. The increased expression of the genes encoding Scd1, Elovl6, and other key lipogenic enzymes may favor fat storage after chronic food restriction/refeeding and may be part of the molecular mechanism by which food restriction/refeeding increases body weight and enhances susceptibility to insulin resistance. 相似文献
112.
Grajkowski A Cieślak J Gapeev A Schindler C Beaucage SL 《Bioconjugate chemistry》2010,21(11):2147-2152
The ribonucleoside building block, N2-isobutyryl-2'-O-propargyl-3'-O-levulinyl guanosine, was prepared from commercial N2-isobutyryl-5'-O-(4,4'-dimethoxytrityl)-2'-O-propargyl guanosine in a yield of 91%. The propargylated guanylyl(3'-5')guanosine phosphotriester was synthesized from the reaction of N2-isobutyryl-2'-O-propargyl-3'-O-levulinyl guanosine with N2-isobutyryl-5'-O-(4,4'-dimethoxytrityl)-2'-O-tert-butyldimethylsilyl-3'-O-[(2-cyanoethyl)-N,N-diisopropylaminophosphinyl] guanosine and isolated in a yield of 88% after P(III) oxidation, 3'-/5'-deprotection, and purification. The propargylated guanylyl(3'-5')guanosine phosphotriester was phosphitylated using 2-cyanoethyl tetraisopropylphosphordiamidite and 1H-tetrazole and was followed by an in situ intramolecular cyclization to give a propargylated c-di-GMP triester, which was isolated in a yield of 40% after P(III) oxidation and purification. Complete N-deacylation of the guanine bases and removal of the 2-cyanoethyl phosphate protecting groups from the propargylated c-di-GMP triester were performed by treatment with aqueous ammonia at ambient temperature. The final 2'-desilylation reaction was effected by exposure to triethylammonium trihydrofluoride affording the desired propargylated c-di-GMP diester, the purity of which exceeded 95%. Biotinylation of the propargylated c-di-GMP diester was easily accomplished through its cycloaddition reaction with a biotinylated azide derivative under click conditions to produce the biotinylated c-di-GMP conjugate of interest in an isolated yield of 62%. 相似文献
113.
At the onset of swimbladder inflation, Tinca tinca larvae were exposed for 24 h to cadmium or copper at 0.0 (control concentration), 0.1, 0.2 and 0.3 mg dm−3 at 22°C. From then larvae were reared at 25°C for 9 days in un-supplemented water. Both metals resulted in a significantly
reduced growth, survival, and retarded swimbladder inflation in a dose-response manner. The highest Cd and Cu concentration
delayed the onset of exogenous feeding (live artemia nauplii) for 2 or 1 days, respectively, comparing to the control concentration.
Our results demonstrate a highly toxic effect of Cd and Cu in the studied period of larval ontogeny, when fish seem especially
sensitive. Although, at low concentrations and long exposure period, Cu is considered more toxic to fish than Cd, our study
revealed the reverse effect for first-feeding larvae of both metals at high concentrations and short exposure. 相似文献
114.
Gabriela Bugla-Płoskońska Jacek Rybka Bożena Futoma-Kołoch Agnieszka Cisowska Andrzej Gamian Włodzimierz Doroszkiewicz 《Microbial ecology》2010,59(3):601-613
Sialic acid (N-acetylneuraminic acid, NeuAc) plays an essential role in protecting gram-negative bacteria against the bactericidal
activity of serum and may contribute to the pathogenicity of bacteria by mimicking epitopes that resemble host tissue components
(molecular mimicry). The role of sialic acid (NeuAc)-containing lipopolysaccharides (LPS) of Salmonella O48 strains in the complement activation of normal human serum (NHS) was investigated. NeuAc-containing lipooligosaccharides
cause a downregulation of complement activation and may serve to camouflage the bacterial surface from the immunological response
of the host. Serotype O48 Salmonella strains have the O-antigen structure containing NeuAc while its serovars differ in outer membrane protein composition. In
this study, the mechanisms of complement activation responsible for killing Salmonella O48 serum-sensitive rods by NHS were established. Four of such mechanisms involving pathways, which are important in the
bactericidal mechanism of complement activation, were distinguished: only the classical/lectin pathways, independent activation
of the classical/lectin or alternative pathway, parallel activation of the classical/lectin and alternative pathways, and
only the alternative pathway important in the bactericidal action of human serum. To further study the role of NeuAc, its
content in bacterial cells was determined by gas-liquid chromatography-mass spectrometry in relation to 3-deoxy-D-manno-2-octulosonic
acid (Kdo), an inherent constituent of LPS. The results indicate that neither the presence of sialic acid in LPS nor the length
of the O-specific part of LPS containing NeuAc plays a decisive role in determining bacterial resistance to the bactericidal
activity of complement and that the presence of sialic acid in the structure of LPS is not sufficient to block the activation
of the alternative pathway of complement. We observed that for three strains with a very high NeuAc/Kdo ratio the alternative
pathways were decisive in the bactericidal action of human serum. The results indicated that those strains are not capable
of inhibiting the alternative pathway very effectively. As the pathogenicity of most Salmonella serotypes remains undefined, research into the interactions between these bacterial cells and host organisms is indispensable. 相似文献
115.
A number of unexpected reactions were observed during attempts to invert configuration at C16 in 16α,17α,22-triol 3a. The PDC oxidation of 3a produced the D-seco-aldehyde 4a. Analogous compound 4b was obtained by Swern oxidation of the 16α,17α-dihydroxy-22-O-TES-ether 3b in addition to the desired 16-ketone 7. The unprotected triol 3a yielded pentacyclic products 5 and 6 under similar conditions. The Mitsunobu reaction of the triol 3a afforded 16-ketone 8 with inverted configuration of the side chain. During heating of a solution of 3a in THF with NaH at reflux autoxidation to the 16-ketone cyclic hemiketal 5, identical to one of the Swern oxidation products, took place. 相似文献
116.
Agnieszka Jazwa Paulina Kucharzewska Justyna Leja Anna Zagorska Aleksandra Sierpniowska Jacek Stepniewski Magdalena Kozakowska Hevidar Taha Takahiro Ochiya Rafal Derlacz Elisa Vahakangas Seppo Yla-Herttuala Alicja Jozkowicz Jozef Dulak 《Genetic vaccines and therapy》2010,8(1):1-16
Background
Impaired wound healing in diabetes is related to decreased production of growth factors. Hence, gene therapy is considered as promising treatment modality. So far, efforts concentrated on single gene therapy with particular emphasis on vascular endothelial growth factor-A (VEGF-A). However, as multiple proteins are involved in this process it is rational to test new approaches. Therefore, the aim of this study was to investigate whether single AAV vector-mediated simultaneous transfer of VEGF-A and fibroblast growth factor 4 (FGF4) coding sequences will improve the wound healing over the effect of VEGF-A in diabetic (db/db) mice.Methods
Leptin receptor-deficient db/db mice were randomized to receive intradermal injections of PBS or AAVs carrying β-galactosidase gene (AAV-LacZ), VEGF-A (AAV-VEGF-A), FGF-4 (AAV-FGF4-IRES-GFP) or both therapeutic genes (AAV-FGF4-IRES-VEGF-A). Wound healing kinetics was analyzed until day 21 when all animals were sacrificed for biochemical and histological examination.Results
Complete wound closure in animals treated with AAV-VEGF-A was achieved earlier (day 19) than in control mice or animals injected with AAV harboring FGF4 (both on day 21). However, the fastest healing was observed in mice injected with bicistronic AAV-FGF4-IRES-VEGF-A vector (day 17). This was paralleled by significantly increased granulation tissue formation, vascularity and dermal matrix deposition. Mechanistically, as shown in vitro, FGF4 stimulated matrix metalloproteinase-9 (MMP-9) and VEGF receptor-1 expression in mouse dermal fibroblasts and when delivered in combination with VEGF-A, enhanced their migration.Conclusion
Combined gene transfer of VEGF-A and FGF4 can improve reparative processes in the wounded skin of diabetic mice better than single agent treatment. 相似文献117.
The paper presents recent trends in solventless sample preparation techniques for environmental analysis. First, a general classification of solventless methods is given. Next, three of them, treated as preferable techniques, i.e. SPME, SDME and HS, are presented in detail, with respect to their usability and effectiveness for environmental samples. Examples of all discussed techniques are given in the tables. 相似文献
118.
Radwan J 《Experimental & applied acarology》2007,42(3):151-158
Whether benefits of mate choice accrued by females outweigh costs associated with sexual selection remains largely unresolved.
The ‘good genes’ perspective, posing that mate choice benefits females genetically has been challenged by the arguments that
sexual selection is driven mostly by direct costs and inter-sexual conflict. Here, I present an overview of experimental tests
of predictions of good genes and sexual conflict mechanisms in the bulb mite Rhizoglyphus robini. 相似文献
119.
New synthetic pathway towards 19-functionalized derivatives of 1alpha-hydroxy-5,6-trans-vitamin D3 was described. Ring-closing metathesis (RCM) of 1alpha-hydroxy-5,6-trans-vitamin D3 1-omega-alkenoates was a key-step. Hydride reduction of resulting lactones led to the new vitamin D3 analogues. 相似文献
120.