Recent progress on the effects of structured lipids and fluidity of plasma membrane on tumor metastasis / 药学学报

The lipid composition of cell plasma membranes of aggressive tumors is significantly altered from normal, affecting the membrane fluidity and function. Plasma membrane fluidity involves multiple steps in tumor invasion and metastasis, including cell movement, adhesion, lateral diffusion of membrane molecules, signal transduction, material exchange and so on. This review highlights the difference in plasma membrane lipid composition and fluidity between normal and cancer cells, as well as the correlation with the invasion and metastasis potential of cancer. We also point out that the proliferation, invasion and metastasis of tumors can be inhibited by improving membrane fluidity or interfering with the membrane structured lipid composition, this focusing more on changing the biophysical properties of cancer cell membranes, and providing a novel strategy that works for treatment of tumor metastasis.

Effect of fish oil on oxidative stress markers in patients with probable Alzheimer´s disease

High intake of omega-3 fatty acids has been associated with synaptic plasticity, neurogenesis and memory in several experimental models. To assess the efficacy of fish oil supplementation on oxidative stress markers in patients diagnosed with probable Alzheimer´s disease (AD) we conducted a double blind, randomized, placebo controlled clinical trial. AD patients who met the inclusive criteria were given fish oil (containing 0.45 g eicosapentaenoic acid and 1 g docosahexaenoic acid) or placebo daily for 12 months. Oxidative stress markers [lipoperoxides, nitric oxide catabolites levels, oxidized/reduced glutathione ratio, and membrane fluidity] and fatty acid profile in erythrocytes were assessed at enrollment, and 6 and 12 months after the start of the testing period. At the end of the trial, in patients who received fish oil, we detected a decrease in the omega 6/omega 3 ratio in erythrocyte membrane phospholipids. This change was parallel with decreases in plasma levels of lipoperoxides and nitric oxide catabolites. Conversely, the ratio of reduced to oxidized glutathione was significantly increased. In addition, membrane fluidity was increased significantly in plasma membrane samples. In conclusion fish oil administration has a beneficial effect in decreasing the levels of oxidative stress markers and improving the membrane fluidity in plasma(AU)

El alto consumo de ácidos grasos omega-3 se asocia con la plasticidad sináptica, neurogénesis y memoria en varios modelos experimentales. Para evaluar la eficacia de la suplementación con aceite de pescado en los marcadores de estrés oxidativo en pacientes con diagnóstico de la enfermedad de Alzheimer (EA) probable realizamos un ensayo clínico doble ciego, aleatorizado, controlado con placebo. A los pacientes con la EA que cumplían los criterios de inclusión se les administró aceite de pescado (que contenía 0,45 g de ácido eicosapentaenoico y 1 g de ácido docosahexaenoico) o placebo diariamente durante 12 meses. Los marcadores de estrés oxidativo plasmático [niveles de lipoperóxidos y catabolitos del óxido nítrico, cociente de glutatión reducido a glutatiónoxidado) y fluidez de la membrana] y el perfil de ácidos grasos en los eritrocitos se evaluaron al inicio, 6 meses y alos 12 meses. Al final del ensayo, en pacientes que recibieron aceite de pescado detectamos una disminución en el cociente de ácidos grasos omega 6/omega 3 en los fosfolípidos de la membrana eritrocitaria. Este cambio ocurrió en paralelo a la disminución de los niveles plasmáticos de lipoperóxidos y catabolitos del óxido nítrico. Por el contrario, el cociente de glutatión reducido a glutatión oxidado se incrementó significativamente. Además, la fluidez de la membrana aumentó significativamente en las muestras analizadas. En conclusión, la administración de aceite de pescado tiene un efecto beneficioso al disminuir los niveles de marcadores de estrés oxidativo plasmático y mejorar la fluidez de la membrana plasmática(AU)

Study on mechanism of enhanced HaCaT cellular uptake of tetrahydropalmatine by asarum essential oil and sinapine in Sanfu Patch / 中草药

Objective To study the mechanism of enhanced HaCaT cellular uptake of tetrahydropalmatine (THP) by asarum essential oil (AEO) and sinapine thiocyanate (SPT) in Sanfu Patch. Methods Effect of SPT, AEO, and THP on cell viability of HaCaT were determined by MTT. HaCaT cellular uptake of THP and the enhancing effects of AEO and SPT on THP uptake were visualized with confocal laser scanning microscope (CLSM) based on the green autofluorescence of THP, and the THP uptake content by HaCaT was further determined with HPLC. Moreover, HaCaT cells were labeled with diphenylhexatriene (DPH). After the labeled cells were treated with AEO, SPT, and THP, respectively, the cellular membrane fluidity was determined with fluorescence polarization technology. Results THP fluorescence intensity within HaCaT cells was significantly increased when THP was co-delivered with AEO or SPT respectively, and the THP content with each group within the cells was also significantly higher than that of THP delivered alone. In addition, AEO was superior to SPT in enhancing THP uptake by HaCaT cells. The fluorescence polarization and membrane micro-viscosity of HaCaT cells were significantly decreased after AEO treatment, which indicated that membrane fluidity was increased by the treatment with AEO. However, SPT or THP did not present the character of increasing the membrane fluidity.Conclusion HaCaT cellular uptake of THP can be enhanced by AEO and SPT of Sanfu Patch, in which AEO enhances the cellular uptake of THP through increasing the cellular membrane fluidity, while the mechanism of SPT in enhancing THP cellular uptake remains further clarification.

Effects of microemulsion on transport and mechanism of puerarin in MDCK-MDR1 cells / 中草药

Objective To explore the effect of microemulsion on the transport and mechanism of puerarin in blood brain barrier (BBB) cell model MDCK-MDR1. Methods MTT assay was used to evaluate the cytotoxicity of puerarin microemulsion and solution, and determine the appropriate concentration of administration. The bilateral transport characteristics of puerarin solution-microemulsion was investigated in MDCK-MDR1 monolayer. Immunohistochemical staining was used to study the expression of tight junction proteins, and the changes in cell membrane fluidity was studied by fluorescence bleaching recovery, and the changes of membrane potential was measured by anion probe combined with flow cytometry. The mechanism of the effect of microemulsion on puerarin transport was clarified. Results The MDCK-MDR1 showed no significant toxicity when the mass concentration of puerarin solution ranged from 50 to 300 μg/mL and the microemulsion dilution was over 500 times. The Papp value in absorption direction of puerarin solution on MDCK-MDR1 monolayer was 1.04 × 10-6 cm/s, and the Papp value of excretion direction was 1.05 × 10-6 cm/s. The Papp value of puerarin in microemulsion was significantly increased compared with that in solution (P < 0.05). Microemulsification could reduce the expression of Claudin-1, Occludin, ZO-1, and F-actin in MDCK-MDR1, promote cell membrane flow, and decrease cell membrane potential. Conclusion Microemulsion can promote the bilateral transport of puerarin in the BBB cell model MDCK-MDR1. The mechanism is closely connected with the opening of tight junctions, increasing the cell membrane fluidity, making the cell depolarizing and reducing membrane potential, and increasing the permeation of paracellular.

Effect of paeoniflorin and menthol on membrane fluidity, Na⁺-K⁺-ATPase activity and Ca²⁺-ATPase activity during transport of puerarin in Calu-3 cell / 中国中药杂志

The aim of this research is to investigate the effects of paeoniflorin and menthol on the physiological function of Calu-3 cell membrane during the transport of puerarin. Calu-3 cell was used as the cell model to simulate nasal mucosa tissues, and the cell membrane fluidity, Na⁺-K⁺-ATPase activity and Ca²⁺-ATPase activity were detected by fluorescence recovery after photobleaching(FRAP) and ultramicro enzyme activity testing, in order to explore the mechanism of compatible drugs on promoting puerarin transport. The results showed that when puerarin associated with low, middle and high concentration of menthol or both paeoniflorin and menthol, the fluorescence recovery rate was increased significantly, while Na⁺-K⁺-ATPase activity had no significant change and Ca²⁺-ATPase activity was enhanced significantly as compared with puerarin alone. Therefore, it was concluded that menthol had the abilit of promoting the transport and the mechanism might be related to increasing membrane fluidity and activating Ca²⁺-ATPase.

Effects of Borneol on Membrane Fluidity and Membrane Potential of HaCaT Cell / 中国中医药信息杂志

Objective To investigate the action mode of borneol on activity of epidermal skin;To investigate action mode of borneol as penetration enhancer. Methods The well-established and standard penetration enhancer Azone was employed as a positive control in this study. The cytotoxicities of borneol and Azone on HaCaT cells were detected by CCK-8 assay, and their half 50% inhibitory concentrations (IC50) were calculated. The fluorescence recovery after photo bleaching was employed to investigate the effect of borneol and Azone on membrane fluidity, and the flow cytometer was used to monitor the changes of membrane potential of HaCaT cell after treated with these penetration enhancers. Results The IC50 values of borneol and Azone were 2.826 , 0.172 mmol/L, respectively. Borneol could significantly improve the membrane fluidity in a concentration-dependent manner, and effectively decrease the membrane potential of HaCaT cell, which exhibited the performances similar to those of Azone. Conclusion The penetration enhancement mechanism of borneol was associated with the concentrations of Ca2+ in keratinocytes, which changes the membrane fluidity and membrane potential of HaCaT cell.

Mitochondrial ATPase activity and membrane fluidity changes in rat liver in response to intoxication with Buckthorn (Karwinskia humboldtiana)

BACKGROUND: Karwinskia humboldtiana (Kh) is a poisonous plant of the rhamnacea family. To elucidate some of the subcellular effects of Kh toxicity, membrane fluidity and ATPase activities as hydrolytic and as proton-pumping activity were assessed in rat liver submitochondrial particles. Rats were randomly assigned into control non-treated group and groups that received 1,1.5 and 2 g/Kg body weight of dry powder of Kh fruit, respectively. Rats were euthanized at day 1 and 7 after treatment. RESULTS: Rats under Kh treatment at all dose levels tested, does not developed any neurologic symptoms. However, we detected alterations in membrane fluidity and ATPase activity. Lower dose of Kh on day 1 after treatment induced higher mitochondrial membrane fluidity than control group. This change was strongly correlated with increased ATPase activity and pH gradient driven by ATP hydrolysis. On the other hand, membrane fluidity was hardly affected on day 7 after treatment with Kh. Surprisingly, the pH gradient driven by ATPase activity was significantly higher than controls despite an diminution of the hydrolytic activity of ATPase. CONCLUSIONS: The changes in ATPase activity and pH gradient driven by ATPase activity suggest an adaptive condition whereby the fluidity of the membrane is altered.

Caracterização da superexpressão do fator sigma ECF σx em Pseudomonas aeruginosa PA14 / Characterization ofthe ECF sigma fator σx overexpression in Pseudomonas aeruginosa PA14

Pseudomonas aeruginosa é uma proteobactéria do grupo gama muito versátil, capaz de colonizar ambientes variados e infectar hospedeiros filogeneticamente distintos, incluindo humanos imunocomprometidos. Os fatores sigma de função extracitoplasmática (ECF) são membros de sistemas de sinalização de superfície celular (CSS), abundantes em P. aeruginosa. Vinte genes codificando fatores sigma ECF estão presentes nos genomas sequenciados de P. aeruginosa, a maioria fazendo parte de sistemas TonB relacionados à captação de ferro. Neste trabalho, seis fatores sigma pobremente caracterizados foram superexpressos na linhagem PA14 a partir de um promotor induzível por arabinose para investigar seu papel na expressão dos sistemas de dois componentes PvrSR e RcsCB, que atuam na regulação da fímbria CupD, além de sua influência no crescimento de culturas de P. aeruginosa. Não foi observado efeito positivo de nenhum dos fatores sigma testados na expressão dos sistemas de dois componentes e a superexpressão de cinco deles tampouco levou a qualquer alteração no crescimento, porém a produção de piocianina foi alterada na superexpressão de PA14_55550 e a superexpressão de PA14_26600 e PA14_46810 levou a um discreto aumento no início da formação de biofilme em PA14. Por outro lado, culturas superexpressando σx (ALB04) apresentaram um perfil alterado de lipopolissacarídeo e uma curva de crescimento bifásica, alcançando precocemente uma fase estacionária seguida de uma recuperação do crescimento até uma segunda fase estacionária. Durante a primeira fase estacionária, a maior parte das células aumenta de tamanho e morre, mas as células remanescentes retornam à morfologia selvagem e seguem para a segunda fase de crescimento exponencial. Isso não acontece devido a mutações compensatórias, uma vez que células coletadas de pontos tardios da curva e diluídas em meio novo repetem este comportamento. Apesar de trabalhos com a linhagem PAO1 associarem σx à transcrição de oprF, que codifica a principal porina não específica de Pseudomonas, nas condições dos nossos ensaios em PA14 a expressão dessa porina não foi induzida pela superexpressão de σx. Assim, os efeitos observados nessa superexpressão também não podem ser atribuídos a OprF. A transcrição de oprF em PA14 mostrou-se majoritariamente dependente da região promotora a que se atribui a ligação de σ70, ao contrário dos relatos na literatura da dependência da região de ligação a σx. Análises proteômicas foram realizadas para investigar os elementos envolvidos nesses efeitos de superexpressão de σx, o que revelou a indução de diversas enzimas envolvidas na via de biossíntese de ácidos graxos. As células superexpressando σx apresentam uma maior proporção de ácidos hexadecanoico (C16) e hexadecenoico (C16:1) e dados de anisotropia mostram uma maior fluidez da(s) membrana(s). Este trabalho é o primeiro relato de um fator sigma ECF envolvido em biossíntese de lipídeos em P. aeruginosa

Pseudomonas aeruginosa is a very versatile gammaproteobacteria, able to colonize different environments and to infect phylogenetically distinct hosts, including immunocompromised humans. The extracytoplasmic function sigma factors (ECFs) are members of cell signaling systems (CSS), abundant in P. aeruginosa. Twenty genes coding for ECF sigma factors are present in the sequenced genomes of P. aeruginosa, most of them being part of TonB systems related to iron uptake. In this work, six poorly characterized sigma factors were overexpressed in strain PA14 from an arabinose inducible promoter to investigate their role in the expression of the two-component systems PvrSR and RcsCB, which regulates CupD fimbria, and their influence in P. aeruginosa cultures growth. None of the tested sigma factors led to two-component systems upregulation and overexpression of five of them caused no change in the growth profile, but pyocyanin production was altered in PA14_55550 overexpression and PA14_26600 and PA14_46810 overexpression led to a slight increase in biofilm initiation in PA14. By the other side, cultures overexpressing σx (ALB04) presented an altered lipopolysaccharide profile and a biphasic growth curve, reaching an early stationary phase followed by a growth resuming untill a second stationary phase. During the early stationary phase, most cells swells and dies, but the remaining cells return to wild type morphology and proceed to the second exponential phase of growth. This is not due to compensatory mutations, since cells collected from late points of the curve and diluted in fresh medium repeat this behavior. Although studies with strain PAO1 associate σx with transcription of oprF, encoding the major nonspecific porin of Pseudomonas, under our experiments conditions with PA14, this porin expression is not induced by σx overexpression. Thus, the effects observed in this overexpression cannot be attributed to OprF. Transcription of oprF in PA14 proved to be mainly controlled by the σ70-dependent promoter region instead of the σx-dependent promoter region reported in the literature. Proteomic analyses were performed to investigate the elements involved in these effects of σx overexpression, which revealed the induction of several enzymes involved in fatty acids biosynthesis. Cells overexpressing σx exhibit a greater proportion of hexadecanoic (C16) and hexadecenoic (C16: 1) acids and anisotropy data show higher fluidity of the membrane (s). This work is the first report of an ECF sigma factor involved in lipid biosynthesis in P. aeruginosa

F2α-isoprostane, Na+-K+ ATPase and membrane fluidity of placental syncytiotrophoblast cell in preeclamptic women with vitamin E supplementation.

Background: The aim of our study was to analyze F2α-isoprostane level, Na+-K+ ATPase activity and placental syncytiotrophoblast cell membrane fluidity in preeclamptic women who received vitamin E supplementation. Methods: The study was conducted between September 2003 and February 2005 at Budi Kemuliaan Maternity Hospital, Central Jakarta. Samples were 6 preeclamptic women with vitamin E supplementation, 6 preeclamptic women without vitamin E supplementation and 6 normal pregnant women. The dose of vitamin E was 200 mg daily. F2α-isoprostane was measured with ELISA reader at λ of 450 nm. Cell membrane fluidity was measured by comparing the molar ratio of total cholesterol and cell membrane phospholipid concentration. The cholesterol was measured by Modular C800 using Roche reagent. Phospholipid was measured by Shimadzu RF5301PC spectrofluorometer (excitation 267 nm, emission 307 nm). Na+-K+ ATPase activity was inhibited by ouabain. Pi production was measured with Fiske and Subbarow method using spectrophotometer at λ of 660 nm. Data was analyzed using F test with one-way ANOVA. Results: Vitamin E supplementation in preeclamptic women decreased the oxidative stress, indicated by significantly lower level of F2α-isoprostane compared to those without vitamin E (26.72 ± 11.21 vs 41.85 ± 7.09 ng/mL, respectively, p = 0.017). Membrane fluidity in syncytiotrophoblast cell of preeclampsia with vitamin E group was maintained at 0.39 ± 0.08 while in those without vitamin E was 0.53 ± 0.14 (p = 0.04). Na+-K+ ATPase activity in syncytiotrophoblast cell membrane was not affected by vitamin E (p = 0.915). Conclusion: Vitamin E supplementation in preeclamptic women decreases F2α-isoprostane level and maintains cell membrane fluidity of syncytiotrophoblast cells; however, it does not increase Na+-K+ ATPase enzyme activity.

Radiomodulation by Hoechst 33258 against radiation- induced damage in murine splenocytes.

In this study modulatory effect of Hoechst 33258 on radiation induced membrane related signaling events which ultimately leads to apoptosis has been investigated. Splenocytes from swiss albino mice were irradiated in air at room temperature in a gamma chamber (240 TBq 60Co Model 4000 A) at the dose-rate of 0.052 Gys-1. Membrane lipid peroxidation, fluidity, specific activities of antioxidant enzymes, levels of nitric oxide, glutathione and apoptosis in presence and absence of different concentrations of Hoechst 33258 has been assayed. DNA binding activity of nuclear factor kappa B and activator protein–1 was also assayed by electrophoretic mobility shift assay. Modulatory effect of Hoechst 33258 was examined at 3 and 5 Gy using different concentrations (10, 20 and 30 µM). Hoechst 33258 was found to inhibit radiation induced peroxidative damage and fluidity and lowered the level of nitric oxide and apoptosis - as evident by DNA ladder assay and FACS, indicating free radicals scavenging potential. Dot plot diagramme clearly showed that 30 µM Hoechst 33258 caused 14% and 19% decrease in apoptotic cells at 3 Gy and 5 Gy of radiation respectively (compared to irradiated control group). Further DNA binding activity of nuclear factor kappa B and activator protein–1 was also inhibited but the antioxidant potential of the cells was enhanced. These findings support that Hoechst 33258 protects the cell from undergoing apoptosis. Hoechst 33258 may have interacted and has an ability to protect splenocytes against radiation induced apoptosis through modulation of membrane-related signaling events and antioxidant status.

Electron paramagnetic resonance study of lipid and protein membrane components of erythrocytes oxidized with hydrogen peroxide

Electron paramagnetic resonance (EPR) spectroscopy of spin labels was used to monitor membrane dynamic changes in erythrocytes subjected to oxidative stress with hydrogen peroxide (H2O2). The lipid spin label, 5-doxyl stearic acid, responded to dramatic reductions in membrane fluidity, which was correlated with increases in the protein content of the membrane. Membrane rigidity, associated with the binding of hemoglobin (Hb) to the erythrocyte membrane, was also indicated by a spin-labeled maleimide, 5-MSL, covalently bound to the sulfhydryl groups of membrane proteins. At 2% hematocrit, these alterations in membrane occurred at very low concentrations of H2O2 (50 µM) after only 5 min of incubation at 37°C in azide phosphate buffer, pH 7.4. Lipid peroxidation, suggested by oxidative hemolysis and malondialdehyde formation, started at 300 µM H2O2 (for incubation of 3 h), which is a concentration about six times higher than those detected with the probes. Ascorbic acid and α-tocopherol protected the membrane against lipoperoxidation, but did not prevent the binding of proteins to the erythrocyte membrane. Moreover, the antioxidant (+)-catechin, which also failed to prevent the cross-linking of cytoskeletal proteins with Hb, was very effective in protecting erythrocyte ghosts from lipid peroxidation induced by the Fenton reaction. This study also showed that EPR spectroscopy can be useful to assess the molecular dynamics of red blood cell membranes in both the lipid and protein domains and examine oxidation processes in a system that is so vulnerable to oxidation.

Growth, fatty acid profile in major lipid classes and lipid fluidity of Aurantiochytrium mangrovei Sk-02 as a function of growth temperature

Aurantiochytrium mangrovei Sk-02 was grown in a medium containing glucose (40 g/l), yeast extract (10 g/L) and sea salts (15 g/L) at temperatures ranging from 12 to 35°C. The fastest growth (µmax= 0.15 h-1) and highest fatty acid content of 415 mg/g-dry cell weight were found in the cells grown at 30°C. However, the cells grown at 12°C showed the highest percentage of polyunsaturated fatty acid (PUFA) (48.6% of total fatty acid). The percentage of docosahexaenoic acid (DHA) and pentadecanoic acid (C15:0) decreased with an increase in the growth temperature, whereas, palmitic acid (C16:0), stearic acid (C18:0) and DPA (C22:5n6) increased with an increase in the growth temperature. The composition of the major lipid class (%w/w) was slightly affected by the growth temperature. The fluidity of the organelle membrane or intracellular lipid (by DPH measurement) decreased with an increase in the growth temperatures, while the plasma membrane fluidity (by TMA-DPH measurement) could still maintain its fluidity in a wide range of temperatures (15 - 37°C). Furthermore, the distribution of DHA was found to be higher (36 - 54%) in phospholipid (PL) as compared to neutral lipid (NL) (20 - 41%).

Effect of silybin on high-fat-induced fatty liver in rats

Silybin, a natural antioxidant, has been traditionally used against a variety of liver ailments. To investigate its effect and the underlying mechanisms of action on non-alcoholic fatty liver in rats, we used 60 4-6-week-old male Sprague-Dawley rats to establish fatty liver models by feeding a high-fat diet for 6 weeks. Hepatic enzyme, serum lipid levels, oxidative production, mitochondrial membrane fluidity, homeostasis model assessment-insulin resistance index (HOMA-IR), gene and protein expression of adiponectin, and resistin were evaluated by biochemical, reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. Compared with the model group, silybin treatment (26.25 mg·kg-1·day-1, started at the beginning of the protocol) significantly protected against high-fat-induced fatty liver by stabilizing mitochondrial membrane fluidity, reducing serum content of alanine aminotransferase (ALT) from 450 to 304 U/L, decreasing hepatic malondialdehyde (MDA) from 1.24 to 0.93 nmol/mg protein, but increasing superoxide dismutase (SOD) and glutathione (GSH) levels from 8.03 to 9.31 U/mg protein and from 3.65 to 4.52 nmol/mg protein, respectively. Moreover, silybin enhanced the gene and protein expression of adiponectin from 215.95 to 552.40, but inhibited that of resistin from 0.118 to 0.018. Compared to rosiglitazone (0.5 mg·kg-1·day-1, started at the beginning of the protocol), silybin was effective in stabilizing mitochondrial membrane fluidity, reducing SOD as well as ALT, and regulating gene and protein expression of adiponectin (P < 0.05). These results suggest that mitochondrial membrane stabilization, oxidative stress inhibition, as well as improved insulin resistance, may be the essential mechanisms for the hepatoprotective effect of silybin on non-alcoholic fatty liver disease in rats. Silybin was more effective than rosiglitazone in terms of maintaining mitochondrial membrane fluidity and reducing oxidative stress.

Effect of 8-alkylberberine homologues on erythrocyte membrane.

8-alkylberberine homologues (Ber-C8-n, where n indicates carbon atom number of gaseous normal alkyl at 8 position, n =0, 2, 4, 6, 8, 10, 12, or 16) were synthesized and their effects on the hemolysis of rabbit erythrocyte, the fluidity of membrane and the fluorescence of membrane protein were investigated by fluorescence analysis technique. Ber-C8-n with mediate length alkyl (4<n<10) exhibited obvious hemolysis effect on rabbit erythrocyte when their concentration exceed 1.25×10-4 mol/L, and Ber-C8-8 displayed the highest hemolysis effect among all tested homologues. All of Ber-C8-n influenced the fluidity of erythrocyte membrane to different extents, which exhibited an obvious dose-effect relationship. The effect of Ber-C8-n on fluidity increased as the length of alkyl chain was elongated and decreased gradually when the alkyl carbon atoms exceeded 8. The fluorescence of erythrocyte membrane protein was quenched by Ber-C8-n, which showed a similar changing tendency on membrane fluidity. Experiments in vitro suggested that disturbing effects of Ber-C8-n on the conformation and function of membrane protein leaded to the changes of membrane fluidity and stability, and then the membrane was broken down.

Thermodynamics of molecular recognitions between antineoplastic drug taxol and phosphatidylcholine

The aim of this study was to study the basic features of Taxol recognition with phospholipids by applying the thermodynamic and spectroscopic measurements. The obtained information could be used further for deductions on its precise cellular and pharmacological mechanisms of action, on improvements of its solubility properties by phospholipids, as well as for designing the novel lipidic carriers for drug delivery.

Membrane fluidity and lipid composition of fluconazole resistant and susceptible strains of Candida albicans isolated from diabetic patients / Fluidez e composição lipídica da membrana de cepas de Candida albicans resistentes e sensíveis ao fluconazol, isoladas de pacientes diabéticos

Ten clinical isolates of Candida albicans, five strains belonging to each of fluconazole resistant and susceptible groups isolated from diabetic patients, were studied for the membrane fluidity and lipid composition. Compared to fluconazole susceptible strains, fluconazole resistant ones exhibited enhanced membrane fluidity as measured by fluorescence polarization technique. The increased membrane fluidity was reflected in the decreased p-values exhibited by the resistant strains. On the other hand, susceptible isolates contained higher amount of ergosterol, almost twice as compared to resistant isolates which might have contributed to their lower membrane fluidity. However, no significant alteration was observed in the phospholipid and fatty acid composition of these isolates. Labeling experiments with fluorescamine dye revealed that the percentage of the exposed aminophospholipid, phosphatidylethanolamine was highest in the resistant strains as compared to the susceptible strains, indicating a possible overexpression of CDR1 and CDR2 genes in resistant strains. The results presented here suggest that the changes in the ergosterol content and overexpression of ABC transporter genes CDR1 and CDR2 could contributeto fluconazole resistance in C. albicans isolated from diabetic patients.

Dez isolados clínicos, sendo cinco resistentes e cinco sensíveis ao fluconazol, obtidos de pacientes diabéticos, foram estudados quanto à fluidez e composição química da membrana. Quando comparados aos isolados sensíveis ao fluconazol, os isolados resistentes apresentaram fluidez de membrana aumentada, conforme mensurado pela técnica de polarização fluorescente. A fluidez de membrana aumentada refletiu-se pelos valores mais baixos de p. Por outro lado, os isolados sensíveis continham quantidades mais elevadas de ergosterol, quase o dobro dos isolados resistentes, o que pode ter contribuído para a fluidez de membrana mais baixa. Entretanto, não se observou alteração significativa na composição fosfolipídica e de ácidos graxos nesses isolados. Experimentos de marcação com corante fluorescamina indicaram que a porcentagem de aminofosfolípides e fosfatidiletanolamina expostos foi mais elevada nos isolados resistentes do que nos sensíveis, indicando uma possível superexpressão dos genes CDR1 e CDR2 nos isolados resistentes. Os resultados aqui apresentados sugerem que alterações no teor de ergosterol e superexpressão dos genes ABC transportadores CDR1 e CDR2 podem contribuir na resistência ao fluconazol em isolados de C. albicans de pacientes diabéticos.

Effects of polyphenols of vitis amurensis Rupr on rat heart mitochondria injury induced by vitamin C and FeSO_4 / 吉林大学学报(医学版)

Objective To study the protective effects of the polyphenols of vitis amurensis Rupr(PVAR) on rat heart mitochondria injury induced by oxygen radicals.Methods Experiment was designed into 5 groups:normal group,injury group and 25,50,100 mg?L-1PVAR+injury group.In experiment of rat heart mitochondria injury in vitro,vitamin C and FeSO4 played as an injury agent,PVAR played as a protective agent.The cardiolipin and MDA level of the mitochondria were determined.The membrane fluidity,ATPase activity and swelling of the mitochondria were examined.Results Compared with injury group,the cardiolipin was increased(P

Effects of phellodendron and its main components on the cell membrane fluidity / 中国病理生理杂志

AIM: To investigate the effect of phellodendron and three kinds of its main components, which have asuppressive effect on the immune system, on the membrane fluidity of normal murine splenocytes. METHODS: The fluidity ofmembrane lipid regions of splenocytes was determined by the fluorescence polarization technique using 1, 6 - diphenyl - 1, 3, 5- heatriene (DPH) as a fluorescence probe. RESULTS: The results showed that the water extract of phellodendron and one of itsmain components (palmatine) increased the cell membrane fluidity in the inactive state, but the other two components, berberineand jatrorrhizine, decreased the cell membrane fluidity. After activated by ConA, all of them can decrease the cell membrane flu-idity. CONCLUSION: These results suggest that their immunosuppressive function might be due to decreasing the cell membranefluidity.

Effect of total flavonoids of acanthopanax senticosus on erythrocyte membrane fluidity in mice / 中国基层医药

Objective To observe contents and effect of total flavonoids of acanthopanax senticosus extract on erythrocyte membrane fluidity.Methods The contents of total flavonoids of acanthopanax sentieosus were deter- mined by spectrophotometry,and erythrocyte membrane fluidity and microviscosity were measured by fluorescence polarization technique.Results The total flavonoids contents of acanthopanax senticosus extract and injection were alike.Both of them increased erythrocyte membrane fluidity and lowered microviscosity,and the effect of acan- thopanax senticosus injection was more significant.Conclusion Total flavonoids of acanthopanax senticosus can in- crease erythrocyte membrane fluidity,so that blood viscosity is lowered and hemorheology factors are improved.

Fosfolipase A2, fluidez de membrana e proteína precursora do amilóide em plaquetas na doença de Alzheimer e comprometimento cognitivo leve / mPhospholipase A2, membrane fluidity and ayloid precursor protein in platelets in Alzheimer's disease and mild cognitive impairment

A Doença de Alzheimer (DA) é uma desordem neurodegenerativa progressiva que causa comprometimento cognitivo em idosos. O diagnóstico clínico da DA é complexo. Existe uma grande necessidade de técnicas capazes de detectar a doença nos estágios iniciais, tanto para auxiliar o diagnóstico quanto para monitorar a efetividade dos tratamentos disponíveis. As alterações bioquímicas da DA são resultado de processos celulares como o metabolismo da proteína precursora do amilóide (APP), fosforilação da tau, stress oxidativo, inflamação e desregulação lipídica. Até o momento não existem marcadores bioquímicos para auxiliar o diagnóstico da DA. Este trabalho avaliou três possíveis candidatos a marcadores bioquímicos para a DA. Foram investigados a razão da APP (rAPP) de 130/110 kDa, fluidez de membrana e atividade da fosfolipase A2 em plaquetas de pacientes com DA e Comprometimento Cognitivo Leve (CCL), comparando-se seus resultados com controles idosos saudáveis. A fluidez das membranas das plaquetas foi avaliada por meio da anisotropia com a sonda fluorescente DPH (Difenilhexatrieno); a comparação das razões da APP foi realizada por Western Blotting empregando o anticorpo 22C11 e a da atividade da PLA2 foi determinada por ensaio radioenzimático com substratos e concentrações de cálcio específicas para cada um dos três principais grupos da enzima. A rAPP, as atividades da sPLA2 e iPLA2 estavam significantemente reduzidas na DA quando comparadas com controles, enquanto que a cPLA2 e a fluidez de membrana não apresentaram diferenças entre os grupos. A rAPP e a iPLA2 também apresentaram diferenças significativas entre CCL e DA, além de estarem correlacionadas com os parâmetros cognitivos MEEM e CAMCOG. A rAPP também estava correlacionada com a anistropia do DPH.

Alzheimer disease (AD) is a progressive neurodegenerative disorder that causes cognitive impairment in the elderly. The clinical diagnosis of AD is complex. Thus, there is a great need for sensitive techniques to detect neurodegeneration in the early stages to asset in the diagnosis and to follow the effectiveness of therapy. The biochemical alterations in the AD brain result from cellular processes such as amyloid precursor protein (APP) metabolism, tau phosphorylation, oxidative stress, inflammation and lipid dysregulation. So far there are no biochemical markers to help the AD diagnosis. The purpose of this study was to evaluate three possible candidates to biochemical marker of AD. The APP 130/110 kDa ratio, membrane fluidity and phospholipase A2 activity in platelets of patients with AD and mild cognitive impairment (MCI) were investigated compared to their results with healthy elderly controls. The membrane fluidity of platelets was assessed by the fluorescence anisotropy of DPH (diphenyl-hexatriene); the levels of APP isoforms were evaluated by Western Blot analysis using 22C11 antibody and the PLA2 activity was measured by radio-enzymatic assay with enzyme specific substrate and calcium concentrations for each one of the three main groups of the enzyme. The APP ratio (APPr), the sPLA2 and iPLA2 activity were markedly decreased in AD in comparing with controls, whereas a cPLA2 and membrane fluidity didn't show any alteration between the groups evaluated. The APPr and iPLA2 also showed significant differences between MCI e AD, and were correlated with cognitive parameters MMSE and CAMCOG. The APPr was also correlated with DPH anisotropy.