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Incubation Medium (incubation + medium)
Selected AbstractsGlucose-induced release of tumour necrosis factor-alpha from human placental and adipose tissues in gestational diabetes mellitusDIABETIC MEDICINE, Issue 11 2001M. T. Coughlan Abstract Aims, The cytokine tumour necrosis factor-alpha (TNF-,) has been implicated in the pathogenesis of insulin resistance in Type 2 diabetes mellitus, but limited data are available in relation to gestational diabetes mellitus (GDM), a disease in which similar biochemical abnormalities exist. We investigated the effect of exogenous glucose on the release of TNF-, from placental and adipose (omental and subcutaneous) tissue obtained from normal pregnant women, and women with GDM. Methods, Human tissue explants were incubated for up to 24 h and TNF-, concentration in the incubation medium quantified by ELISA. The effect of normal (5 mmol/l) and high (15 and 25 mmol/l) glucose concentrations on the release of TNF-, was assessed. Results, In placental and subcutaneous adipose tissues obtained from women with GDM (n = 6), TNF-, release was significantly greater under conditions of high glucose compared with normal glucose (placenta, 25 mmol/l 5915.7 ± 2579.6 and 15 mmol/l 4547.1 ± 2039.1 vs. 5 mmol/l 1897.1 ± 545.5; subcutaneous adipose tissue, 25 mmol/l 423.5 ± 207.0 and 15 mmol/l 278.5 ± 138.7 vs. 5 mmol/l 65.3 ± 28.5 pg/mg protein; P < 0.05). In contrast, there was no stimulatory effect of high glucose on TNF-, release by tissues obtained from normal pregnant women (n = 6) (placenta, 25 mmol/l 1542.1 ± 486.2 and 15 mmol/l 4263.3 ± 2737.7 vs. 5 mmol/l 5422.4 ± 1599.0; subcutaneous adipose tissue, 25 mmol/l 189.8 ± 120.4 and 15 mmol/l 124.5 ± 32.3 vs. 5 mmol/l 217.9 ± 103.5 pg/mg protein). Conclusions, These observations suggest that tissues from patients with GDM release greater amounts of TNF-, in response to high glucose. As TNF-, has been previously implicated in the regulation of glucose and lipid metabolism, and of insulin resistance, these data are consistent with the hypothesis that TNF-, may be involved in the pathogenesis and/or progression of GDM. Diabet. Med. 18, 921,927 (2001) [source] Fatty acid incorporation in endothelial cells and effects on endothelial nitric oxide synthaseEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 9 2007S. Couloubaly Abstract Background The nature of fatty acids provided by the diet as well as plasma lipid metabolism can modify the composition and properties of plasma membrane and thus the activity of membrane proteins. In humans, as well as in experimental models, diabetes is associated with both an alteration in serum lipid profile and a documented endothelial dysfunction. This in vitro study investigated on an immortalized human endothelial cell line (EA.hy 926) the specific effects of several free fatty acids (FFAs) on the composition of cellular membranes and the regulation of endothelial nitric oxide synthase (eNOS). Materials and methods 0·1% of lipid deprived serum was added to the incubation medium with 25 mm glucose in order to study the effects of individual fatty acids: myristic acid, palmitic acid, stearic acid, oleic acid or linoleic acid at 100 µm bound with albumin. The effects of the FFAs on the endothelial nitric oxide synthase were investigated on mRNA level by quantitative PCR, on protein level and Ser1177 phosphorylation by Western blot and on enzymatic activity on living cells using radiolabelled arginine. Results Free linoleic acid increased the membrane content in n-6 fatty acids (mainly C18: n-6 and its metabolites) with a decrease in saturated and monounsaturated fatty acids. These conditions decreased the basal eNOS activity and reduced the phosphorylation of eNOS-Ser1177 due to activation by histamine. Free palmitic acid enriched the membranes with 16 : 0 with a slight decrease in monounsaturated fatty acids. These conditions increased eNOS activation without increasing Ser1177 phosphorylation upon histamine activation. The addition of the other FFAs also resulted in modifications of membrane composition, which did not to affect eNOS-Ser1177 phosphorylation. Conclusion Among the fatty acids used, only modification of the membrane composition due to linoleic acid supply disturbed the basal enzymatic activity and Ser1177 phosphorylation of eNOS in a way that limited the role of histamine activation. Linoleic acid might involve the dysfunction of both eNOS basal activity and its phosphorylation status and may then contribute to an impaired vasodilatation in vivo. [source] Progressive CD127 down-regulation correlates with increased apoptosis of CD8 T cells during chronic HIV-1 infectionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 5 2009Shu-Ye Zhang Abstract Chronic HIV-1 infection can induce a significant decrease in CD127 expression on CD8 T cells, but the underlying mechanisms and immunological consequences are unclear. In this study, we investigated CD127 expression on CD8 T cells from a total of 51 HIV-1-infected subjects and 16 healthy individuals and analyzed the association between CD127 expression and CD8 T-cell apoptosis in these HIV-1-infected subjects. We found that CD127 expression on total CD8 T cells was significantly down-regulated, which was correlated with the increased CD8 T-cell apoptosis and disease progression of chronic HIV-1 infection. The in vitro addition of IL-7 efficiently rescued the spontaneous apoptosis of CD8 T cells from HIV-1-infected individuals. IL-7 stimulation also transiently down-regulated CD127 expression, whereas some of the CD127, CD8 T cells regained CD127 expression soon after IL-7 was retracted from the incubation medium. Thus, IL-7 stimulation reduced apoptosis of both CD127+ and CD127,CD8 T cells to some degree. These data indicate that CD127 loss might impair IL-7 signaling and increase CD8 T-cell apoptosis during HIV-1 infection. This study, therefore, will extend the notion that IL-7 could be a good candidate for immunotherapy in HIV-1-infected patients. [source] Biotransformation enzymes in Cunninghamella blakesleeana (NCIM-687)JOURNAL OF BASIC MICROBIOLOGY, Issue 6 2006Sanjyot Bhosale Presence of higher enzyme levels of aminopyrine N-demethylase, aniline hydroxylase and 11- , hydroxylase activities were observed in Cunninghamella blakesleeana grown in potato-dextrose medium for 96 h. The enzyme activity preferred NADPH as a cofactor and showed inhibition with CO, indicating cytochrome P450 mediated reactions. A significant increase in aniline hydroxylase enzyme activity was observed when mycelia incubated in incubation medium containing different inducers (viz. camphor, cholesterol, naphthalene, veratrole, phenobarbital, n -hexadecane and ethyl alcohol) when compared with mycelia incubated in same way but in absence of inducers. Cunninghamella blakesleeana (NCIM 687) have shown the ability to degrade cholesterol, camphor and naphthalene when 96 h grown mycelia incubated in incubation medium containing these organic compounds. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Possible involvement of protein kinase C in the induction of adipose differentiation-related protein by Sterol ester in RAW 264.7 macrophagesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2001Jin-Shan Chen Abstract The accumulation of lipid droplets in macrophages contributes to the formation of foam cells, an early event in atherosclerosis. It is, therefore, important to elucidate the mechanisms by which lipid droplets accumulate and are utilized. Sterol ester (SE)-laden RAW 264.7 macrophages accumulated lipid droplets in a time-dependent manner up to 16 h, which was enhanced by cotreatment with 0.1 ,M phorbol 12-myristate 13-acetate (PMA). Inhibition of protein kinase C (PKC) activity by cotreatment with 0.3 ,M calphostin C CAL for 16 h resulted in coalescence of small lipid droplets into large ones and increased accumulation of lipid droplets, although to a lesser extent than after PMA cotreatment. Immunostaining for adipose differentiation-related protein (ADRP) revealed a fluorescent rim at the surface of each medium to large lipid droplet. ADRP appearance correlated with lipid droplet accumulation and was regulated by PMA in a time-dependent manner. Induction of ADRP expression by PMA or CAL required SE, since ADRP levels in PMA- or CAL-treated non-SE-laden macrophages were comparable to those in untreated cells. Removal of SE from the incubation medium resulted in the concomitant dissolution of lipid droplets and down-regulation of ADRP. In conclusion, the above results suggest that ADRP may be an important protein in the regulation of lipid droplet metabolism in lipid-laden macrophages and that this regulation may be mediated by PKC activity. J. Cell. Biochem. 83: 187,199, 2001. © 2001 Wiley-Liss, Inc. [source] Intracellular uptake and trafficking of Pluronic micelles in drug-sensitive and MDR cells: Effect on the intracellular drug localizationJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2002Natalya Rapoport Abstract The intracellular uptake and localization of a fluorescently labeled Pluronic P-105 in HL-60 leukemia cells and in A2780 drug-sensitive and A2780/ADR MDR ovarian carcinoma cells were characterized by flow cytometry and fluorescence microscopy. Pluronic P-105 molecules were labeled with a pH-sensitive fluorescent label, 5-(and 6-)carboxy-2,7,-dichlorofluorescein. The fluorescence intensity of labeled Pluronic was about twofold higher at pH 7.4 than at pH 5.5. At Pluronic concentrations exceeding the critical micelle concentration (cmc), flow cytometry histograms manifested bimodal distribution of cell fluorescence for all types of cells. Cell population characterized by higher fluorescence intensity presumably resulted from Pluronic transfer from the acidic environment of cytoplasmic vesicles (endosomes or lysosomes) into the neutral environment of the cytoplasm and cell nuclei, which suggested the permeabilization of the membranes of acidic vesicle by Pluronic molecules. For the MDR cells, the bimodal distribution of cell fluorescence was already observed at very low Pluronic concentrations in the incubation medium (i.e., below the cmc). The data suggest that the membranes of acidic vesicles of MDR cells are more susceptible to the action of polymeric surfactants than those of drug-sensitive cells. Permeabilization of acidic vesicles had a dramatic effect on the intracellular trafficking of drugs: when delivered in PBS, the anthracyclin drug ruboxyl (Rb) sequestered in cytoplasmic vesicles and was excluded from cell nuclei; however, when delivered in Pluronic micelles, drug accumulated in cell nuclei. Drug uptake from/with Pluronic micelles was substantially enhanced by ultrasound. These findings suggest that the nuclear accumulation of drugs internalized via fluid-phase endocytosis can be enhanced by the application of Pluronic micelles and can be further augmented by ultrasonic irradiation. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:157,170, 2002 [source] CJY, an isoflavone, reverses P-glycoprotein-mediated multidrug-resistance in doxorubicin-resistant human myelogenous leukaemia (K562/DOX) cellsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 7 2007Bian-Sheng Ji In an effort to develop safe and effective multidrug-resistance (MDR) reversing agents, the effect of CJY, an isoflavone, on the P-glycoprotein (P-gp) function and P-gp-mediated MDR was evaluated in doxorubicin-resistant human myelogenous leukaemia (K562/DOX) cells. The results showed that CJY caused a marked increase in accumulation and a notable decrease in efflux of rhodamine 123 (Rh123). The inhibitory effect of the agent on P-gp function persisted for at least 120 min after removal of 2.5 ,M CJY from the incubation medium. The doxorubicin-induced cytotoxicity, apoptosis and cell cycle perturbations were significantly potentiated by CJY. The intracellular accumulation of doxorubicin was also enhanced. The compound exhibited potent effects in-vitro on the reversal of P-gp-mediated MDR, suggesting that it could become a candidate as an effective MDR reversing agent in cancer chemotherapy. [source] Metabolism of curcumin and induction of mitotic catastrophe in human cancer cellsMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 9 2008Julia S. Dempe Abstract In cultured cells, curcumin (CUR) causes cell death by interfering with mitosis and leading to fragmented nuclei and disrupted microtubules, a process named mitotic catastrophe. In order to clarify the role of the known CUR metabolites hexahydro-CUR (HHC) and CUR-glucuronide (CUR-gluc) in mitotic catastrophe, the effects of CUR were studied in three human cancer cell lines with different metabolism of CUR. In Ishikawa and HepG2 cells, CUR was metabolized to HHC and small amounts of octahydro-CUR (OHC), whereas the only metabolism in HT29 cells was the formation of CUR-gluc. Despite their different metabolism, all three cell systems responded to CUR with arrest in G2/M phase and mitotic catastrophe. Fractionation of the cells showed that concentrations of CUR were higher in the ER and cytosol than in the incubation medium by a factor of up to about 150 and 8, respectively. In contrast to CUR, the metabolite HHC and the products of spontaneous degradation did not elicit any effects in Ishikawa cells. These results imply that the causative agent of mitotic catastrophe is the parent CUR molecule, whereas reductive metabolism and chemical degradation render CUR inactive. [source] A unique mechanism for cyclic adenosine 3,,5,-monophosphate-induced increase of 32-kDa tyrosine-phosphorylated protein in boar spermatozoa,MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 2 2004Hiroshi Harayama Abstract A cAMP-induced increase of tyrosine-phosphorylated proteins is involved in the expression of fertilizing ability in mammalian spermatozoa. We (Harayama, 2003: J Androl 24:831,842) reported that incubation of boar spermatozoa with a cell-permeable cAMP analog (cBiMPS) increased a 32-kDa tyrosine-phosphorylated protein (TyrP32). The purpose of this study is to characterize the signaling cascades that regulate the cAMP-induced increase of TyrP32. We examined effects of tyrosine kinase inhibitor (lavendustin A), tyrosine phosphatase inhibitor (Na3VO4), cell-permeable calcium chelator (BAPTA-AM), and cholesterol acceptor (methyl-,-cyclodextrin: MBC) on the increase of TyrP32 and the change and loss of acrosomes in boar spermatozoa. The spermatozoa were used for detection of tyrosine-phosphorylated proteins by Western blotting and indirect immunofluorescence and for examination of acrosomal integrity by Giemsa staining. At least eight tyrosine-phosphorylated proteins including TyrP32 exhibited the cAMP-dependent increase during incubation with cBiMPS. In many proteins of them, this increase was reduced by lavendustin A but was enhanced by Na3VO4. In contrast, the cAMP-induced increase of TyrP32 was abolished by Na3VO4 but was hardly affected by lavendustin A. Giemsa staining showed that the increase of spermatozoa with weakly Giemsa-stained acrosomes (severely damaged acrosomes) or without acrosomes was correlative to the cAMP-induced increase of TyrP32. Moreover, the lack of calcium chloride in the incubation medium or pretreatment of spermatozoa with BAPTA-AM blocked the change and loss of acrosomes and the increase of TyrP32, suggesting these events are dependent on the extracellular and intracellular calcium. On the other hand, incubation of spermatozoa with MBC in the absence of cBiMPS could mimic the change and loss of acrosomes and increase of TyrP32 without increase of other tyrosine-phosphorylated proteins. Based on these results, we conclude that the cAMP-induced increase of TyrP32 is regulated by a unique mechanism that may be linked to the calcium-dependent change and loss of acrosomes. Mol. Reprod. Dev. 69: 194,204, 2004. © 2004 Wiley-Liss, Inc. [source] Effect of Salt Stress on Carbon Metabolism and Bacteroid Respiration in Root Nodules of Common Bean (Phaseolus vulgaris L.)PLANT BIOLOGY, Issue 4 2000A. Ferri Abstract: In the present work, we examined the effect of salinity on growth, N fixation and carbon metabolism in the nodule cytosol and bacteroids of Phaseolus vulgaris, and measured the O2 consumption by bacteroids incubated with or without the addition of exogenous respiratory substrates. The aim was to ascertain whether the compounds that accumulate under salt stress can increase bacteroid respiration and whether this capacity changes in response to salinity in root nodules of Phaseolus vulgaris. The plants were grown in a controlled environment chamber, and 50, 100 mM or no NaCl (control) was added to the nutrient solution. Two harvests were made, at the vegetative growth period and at the beginning of the reproductive period. The enzyme activities in the nodule cytosol were reduced by the salt treatments, while in the bacteroid cytosol the enzyme activities increased at high salt concentrations at the first harvest and for ADH in all treatments. The data presented here confirm that succinate and malate are the preferred substrates for bacteroid respiration in common bean, but these bacteroids may also utilize glucose, either in control or under saline conditions. The addition of proline or lactate to the incubation medium significantly raised oxygen consumption in the bacteroids isolated from plants treated with salt. [source] Effect of pH on the development of acrosomal responsiveness of human spermANDROLOGIA, Issue 2 2007N. L. Cross Summary Human sperm incubated in vitro gradually become responsive to inducers of the acrosome reaction. The roles of constituents of the incubation medium are not well understood. These experiments tested the effect of the extracellular pH on sperm acrosomal responsiveness. Sperm were incubated 24 h in media with pH varying between 6.7 and 7.6 and then exposed to progesterone to determine the number of sperm that had become acrosomally responsive. The number of responsive sperm was very low following incubation at pH 6.7,7.0, and increased with the pH over the range 7.0,7.6. Sperm incubated at low pH were not damaged as assessed by motility or viability, and if they were transferred to medium of high pH for 8 h, the inhibition of acrosomal responsiveness was reversed. Inhibition of acrosomal responsiveness at low pH was not due to impaired loss of sperm cholesterol, but was correlated with a reduced intracellular pH. The inhibition of acrosomal responsiveness by media of low pH may result from preventing the normal capacitation-related rise in intracellular pH. [source] Sperm motility in the steelhead Oncorhynchus mykiss (Walbaum): influence of the composition of the incubation and activation mediaAQUACULTURE RESEARCH, Issue 3 2006Joshua Woolsey Abstract This study examined the pH sensitivity of steelhead, Oncorhynchus mykiss (Walbaum), sperm motility relative to the composition of incubation and activation media. The percentage of sperm that initiated motility following incubation in a sperm immobilizing solution (SI) titrated to different pH values and subsequent activation by dilution in buffered swimming medium (SM) at pH 8.5 or 50% ovarian fluid (OF) showed little or no pH sensitivity; sperm diluted in de-ionized water (DI) showed no motility after incubation at any pH. In contrast, motility of sperm diluted in tap water (TAP) was highly sensitive to the pH of the incubation medium. Sperm incubated with buffered seminal plasma at high, but not low pH demonstrated high percent motility when diluted with DI. Sperm incubated in low-pH SI demonstrated high motility only when diluted into high-pH SM. The effects of the composition of incubation and activation media on sperm motility were generally reflected in comparable effects on fertility. Therefore, these data indicate that the pH sensitivity of sperm motility and fertility depends on the composition of commonly used incubation as well as activation media. [source] Fractional contribution of major ions to the membrane potential of Drosophila melanogaster oocytesARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 4 2009Susan M. Munley Abstract In ovarian follicles of Drosophila melanogaster, ion substitution experiments revealed that K+ is the greatest contributor (68%) in setting oocyte steady-state potential (Em), while Mg2+ and a metabolic component account for the rest. Because of the intense use made of Drosophila ovarian follicles in many lines of research, it is important to know how changes in the surrounding medium, particularly in major diffusible ions, may affect the physiology of the cells. The contributions made to the Drosophila oocyte membrane potential (Em) by [Na+]o, [K+]o, [Mg2+]o, [Ca2+]o, [Cl,]o, and pH (protons) were determined by substitutions made to the composition of the incubation medium. Only K+ and Mg2+ were found to participate in setting the level of Em. In follicles subjected to changes in external pH from the normal 7.3 to either pH 6 or pH 8, Em changed rapidly by about 6,mV, but within 8,min had returned to the original Em. Approximately half of all follicles exposed to reduced [Cl,]o showed no change in Em, and these all had input resistances of 330,k, or greater. The remaining follicles had smaller input resistances, and these first depolarized by about 5,mV. Over several minutes, their input resistances increased and they repolarized to a value more electronegative than their value prior to reduction in [Cl,]o. Together, K+ and Mg2+ accounted for up to 87% of measured steady-state potential. Treatment with sodium azide, ammonium vanadate, or chilling revealed a metabolically driven component that could account for the remaining 13%. © 2009 Wiley Periodicals, Inc. [source] Long-term streptozotocin-induced diabetes alters prostanoid production in rat aorta and mesenteric bedAUTONOMIC & AUTACOID PHARMACOLOGY, Issue 4 2006H. A. Peredo Summary 1 Vascular disease is a major cause of mortality and morbidity in chronic diabetes mellitus. 2 Prostanoids, metabolites of arachidonic acid, include vasoactive substances produced and released from the vascular wall. Alterations in prostanoid production have been reported in the vasculature of diabetic humans and experimental animals. 3 The aim of the present work was to study the influence of three different periods of long-term streptozotocin-induced diabetes, 30, 120 and 180 days in the production of prostanoids in the thoracic aorta and in the mesenteric vascular bed of the rat. The prostanoids released to the incubation medium by the tissues were extracted and measured by reversed-phase HPLC. 4 In the diabetic groups, body weight was reduced and glycaemia was increased when compared with the corresponding non-diabetic controls. 5 In the aorta, 30 days of diabetes did not modify the prostanoid release pattern, meanwhile 120 and 180 days of incubation decreased prostacyclin (PGI2) production. In the mesenteric bed, at 30 days the release of the vasodilators PGI2 and prostaglandin (PGE2) and the vasoconstrictor thromboxane (TXA2) was reduced. At 120 days the vasodilators were reduced and at 180 days such reduction was joined by an increase of the release of vasoconstrictor metabolites. 6 Thirty days of diabetes did not modify the PGI2/TXA2 ratio in the aorta or mesenteric bed. On the other hand, 120 and 180 days of diabetes reduced significantly the ratio when compared with the corresponding controls. 7 In conclusion, the mesenteric bed, a resistance vascular bed, seems to be more sensitive than the aorta, a conductance vessel, to the effects of diabetes on prostanoid production. The observed effects contribute to a displacement of the balance of prostanoid release in favour of the vasoconstrictor metabolites, a phenomenon that could be related to the vascular complications of diabetes mellitus. [source] Cortisol and IGF-1 synergistically up-regulate taurine transport by the rat skeletal muscle cell line, L6BIOFACTORS, Issue 1-4 2004Sung-Hee Park Abstract This study was undertaken to evaluate effects of exercise-induced hormones, cortisol, IGF-1, and ,-endorphin, on the regulation of taurine transport activity in rat skeletal myoblasts, L6 cells. Challenge of L6 cells with cortisol (100 nM) for 24 hrs resulted in a 165% increase in taurine transport activity, 220% increase in Vmax of the taurine transporter, and 55% increase in taurine transporter/ ,-actin mRNA level compared with untreated control cells. Neither IGF-1 (1,100 nM) nor ,-endorphin (1,20 nM), added in the incubation medium separately for 24 hrs, affected taurine uptake by L6 cells. However, when cells were co-treated with IGF-1 (10 nM) plus cortisol (100,nM), taurine transport activity (37% increase, p < 0.05), Vmax of the transporter (54%, p < 0.05), and taurine transporter/ ,-actin mRNA level were further increased compared to the value for cells treated with cortisol alone. These results suggest that taurine transport by skeletal muscle cells appear to be synergistically up-regulated during a prolonged exercise via elevated levels of cortisol and IGF-1 in muscle. [source] Effects of nest temperature and moisture on phenotypic traits of hatchling snakes (Tropidonophis mairii, Colubridae) from tropical AustraliaBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2006GREGORY P. BROWN Previous research on developmentally plastic responses by reptile embryos has paid relatively little attention to tropical species, or to possible interactions between the effects of thermal and hydric regimes. In the present study, eggs of keelback snakes (Tropidonophis mairii), from a tropical area with strong temporal and spatial variation in soil temperatures and moisture levels, were incubated. The phenotypic traits of hatchling snakes (body size, shape, muscular strength) were affected by moisture content of the incubation medium (vermiculite plus 100% vs. 50% water by mass), by mean incubation temperatures (25.7 vs. 27.9 °C) and by diel thermal variation (diel range 6.0 vs. 8.4 °C). Interactions between these factors were negligible. Cooler, more thermostable, moister conditions resulted in larger offspring, a trait under strong selection in this population. Thermal and hydric conditions covary in potential nest-sites (e.g. deeper nests are more thermostable as well as moister). This covariation may influence the evolution of reaction norms for embryogenesis. For example, if moister nests enhance offspring fitness and are cooler, then selection will favour the ability to develop in cool as well as moist conditions. Thus, the evolution of optimal incubation conditions with respect to one variable (e.g. temperature) may be driven by patterns of association with another variable (e.g. soil moisture) among natural nest-sites. Perhaps for this reason, the thermal optimum for incubation is surprisingly low in this tropical species. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89, 159,168. [source] Mechanism of cell death by 5-aminolevulinic acid-based photodynamic action and its enhancement by ferrochelatase inhibitors in human histiocytic lymphoma cell line U937CELL BIOCHEMISTRY AND FUNCTION, Issue 8 2009Takashi Amo Abstract Photodynamic therapy (PDT) for tumors is based on the tumor-selective accumulation of a photosensitizer, protoporphyrin IX (PpIX), followed by irradiation with visible light. However, the molecular mechanism of cell death caused by PDT has not been fully elucidated. The 5-aminolevulinic acid (ALA)-based photodynamic action (PDA) was dependent on the accumulation of PpIX, the level of which decreased rapidly by eliminating ALA from the incubation medium in human histiocytic lymphoma U937 cells. PDA induced apoptosis characterized by lipid peroxidation, increase in Bak and Bax/Bcl-xL, decrease in Bid, membrane depolarization, cytochrome c release, caspase-3 activation, phosphatidylserine (PS) externalization. PDT-induced cell death seemed to occur predominantly via apoptosis through distribution of PpIX in mitochondria. These cell death events were enhanced by ferrochelatase inhibitors. These results indicated that ALA-based-PDA induced apoptotic cell death through a mitochondrial pathway and that ferrochelatase inhibitors might enhanced the effect of PDT for tumors even at low concentrations of ALA. Copyright © 2009 John Wiley & Sons, Ltd. [source] Expression of the neutrophil-activating CXC chemokine ENA-78/CXCL5 by human eosinophilsCLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2003T. Persson Summary Background Eosinophils are seen at sites of inflammation in diseases such as helminthic infestation, asthma, ulcerative colitis and some neoplastic diseases. They are also associated with connective tissue remodelling, for example in longstanding asthma. In the present study, we investigated whether eosinophils express the CXC chemokine epithelial cell-derived neutrophil activating peptide (ENA-78/CXCL5), a chemokine that can activate neutrophils and in addition possesses angiogenic properties. Immunocytochemistry detected CXCL5 in eosinophils and the peptide was localized in the specific granules by immunoelectron microscopy. Methods and Results In eosinophil lysates, 12 ± 2 pg (mean ± SEM) of CXCL5 was detected per 106 cells by enzyme-linked immunosorbent assay (ELISA). Weak constitutive expression of CXCL5, as well as the related CXC chemokine IL,8/CXCL8, could be detected in freshly isolated eosinophils by RT,PCR. However, during prolonged incubation of eosinophils, a strong increase in both CXCL5 and IL-8/CXCL8 expression was seen, as detected by RT-PCR, and increasing amounts of CXCL5 peptide with time were detected in the incubation medium by ELISA. Addition of TNF-, neutralizing antibodies during prolonged incubation significantly inhibited CXCL5 production, demonstrating involvement of auto- and paracrine effects from TNF-, produced by eosinophils themselves. Addition of IFN-, showed a strong inhibitory effect on CXCL5 synthesis. Conclusion These findings suggest that, through expression of CXCL5, eosinophils can recruit and activate CXC receptor 2 (CXCR2)-bearing cells such as neutrophils at sites of inflammation. Eosinophils may also promote connective tissue remodelling through release of this peptide. [source] | ||||||||||||||||