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Nmol G (nmol + g)
Selected AbstractsExperimental hyperhomocysteinaemia: differences in tissue metabolites between homocystine and methionine feeding in a rat modelACTA PHYSIOLOGICA, Issue 1 2009A. Pexa Abstract Aim:, Hyperhomocysteinaemia, diagnosed by serum levels, is regarded as an independent risk indicator for cardiovascular events and is associated with various diseases. The pathomechanisms seem to be partly due to concentrations of homocysteine metabolites and their effect on the cellular transmethylation processes. Methods:, We compared two common models for experimental hyperhomocysteinaemia , high methionine diet and homocystine-enriched diet , regarding their effects on tissue concentrations of homocysteine metabolites. Results:, Both diets induced hyperhomocysteinaemia without affecting renal function or vitamine status. However, the tissue contents of homocysteine and its precursors S -adenosyl-homocysteine (SAH) and S -adenosyl-methionine exhibited major differences between both models. Transmethylation potential was elevated 1.7-fold in liver of rats fed the methionine diet, whereas it was unaltered after homocystine-enriched diet. Kidneys of rats fed the methionine diet did not show any alterations in tissue content of homocysteine and its precursors, whereas in the homocystine group homocysteine and the transmethylation inhibitor SAH were elevated from 23.1 ± 10.4 to 78.0 ± 26.0 nmol g,1 and from 106 ± 4 to 170 ± 22 nmol g,1 respectively. Homocysteine tissue content was elevated in the homocystine, but not in the methionine group. Conclusions:, Alterations to homocysteine metabolism are distinct in both models. These findings may explain divergent results, which have been published for these models of hyperhomocysteinaemia and which have resulted in controversial discussions in the past. [source] Soil chemistry versus environmental controls on production of CH4 and CO2 in northern peatlandsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2005J. B. Yavitt Summary Rates of organic carbon mineralization (to CO2 and CH4) vary widely in peat soil. We transplanted four peat soils with different chemical composition into six sites with different environmental conditions to help resolve the debate about control of organic carbon mineralization by resource availability (e.g. carbon and nutrient chemistry) versus environmental conditions (e.g. temperature, moisture, pH). The four peat soils were derived from Sphagnum (bog moss). Two transplant sites were in mid-boreal Alberta, Canada, two were in low-boreal Ontario, Canada, and two were in the temperate United States. After 3 years in the field, CH4 production varied significantly as a function of peat type, transplant site, and the type,site interaction. All four peat soils had very small rates of CH4 production (< 20 nmol g,1 day,1) after transplant into two sites, presumably caused by acid site conditions (pH < 4.0). One peat soil had small CH4 production rates regardless of transplant site. A canonical discriminant analysis revealed that large rates of CH4 production (4000 nmol g,1 day,1) correlated with large holocellulose content, a large concentration of p -hydroxyl phenolic compounds in the Klason lignin, and small concentrations of N, Ca and Mn in peat. Significant variation in rates of CO2 production correlated positively with holocellulose content and negatively with N concentrations, regardless of transplant site. The temperature response for CO2 production varied as a function of climate, being greater for peat formed in a cold climate, but did not apply to transplanted peat. Although we succeeded in elucidating some aspects of peat chemistry controlling production of CH4 and CO2 in Sphagnum -derived peat soils, we also revealed idiosyncratic combinations of peat chemistry and site conditions that will complicate forecasting rates of peat carbon mineralization into the future. [source] Long-term ozone effects on vegetation, microbial community and methane dynamics of boreal peatland microcosms in open-field conditionsGLOBAL CHANGE BIOLOGY, Issue 8 2008SAMI K. MÖRSKY Abstract To study the effects of elevated ozone concentration on methane dynamics and a sedge species, Eriophorum vaginatum, we exposed peatland microcosms, isolated by coring from an oligotrophic pine fen, to double ambient ozone concentration in an open-air ozone exposure field for four growing seasons. The field consists of eight circular plots of which four were fumigated with elevated ozone concentration and four were ambient controls. At the latter part of the first growing season (week 33, 2003), the methane emission was 159±14 mg CH4 m,2 day,1 (mean±SE) in the ozone treatment and 214±8 mg CH4 m,2 day,1 under the ambient control. However, towards the end of the experiment the ozone treatment slightly, but consistently, enhanced the methane emission. At the end of the third growing season (2005), microbial biomass (estimated by phospholipid fatty acid biomarkers) was higher in peat exposed to ozone (1975±108 nmol g,1 dw) than in peat of the control microcosms (1589±115 nmol g,1 dw). The concentrations of organic acids in peat pore water showed a similar trend. Elevated ozone did not affect the shoot length or the structure of the sedge E. vaginatum leaves but it slightly increased the total number of sedge leaves towards the end of the experiment. Our results indicate that elevated ozone concentration enhances the general growth conditions of microbes in peat by increasing their substrate availability. However, the methane production did not reflect the increase in the concentration of organic acids, probably because hydrogenotrophic methane production dominated in the peat studied. Although, we used isolated peatland microcosms with limited size as study material, we did not find experimental factors that could have hampered the basic conclusions on the effects of ozone. [source] Biochemical changes in cut vs. intact lamb's lettuce (Valerianella olitoria) leaves during storageINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2009Antonio Ferrante Summary Consumers are oriented towards fresh-cut vegetables that provide phytonutrients useful for preventing stress-related diseases. The aim of this work was to evaluate the cut operations on the quality changes of lamb's lettuce (Valerianella olitoria L.) cv. Trofy during storage at 4 °C for 8 days. Results showed that chlorophyll and carotenoids reduction was observed after 8 days of storage. In both treatments, total carotenoids after 8 days decreased from 20 to 16 mg g,1 FW. Free and total phenols increased with storage in both treatments. Total phenols were 23% higher in control (32 ,mol g,1 FW) compared to cut leaves (25 ,mol g,1 FW) after 8 days of storage. Anthocyanins increased after 8 days and reached 30 mg 100 g,1 FW without significant difference between treatments. Ascorbic acid (AsA) and dehydroascorbic (DHA) acid increased in cut leaves compared to control. After 1 day AsA concentration was 3 300 nmol g,1 FW in cut leaves, while in control leaves was 1 500 nmol g,1 FW. Analogously AsA + DHA was higher in cut leaves, 4 100 nmol g,1 FW, while in control leaves the mean was 3 000 nmol g,1 FW. After 5 days of storage the values of AsA returned to initial values, while AsA + DHA were lower. [source] Temporal changes in Sander vitreus egg thiamine levelsJOURNAL OF FISH BIOLOGY, Issue 4 2005M. E. Barnes Thiamine pyrophosphate was the predominant form of thiamine present initially in walleye Sander vitreus eggs from two spawning locations in Lake Oahe, South Dakota, U.S.A. Total thiamine content in the eggs at fertilization was 5·18 and 7·97 nmol g,1 for eggs from the Moreau and Grand River spawning sites respectively, and egg thiamine content in all its forms dropped dramatically at the next sampling period of 48 temperature units (TU). Thiamine values did not significantly drop after the 48 TU period, but mean total thiamine composition was < 0·9 nmol g,1 at the last sampling date (156 TU) just prior to hatching. [source] Effect of apoE/ATP-containing liposomes on hepatic energy stateLIVER INTERNATIONAL, Issue 5 2003S. Chaïb Abstract: Background/Aims: ATP-containing liposomes partially prevent ATP depletion in the cold-stored liver. As hepatocytes can specifically bind apoE, we investigated whether the addition of apoE to large (200 nm) ATP-containing liposomes increases their uptake by the liver and further improves hepatic energy stores. Methods: Livers from fasted male Hartley guinea-pigs (231±3 g) were perfused for 90 min under our standard conditions (Control, n=6) or after a single bolus addition of plain liposomes (Lip, n=6), ATP (5 ,mol)-containing liposomes (ATP-Lip, n=6) or apoE/ATP-containing liposomes (0.8 or 8 mg apoE/g phospholipids; apoE1-Lip and apoE10-Lip, respectively, n=6 in each group). Liposome uptake and its impact on energy and nitrogen metabolism were studied. Results: At its highest concentration, apoE significantly increased liposome uptake (apoE10-Lip:,9.17±0.69 vs apoE1-Lip:,6.18±0.44 vs ATP-Lip:,6.40±0.88 nmol min,1 g,1; P<0.05). This was associated with a significant increase in intrahepatic ATP (apoE10-Lip: 1033±137 vs apoE1-Lip: 811±98 and ATP-Lip: 648±36 nmol g,1; P<0.05), which was restored to its level in non-perfused livers. Hepatic viability and nitrogen metabolism were not affected. Conclusions: Hepatic ATP content being a key factor in the maintenance of liver graft function, apoE/ATP-containing liposomes should be useful in liver preservation for transplantation. [source] Oligocarrageenans and tissue-dependant oxidative burst in Solieria chordalis (Rhodophyceae, Gigartinales)PHYCOLOGICAL RESEARCH, Issue 1 2008Erwan Ar Gall SUMMARY The release of hydrogen peroxide by thallus fragments of the rhodophycean Solieria chordalis (C. Agardh) J. Agardh has been documented both in the presence and in the absence of oligosaccharides. Within 1 h, ramuli were able to release large amounts of peroxide in the absence of any chemical stress. Among potential elicitors tested, only degree of polymerization 1 (DP1) and DP7-8 oligo-iota-carrageenans stimulated defense mechanisms in both axes and ramuli as shown by the occurrence of an oxidative burst. Chopping of the tissues had no effect on the intensity of the burst, therefore suggesting that mainly cortical cell layers were involved in the process. After 5 min incubation, a dose of 125 ,g mL,1 of an oligomeric mixture containing a large proportion of DP1 units proved to be sufficient to obtain a maximal response. The intensity of the burst was significantly higher with isolated ramuli than with pieces of the axis, with outer peroxide accumulations reaching 200 nmol g,1 fresh weight of treated tissue. Altogether, our results show that S. chordalis is able to react to a simulated pathogen attack by an oxidative burst and that the capacity to carry out an oxidative burst is stronger in ramuli than in axes. [source] Effects of different dosages of astaxanthin on giant freshwater prawn Macrobrachium rosenbergii (De Man) challenged with Lactococcus garvieaeAQUACULTURE RESEARCH, Issue 1 2009Isagani P Angeles Jr Abstract The effects of astaxanthin (AX) injected at 0.67 and 1.34 nmol g,1 BW,1 on the survival, antioxidant capacity, total haemocyte count (THC) and hepatopancreas astaxanthin content of giant freshwater prawn, Macrobrachium rosenbergii, challenged with Lactococcus garvieae were evaluated. AX-injected M. rosenbergii at 1.34 nmol g,1 BW,1 had significantly (P,0.05) higher survival rates. However, AX showed no significant effects on the capacity of certain antioxidant indicators (superoxide dismutase, glutathione peroxidase and glutathione reductase). This implies that L. garvieae infection suppressed the activity of the haemolymph antioxidant system of infected M. rosenbergii. This result suggests that the two different dosages used in this study could not exert significant effects on the tested antioxidant capacity of L. garvieae -infected M. rosenbergii. On the other hand, AX-injected M. rosenbergii at either dose showed a significant increase in the THC and hepatopancreas AX content when compared with the challenged control group. Overall, the results of this study indicate that the injected AX led to an improvement in M. rosenbergii's resistance against L. garvieae infection. [source] Pharmacology and autoradiography of human DP prostanoid receptors using [3H]-BWA868C, a DP receptor-selective antagonist radioligandBRITISH JOURNAL OF PHARMACOLOGY, Issue 6 2000N A Sharif A potent and highly selective DP prostanoid receptor antagonist radioligand, [3H]-cyclohexyl-N-BWA868C (3-benzyl-5-(6-carboxyhexyl)-1-(2-cyclohexyl-2-hydroxyethyl-amino) hydantoin, ([3H]-BWA868C)), has been generated for receptor binding and autoradiographic studies. Specific [3H]-BWA868C binding to human platelet membranes achieved equilibrium within 60 min at 23°C and constituted up to 95% of the total binding. The association (K+1) and dissociation (K,1) rate constants of binding were 0.758±0.064 min,1, mmol and 0.0042±0.0002 min,1, respectively, yielding dissociation constants (KDs) of 5.66±0.44 nM (n=4). Specific [3H]-BWA868C bound to DP receptors with a high affinity (KD=1.45±0.01 nM, n=3) and to a finite, saturable number of binding sites (Bmax=21.1±0.6 nmol g,1 wet weight). DP receptor class prostanoids (e.g. ZK118182, BW245C, BWA868C, PGD2) exhibited high (nanomolar) affinities for [3H]-BWA868C binding, while prostanoids selective for EP, FP, IP and TP receptors showed a low (micromolar) affinity. Specific DP receptor binding sites were autoradiographically localized on the ciliary epithelium/process, longitudinal and circular ciliary muscles, retinal choroid and iris in human eye sections using [3H]-BWA868C. While [3H]-PGD2 yielded similar quantitative distribution of DP receptors as [3H]-BWA868C, the level of non-specific binding observed with [3H]-PGD2 was significantly greater than that observed with [3H]-BWA868C. It is concluded that [3H]-BWA868C is a high-affinity and very specific DP receptor radioligand capable of selectively labelling the DP receptor. [3H]-BWA868C may prove useful for future homogenate-based and autoradiographic studies on the DP receptor. British Journal of Pharmacology (2000) 131, 1025,1038; doi:10.1038/sj.bjp.0703686 [source] | ||||||||||||||||