Molecular transformation and degradation of refractory dissolved organic matter in the Atlantic and Southern Ocean

More than 90% of the global ocean dissolved organic carbon (DOC) is refractory, has an average age of 4,000–6,000 years and a lifespan from months to millennia. The fraction of dissolved organic matter (DOM) that is resistant to degradation is a long-term buffer in the global carbon cycle but its chemical composition, structure, and biochemical formation and degradation mechanisms are still unresolved. We have compiled the most comprehensive molecular data set of 197 Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analyses from solid-phase extracted marine DOM covering two major oceans, the Atlantic sector of the Southern Ocean and the East Atlantic Ocean (ranging from 50° N to 70° S). Molecular trends and radiocarbon dating of 34 DOM samples (comprising Δ14C values from -229 to -495‰) were combined to model an integrated degradation rate for bulk DOC resulting in a predicted age of >24 ka for the most persistent DOM fraction. First order kinetic degradation rates for 1,557 mass peaks indicate that numerous DOM molecules cycle on timescales much longer than the turnover of the bulk DOC pool (estimated residence times of >100 ka) and the range of validity of radiocarbon dating. Changes in elemental composition were determined by assigning molecular formulae to the detected mass peaks. The combination of residence times with molecular information enabled modelling of the average elemental composition of the slowest degrading fraction of the DOM pool. In our dataset, a group of 361 molecular formulae represented the most stable composition in the oceanic environment (“island of stability”). These most persistent compounds encompass only a narrow range of the elemental ratios H/C (average of 1.17 ± 0.13), and O/C (average of 0.52 ± 0.10) and molecular masses (360 ± 28 and 497 ± 51 Da). In the Weddell Sea DOC concentrations in the surface waters were low (46.3 ± 3.3 μM) while the organic radiocarbon was significantly more depleted than that of the East Atlantic, indicating average surface water DOM ages of 4,920 ± 180 a. These results are in accordance with a highly degraded DOM in the Weddell Sea surface water as also shown by the molecular degradation index IDEG obtained from FT-ICR MS data. Further, we identified 339 molecular formulae which probably contribute to an increased DOC concentration in the Southern Ocean and potentially reflect an accumulation or enhanced sequestration of refractory DOC in the Weddell Sea. These results will contribute to a better understanding of the persistent nature of marine DOM and its role as an oceanic carbon buffer in a changing climate

Adhesion molecules in early neonatal life

This study investigated whether serum levels of the adhesion molecules VCAM-1, PECAM-1 and L-selectin, all of which have been implicated in normal immune function, change soon after birth. Moreover, the dependence of serum levels of the above-mentioned adhesion molecules on sex and mode of delivery was studied. in healthy neonates, serum levels of L-selectin, PECAM-1, and VCAM-1 do not change during early neonatal life. Thus, significant differences in their serum concentrations soon after birth might imply inflammatory processes or deranged endothelial homeostasis, serving as possible diagnostic markers. Copyright (C) 2000 S. Karger AG, Basel

Angiogenic factors in the perinatal period: Diversity in biological functions reflected in their serum concentrations soon after birth

These studies investigated whether serum levels of the angiogenic factors angiogenin, basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF) change soon after birth due to the elimination of the placenta and to diminished angiogenic but increased adaptational demands in extrauterine life. Also investigated was whether serum levels correlate with sex, birth weight, or mode of delivery. Serum from healthy mothers and their healthy full-term infants at birth (umbilical cord, UC), day 1 (N1) and day 4 (N4) postpartum was analyzed by enzyme immunoassays. Angiogenin levels were higher in maternal serum and rose significantly from UC to N1 and N4, possibly because of the elimination of the placenta, which produces an angiogenin inhibitor. bFGF and VEGF maternal levels were lower than fetal and neonatal ones. Although neonatal bFGF levels did not differ from fetal levels, possibly reflecting diminished angiogenesis ex utero, VEGF levels increased in neonatal serum, possibly signifying adaptational demands. Neither factor depended on sex, mode of delivery, or birth weight. Thus, significant differences from normal reference values of the studied factors might reflect ill-defined situations of the placenta and fetus/newborn serving as early diagnostic markers

Adhesion molecules expression in the placental bed of pregnancies with pre-eclampsia

Objective To compare the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), platelet endothelial cell adhesion molecule-1 (PECAM-1) and E-selectin in placental bed biopsies (endothelium of spiral arteries as well as trophoblastic cells) from normal and pre-eclamptic pregnancies. Design A prospective study. Setting 1. First Department of Obstetrics and Gynaecology, Alexandra Hospital, University of Athens, Greece. 2. Laboratory of Pathophysiology, Laikon Hospital, University of Athens. Population Sixteen placental bed biopsies from women with pre-eclampsia were compared with 20 placental bed biopsies from uncomplicated normotensive women. Main outcome measures Immunocytochemical staining of the placental bed biopsies for ICAM-1, VCAM-1, PECAM-1 and E-selectin. Results No statistically significant differences were found in the expression of the adhesion molecules ICAM-1, VCAM-1, PECAM-1 and E-selectin in the endothelium of the spiral arteries and the trophoblastic cells of the placental bed of the two studied groups. Conclusions Adhesion molecules ICAM-1, VCAM-I, PECAM-1, but not E-selectin, are expressed in the placental bed of normal and pre-eclamptic pregnancies, but there are no differences between the two groups of women. It seems that the above molecules are not likely to be implicated in the aetiology of pre-eclampsia

Serum angiogenin levels in children and adolescents with insulin-dependent diabetes mellitus

Microangiopathy, one of the most important complications of diabetes mellitus in humans, is associated with increased angiogenic response and proliferative lesions in various organs. Angiogenin, a polypeptide with a molecular size of 14 kD, is a potent inducer of vascular growth. This study aimed at investigating whether serum angiogenin levels are elevated in children and adolescents (youngsters) with insulin-dependent diabetes mellitus and whether angiogenin levels are affected by duration and metabolic control of the disease. It is assumed that angiogenin levels reflect the increased angiogenesis associated with microangiopathy, whether clinically evident or not. Forty diabetic youngsters were compared with 30 healthy control subjects (mean age +/- SD, 14.3 +/- 3.6 y and 13.8 +/- 3.6 y, respectively). The patients’ disease duration and glycosylated Hb were (mean +/- SD) 6.2 +/- 1.8 y and 96 +/- 18%. respectively. Angiogenin (ng/mL) was measured in serum samples by an enzyme immunoassay and was found to be significantly higher (mean +/- SE) in patients (353.3 +/- 20.0) than in control subjects (244.7 +/- 9.6) (p = 0.0002). Levels did not vary with age, but were significantly higher in females compared with male subjects (p = 0.01). In the diabetic youngsters no significant differences were noticed with respect to duration or metabolic control of the disease. In conclusion, serum angiogenin levels were found to be increased among diabetic youngsters, irrespective of the duration and metabolic control of the disease, as well as in female subjects, with or without diabetes

Molecular cartography in acute <em>Chlamydia pneumoniae</em> infections - a non-targeted metabolomics approach.

Infections with Chlamydia pneumoniae cause several respiratory diseases, such as community-acquired pneumonia, bronchitis or sinusitis. Here, we present an integrated non-targeted metabolomics analysis applying ultra-high-resolution mass spectrometry and ultra-performance liquid chromatography mass spectrometry to determine metabolite alterations in C. pneumoniae-infected HEp-2 cells. Most important permutations are elaborated using uni- and multivariate statistical analysis, logD retention time regression and mass defect-based network analysis. Classes of metabolites showing high variations upon infection are lipids, carbohydrates and amino acids. Moreover, we observed several non-annotated compounds as predominantly abundant after infection, which are promising biomarker candidates for drug-target and diagnostic research

Serum levels of basic fibroblast growth factor and vascular endothelial growth factor in children and adolescents with type 1 diabetes mellitus

Diabetes mellitus is characterized by microangiopathy and increased angiogenic response in various organs. Basic fibroblast growth factor (bFGF) as well as vascular endothelial growth factor (VEGF) are both angiogenic and are involved in vascular endothelial cell growth. The purpose of this study was to determine serum levels of bFGF and VEGF, in children and adolescents (youngsters) with type 1 diabetes mellitus, and correlate them with parameters reflecting the severity of the disease. Forty diabetic youngsters without clinical evidence of complications were compared with 30 healthy control subjects (mean age +/- SD, 14.3 +/- 3.6 and 13.8 +/- 3.6 y, respectively). Diabetes duration and metabolic control (expressed by glycosylated Hb) were (mean +/- SD) 6.2 +/- 3.8 y and 9.6 +/- 1.8%, respectively. bFGF and VEGF (pg/mL) were measured in serum samples by enzyme immunoassays, and both were not significantly different between the type 1 diabetes mellitus and the control group (p = 0.952 and p = 0.559, respectively). Restricting the analysis to the type 1 diabetes mellitus group, neither the duration nor the metabolic control of the disease showed any correlation with bFGF and VEGF serum levels, whereas a significantly positive correlation was found between the two examined angiogenic factors both in the diabetic (r = 0.3464, p = 0.025) and the control group (r = 0.4619, p = 0.0013). In conclusion, serum levels of bFGF and VEGF were not found to vary significantly in diabetic youngsters in relation to controls and had no correlation with the duration and metabolic control of the disease. Nevertheless, a positive correlation was found between these two angiogenic factors both in the type 1 diabetes mellitus and the control group