Pyrimidine Nucleotidases/Phosphotransferases from Human Erythrocyte

Abstract

Two cytoplasmic pyrimidine 5′-nucleotidase have been purified from human erythrocytes to homogeneity and partially characterized. The two enzymes, indicated as PN-I and PN-II, preferentially hydrolyse pyrimidine 5′-monophosphates and 3′-monophosphates, respectively. The kinetic analysis demonstrate that pyrimidine 5′-nucleotidases, in the presence of suitable nucleoside substrates, can operate as phosphotransferases by transferring phosphate to various nucleoside acceptors, including nucleoside analogues known as important drugs widely used in chemotherapy.     

Sphagnum divinum (sp. nov.) and S. medium Limpr. and their relationship to S. magellanicum Brid.

Sphagnum magellanicum has been viewed as being a predominantly circumpolar species in the northern hemisphere, but it occurs in the southern hemisphere and was originally described from the southern parts of Chile. It is an ecologically important species in mire ecosystems and has been extensively used as a model to study processes of growth, carbon sequestration and peat decomposition. Molecular and experimental studies have, however, revealed genetic structure within S. magellanicum, and morphological differences associated with these genetic groups. Here we describe Sphagnum divinum in Sphagnum subgenus Sphagnum (Sphagnaceae, Bryophyta) as a new species, based on molecular and morphological evidence. Sphagnum medium is reinstated as a distinct species and is epitypified. Consequently, a new species concept of S. magellanicum is presented including an epitypification. Important morphological characters to separate these three species in the field and under the microscope are presented. Ecology and distribution differ among the species; S. divinium has a wide habitat range including mire margin, forested peatlands and moist heaths, and a circumpolar distribution around the northern hemisphere. Sphagnum medium seems to be more restricted to ombrotrophic mire expanse habitats and shows an amphi-Atlantic distribution in the northern hemisphere. Sphagnum magellanicum has a very broad ecological niche in peatlands and is found in most mire habitats in Tierra del Fuego on the southern tip of South America.     

Bacteria-produced ferric exopolysaccharide nanoparticles as iron delivery system for truffles (Tuber borchii)

Applied Microbiology and Biotechnology - Iron exopolysaccharide nanoparticles were biogenerated during ferric citrate fermentation by Klebsiella oxytoca DSM 29614. Before investigating their...     

Decreased pulmonary diffusing capacity of divers over a 6-year period

Non-smoking, male, professional firemen divers (n = 15) underwent two pulmonary function tests (PFT) separated by 6 years. Measured data were compared to European Coal Steel Community recommended reference values to permit cross-sectional and then longitudinal study. Higher vital capacity (VC; P < 0.01) and forced expiratory volume in 1 s (FEV₁; P < 0.05), and lower maximal mid-expiratory flow (MMEF) coefficient with VC (MMEF/VC; P < 0.05) were observed in both PFT. Diver's pulmonary diffusing capacity (DL_CO) and the coefficient with alveolar volume (DL_CO/V _A) showed significantly (P < 0.001) different evolution profiles than those expected from predicted values. In divers, DL_CO and DL_CO/V _A decreased from 104.0% to 91.4% and from 106.4% to 91.5% of predicted values respectively. Changes in DL_CO and DL_CO/V _A correlated positively with the initial measurement of DL_CO (r = 0.67, P < 0.01) and DL_CO/V _A (r = 0.74, P < 0.01) respectively, whereas no correlation between changes in pulmonary gas transfer function and age or diving history parameters was found. Thus, it is suggested from our observations that hyperbaric atmosphere exposure increases the effects of aging on pulmonary diffusing capacity and that pulmonary gas transfer function should be regularly tested in professional and recreational divers. Accepted: 22 February 1997     

Biotinylation sites of tumor necrosis factor-alpha determined by liquid chromatography-mass spectrometry.

Tumor pretargeting with biotinylated antibody/avidin complexes improves the therapeutic index of systemically administered biotin-tumor necrosis factor (TNF) conjugates. Since the number of biotins in this conjugate is known to be critical for activity, we have characterized the structure of different biotin-TNF conjugates, prepared by reaction with d-biotinyl-6-aminocaproic acid N-hydroxysuccinimide ester and identified the biotinylation sites by trypsin digestion, reverse-phase chromatography, and electrospray mass spectrometry analyses. The results have shown that N-terminal valine is a preferential biotinylation site at pH 5.8, half of biotins being located on the alpha-amino group of this residue in a conjugate bearing one biotin/trimer (on average). Moreover, evidence has been obtained to suggest that the remaining part of biotins are linked to the epsilon-amino group of lysine 128, 112, and 65, while lysine 11, 90, and 98 were practically unmodified. No evidence of O-biotinylation of serine, threonine and tyrosine was obtained.     

Central and peripheral mechanisms in the control of the diurnal rhythm of flashing in Luciola lusitanica (Charp.)

The mechanisms underlying the diurnal rhythm of flashing in L. lusitanica were investigated. It was shown that the diurnal rhythm of flashing was present also in animals kept in continuous darkness, showing that it was not directly determined by the periodic variations of the ambient light intensity which take place through the nicthemeron. During the hours in which the animals did not flash, photogenic volleys of normal size and contour could still be recorded, although at a lower frequency; however, they were not followed by light emission. Statistical controls ruled out the possibility that the absence of flashing during daytime was due to the reduced repetition rate of the photogenic volleys. The ablation of the gonads performed during day-time was followed by the reappearence of a flash in the wake of each photogenic volley. It is concluded that two mechanism control the diurnal rhythm of flashing, namely; a central mechanism, responsible for the decrease in volley frequency; and a peripheral mechanism, of gonadal origin, which is responsible for the inhibition of the photogenic organ.     

Impact of climate change on alpine vegetation of mountain summits in Norway

Climate change is affecting the composition and functioning of ecosystems across the globe. Mountain ecosystems are particularly sensitive to climate warming since their biota is generally limited by low temperatures. Cryptogams such as lichens and bryophytes are important for the biodiversity and functioning of these ecosystems, but have not often been incorporated in vegetation resurvey studies. Hence, we lack a good understanding of how vascular plants, lichens and bryophytes respond interactively to climate warming in alpine communities. Here we quantified long-term changes in species richness, cover, composition and thermophilization (i.e. the increasing dominance of warm-adapted species) of vascular plants, lichens and bryophytes on four summits at Dovrefjell, Norway. These summits are situated along an elevational gradient from the low alpine to high alpine zone and were surveyed for all species in 2001, 2008 and 2015. During the 15-year period, a decline in lichen richness and increase in bryophyte richness was detected, whereas no change in vascular plant richness was found. Dwarf-shrub abundance progressively increased at the expense of lichens, and thermophilization was most pronounced for vascular plants, but occurred only on the lowest summits and northern aspects. Lichens showed less thermophilization and, for the bryophytes, no significant thermophilization was found. Although recent climate change may have primarily caused the observed changes in vegetation, combined effects with non-climatic factors (e.g. grazing and trampling) are likely important as well. At a larger scale, alpine vegetation shifts could have a profound impact on biosphere functioning with feedbacks to the global climate.     

Match activities of elite women soccer players at different performance levels

We sought to study the physical demands and match performance of women soccer players. Nineteen top-class and 15 high-level players were individually videotaped in competitive matches, and time-motion analysis were performed. The players changed locomotor activity >1,300 times in a game corresponding to every ~4 seconds and covered 9-11 km in total. The top-class players ran 28% longer (P < 0.05) at high intensities than high-level players (1.68 +/- 0.09 and 1.33 +/- 0.10 km, respectively) and sprinted 24% longer (P < 0.05). The top-class group had a decrease (P < 0.05) of 25-57% in high intensity running in the final 15 minutes compared with the first four 15-minutes intervals, whereas the high-level group performed less (P < 0.05) high-intensity running in the last 15 minutes of each half in comparison with the 2 previous 15-minute periods in the respective half. Peak distance covered by high intensity running in a 5-minute interval was 33% longer (P < 0.05) for the top-class players than the high-level players. In the following 5 minutes immediately after the peak interval top-class players covered 17% less (P < 0.05) high-intensity running than the game average. Defenders performed fewer (P < 0.05) intervals of high-intensity running than midfielders and attackers, as well as fewer (P < 0.05) sprints than the attackers. In conclusion, for women soccer players (1) top-class international players perform more intervals of high-intensity running than elite players at a lower level, (2) fatigue develops temporarily during and towards the end of a game, and (3) defenders have lower work rates than midfielders and attackers. The difference in high-intensity running between the 2 levels demonstrates the importance of intense intermittent exercise for match performance in women soccer. Thus, these aspects should be trained intensively in women soccer.