| 1. |
- Deutsch, Barbara, et al.
(författare)
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Nitrogen transformation processes in the Elbe River : Distinguishing between assimilation and denitrification by means of stable isotope ratios in nitrate
- 2009
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Ingår i: Aquatic Sciences. - : Springer Science and Business Media LLC. - 1015-1621 .- 1420-9055. ; 71:2, s. 228-237
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Tidskriftsartikel (refereegranskat)abstract
- During a 9-day Lagrangian sampling campaign along the free-flowing section of the Elbe River in July 2005, water from the river as well as from major tributaries and sewage treatment plants was sampled to investigate major nitrogen transformation processes, focussing on denitrification and N-assimilation by phytoplankton. Samples were analysed for delta N-15 - NO3-, delta O-18 - NO3-, delta N-15 - NH4+, nutrient concentrations, chlorophyll a (Chl a), and particulate organic matter. A strong decrease in nitrate concentration accompanied by strong increases in Chl a, particulate organic carbon (POC) and delta N-15- and delta O-18 - NO3- values were measured along the river. The ratio of the increase in delta N-15 vs. delta O-18 of the river nitrate samples was 0.89:1. Together with the observed decrease in nitrate and the increase in Chl a and POC, this indicates a major role of nitrogen assimilation by phytoplankton. This finding is supported by budget calculations, while nitrate inputs from the sampled tributaries and from sewage treatment plants were of minor importance for the nitrogen budget of the Elbe River. The stable isotope analysis of nitrogen and oxygen in nitrate is shown to be a powerful tool for the identification of N transformation processes along large rivers, particularly if combined with Lagrangian measurements of algal biomass, and dissolved and particulate nutrient concentrations.
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| 2. |
- Scheele, Camilla, et al.
(författare)
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Altered regulation of the PINK1 locus: a link between Type 2 diabetes and neurodegeneration?
- 2007
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Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 21:13, s. 3653-3665
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in PINK1 cause the mitochondrial-related neurodegenerative disease Parkinson’s. Here we investigate whether obesity, type 2 diabetes, or inactivity alters transcription from the PINK1 locus. We utilized a cDNA-array and quantitative real-time PCR for gene expression analysis of muscle from healthy volunteers following physical inactivity, and muscle and adipose tissue from nonobese or obese subjects with normal glucose tolerance or type 2 diabetes. Functional studies of PINK1 were performed utilizing RNA interference in cell culture models. Following inactivity, the PINK1 locus had an opposing regulation pattern (PINK1 was down-regulated while natural antisense PINK1 was up-regulated). In type 2 diabetes skeletal muscle, all transcripts from the PINK1 locus were suppressed and gene expression correlated with diabetes status. RNA interference of PINK1 in human neuronal cell lines impaired basal glucose uptake. In adipose tissue, mitochondrial gene expression correlated with PINK1 expression although remained unaltered following siRNA knockdown of Pink1 in primary cultures of brown preadipocytes. In conclusion, regulation of the PINK1 locus, previously linked to neurodegenerative disease, is altered in obesity, type 2 diabetes and inactivity, while the combination of RNAi experiments and clinical data suggests a role for PINK1 in cell energetics rather than in mitochondrial biogenesis.
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| 3. |
- Schmid, Eduard, et al.
(författare)
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Neurokinin A is a main constituent of sensory neurons innervating the anterior segment of the eye
- 2005
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Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 46:1, s. 268-274
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE. To study the innervation pattern of the anterior segment of the eye by neurokinin (NK)-A-immunoreactive nerves and to determine their sensory origin. METHODS. The presence and distribution of NKA was examined in human eyes by radioimmunoassay and immunofluorescence. The source of nerves was determined by measuring the concentration of NKA in the trigeminal ganglion (TG) in comparison with that of the classic sensory peptides substance P (SP) and calcitonin gene-related peptide (CGRP) and in eye tissues in capsaicin-pretreated rats versus control subjects. The NKA-like immunoreactivities were further characterized by reversed phase HPLC in the rat TG and the human iris- ciliary body complex. The presence of γ-PPT-A mRNA was studied in the rat TG by in situ hybridization. RESULTS. The levels of NKA in human eye tissues were approximately 10 times higher than those of SP but lower than those of CGRP. Nerve fibers were visualized in the cornea, the trabecular meshwork, the iridial stroma, and, prominently, in the sphincter muscle, the ciliary body stroma and muscle and processes, and the choroidal stroma and surrounding blood vessels. In the rat TG, the concentration of NKA was approximately five times higher than that of SP. Capsaicin led to a >60% decrease of the concentration of the peptide in the rat TG and rat eye tissues except for the retina. NKA-like immunoreactivities were present in a single peak corresponding to synthetic NKA, both in the rat TG and in the human iris- ciliary body complex, and numerous ganglion cells of small size were labeled by a γ-PPT-A probe in the rat TG. CONCLUSIONS. The present results clearly demonstrate that NKA is a main constituent of sensory neurons innervating the anterior segment of the eye. The presence of the peptide in C fibers in ocular tissues indicates a participation in sensory transmission and an involvement in the irritative response in the eye, a model for neurogenic inflammation in lower mammals.
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