Nutrient mineralization patterns in shelf waters of the Western Iberian upwelling

24 páginas, 10 figuras, 2 tablasA set of hydrographicdata collectedduring severalcruisesto theNWIberian upwelling systemhas been used to assess the patterns of nutrient mineralizationover the shelf. Mineralized nutrient ratios (N/P and N/Si)in the lowerwatercohrmnare clearlybelowthe ratios characteristicof freshly upwelled oceanic waters. Nitrogen mineralization, in comparison to phosphorus mineralization, is incomplete,in agreementwith phosphate’sfaster regenerationrate and the low residence time of water, which precludes complete mineralization. Silicate shows the highest enrichmentas a consequenceof the selectiveconcentrationof particulate biogenicsilica in the near bottom waters. Diffusionof nutrients mineralizedin the sedimentsseemsto representan important contribution.TheIowestmineralizationof the surveyedarea is foundto the north of CapeFinisterre, especiallywith regard to silicate.To the South, the Rias Baixas(four large embayments)return as reducingparticulate organicmatter (POM)a smallfraction of the upwellednutrientsimportedfrom the shelf. However,the out-flowingfreshwatercontributesto stratificationof coastal waters, which favoursPOMproduction,accumulationand sedimentation.In addition,highlevelsofnewdissolved organic matter (DOM) in the outflowcan also enhanceprimary productionin shelfsurface waters. Finally, highest mineralization was found to the south of the River Miiio, where there are no embayments and the shelf is wider. Mineralization tends to: (1) increase the potential primary productionof thisecosystembyupto 50%,(nitrogenIimitation)orup to 80%(siliconlimitation);(2) favour the developmentof phytoplanktonassemblagesdominatedbydiatoms(Sienrichmentdouble that ofN and P); and (3)bufferthe largespatial and temporaldifferencesintroducedbythe advected nutrientsSupport for this work came from EU projects contract No. MAST-CT90-0017and MAS2- CT93-006Peer reviewe

Prognostic value of discs large homolog 7 transcript levels in prostate cancer.

Hypoxia has been associated with malignant progression, metastasis and resistance to therapy. Hence, we studied expression of hypoxia-regulated genes in 100 prostate cancer (CaP) bulk tissues and 71 adjacent benign tissues. We found 24 transcripts significantly overexpressed (p ≤ 0.02). Importantly, higher transcript levels of disc large (drosophila) homolog-associated protein 5 (DLGAP5)/discs large homolog 7 (DLG7)/hepatoma up-regulated protein (HURP), hyaluronan-mediated motility receptor (HMMR) and cyclin B1 (CCNB1) were associated with higher Gleason score and more advanced systemic progression. Since the products of HMMR and CCNB1 have been identified recently as molecular markers of CaP progression, we postulated that DLG7 has prognostic value too. To test this hypothesis, we measured transcript levels for DLG7 in a 150-pair case-control cohort. The cases (progression to systemic disease within six years of surgery) and controls (no progression within eight years) were matched for clinical and pathologic prognostic variables, including grade, stage, and preoperative serum levels of PSA. The overall prognostic ability of DLG7, as tested in receiver operating characteristic analysis was of 0.74 (95% CI, 0.68 to 0.8). Overall, our data indicate that expression of DLG7, a hypoxia-controlled gene, holds prognostic potential in high-risk CaP; this also demonstrates that variation of oxygen tension may constitute a tool for identification of novel biomarkers for CaP

Three hypoxia-controlled genes associated with Gleason score and prognosis.

<p>Among the hypoxia-regulated genes significantly overexpressed in CaP, cyclin B1 (CCNB1), DLGAP5 and hyaluronan-mediated motility receptor (HMMR) were associated with Gleason score and disease outcome.</p

Transcript levels for CCNB1, DLG7, and HMMR measured in CaP and noncancerous prostate tissue.

<p>Panels on the left compare transcript levels in CaP bulk tissue (full symbols) with the levels measured in benign prostate tissue (open symbols) from men free of CaP (BP) and in benign prostate tissue (BPC) adjacent to CaP of combined Gleason score 6 (gs6). Panels on the right display transcript levels measured in non-neoplastic prostate epithelial cells isolated by laser capture microdissection (LCM) in benign tissues (open symbols): BP, benign prostatic hyperplasia (BPH) and BPC adjacent to CaP of the indicated Gleason score (gs). Full symbols in panels on the right denote transcript levels measured in LCM-isolated CaP cells: high-grade prostatic intraepithelial neoplasia (HGPIN), the cells isolated from areas of combined Gleason scores 6 through 8 and cells isolated from lymph node metastases (met). CCNB1, cyclin B1; DLG7, discs large homolog 7; HMMR, hyaluronan-mediated motility receptor.</p