Similarity between contemporary vegetation and plant remains in the surface sediment in Mediterranean lakes

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Angiogenic factors in women ten years after severe very early onset preeclampsia

Background

Women with a history of mainly severe and early onset preeclampsia have an increased risk of future cardiovascular disease. During these complicated pregnancies increased levels of anti-angiogenic factors can be found. We hypothesize that women with a history of severe very early onset preeclampsia still have increased levels of these biomarkers years after this pregnancy, resulting in increased risk for cardiovascular disease.

Methods

Twenty women with severe early onset preeclampsia before 24 weeks'' gestation, who delivered between 1993–2003 in a tertiary referral centre and twenty matched controls with uncomplicated pregnancies and healthy term infants, were addressed for participation in the study. Venous plasma samples were analyzed for basic fibroblast growth factor (bFGF), placental growth factor (PLGF), soluble fms-like tyrosine kinase-1 (sFlt-1), vascular endothelial growth factor (VEGF), E- and P-selectin, soluble intercellular adhesion molecule-3 (sICAM-3) and thrombomodulin by ELISA.

Results

Sixteen case subjects and 18 control subjects consented participation. The median time interval index pregnancy to study was 9.4 and 9.7 years for cases and controls, respectively. Median levels for cases-controls (p-value) were not different; bFGF: 17.43–11.11 pg/mL (0.33), sFlt-1: 102.98–101.92 pg/ml (0.84), PLGF: 3.57–4.20 pg/mL (0.38), VEGF: 64.05–45.72 pg/mL (0.73), E-selectin: 5.11–4.68 ng/mL (0.20), P-selectin: 85.35–71.69 ng/mL (0.69), sICAM-3: 0.42–0.63 ng/mL (0.41) and Thrombomodulin: 0.92–0.93 ng/mL (0.59).

Conclusion

There were no differences in angiogenic biomarkers between women with a history of severe early onset preeclampsia versus uncomplicated pregnancy almost 10 years later, suggesting that these angiogenic factors will not contribute to the early detection of women at risk for future cardiovascular disease.     

High-resolution mapping by YAC fragmentation of a 2.5-Mb Xp22 region containing the human RS, KFSD and CLS disease genes

The disease loci for X-linked Retinoschisis (RS), Keratosis follicularis spinulosa decalvans (KFSD), and Coffin-Lowry syndrome (CLS) have been localized to the same, small region in Xp22 on the human X Chromosome (Chr). To generate a high-resolution map of the available contig in this area, we have used the YAC fragmentation vectors pBP108/ADE2 and pBP109/ADE2 and generated fragmented YACs from a 2.5-Mb YAC (y939H7) spanning the mentioned disease gene candidate regions. Forty-seven fragmented YACs were generated and analyzed, ranging in size from 170 kb to over 2400 kb. The resulting YAC fragmentation panel was used to construct a detailed restriction map of the region and has been used to bin clones and markers. As a deletion panel, it will present a valuable resource for further mapping. Received: 31 December 1996 / Accepted: 22 February 1997     

Steady-state kinetics of the glutaminase reaction of CTP synthase from Lactococcus lactis. The role of the allosteric activator GTP incoupling between glutamine hydrolysis and CTP synthesis.

CTP synthase catalyzes the reaction glutamine + UTP + ATP --> glutamate + CTP + ADP + Pi. The rate of the reaction is greatly enhanced by the allosteric activator GTP. We have studied the glutaminase half-reaction of CTP synthase from Lactococcus lactis and its response to the allosteric activator GTP and nucleotides that bind to the active site. In contrast to what has been found for the Escherichia coli enzyme, GTP activation of the L. lactis enzyme did not result in similar kcat values for the glutaminase activity and glutamine hydrolysis coupled to CTP synthesis. GTP activation of the glutaminase reaction never reached the levels of GTP-activated CTP synthesis, not even when the active site was saturated with UTP and the nonhydrolyzeable ATP-binding analog adenosine 5'-[gamma-thio]triphosphate. Furthermore, under conditions where the rate of glutamine hydrolysis exceeded that of CTP synthesis, GTP would stimulate CTP synthesis. These results indicate that the L. lactis enzyme differs significantly from the E. coli enzyme. For the E. coli enzyme, activation by GTP was found to stimulate glutamine hydrolysis and CTP synthesis to the same extent, suggesting that the major function of GTP binding is to activate the chemical steps of glutamine hydrolysis. An alternative mechanism for the action of GTP on L. lactis CTP synthase is suggested. Here the binding of GTP to the allosteric site promotes coordination of the phosphorylation of UTP and hydrolysis of glutamine for optimal efficiency in CTP synthesis rather than just acting to increase the rate of glutamine hydrolysis itself.     

The influence of crop rotation on the onset of early blight (Alternaria solani)

Field experiments were carried out in 2016 and 2017 to determine the effect of crop rotation on the onset of early blight in three potato varieties in Denmark. Six and seven fields with different histories with potato (rotation‐fields) were used for the experiments in 2016 and 2017, respectively. The results showed that variety and the interaction between variety and rotation‐field had no significant effect on the onset of early blight. Rotation‐field, on the other hand, had a significant effect on the onset of early blight in both years of the study. Early blight occurred earlier in fields with <2 years between subsequent potato crops than in fields where potatoes have not been grown for at least 2 years. The onset of early blight was not different between the fields where there had not been potatoes for at least 2 years. For fields that were preceded by potatoes, early blight occurred earlier in fields in which the severity of early blight in the previous years was higher than that in the fields in which the severity of early blight in the previous years was low or moderate. In conclusion, the results of this study suggest that at least a 2‐year interval between subsequent potatoes in a rotation cycle is necessary to delay the onset of early blight. Moreover, the severity of early blight in the previous years can affect the onset of early blight.     

Interfacial Effects of Tin Oxide Atomic Layer Deposition in Metal Halide Perovskite Photovoltaics

Metal halide perovskites offer a wide and tunable bandgap, making them promising candidates for top‐cell absorbers in tandem photovoltaics. In this work, the authors aim to understand the atomic layer deposition (ALD) precursor–perovskite interactions of the tin oxide ALD system and the role of organic fullerenes at the perovskite–tin oxide interface while establishing a framework for developing alternative perovskite‐compatible ALD processes in the future. It is shown, in the case of tin oxide ALD growth with tetrakis(dimethylamino)tin(IV) and water on FA_0.83Cs_0.17Pb(I_0.83Br_0.17)₃ perovskite, that perovskite stability is most sensitive to metal–organic exposure at elevated temperatures with an onset near 110 °C, resulting in removal of the formamidinium cation. Transitioning from ALD to pulsed‐chemical vapor deposition tin oxide growth can minimize the degradation effects. Investigation of fullerenes at the perovskite interface shows that thin fullerene layers offer minor improvements to perovskite stability under ALD conditions, but significant enhancement in carrier extraction. Fullerene materials are undesirable due to fabrication cost and poor mechanical stability. Compositional tuning of the perovskite material can improve the fullerene‐free device performance. This method is demonstrated with a bromine‐rich perovskite phase to enable an 8.2% efficient perovskite device with all‐inorganic extraction layers.     

Structures of dCTP deaminase from Escherichia coli with bound substrate and product: reaction mechanism and determinants of mono- and bifunctionality for a family of enzymes

dCTP deaminase (EC 3.5.4.13) catalyzes the deamination of dCTP forming dUTP that via dUTPase is the main pathway providing substrate for thymidylate synthase in Escherichia coli and Salmonella typhimurium. dCTP deaminase is unique among nucleoside and nucleotide deaminases as it functions without aid from a catalytic metal ion that facilitates preparation of a water molecule for nucleophilic attack on the substrate. Two active site amino acid residues, Arg(115) and Glu(138), were identified by mutational analysis as important for activity in E. coli dCTP deaminase. None of the mutant enzymes R115A, E138A, or E138Q had any detectable activity but circular dichroism spectra for all mutant enzymes were similar to wild type suggesting that the overall structure was not changed. The crystal structures of wild-type E. coli dCTP deaminase and the E138A mutant enzyme have been determined in complex with dUTP and Mg(2+), and the mutant enzyme also with the substrate dCTP and Mg(2+). The enzyme is a third member of the family of the structurally related trimeric dUTPases and the bifunctional dCTP deaminase-dUTPase from Methanocaldococcus jannaschii. However, the C-terminal fold is completely different from dUTPases resulting in an active site built from residues from two of the trimer subunits, and not from three subunits as in dUTPases. The nucleotides are well defined as well as Mg(2+) that is tridentately coordinated to the nucleotide phosphate chains. We suggest a catalytic mechanism for the dCTP deaminase and identify structural differences to dUTPases that prevent hydrolysis of the dCTP triphosphate.     

Proteome profiles of mucosal immunoglobulin uptake in inflamed porcine gut

Acquisition of passive immunity by endocytosis of intact immunoglobulins (Ig) from colostrum is critical for prevention of intestinal and systemic diseases in neonatal mammals. We compared proteome patterns of healthy and inflamed gut tissues from pre-term piglets to investigate the effect of inflammation on acquisition of passive immunity. A clear difference in the two-dimensional gel electrophoresis protein patterns between healthy and inflamed intestinal tissues was observed, suggesting that inflamed tissues failed to absorb and transfer Ig from colostrum to epithelial cells. We have mapped and identified the Ig proteins that are taken up by healthy intestinal tissues, and found that isoforms of the IgA and IgG heavy chain and Ig kappa and lambda light chains were internalized. Our results indicate that colostrum protein uptake in the porcine gut is a selective process that is obstructed in inflamed pre-term gut.     

Atomic Layer Deposition of CdS Quantum Dots for Solid‐State Quantum Dot Sensitized Solar Cells

Functioning quantum dot (QD) sensitized solar cells have been fabricated using the vacuum deposition technique atomic layer deposition (ALD). Utilizing the incubation period of CdS growth by ALD on TiO₂, we are able to grow QDs of adjustable size which act as sensitizers for solid‐state QD‐sensitized solar cells (ssQDSSC). The size of QDs, studied with transmission electron microscopy (TEM), varied with the number of ALD cycles from 1‐10 nm. Photovoltaic devices with the QDs were fabricated and characterized using a ssQDSSC device architecture with 2,2',7,7'‐tetrakis‐(N,N‐di‐p methoxyphenylamine) 9,9'‐spirobifluorene (spiro‐OMeTAD) as the solid‐state hole conductor. The ALD approach described here can be applied to fabrication of quantum‐confined structures for a variety of applications, including solar electricity and solar fuels. Because ALD provides the ability to deposit many materials in very high aspect ratio substrates, this work introduces a strategy by which material and optical properties of QD sensitizers may be adjusted not only by the size of the particles but also in the future by the composition.