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71.
Guotao Fan Zelin Li Shi Shen Yi Zeng Yishu Yang Minjuang Xu Torsten Bruhn Heike Bruhn Joachim Morschhäuser Gerhard Bringmann Wenhan Lin 《Bioorganic & medicinal chemistry》2010,18(15):5466-5474
Fifteen new DOPA-derived pyrrole alkaloids, named baculiferins A–O (2–16), were isolated from the Chinese marine sponge Iotrochota baculifera, together with the known alkaloids purpurone (1) and ningalin A (17). Most of the new compounds contain one to three O-sulfate units. Their structures were determined by extensive spectroscopic analysis including 1H and 13C NMR (COSY, HMQC, HMBC) and ESIMS data. A possible pathway for the biosynthetic origin of the isolated alkaloids is proposed, in which DOPA is assumed to be a joint biogenetic precursor. Baculiferins C, E–H, and K–N (4, 6–9, 12–15) were found to be potent inhibitors against the HIV-1 IIIB virus in both, MT4 and MAGI cells. Additional bioassay revealed that baculiferins could dramatically bind to the HIV-1 target proteins Vif, APOBEC3G, and gp41, for which structure–activity relationships are discussed. 相似文献
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Phosphorylation of the amino terminus of maize sucrose synthase in relation to membrane association and enzyme activity 下载免费PDF全文
Sucrose synthase (SUS) is phosphorylated on a major, amino-terminal site located at Ser-15 (S15) in the maize (Zea mays) SUS1 protein. Site- and phospho-specific antibodies against a phosphorylated S15 (pS15) peptide allowed direct analysis of S15 phosphorylation in relation to membrane association. Immunoblots of the maize leaf elongation zone, divided into 4-cm segments, demonstrated that the abundance of soluble (s-SUS) and membrane (m-SUS) SUS protein showed distinct positional profiles. The content of m-SUS was maximal in the 4- to 8-cm segment where it represented 9% of total SUS and occurred as a peripheral membrane protein. In contrast, s-SUS was highest in the 12- to 16-cm segment. Relative to s-SUS, m-SUS was hypophosphorylated at S15 in the basal 4 cm but hyperphosphorylated in apical segments. Differing capabilities of the anti-pS15 and anti-S15 peptide antibodies to immunoprecipitate SUS suggested that phosphorylation of S15, or exposure of unphosphorylated SUS to slightly acidic pH, altered the structure of the amino terminus. These structural changes were generally coincident with the increased sucrose cleavage activity that occurs at pH values below 7.5. In vitro S15 phosphorylation of the S170A SUS protein by a maize calcium-dependent protein kinase (CDPK) significantly increased sucrose cleavage activity at low pH. Collectively, the results suggest that (1) SUS membrane binding is controlled in vivo; (2) relative pS15 content of m-SUS depends on the developmental state of the organ; and (3) phosphorylation of S15 affects amino-terminal conformation in a way that may stimulate the catalytic activity of SUS and influence membrane association. 相似文献
75.
UV effects that come and go: a global comparison of marine benthic community level impacts 总被引:2,自引:0,他引:2
Martin Wahl Markus Molis rew Davis† Sergey Dobretsov‡ Simone T. Dürr† Josefin Johansson§ Jeff Kinley† David Kirugara¶ Matthias Langer Heike K. Lotze Martin Thiel Jeremy C. Thomason†† Boris Worm Dafna Zeevi Ben-Yosef‡‡ 《Global Change Biology》2004,10(12):1962-1972
Ambient UV radiation has substantially increased during the last decades, but its impact on marine benthic communities is hardly known. The aim of this study was to globally compare and quantify how shallow hard‐bottom communities are affected by UV during early succession. Identical field experiments in 10 different coastal regions of both hemispheres produced a consistent but unexpected pattern: (i) UV radiation affected species diversity and community biomass in a very similar manner, (ii) diversity and biomass were reduced to a larger extent by UVA than UVB radiation, (iii) ambient UV levels did not affect the composition of the communities, and (iv) any UV effects disappeared during species succession after 2–3 months. Thus, current levels of UV radiation seem to have small, predictable, and transient effects on shallow marine hard‐bottom communities. 相似文献
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Martina Wendel Anna Petzold Roland Koslowski Michael Kasper Antje Augstein Lilla Knels Jörg-Uwe Bleyl Thea Koch 《Histochemistry and cell biology》2000,122(5):507-517
Pulmonary fibrosis is characterized by excessive extracellular matrix deposition with concomitant loss of gas exchange units, and endothelin-1 (ET-1) has been implicated in its pathogenesis. Increased levels of ET-1 from tissues and bronchoalveolar lavage have been reported in patients with pulmonary fibrosis and in animal models after intratracheal bleomycin. We characterized the cellular distribution of alveolar ET receptors by immunohistochemistry in bleomycin-induced pulmonary fibrosis in the rat and determined the regulation by bleomycin of ET receptor mRNA expression in isolated alveolar macrophages and rat lung fibroblasts. We found significant increases in the numbers of fibroblasts and macrophages at day 7 compared to day 28 and control animals. ETB receptor immunoreactivity was observed on fibroblasts and invading monocytes. Isolated fibroblasts expressed both ETA and ETB receptor mRNA, and ETA receptor mRNA was upregulated by bleomycin. Isolated resident alveolar macrophages expressed neither ETA nor ETB receptor mRNA which were also not induced by bleomycin. We conclude that, while ETB receptor stimulation of fibroblasts and monocytes recruited during bleomycin-induced lung injury exerts antagonistic effects on fibroblast collagen synthesis, the observed increase in the number of fibroblasts in vivo and upregulation of fibroblast ETA receptor mRNA by bleomycin in vitro point to a predominance of the profibrotic effects of ET receptor engagement. 相似文献
78.
Clemens G. Borkenstein Josef Knoblechner Heike Frühwirth Michael Schagerl 《Journal of applied phycology》2011,23(1):131-135
The present study reviews the options of cultivating the green alga, Chlorella emersonii, under photoautotrophic conditions with flue gas derived from a cement plant. It was conducted in the Lafarge Perlmooser
plant in Retznei, Austria, where stone coal and various surrogate fuels such as used tyres, plastics and meat-and-bone meal
are incinerated for heating limestone. During 30 days of cultivation, flue gas had no visible adverse effects compared to
the controls grown with pure CO2. The semi-continuous cultivation with media recycling was performed in 5.5-L pH-stat photobioreactors. The essay using CO2 from flue gas yielded a total of 2.00 g L−1 microalgal dry mass and a CO2 fixation of 3.25 g L−1. In the control, a total of 2.06 g L−1 dry mass was produced and 3.38 g L−1 CO2 was fixed. Mean growth rates were between 0.10 day−1 (control) and 0.13 day−1 (flue gas). No accumulation of flue gas residues was detected in the culture medium. At the end of the experiment, however,
the concentration of lead was three times higher in algal biomass compared to the control, indicating that cultures aerated
with this type of flue gas should not be used as food supplements or animal feed. 相似文献
79.
Anna Delprato Ana M. Aransay Heike Kollmus Klaus Schughart Juan M. Falcon-Perez 《Mammalian genome》2013,24(5-6):190-197
The second scientific meeting of the European systems genetics network for the study of complex genetic human disease using genetic reference populations (SYSGENET) took place at the Center for Cooperative Research in Biosciences in Bilbao, Spain, December 10–12, 2012. SYSGENET is funded by the European Cooperation in the Field of Scientific and Technological Research (COST) and represents a network of scientists in Europe that use mouse genetic reference populations (GRPs) to identify complex genetic factors influencing disease phenotypes (Schughart, Mamm Genome 21:331–336, 2010). About 50 researchers working in the field of systems genetics attended the meeting, which consisted of 27 oral presentations, a poster session, and a management committee meeting. Participants exchanged results, set up future collaborations, and shared phenotyping and data analysis methodologies. This meeting was particularly instrumental for conveying the current status of the US, Israeli, and Australian Collaborative Cross (CC) mouse GRP. The CC is an open source project initiated nearly a decade ago by members of the Complex Trait Consortium to aid the mapping of multigenetic traits (Threadgill, Mamm Genome 13:175–178, 2002). In addition, representatives of the International Mouse Phenotyping Consortium were invited to exchange ongoing activities between the knockout and complex genetics communities and to discuss and explore potential fields for future interactions. 相似文献
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