The Phosphorus Economy of Mediterranean Oak Saplings Under Global Change

While a severe decrease in phosphorus (P) availability is already taking place in a large number of ecosystems, drought and nitrogen (N) deposition will likely further decrease the availability of P under global change. Plants have developed physiological strategies to cope with decreasing P resources, but it is unclear how these strategies respond to elevated N deposition and summer droughts. We investigated the influence of N and P availability and soil drought on P uptake (H333PO4 feeding experiment) and use efficiencies in young Quercus calliprinos Webb. trees. We hypothesized that (H1) the expected increases in soil N:P ratios will increase the efficiencies of P uptake and use of oak saplings but will decrease the efficiencies of N uptake and use, whereas (H2) drought will affect P uptake efficiency more than N uptake efficiency. In confirmation of (H1) we found that a sharp increase of the soil N:P ratio from 4 to 42 g g-1 significantly increased the instantaneous 33P uptake efficiency (33PUptakeE) by five-fold and long-term P uptake efficiency (PUptakeE) by six-fold, while it decreased N uptake efficiency (NUptakeE) and N use efficiency (NUE). In contradiction to (H1), P use efficiency (PUE) did not respond to the simulated extended gradient of soil N:P ratios but remained relatively constant. (H2) was only partially confirmed as soil drought reduced PUptakeE by up to a fourth at high soil N:P ratios but had no significant effect on NUptakeE. As a consequence, increasing summer droughts may decrease the response of PUptakeE to increasing P limitation, which – in the absence of adjustments of the efficiency of P use – can aggravate growth reductions in this eastern Mediterranean tree species under global change

Reassessing evidence of Moon–Earth dynamics from tidal bundles at 3.2 Ga (Moodies Group, Barberton Greenstone Belt, South Africa)

Past orbital parameters of the Moon are difficult to reconstruct from geological records because relevant data sets of tidal strata are scarce or incomplete. The sole Archean data point is from the Moodies Group (ca 3.22 Ga) of the Barberton Greenstone Belt, South Africa. From the time-series analysis of tidal bundles from a well-exposed subaqueous sand wave of this unit, Eriksson and Simpson (Geology, 28, 831) suggested that the Moon’s anomalistic month at 3.2 Ga was closer to 20 days than the present 27.5 days. This is in apparent accordance with models of orbital mechanics which place the Archean Moon in a closer orbit with a shorter period, resulting in stronger tidal action. Although this study’s detailed geological mapping and section measuring of the site confirmed that the sandstone bed in question is likely a migrating dune, the presence of angular mud clasts, channel-margin slumps, laterally aggrading channel fills and bidirectional paleocurrents in overlying and underlying beds suggests that this bedform was likely located in a nearshore channel near lower-intertidal flats and subtidal estuarine bars; it thus carries risk of incomplete preservation. Repeated measurements of foreset thicknesses along the published traverse, measured perpendicular to bedding, failed to show consistent spectral peaks. Larger data sets acquired along traverses measured parallel to bedding along the 20.5 m wide exposure are affected by minor faulting, uneven outcrop weathering, changing illumination, weather, observer bias and show a low reproducibility. The most robust measurements herein confirm the periodicity peak of approximately 14 in the original data of Eriksson and Simpson (Geology, 28, 831). Because laminae may have been eroded, the measurements may represent a lower bound of about 28 lunar days per synodic month. This estimate agrees well with Earth–Moon dynamic models which consider the conservation of angular momentum and place the Archaean Moon in a lower orbit around a faster-spinning Earth

Reassessing evidence of Moon–Earth dynamics from tidal bundles at 3.2 Ga (Moodies Group, Barberton Greenstone Belt, South Africa)

Past orbital parameters of the Moon are difficult to reconstruct from geological records because relevant data sets of tidal strata are scarce or incomplete. The sole Archean data point is from the Moodies Group (ca 3.22 Ga) of the Barberton Greenstone Belt, South Africa. From the time-series analysis of tidal bundles from a well-exposed subaqueous sand wave of this unit, Eriksson and Simpson (Geology, 28, 831) suggested that the Moon’s anomalistic month at 3.2 Ga was closer to 20 days than the present 27.5 days. This is in apparent accordance with models of orbital mechanics which place the Archean Moon in a closer orbit with a shorter period, resulting in stronger tidal action. Although this study’s detailed geological mapping and section measuring of the site confirmed that the sandstone bed in question is likely a migrating dune, the presence of angular mud clasts, channel-margin slumps, laterally aggrading channel fills and bidirectional paleocurrents in overlying and underlying beds suggests that this bedform was likely located in a nearshore channel near lower-intertidal flats and subtidal estuarine bars; it thus carries risk of incomplete preservation. Repeated measurements of foreset thicknesses along the published traverse, measured perpendicular to bedding, failed to show consistent spectral peaks. Larger data sets acquired along traverses measured parallel to bedding along the 20.5 m wide exposure are affected by minor faulting, uneven outcrop weathering, changing illumination, weather, observer bias and show a low reproducibility. The most robust measurements herein confirm the periodicity peak of approximately 14 in the original data of Eriksson and Simpson (Geology, 28, 831). Because laminae may have been eroded, the measurements may represent a lower bound of about 28 lunar days per synodic month. This estimate agrees well with Earth–Moon dynamic models which consider the conservation of angular momentum and place the Archaean Moon in a lower orbit around a faster-spinning Earth

The genomes of two key bumblebee species with primitive eusocial organization

Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation

Evaluation of ergoline derivatives with antiplasmodial activity and in vitro bioactivity-guided fractionation of tropical medicinal plants traditionally used as antimalarials

0 Titelblatt 1 Einleitung 1.1 Malaria 1.2 Exostema mexicanum GRAY (Rubiaceae) 1.3 Calea tenuifolia KUNTH (Asteraceae) 1.4 Microglossa pyrifolia (LAM.) KUNTZE (Asteraceae) 1.5 Natürliche und semisynthetische Ergolinderivate 1.6 Zielsetzung 2 Hauptteil 2.1 Screening verschiedener Heilpflanzen aus El Salvador 2.2 Screening verschiedener Heilpflanzen aus Ghana 2.3 Exostema mexicanum GRAY 2.4 Calea tenuifolia KUNTH 2.5 Microglossa pyrifolia (LAM.) KUNTZE 2.6 Berechnung des log P-Wertes und log D-Wertes 2.7 Untersuchung weiterer Pflanzenextrakte 2.8 Untersuchung von monomeren Ergolinen und ihren semisynthetischen N, N'-verknüpften oligomeren Derivaten 3 Diskussion 3.1 Untersuchungen von Exostema mexicanum GRAY (Rubiaceae) 3.2 Untersuchungen von Calea tenuifolia KUNTH (Asteraceae) 3.3 Untersuchungen von Microglossa pyrifolia (LAM.) KUNTZE (Asteraceae) 3.4 Bedeutung von Heilpflanzen in der traditionellen Malariatherapie 3.5 Antiplasmodiale Wirkung von monomeren Ergolinen und ihren semisynthetischen N, N'-verknüpften oligomeren Derivaten 3.6 Ausblick 4 Zusammenfassung 5 Experimenteller Teil 5.1 Pflanzenmaterial 5.2 In-vitro-Testsystem gegen Plasmodium falciparum 5.3 Untersuchung zur Zytotoxizität 5.4 Log P- und log D-Wert-Berechnung 5.5 Phytochemische Methoden 5.6 Isolierung der Verbindungen aus aktiven Fraktionen von Exostema mexicanum 5.7 Eigenschaften der isolierten Verbindungen aus den Zweigen und der Stammrinde von Exostema mexicanum 5.8 Isolierung der Verbindungen aus aktiven Fraktionen von Calea tenuifolia 5.9 Eigenschaften der isolierten Verbindungen aus den Blättern von Calea tenuifolia 5.10 Isolierung der Verbindungen aus aktiven Fraktionen von Microglossa pyrifolia 5.11 Eigenschaften der isolierten Verbindungen aus M. pyrifolia 5.12 Synthese von 19-Hydroxy-6E,10E,14E-geranylgeraniol (32) 5.13 Untersuchung weiterer Pflanzendrogenextrakte 5.14 Synthese der semisynthetischen N,N'-verknüpften Ergolinoligomere 6 Abkürzungsverzeichnis 7 Literatur 8 AnhängeEs wurden zentralamerikanische und westafrikanische Heilpflanzen untersucht, deren Anwendung in der traditionellen Malariatherapie aufgrund von Literaturdaten bzw. ethnobotanischen Informationen bekannt war. Von acht Pflanzenarten El Salvadors und elf pflanzlichen Drogen Ghanas, die jeweils in der landeseigenen traditionellen Phytotherapie angewendet werden, wurden aus verschiedenen Pflanzenteilen Rohextrakte unterschiedlicher Polaritaet hergestellt. Diese Extrakte wurden einem in-vitro-Testsystem zugefuehrt um deren Hemmwirkung gegenueber dem Chloroquin-sensiblen Stamm PoW und dem Chloroquin-resistenten Klon Dd2 von Plasmodium falciparum zu bestimmen. Aufgrund der gezeigten antiplasmodialen Aktivitaet wurden die Rindendroge von Exostema mexicanum GRAY (Rubiaceae), die Blattdroge von Calea tenuifolia KUNTH (Asteraceae) und die oberirdischen Pflanzenteile von Microglossa pyrifolia (LAM.) KUNTZE (Asteraceae) im Sinne einer aktivitaetsgeleiteten Fraktionierung untersucht. Aus aktiven Fraktionen von E. mexicanum wurden sieben 4-Phenylcumarine erhalten. Bei 4',5,7,8-Tetramethoxy-4-phenylcumarin [O -Methyl-exostemin], 4',8-Dihydroxy-5,7-dimethoxy-4-phenylcumarin [Exomexin A] und 3',4'-Dihydroxy-5,7,8-trimethoxy-4-phenylcumarin [Exomexin B] handelt es sich um neue Naturstoffe. Die hoechste antiparasitaere Hemmwirkung besass O -Methyl-exostemin (IC50-Werte: 10,5 µM [PoW] und 4,7 µM [Dd2]). Zusaetzlich wurde von allen aktiven Verbindungen der zytotoxische Effekt an der humanen Endothelzelllinie ECV 304 untersucht. Hierbei zeigten die getesteten 4-Phenylcumarine eine signifikante zytotoxische Aktivitaet mit IC50-Werten zwischen 1,2 µM und 10,0 µM. Alle erhaltenen in-vitro-Daten deuten daraufhin, dass eine uneingeschraenkte phytotherapeutische Anwendung von E. mexicanum nicht empfohlen werden kann. Aus aktiven Fraktionen von C. tenuifolia konnten fuenf Flavone und zwei ungesaettigte Fettsaeuren isoliert werden, die alle eine antiplasmodiale in-vitro-Aktivitaet aufwiesen. Die hoechste Hemmwirkung gegenueber dem Parasiten zeigte 7-Methylacacetin (IC50-Werte: 20,1 µM [PoW] und 17,1 µM [Dd2]). Alle Inhaltsstoffe wurden dem in-vitro-Zytotoxizitaetstest an der humanen Endothelzelllinie ECV 304 zugefuehrt. Anhand der erhaltenen in- vitro-Daten kann die phytotherapeutische Relevanz von C. tenuifolia nicht vollstaendig bewertet werden. Jedoch konnte die antiplasmodiale Aktivitaet der zentralamerikanischen Heilpflanze in vitro bestaetigt werden. Die aktivitaetsgeleitete Fraktionierung von M. pyrifolia fuehrte zur Isolierung von achtzehn Inhaltsstoffen, u.a. verschiedene Furanoditerpene und Geranylgeraniol-Derivate. Bei Sinapyldiangelat und 1-Acetyl-6E,10E,14E- geranylgeraniol-19-carbonsaeure und 19-Oxo-6E,10E,14E-geranylgeraniol handelt es sich um neue Naturstoffe. Die hoechste Hemmwirkung gegenueber P. falciparum wiesen 2E-Phytol und 6E,10E,14E-Geranylgeraniol-19-carbonsaeure auf (IC50-Werte zwischen 8,4 µM [PoW] und 16,3 µM [Dd2]). Die aktiven Verbindungen besassen eine geringe Zytotoxizitaet gegenueber ECV 304 mit IC50-Werten zwischen 95,6 µM und 200,2 µM bzw. erwiesen sich als nicht zytotoxisch. Im Laufe der Untersuchungen an M. pyrifolia konnte die antiplasmodiale in-vitro- Aktivitaet der Droge nachgewiesen werden. In einer weiteren Studie wurde die antiparasitaere in-vitro-Wirkung von monomeren Ergolinen und semi- synthetischen N,N'-verknuepften Oligomeren, mit Festuclavin, Tergurid und Pergolid als Monomer, bestimmt. Die Ergebnisse zeigten, dass eine N?1,N?1'- bzw. eine N-6,N-6'-Dimerisierung zu einer Erhoehung der antiplasmodialen Aktivitaet fuehrte. Fuer ein N-6,N-6'-verknuepftes Dimer mit Depropylpergolid als Monomer wurde die staerkste Hemmwirkung festgestellt (IC50-Werte: 0,14 µM [PoW] und 0,13 µM [Dd2]). Von allen Verbindungen wurde zusaetzlich der zytotoxische Effekt an der murinen Fibroblastenzelllinie NIH 3T3 bestimmt. Fuer weitergehende Untersuchungen sind ein N-1,N-1'-verknuepftes Tergurid- Tetramer und ein N-1,N-1'-substituiertes Festuclavin-Trimer von Interesse. Beide Verbindungen erwiesen sich als nicht zytotoxisch bei einer gleichzeitig guten antiplasmodialen Wirkung mit IC50-Werten zwischen 0,54 µM [Dd2] und 1,53 µM [Dd2].Malaria is still the most dangerous parasitic infectious disease causing millions of deaths every year. In many countries where Malaria is endemic the traditional medical methods constitute a strong part in the public health care system. Phytochemical research on medicinal plants traditionally used as antimalarials are urgently needed. In this context we looked at several Central American and West African medicinal plants, which are traditionally used against malaria and/or symptoms of the disease. Analysis of all plant species was based on literature and/or ethnobotanical studies. We produced plant extracts of different polarity from various plant parts of eight species from El Slavador and eleven species from Ghana, which are still used in the Central American and West African traditional phytotherapy, All extracts were tested for their in vitro actvity against a Chloroquine-sensitive strain PoW and a Chloroquine-resistent clone Dd2 of Plasmodium falciparum. The stem bark from Exostema mexicanum Gray (Rubiaceae), the leaves from Calea tenuifolia Kunth (Asteraceae), and the aerial parts from Microglossa pyrifolia (Lam.) Kuntze (Asteraceae) exhibited a promising antiplasmodial activity. Thus bioactivity-guided fractionations were carried out in order to isolate and characterize the major antiprotozoan principles of this species. Further purification of the active lipophilic extract (petrol ether/ methanol 1:1) and the methanolic extract of E. mexicanum led to the isolation of seven 4-phenylcoumarines, with 4',5,7,8-tetramethoxy-4-phenylcoumarin [O-methyl- exostemin], 4',8-dihydroxy-5,7-dimethoxy-4-phenylcoumarin [exomexin A], and 3',4'-dihydroxy-5,7,8-trimethoxy-4-phenylcoumarin [exomexin B] as new natural compounds. O-Methyl-exostemin showed a significant activity against P. falciparum (IC50-values: 10.5 µM [PoW] and 4.7 µM [Dd2]). Additionally, of all active compounds the cytotoxic effect on the human endothelium cell line (ECV 304) in vitro were assessed. Here, all tested 4-phenylcoumarines exhibited a significant cytotoxic activity with IC50-values between 1,2 µM and 10,0 µM. Given this result, the unrestricted use of the E. mexicanum as an ethnomedicinal substance cannot be recommended based. Bioactivity-guided fractionation of the lipophilic leaf extract of C. tenuifolia led to the isolation of five flavones and two unsaturated fatty acids. All compounds showed activities against P. falciparum, with 7-methylacacetin exhibiting the strongest inhibition of the parasite (IC50-values: 20.1 µM [PoW] and 17.1 µM [Dd2]). All seven compounds were also tested on the human endothelium cell line (ECV 304). Based on our results, we cannot completely assess the antiplasmodial potential of this plant species. However our findings may represent a rational explanation for a potential antimalarial effect of the leaves of C. tenuifolia. Bioactivity-guided fractionation of the aerial parts of M. pyrifolia lead to the isolation of 18 natural compounds, e.g. different furanoditerpenes and geranylgeraniol derivatives. Sinapyl diangelate, 1 -acetyl-6E, 10E, 14E-geranylgeraniol-19-oic acid and 19-oxo-6E, 10E, 14E- geranylgeraniol were identified as new natural compounds. The strongest inhibition of P. falciparum could be observed for 2E- phytol and 6E, 10E, 14E- geranylgeraniol-19-oic acid with IC50-values ranging from 8.4 µM [PoW] to 16.3 µM [Dd2]. All active compounds showed only a weak cytotoxic effect on ECV 304 with IC50-values between 95.6 µM and 200.2 µM, or they were not cytotoxic. From several active fractions we isolated 6E, 10E, 14E-geranylgeraniol-19-oic acid. This diterpene was also detectable in the aqueous extract despite of its rather lipophilic character. Therefore, we assume that the aliphatic unsaturated compounds are representing the antiprotozoan principle of this species, and 6E, 10E, 14E -geranylgeraniol-19-oic acid supposed to be mainly responsible for a moderate antiplasmodial activity of a traditional plant preparation of M. pyrifolia. During another study, the three monomeric ergolines terguride, festuclavine, pergolide, and their N, N'-spacer-linked oligomeric derivatives have been investigated for their in vitro activity against P. falciparum. All monomers have shown only a weak antiplasmodial effect, but either N-1, N-1'- or N-6, N-6'-spacer-linked dimerization are able to enhance their antiparasitic activity. A N-6, N-6?-spacer-linked depropylpergolide dimer exhibited the highest activities with IC50-values of 0.14 µM and 0.13 µM against PoW and Dd2, respectively. Additionally from all tested compounds the cytotoxic effects against mouse fibroblasts (NIH 3T3) in vitro were evaluated. For further studies a N-1, N-1'-spacer-linked festuclavine trimer and a N-1, N-1'-spacer-linked terguride tetramer are interesting. Both compounds were not cytotoxic and possessed good aniplasmodial activities with IC50-values between 0.54 µM and 1.53 µM against Dd2

Phasor analysis reveals multicomponent fluorescence kinetics in the LH2 complex from Marichromatium purpuratum

We investigated the fluorescence kinetics of LH2 complexes from Marichromatium purpuratum, the cryo-EM structure of which has been recently elucidated with 2.4 Å resolution. The experiments have been carried out as a function of the excitation density by varying both the excitation fluence and the repetition rate of the laser excitation. Instead of the usual multiexponential fitting procedure, we applied the less common phasor formalism for evaluating the transients because this allows for a model-free analysis of the data without a priori knowledge about the number of processes that contribute to a particular decay. For the various excitation conditions, this analysis reproduces consistently three lifetime components with decay times below 100 ps, 500 ps, and 730 ps, which were associated with the quenched state, singlet-triplet annihilation, and fluorescence decay, respectively. Moreover, it reveals that the number of decay components that contribute to the transients depends on whether the excitation wavelength is in resonance with the B800 BChl a molecules or with the carotenoids. Based on the mutual arrangement of the chromophores in their binding pockets, this leads us to conclude that the energy transfer pathways within the LH2 complex of this species differ significantly from each other for exciting either the B800 BChl molecules or the carotenoids. Finally, we speculate whether the illumination with strong laser light converts the LH2 complexes studied here into a quenched conformation that might be related to the development of the non-photochemical quenching mechanism that occurs in higher plants