The 10 most recently published documents
Bielefelder Botaniker zu Gast im Kreis Höxter
- Unter Führung des bekannten Bryologen Dr. Fritz Koppe (1896 - 1981), von 1940 bis 1964 Vorsitzender des Naturwissenschaftlichen Vereins für Bielefeld und Umgegend, fand sich eine kleine Gruppe von Spezialisten zusammen, die in wechselnder Zusammensetzung zwischen 1952 und 1959 an Fahrten und Exkursionen in den Kreis Höxter teilgenommen hat. Ihr gehörten an der Paläontologe Dr. Walter Adrian (1906 - 1990), Karl Behrmann (1897 - 1964), der Ornithologe Dr. Klaus Conrads (* 1925), der Geologe Adolf Deppe (1889 - 1965), der Mediziner Dr. Werner Hollborn (1910 - 1984) und der Botaniker Richard Rehm (1900 - 1963). In dieser Gruppe war es üblich, dass einer der Teilnehmer ein Protokoll mit bemerkenswerten Beobachtungen und Arten anfertigte, das den anderen Teilnehmern als Maschinendurchschlag zur Verfügung gestellt wurde. Einige dieser Protokolle, die natürlich keine vollständigen Artenlisten enthalten, wurden mir jetzt erst zugänglich. Sie stammen aus dem Nachlass von Dr. Werner Hollborn, über dessen Herbar bereits an anderer Stelle berichtet wurde (vergl. Lienenbecker & Raabe 1986).
Autophagy during vertebrate development
María Rodriguez Aburto
Juan M. Hurlé
- Autophagy is an evolutionarily conserved catabolic process by which cells degrade their own components through the lysosomal machinery. In physiological conditions, the mechanism is tightly regulated and contributes to maintain a balance between synthesis and degradation in cells undergoing intense metabolic activities. Autophagy is associated with major tissue remodeling processes occurring through the embryonic, fetal and early postnatal periods of vertebrates. Here we survey current information implicating autophagy in cellular death, proliferation or differentiation in developing vertebrates. In developing systems, activation of the autophagic machinery could promote different outcomes depending on the cellular context. Autophagy is thus an extraordinary tool for the developing organs and tissues.
Ein Beitrag zur Moosflora des Kreises Höxter
- Wilhelm Kleinewächter (1904-1976), als Lehrer an verschiedenen Schulen im Kreis Herford tätig, kam durch seine Bekanntschaft mit Koppe 1930 zur Bryologie. Von 1931 bis 1937 und nach dem Kriege bis 1950 hat er zahlreiche Exkursionen mit Koppe unternommen und sich umfassende bryologische Kenntnisse angeeignet. Er hat sehr sorgfältige Exkursionsprotokolle geführt und ein umfangreiches Moosherbarium (ca. 5000 Belege mit zahlreichen von Koppe selbst gesammelten Exsikkaten) angelegt, das sich heute im Westfälischen Museum für Naturkunde in Münster befindet.
Kleinewächter selbst hat seine Daten nicht publiziert, er wird aber immer wieder von Koppe (1934 ff.) als Gewährsmann genannt. Während die Daten zu den Farn- und Blütenpflanzen bereits an anderer Stelle (vergl. Lienenbecker 1990) zusammengefasst wurden, sind in dem folgenden Beitrag alle Fundortangaben der Laub- und Lebermoose, soweit sie im heutigen Kreis Höxter liegen, aus den Exkursionstagebüchern zusammengestellt. In der folgenden Auflistung sind alle 188 Arten aufgeführt, die Kleinewächter in seinen Tagebüchern im Kreis Höxter protokolliert hat.
Do non-genomically encoded fusion transcripts cause recurrent chromosomal translocations?
- We among others have recently demonstrated that normal cells produce “fusion mRNAs”. These fusion mRNAs do not derive from rearranged genomic loci, but rather they are derived from “early-terminated transcripts” (ETTs). Premature transcriptional termination takes place in intronic sequences that belong to “breakpoint cluster regions”. One important property of ETTs is that they exhibit an unsaturated splice donor site. This results in: (1) splicing to “cryptic exons” present in the final intron; (2) Splicing to another transcript of the same gene (intragenic trans-splicing), resulting in “exon repetitions”; (3) splicing to a transcript of another gene (intergenic trans-splicing), leading to “non-genomically encoded fusion transcripts” (NGEFTs). These NGEFTs bear the potential risk to influence DNA repair processes, since they share identical nucleotides with their DNA of origin, and thus, could be used as “guidance RNA” for DNA repair processes. Here, we present experimental data about four other genes. Three of them are associated with hemato-malignancies (ETV6, NUP98 and RUNX1), while one is associated with solid tumors (EWSR1). Our results demonstrate that all genes investigated so far (MLL, AF4, AF9, ENL, ELL, ETV6, NUP98, RUNX1 and EWSR1) display ETTs and produce transpliced mRNA species, indicating that this is a genuine property of translocating genes.
Venomous Secretions from Marine Snails of the Terebridae Family Target Acetylcholine Receptors
- Venoms from cone snails (Conidae) have been extensively studied during the last decades, but those from other members of the suborder Toxoglossa, such as of Terebridae and Turridae superfamilies attracted less interest so far. Here, we report the effects of venom and gland extracts from three species of the superfamily Terebridae. By 2-electrode voltage-clamp technique the gland extracts were tested on Xenopus oocytes expressing nicotinic acetylcholine receptors (nAChRs) of rat neuronal (α3β2, α3β4, α4β2, α4β4, α7) and muscle subtypes (α1β1γδ), and expressing potassium (Kv1.2 and Kv1.3) and sodium channels (Nav1.2, 1.3, 1.4, 1.6). The extracts were shown to exhibit remarkably high inhibitory activities on almost all nAChRs tested, in particular on the α7 subtype suggesting the presence of peptides of the A-superfamily from the venom of Conus species. In contrast, no effects on the potassium and sodium channels tested were observed. The venoms of terebrid snails may offer an additional source of novel biologically active peptides.
Biological activities of ethanolic extracts from deep-sea antarctic marine sponges
Jerneja Ambrožič Avguštin
- We report on the screening of ethanolic extracts from 33 deep-sea Antarctic marine sponges for different biological activities. We monitored hemolysis, inhibition of acetylcholinesterase, cytotoxicity towards normal and transformed cells and growth inhibition of laboratory, commensal and clinically and ecologically relevant bacteria. The most prominent activities were associated with the extracts from sponges belonging to the genus Latrunculia, which show all of these activities. While most of these activities are associated to already known secondary metabolites, the extremely strong acetylcholinesterase inhibitory potential appears to be related to a compound unknown to date. Extracts from Tetilla leptoderma, Bathydorus cf. spinosus, Xestospongia sp., Rossella sp., Rossella cf. racovitzae and Halichondria osculum were hemolytic, with the last two also showing moderate cytotoxic potential. The antibacterial tests showed significantly greater activities of the extracts of these Antarctic sponges towards ecologically relevant bacteria from sea water and from Arctic ice. This indicates their ecological relevance for inhibition of bacterial microfouling.
Unmanned Aerial Vehicle (UAV) for Monitoring Soil Erosion in Morocco
Klaus Daniel Peter
Johannes B. Ries
- This article presents an environmental remote sensing application using a UAV that is specifically aimed at reducing the data gap between field scale and satellite scale in soil erosion monitoring in Morocco. A fixed-wing aircraft type Sirius I (MAVinci, Germany) equipped with a digital system camera (Panasonic) is employed. UAV surveys are conducted over different study sites with varying extents and flying heights in order to provide both very high resolution site-specific data and lower-resolution overviews, thus fully exploiting the large potential of the chosen UAV for multi-scale mapping purposes. Depending on the scale and area coverage, two different approaches for georeferencing are used, based on high-precision GCPs or the UAV’s log file with exterior orientation values respectively. The photogrammetric image processing enables the creation of Digital Terrain Models (DTMs) and ortho-image mosaics with very high resolution on a sub-decimetre level. The created data products were used for quantifying gully and badland erosion in 2D and 3D as well as for the analysis of the surrounding areas and landscape development for larger extents.
Molecular Mechanisms of Adaptation of the Moderately Halophilic Bacterium Halobacillis halophilus to Its Environment
- The capability of osmoadaptation is a prerequisite of organisms that live in an environment with changing salinities. Halobacillus halophilus is a moderately halophilic bacterium that grows between 0.4 and 3 M NaCl by accumulating both chloride and compatible solutes as osmolytes. Chloride is absolutely essential for growth and, moreover, was shown to modulate gene expression and activity of enzymes involved in osmoadaptation. The synthesis of different compatible solutes is strictly salinity- and growth phase-dependent. This unique hybrid strategy of H. halophilus will be reviewed here taking into account the recently published genome sequence. Based on identified genes we will speculate about possible scenarios of the synthesis of compatible solutes and the uptake of potassium ion which would complete our knowledge of the fine-tuned osmoregulation and intracellular osmolyte balance in H. halophilus.
Predator avoidance in extremophile fish
Jeane Rimber Indy
- Extreme habitats are often characterized by reduced predation pressures, thus representing refuges for the inhabiting species. The present study was designed to investigate predator avoidance of extremophile populations of Poecilia mexicana and P. sulphuraria that either live in hydrogen sulfide-rich (sulfidic) springs or cave habitats, both of which are known to have impoverished piscine predator regimes. Focal fishes that inhabited sulfidic springs showed slightly weaker avoidance reactions when presented with several naturally occurring predatory cichlids, but strongest differences to populations from non-sulfidic habitats were found in a decreased shoaling tendency with non-predatory swordtail (Xiphophorus hellerii) females. When comparing avoidance reactions between P. mexicana from a sulfidic cave (Cueva del Azufre) and the adjacent sulfidic surface creek (El Azufre), we found only slight differences in predator avoidance, but surface fish reacted much more strongly to the non-predatory cichlid Vieja bifasciata. Our third experiment was designed to disentangle learned from innate effects of predator recognition. We compared laboratory-reared (i.e., predator-naïve) and wild-caught (i.e., predator-experienced) individuals of P. mexicana from a non-sulfidic river and found no differences in their reaction towards the presented predators. Overall, our results indicate (1) that predator avoidance is still functional in extremophile Poecilia spp. and (2) that predator recognition and avoidance reactions have a strong genetic basis.
Impact of climate change on renewable groundwater resources: assessing the benefits of avoided greenhouse gas emissions using selected CMIP5 climate projections
Felix Theodor Portmann
- Reduction of greenhouse gas (GHG) emissions to minimize climate change requires very significant societal effort. To motivate this effort, it is important to clarify the benefits of avoided emissions. To this end, we analysed the impact of four emissions scenarios on future renewable groundwater resources, which range from 1600 GtCO2 during the 21st century (RCP2.6) to 7300 GtCO2 (RCP8.5). Climate modelling uncertainty was taken into account by applying the bias-corrected output of a small ensemble of five CMIP5 global climate models (GCM) as provided by the ISI-MIP effort to the global hydrological model WaterGAP. Despite significant climate model uncertainty, the benefits of avoided emissions with respect to renewable groundwater resources (i.e. groundwater recharge (GWR)) are obvious. The percentage of projected global population (SSP2 population scenario) suffering from a significant decrease of GWR of more than 10% by the 2080s as compared to 1971–2000 decreases from 38% (GCM range 27–50%) for RCP8.5 to 24% (11–39%) for RCP2.6. The population fraction that is spared from any significant GWR change would increase from 29% to 47% if emissions were restricted to RCP2.6. Increases of GWR are more likely to occur in areas with below average population density, while GWR decreases of more than 30% affect especially (semi)arid regions, across all GCMs. Considering change of renewable groundwater resources as a function of mean global temperature (GMT) rise, the land area that is affected by GWR decreases of more than 30% and 70% increases linearly with global warming from 0 to 3 ° C. For each degree of GMT rise, an additional 4% of the global land area (except Greenland and Antarctica) is affected by a GWR decrease of more than 30%, and an additional 1% is affected by a decrease of more than 70%.