A Model Rock Biofilm Growing in Percolation Columns

Sub-aerial biofilms (SAB) are ubiquitous, self-sufficient microbial ecosystems found on mineral surfaces at all altitudes and latitudes. SABs, which are the principal causes of weathering on exposed terrestrial surfaces, are characterized by patchy growth dominated by associations of algae, cyanobacteria, fungi and heterotrophic bacteria. A recently developed in vitro system to study colonization of rocks exposed to air included two key SAB participants - the rock-inhabiting ascomycete Knufia petricola (CBS 123872) and the phototrophic cyanobacterium Nostoc punctiforme ATCC29133. Both partners are genetically tractable and we used them here to study weathering of granite, K-feldspar and plagioclase. Small fragments of the various rocks or minerals (1–6 mm) were packed into flow-through columns and incubated with 0.1% glucose and 10 μM thiamine-hydrochloride (90 μL min−1) to compare weathering with and without biofilms. Dissolution of the minerals was followed by: (i) analysing the degradation products in the effluent from the columns via Inductively Coupled Plasma Spectroscopy and (ii) by studying polished sections of the incubated mineral fragments/grains using scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray analyses. K. petricola/N. punctiforme stimulated release of Ca, Na, Mg and Mn. Analyses of the polished sections confirmed depletion of Ca, Na and K near the surface of the fragments. The abrupt decrease in Ca concentration observed in peripheral areas of plagioclase fragments favored a dissolution- reprecipitation mechanism. Percolation columns in combination with a model biofilm can thus be used to study weathering in closed systems. Columns can easily be filled with different minerals and biofilms, the effluent as well as grains can be collected after long-term exposure under axenic conditions and easily analyzed

Genotoxicity testing of nanomaterials

Nanomaterials have outstanding and unprecedented advantageous material properties but may also cause adverse effects in humans upon exposure. Testing nanomaterials for genotoxic properties is challenging because traditional testing methods were designed for small, soluble molecules and may not be easily applicable without modifications. This review critically examines available genotoxicity tests for use with nanomaterials, including DNA damage tests such as the comet assay, gene mutation tests such as the mouse lymphoma and hprt assay, and chromosome mutation tests such as the micronucleus test and the chromosome aberration test. It presents arguments for the relative usefulness of various tests, such as preferring the micronucleus test over the chromosome aberration test for scoring chromosome mutations and preferring mammalian cell gene mutation tests because the Ames test has limited utility. Finally, it points out the open questions and further needs in adapting genotoxicity tests for nanomaterials, such as validation, reference nanomaterials, and the selection of top test concentrations, as well as the relevance and applicability of test systems and the need to define testing strategies. This article is categorized under: Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicin

Characterisation of rock colonisation and weathering by a model biofilm

1\. Einleitung 13 1.1 Gesteinsverwitterung 13 1.1.1 Gesteinsverwitterung generell 13 1.1.2 Stand der Forschung biotisch induzierter Verwitterung 21 1.1.3 Quantifizierung von Verwitterung 22 1.2 Biofilme auf Gesteinen 25 1.2.1 Biofilme generell 25 1.2.2 Biofilme und ihre Sukzession auf Gesteinsformationen 26 1.3 Ein Modellbiofilm 33 1.3.1 Nostoc punctiforme 33 1.3.2 Knufia petricola 34 1.3.3 Fakultative Symbiose 34 1.4 Ziele der Arbeit 34 2.1 Material 35 2.1.1 Gesteinsmaterial 35 2.1.1.1 Experimente zum Gesteinsbewuchs und zur Elementanreicherung in Gesteinsbiofilmen 35 2.1.1.2 Experimente zur Granitverwitterung 37 2.1.1.3 Experimente zur Verwitterung einzelner Minerale 38 2.1.2 Biologisches Material 38 2.1.3 Verwendete Chemikalien 39 2.1.3.1 Chemikalienliste 39 2.1.3.2 Rezepte für verwendete Lösungen/Medien 41 2.1.4 Verwendete Geräte und Materialien 45 2.1.4.1 Allgemein verwendete Geräte 45 2.1.4.2 Allgemein verwendete Labormaterialien 46 2.1.4.3 Verwendete Geräte und Materialien für Versuche zum Gesteinsbewuchs unter variierenden Bedingungen 47 2.1.4.4 Verwendete Geräte und Materialien für Versuche zur Gesteinsverwitterung 47 2.2 Methoden 48 2.2.1 Generelle Methoden 48 2.2.2 Wachstumsexperimente auf BG11/BG110 Festmedium 54 2.2.3 Gesteinsbewuchs unter variierenden Witterungsbedingungen 55 2.2.3.1 Wachstum in Schüttelkultur bei unterschiedlichen Temperaturen 56 2.2.3.2 Wachstum unter dis- und semikontinuierlichen Bedingungen 56 2.2.4 Elementanreicherung in Gesteinsbiofilmen 67 2.2.5 Verwitterung von Gesteinen 68 2.2.5.1 Verwitterung von Granit, Albit und Mikroklin 68 2.2.5.2 Verwitterung einzelner Minerale 75 3\. Ergebnisse und Diskussion 79 3.1 Wachstum des Modellbiofilms auf Nährmedium 79 3.2 Gesteinsbewuchs unter variierenden Witterungsbedingungen 84 3.3 Gesteinsverwitterung 101 3.3.1 Elementanreicherung in Gesteinsbiofilmen 101 3.3.2 Verwitterung von Granit 104 3.3.3 Verwitterung einzelner Minerale 130 4\. Fazit und Ausblick 139 5\. Literaturverzeichnis 142 6 Anhang 158 6.1 Abkürzungsverzeichnis 158 6.2 Publikationen 164 6.2.1 Publikationen in Fachzeitschriften 164 6.2.2 Konferenzbeiträge 164Natürliche Gesteinsformationen und von Menschen aus Gesteinsmaterial erschaffene Gebäude oder Monumente werden bei genügend langer Inkubation von zahlreichen Mikroorganismen besiedelt, welche komplexe Ökosysteme bilden. Dies führt oft zu Verfärbungen der Gesteinsoberflächen durch Pigmente der Mikroorganismen. Zudem können die Organismen das Gestein angreifen und zusammen mit abiotischen Faktoren eine Auflösung herbeiführen, was von essenzieller Bedeutung für die Bildung von Böden und gleichzeitig kritisch für die Erhaltung von Kulturgütern ist. Ein profundes Verständnis der Primärbesiedlung auf Gesteinen ist eine Voraussetzung, um Prozesse der Sukzession und der Gesteinsverwitterung besser nachvollziehen und modellieren zu können. Mischkulturen, die aus dem phototrophen Cyanobakterium Nostoc punctiforme ATCC 29133 und dem mikrokolonialen Ascomycet Knufia petricola CBS 726.95 bestanden, wurden als Modell für die ersten Schritte der Gesteinsbesiedlung in Form von Biofilmen und hinsichtlich des biologischen Einflusses auf die Gesteinsverwitterung hin getestet. Dazu wurden unterschiedliche Gesteine als Substrate angeboten, unter verschiedenen Kultivierungs- und Witterungsbedingungen mit den Mischkulturen inkubiert und die sich bildenden Biofilme bzgl. ihrer Morphologie und Abundanz hin analysiert. Es zeigte sich, dass das Wachstum der Biofilme deutlich von den verwendeten Gesteinen und Witterungsbedingungen abhing und die Anordnung und Morphologie der Zellen und der aus diesen ausgeschiedenen polymeren Substanzen innerhalb der Biofilme sich je nach eingesetztem Gesteinssubstrat deutlich unterschieden. Der biologische Einfluss auf die Verwitterung von Gestein wurde in einem Durchfluss-System an einem Granit und in Batch-Kulturen an Calcit, Forsterit und Olivin getestet, indem nach Inkubation für 45-180 d in An- und Abwesenheit der Mikroorganismen die in der Flüssigphase angereicherten Elemente und die chemischen Veränderungen in der Mineralphase vergleichend gemessen wurden. Dabei zeigte sich, dass der Biofilm die Auflösung von Calcium, Natrium, Magnesium und Mangan aus Granit sowie von Magnesium aus Forsterit und Olivin verstärkte. In einigen Experimenten wurden biotische Effekte von Misch- und Einzelkulturen in verschiedenen Ansätzen verglichen. Einzelkulturen von K. petricola und Mischkulturen führten zu verstärkter Magnesiumauflösung, Einzelkulturen von N. punctiforme zeigten die gleichen Effekte wie abiotische Kontrollen. Beide Mikroorganismen wuchsen deutlich besser in Mischkulturen, sodass ein indirekter biotischer Effekt auf die Mineralauflösung von N. punctiforme durch die Verstärkung des Wachstums von K. petricola innerhalb einer mutualistischen Gemeinschaft als plausibel erscheint. Der Mechanismus der biotisch induziert verstärkten Gesteinsverwitterung konnte aufgrund der hier vorliegenden Ergebnisse nicht eruiert werden. Die verwendeten Mischkulturen aus K. petricola und N. punctiforme konnten als nützliches Modell zur Untersuchung von Gesteinsbewuchs und -verwitterung etabliert werden.Natural rock formations and buildings or monuments constructed by mankind with rock materials are colonised by various microorganisms within complex ecosystems if incubated for sufficient periods of time. This often causes discolouration of rock surfaces by microbial pigments. Microorganisms can also attack the rocks and give rise to their decomposition in combination with abiotic factors being of essential importance for soil formation and critical to the conservation of cultural heritage. For the comprehension and modellizing of processes like succession and rock weathering, a profound understanding of primary colonisation is required. Mixed cultures consisting of the phototrophic cyanobacterium Nostoc punctiforme ATCC 29133 and the microcolonial ascomycete Knufia petricola CBS 726.95 were used as a model to study the first steps of rock colonisation by biofilms and the biotic influence on rock weathering. For that purpose different rocks were offered as substrates, incubation with mixed cultures was done under differing cultivation and atmospheric conditions and forming biofilms were analysed for their morphology and abundance. Results indicate that growth of the biofilms depended precisely on the offered rock substrates and atmospheric conditions. Arrangement and morphology of cells and their excreted polymeric substances within biofilms differed depending on the rock substrate. The biological influence on rock weathering was examined in a percolation system for granite and in batch cultures for calcite, forsterite and olivine. After incubation for 45-180 d with and without microorganisms accumulated elements within the liquid phase and chemical changes within the mineral phase were measured comparatively. Results indicate that dissolution of calcium, sodium, magnesium and manganese from granite and magnesium from forsterite and olivine were enhanced in the presence of the biofilm. For some mineral experiments, biotic effects of mixed and single cultures were distinguished. K. petricola single cultures and mixed cultures enhanced magnesium dissolution, N. punctiforme single cultures showed effects comparable to the abiotic controls. Both microorganisms grew better within mixed cultures, suggesting an indirect biotic effect of N. punctiforme for mineral dissolution, acting as growth enhancing factor for K. petricola within mutualistic biofilms. The mechanism of biotically increased rock weathering could not be determined by the here presented results. Mixed cultures of K. petricola and N. punctiforme could be established as a useful model to study colonisation and weathering of rocks

Homing behavior and locality preferences in patellid and trochid gastropods

In the present study we examined the homing behavior, distribution and locality-preferences of two groups of Gastropods, Patellidae and Trochidae, in the Eulittoral of the rocky shore at Le Cabellou, Brittany/France. By daily counting of marked individuals during low tide in a period if three days we documented significant locality constancy for individuals of both groups. In two other tests a preference and an active movement to cervices were observed in Trochidae but not in Patellidae.In der vorliegenden Studie haben wir das Heimfindeverhalten, die Verbreitung und die Lokalitätspräferenzen von zwei Gruppen von Gastropoden, Patellidae und Trochidae, im Eulittoral der felsigen Küste von Le Cabellou, Bretagne/Frankreich untersucht. Durch tägliches Zählen markierter Individuen bei Ebbe in einem Zeitraum von drei Tagen dokumentierten wir eine signifikante Ortskonstanz für Individuen beider Gruppen. In zwei weiteren Tests wurde bei Trochidae eine Bevorzugung und aktive Bewegung zum Hals beobachtet, nicht jedoch bei Patellidae.Peer Reviewe

Vocal music. Selections

Sacred music for 1-5 voices with 1-6 string instruments and organ. --- 1. Salve Cœlestis Pater, basso solo con violino. -- 2. O Jesu dulcissime, basso solo con 2 violini. -- 3. Salve mi Jesu, contra alto solo con 5 viole. -- 4. Da mihi Domine, basso solo con 5 viole. -- 5. Herr, nun lässet du deien diener, 2 bass! con 5 viole. -- 6. Nisi Dominus aedificaverit, dialogo o concerto a 2 canti, basso con 2 violini. -- 7. Dominus illuminatio mea, 5 voci con 2 violini. -- 8. Nis; Dominus aedificaverit, 5 voci con 5 viole. -- 9. Hoslanna dem Sohne David, in adventu. Jubilate et exultate, vivat rex Carolus, 5 voci con 5 stromenti. -- 10. Aria, Ein kleines kindelein, soprano solo con 5 stromenti. -- 11. Ach Herr, lass deine lieben engelein, soprano solo con 4 viole. --- (cont'd) 12. Wachet auf! ruft uns die stimme, canto solo con 3 viole. -- 13. An wasserflüssen Babylon, canto solo con 5 viole. -- 14. Aria, Streuet mit palmen, 5 voci con 5 stromenti -- 15. Helft mir Gott's güte preisen, 5 voci con 5 viole. -- 16. Wend' ab deinen zorn, lieber Herr, mit gnaden, 6 voci con 6 stromenti. -- 17. Ein' feste burg ist unser Gott, 4 voci con 2 violini e 4 viole. -- Anhang: Sinfonia à 7 viole. Diese sinfonia ist gesetzt für ein muttedt, Da pacem Domine

Object constancy in adolescents with borderline personality disorder pathology.

Persistent, interpersonal difficulties are a core feature of borderline personality disorder (BPD). Theories propose that these may result from an insufficient object constancy, for example, the insufficient capacity to maintain feelings of closeness (FC) toward a person when he or she is absent. Based on this assumption, this study examined whether FC toward the mother or the best friend were more dependent on previous contact in adolescents with BPD pathology compared with healthy controls. In addition, the influence of different contact modes was explored. N = 52 female adolescents aged 14 to 18 years (n = 24 with ≥ 5 BPD symptoms [full-threshold BPD], n = 10 with 1-4 BPD symptoms [subthreshold BPD], n = 18 healthy controls) completed up to 12 e-diaries a day on 2 consecutive weekends. Using multilevel mixed-effect regression analyses, we found that the more BPD symptoms a patient fulfilled, the more dependent were FC toward the best friend on actual contact. In contrast, BPD pathology did not influence the dependency of the FC toward the mother on actual contact. Finally, the mode of contact seems to matter: The more BPD symptoms a patient met, the more was the FC toward the best friend dependent on personal compared with written or no contact, whereas phone or written contact was no different from no contact. The present findings partially support the theory of an insufficient object constancy in BPD that seems to become apparent in adolescence mainly in relationships with peers. Replication of the findings, particularly with regard to the impact of mode of contact, in larger samples is required

Proceedings in Marine Biology

“Proceedings in Marine Biology” is an international journal publishing original research by graduate students on all aspects of marine biology. Subjects covered include: ecological surveys and population studies of oceanic, coastal and shore communities; physiology and experimental biology; taxonomy, morphology and life history of marine animals and plants. Papers are also published on techniques em- ployed at sea for sampling, recording, capture and observation of marine organisms.Zeitschrift zur Kursabschlussreise der Humboldt-Universität zu Berlin (Deutschland) im Bereich Elektronenmikroskopie.Peer Reviewe

Regulation of the hyperpolarization-activated cationic current I(h) in mouse hippocampal pyramidal neurones by vitronectin, a component of extracellular matrix

Because the hyperpolarization-activated cation-selective current I(h) makes important contributions to neural excitability, we examined its long-term regulation by vitronectin, an extracellular matrix component commonly elevated at injury sites and detected immunochemically in activated microglia. Focusing on mouse hippocampal pyramidal neurones in organotypic slice cultures established at postnatal day 0 or 1 and examined after 3–4 days in vitro, we observed differences in the amplitude and activation rate of I(h) between neurones in naive and vitronectin-exposed slices (10 μg ml(−1) added to serum-free medium), and between neurones in slices derived from wild-type and vitronectin-deficient mice. The potassium inward rectifier I(K(ir)), activated at similar voltages to I(h), was not affected by vitronectin. In CA1, differences in I(h) amplitude primarily reflected changes in maximum conductance (G(max)): a 23.3% increase to 3.18 ± 0.64 nS from 2.58 ± 0.96 nS (P < 0.05) in vitronectin-exposed neurones, and a 17.9% decrease to 2.24 ± 0.26 nS from 2.73 ± 0.64 nS (P < 0.05) in neurones from vitronectin-deficient slices. The voltage of one-half maximum activation (V(½)) was not significantly affected by vitronectin exposure (−78.1 ± 2.3 mV versus −80.0 ± 4.9 mV in naive neurones; P > 0.05) or vitronectin deficiency (−83.8 ± 3.1 mV versus −82.0 ± 2.9 mV in wild-type neurones; P > 0.05). In CA3 neurones, changes in I(h) reflected differences in both G(max) and V(½): in vitronectin-exposed neurones there was a 35.4% increase in G(max) to 1.30 ± 0.49 nS from 0.96 ± 0.26 nS (P < 0.01), and a +3.0 mV shift in V(½) to −89.8 mV from −92.8 mV (P < 0.05). The time course of I(h) activation could be fitted by the sum of two exponential functions, fast and slow. In both CA1 and CA3 neurones the fast component amplitude was preferentially sensitive to vitronectin, with its relatively larger contribution to total current in vitronectin-exposed cells contributing to the acceleration of I(h) activation. Further, HCN1 immunoreactivity appeared elevated in vitronectin-exposed slices, while HCN2 levels appeared unaltered. We suggest that vitronectin-stimulated increases in I(h) may potentially affect excitability under pathological conditions

Imaging correlates of behavioral impairments: An experimental PET study in the rat pilocarpine epilepsy model

Psychiatric comorbidities are prevalent in patients with epilepsy and greatly contribute to the overall burden of disease. The availability of reliable biomarkers to diagnose epilepsy-associated comorbidities would allow for effective treatment and improved disease management. Due to their non-invasive nature, molecular imaging techniques such as positron emission tomography (PET) are ideal tools to measure pathologic changes. In the current study we investigated the potential of [18F]fluoro-2-deoxy-D-glucose ([18F]FDG) and 2′-methoxyphenyl-(N-2′-pyridinyl)-p-18F-fluoro-benzamidoethylpiperazine ([18F]MPPF) as imaging correlates of neurobehavioral comorbidities in the pilocarpine rat model of epilepsy. Findings from rats with epilepsy revealed a regional reduction in [18F]FDG uptake indicating thalamic hypometabolism. In addition, an increase in septal [18F]MPPF binding was observed in rats with spontaneous recurrent seizures. Both thalamic [18F]FDG and septal [18F]MPPF data proved to correlate with behavioral alterations including decreases in luxury behavior such as burrowing and social interaction, and changes in behavioral patterns in anxiety tests. A correlation with seizure frequency was confirmed for thalamic [18F]FDG data. Moreover, thalamic [18F]FDG and septal [18F]MPPF data exhibited a correlation with brain-derived neurotrophic factor (BDNF) serum concentrations, which were lowered in rats with epilepsy. In conclusion, μPET data from rats with pilocarpine-induced epileptogenesis indicate altered septal 5-HT1A receptor binding. Further research is necessary assessing whether septal 5-HT1A receptor binding may serve as an imaging correlate of neuropsychiatric comorbidities in epilepsy patients and for severity assessment in rodent epilepsy models. In contrast, we obtained evidence that [18F]FDG uptake also reflects the severity of epilepsy and, thus, might not constitute a biomarker with sufficient specificity for psychiatric comorbidities. Evidence has been obtained that BDNF might serve as a peripheral circulatory biomarker. Further experimental and clinical assessment is necessary for validation of the marker candidates