Growth,aluminium uptake and mucous cell morphometrics of early life stages of brown trout,Salmo trutta,in low pH water

Synopsis Young (7–10 days after hatching) brown trout (Salmo trutta) exposed for 5 days to pH 5 in high calcium water and at 2 temperatures (12°, 4°C) in the laboratory displayed no alterations in growth or in mucous cell concentration and volume, compared to the control group kept at pH 7.2. Contamination of acid-stressed young with 230 μg All^-1 resulted in significant growth depression and Al accumulation, but in no changes of mucous cell morphometrics. Field tests in low calcium water produced high mortality at low pH (5.1), but showed consistent effects on mucous cells as in laboratory experiments. Three-month-old juveniles of brown trout, subjected to decreased pH values at 12° and in high calcium water for 8 days exhibited mucous cell hyperplasia (without hypertrophy) within 3 h of the acid addition. After 120 h sloughing of the integument occurred with full recovery not possible within a 4-day-recovery period. Although the results presently apply only to hard water conditions, the differences between juveniles and recently hatched young in tolerance to pH- and Al-mediated stress may also be of importance for soft waters affected by acid rain.     

Fractal Analysis of Cervical Intraepithelial Neoplasia

Introduction

Cervical intraepithelial neoplasias (CIN) represent precursor lesions of cervical cancer. These neoplastic lesions are traditionally subdivided into three categories CIN 1, CIN 2, and CIN 3, using microscopical criteria. The relation between grades of cervical intraepithelial neoplasia (CIN) and its fractal dimension was investigated to establish a basis for an objective diagnosis using the method proposed.

Methods

Classical evaluation of the tissue samples was performed by an experienced gynecologic pathologist. Tissue samples were scanned and saved as digital images using Aperio scanner and software. After image segmentation the box counting method as well as multifractal methods were applied to determine the relation between fractal dimension and grades of CIN. A total of 46 images were used to compare the pathologist''s neoplasia grades with the predicted groups obtained by fractal methods.

Results

Significant or highly significant differences between all grades of CIN could be found. The confusion matrix, comparing between pathologist''s grading and predicted group by fractal methods showed a match of 87.1%. Multifractal spectra were able to differentiate between normal epithelium and low grade as well as high grade neoplasia.

Conclusion

Fractal dimension can be considered to be an objective parameter to grade cervical intraepithelial neoplasia.     

Paraphyly and budding speciation in the hairy snail (Pulmonata,Hygromiidae)

Delimitation of species is often complicated by discordance of morphological and genetic data. This may be caused by the existence of cryptic or polymorphic species. The latter case is particularly true for certain snail species showing an exceptionally high intraspecific genetic diversity. The present investigation deals with the Trochulus hispidus complex, which has a complicated taxonomy. Our analyses of the COI sequence revealed that individuals showing a T. hispidus phenotype are distributed in nine highly differentiated mitochondrial clades (showing p‐distances up to 19%). The results of a parallel morphometric investigation did not reveal any differentiation between these clades, although the overall variability is quite high. The phylogenetic analyses based on 12S, 16S and COI sequences show that the T. hispidus complex is paraphyletic with respect to several other morphologically well‐defined Trochulus species (T. clandestinus, T. villosus, T. villosulus and T. striolatus) which form well‐supported monophyletic groups. The nc marker sequence (5.8S–ITS2–28S) shows only a clear separation of T. o. oreinos and T. o. scheerpeltzi, and a weakly supported separation of T. clandestinus, whereas all other species and the clades of the T. hispidus complex appear within one homogeneous group. The paraphyly of the T. hispidus complex reflects its complicated history, which was probably driven by geographic isolation in different glacial refugia and budding speciation. At our present state of knowledge, it cannot be excluded that several cryptic species are embedded within the T. hispidus complex. However, the lack of morphological differentiation of the T. hispidus mitochondrial clades does not provide any hints in this direction. Thus, we currently do not recommend any taxonomic changes. The results of the current investigation exemplify the limitations of barcoding attempts in highly diverse species such as T. hispidus.     

Weathering-Associated Bacteria from the Damma Glacier Forefield: Physiological Capabilities and Impact on Granite Dissolution

Several bacterial strains isolated from granitic rock material in front of the Damma glacier (Central Swiss Alps) were shown (i) to grow in the presence of granite powder and a glucose-NH₄Cl minimal medium without additional macro- or micronutrients and (ii) to produce weathering-associated agents. In particular, four bacterial isolates (one isolate each of Arthrobacter sp., Janthinobacterium sp., Leifsonia sp., and Polaromonas sp.) were weathering associated. In comparison to what was observed in abiotic experiments, the presence of these strains caused a significant increase of granite dissolution (as measured by the release of Fe, Ca, K, Mg, and Mn). These most promising weathering-associated bacterial species exhibited four main features rendering them more efficient in mineral dissolution than the other investigated isolates: (i) a major part of their bacterial cells was attached to the granite surfaces and not suspended in solution, (ii) they secreted the largest amounts of oxalic acid, (iii) they lowered the pH of the solution, and (iv) they formed significant amounts of HCN. As far as we know, this is the first report showing that the combined action of oxalic acid and HCN appears to be associated with enhanced elemental release from granite, in particular of Fe. This suggests that extensive microbial colonization of the granite surfaces could play a crucial role in the initial soil formation in previously glaciated mountain areas.Glaciers in alpine regions are highly sensitive to changes in climatic conditions (29). Increasing global atmospheric temperatures over the last decades have resulted in the recession of alpine glaciers (18). Forefields of temperate alpine glaciers provide unique opportunities to study initial soil formation as well as microbial and plant succession along the chronosequences (12, 26, 34, 36). The forefields close to the glacier terminus are initially vegetation free and consist mainly of rock material with high fractions of silt-sized grains with low C and N content and small amounts of available nutrients (14). Mineral weathering is a key process in the formation of soils (1, 26), and the crucial importance of microbially promoted mineral weathering for nutrient acquisition is increasingly recognized (2, 4, 39, 46). Recently exposed rock surfaces can be considered primary ecosystems where only a few microbes that are adapted due to their mineral-weathering abilities can grow (17). Some cations of rock-forming minerals are essential for proper cell functions. However, our understanding of geochemically significant microbes in forefields of temperate alpine glacier is still very limited but is crucial for increasing our knowledge of nutrient mobilization and the buildup of organic matter that is essential for the development of macroorganisms.The area of the Damma glacier in Central Switzerland is characterized by a relatively homogenous granitic rock basement and is used as field site of the interdisciplinary research project “Biosphere-Geosphere interactions: Linking climate change, weathering, soil formation and ecosystem evolution (BigLink)” (5). In the frame of this research project, we studied the functional roles of granite-colonizing microbes as biotic weathering agents in previously glaciated areas. So far, relatively little is known about microbe-granite interactions, especially regarding the release of trace elements. Several studies have examined the dissolution of specific granite-forming minerals in the presence of actively metabolizing bacteria or compounds that simulate metabolic activity (24, 30, 31, 37, 38, 44). There is a general agreement that microbially produced organic acids, siderophores, and extracellular polysaccharides can all promote dissolution of minerals. Previous dissolution experiments have mainly been performed with (i) commercially obtained minerals (23, 45), (ii) model microorganisms that were commercially obtained from culture collections (3, 35, 45), or (iii) laboratory strains, such as those of Bacillus subtilis (23) and Burkholderia fungorum (47). Most studies have focused on individual mineral specimens rather than on the mixture of minerals that are present in granite rock (47). Few studies observed mineral weathering of collected rock and bacteria isolated from volcanic areas covered with vegetation (30, 31). Moreover, there are no studies on microbial weathering for such immediately deglaciated environments combining functional and taxonomic investigations, probably due to the difficulties in obtaining heterotrophic bacterial isolates from granitic glacier forefields. In spite of this, a comprehensive culture collection containing approximately 500 bacterial strains, which were isolated from the glacier tongue of the Damma glacier, was established. Full-length 16S rRNA gene sequences of 120 isolates revealed that many isolates obtained from oligotrophic media were closely related to readily cultivable heterotrophic bacteria (e.g., Arthrobacter sp., Collimonas sp., Paenibacillus sp., and Pseudomonas sp.). These bacteria have been found to enhance mineral dissolution (39).Our aim was to characterize the impact of microorganisms on granite weathering. We performed laboratory dissolution experiments with sterile crushed granite rock material, 12 bacterial strains, and 1 algal strain. To investigate the potential weathering abilities of these isolates, granite dissolution experiments were performed abiotically with model agents, such as HCl for proton-promoted weathering or oxalate and citrate and KCN for ligand-promoted weathering.     

Intraventrikuläre markhaltige Nervenfasern nahe der Apertura lateralis ventriculi quarti des Kaninchengehirns

Zusammenfassung In der Gegend der Apertura lateralis ventriculi quarti des Kaninchengehirns wurden intraventrikuläre markhaltige Nervenfasern der Fasergruppe B gefunden. Ihre Markscheide beginnt oder endigt innerhalb des Ventrikellumens. Besonderheiten des Ependyms dieser Gegend werden mitgeteilt.

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Summary In the 4th ventricle of the brain near the apertura lateralis in rabbit myelinated nerve fibers occur. These nerve fibers belong to the fiber group B. Their myelin sheath begins or ends in the ventricular cavity. Peculiarities of the ependyma of this region are discussed.

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Die Untersuchung wurde mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft durchgeführt.     

Peroxisomal Targeting of PTS2 Pre-Import Complexes in the Yeast Saccharomyces cerevisiae

Posttranslational matrix protein import into peroxisomes uses either one of the two peroxisomal targeting signals (PTS), PTS1 and PTS2. Unlike the PTS1 receptor Pex5p, the PTS2 receptor Pex7p is necessary but not sufficient to target cargo proteins into the peroxisomal matrix and requires coreceptors. Saccharomyces cerevisiae possesses two coreceptors, Pex18p and Pex21p, with a redundant but not a clearly defined function. To gain further insight into the early events of this import pathway, PTS2 pre-import complexes of S. cerevisiae were isolated and characterized by determination of size and protein composition in wild-type and different mutant strains. Mass spectrometric analysis of the cytosolic PTS2 pre-import complex indicates that Fox3p is the only abundant PTS2 protein under oleate growth conditions. Our data strongly suggest that the formation of the ternary cytosolic PTS2 pre-import complex occurs hierarchically. First, Pex7p recognizes cargo proteins through its PTS2 in the cytosol. In a second step, the coreceptor binds to this complex, and finally, this ternary 150 kDa pre-import complex docks at the peroxisomal membrane, where both the PTS1 and the PTS2 import pathways converge. Gel filtration analysis of membrane-bound subcomplexes suggests that Pex13p provides the initial binding partner at the peroxisomal membrane, whereas Pex14p assembles with Pex18p in high-molecular-weight complexes after or during dissociation of the PTS2 receptor.     

Teaching fluid shifts during orthostasis using a classic paper by Foux et al

Hypovolemic and orthostatic challenge can be simulated in humans by the application of lower body negative pressure (LBNP), because this perturbation leads to peripheral blood pooling and, consequently, central hypovolemia. The classic paper by Foux and colleagues clearly shows the effects of orthostasis simulated by LBNP on fluid shifts and homeostatic mechanisms. The carefully carried out experiments reported in this paper show the interplay between different physiological control systems to ensure blood pressure regulation, failure of which could lead to critical decreases in cerebral blood flow and syncope. Here, a teaching seminar for graduate students is described that is designed in the context of this paper and aimed at allowing students to learn how Foux and colleagues have advanced this field by addressing important aspects of blood regulation. This seminar is also designed to put their research into perspective by including important components of LBNP testing and protocols developed in subsequent research in the field. Learning about comprehensive protocols and carefully controlled studies can reduce confounding variables and allow for an optimal analysis and elucidation of the physiological responses that are being investigated. Finally, in collaboration with researchers in mathematical modeling, in the future, we will incorporate the concepts of applicable mathematical models into our curriculum.     

Ammoniteli der GattungParapatoceras aus dem Oberen Mitteljura des Süntels (östliches Wesergebirge,Niedersachsen)

The Parapatocerates from the Süntel (Weser mountains, Northwest Germany) are described being an utmost variable subspecies respectively geographical raceParapatoceras distans (?) bentzi (Potonié) with two possibly modificatorily separated form groups. They differ from the similarP. distans(?) crioconus (Buckman) (=Crioconites Buckman) of Chippenham (England) in primary quadrilobaty and further characteristics accessible only by precise analysis. To establish the speciesdistans Baugier & Sauzé and with this the genusParapatoceras, recovery of the holotype or a determination of a neotype is required. A very similar but probably quinquelobate specimen (Parapatoceras sp.) from the Macrocephalus oolite of Hanover seems to accentuate once more the taxonomically minor degree of the quadri- or quinquelobaty inParapatoceras.     

Ein einfaches Mikrokolorimeter

Ohne Zusammenfassung     

Effect of novel non-peptidic delta opioid receptor antagonists on human T and B cell activation

The effects of the antagonist naltrindole (NTI) on cells of the immune system have been largely studied although the mechanisms of action are still unclear. The aim of this study is to evaluate, in vitro, the immunomodulatory activity of four new delta-selective opioid compounds structurally related to naltrindole. The effects at different concentrations of these opioid antagonists on proliferative response were studied on normal human peripheral blood mononuclear cells (PBMC) stimulated with different stimuli: mitogens, the antigen PPD, the anti-CD3 monoclonal antibodies (mAb), the superantigen Staphylococcus aureus Cowan strain 1 (SAC) and alloantigens in the mixed lymphocyte cultures (MLR). The immunomodulatory capacity of these compounds was evaluated by determining the interleukin-2 (IL-2) release in mitogen activated PBMC. The present study shows that all the new delta opioid antagonists at 10(-5) M concentration are immunosuppressive. The inhibitory action is also evident at lower concentrations when anti-CD3 mAb and SAC were used as stimulators. In addition, the production of IL-2 was inhibited by the opioid treatment, but this might not be the only mechanism of action.