Nutrient regeneration from phytoplankton decomposing in seawater

A laboratory model of the regeneration of the inorganic nutrient salts of phosphorus, nitrogen, and silicon from diatom cells decaying in the dark while subject to bacterial attack was studied. The system was analyzed for phosphate, dissolved and particulate organic phosphorus, ammonia, nitrite, nitrate, dissolved and particulate nitrogen, and orthosilicate concentrations. The observations extended over a period of more than one year, but the significant changes appear to have been restricted to the first five months...

Magneto-resistance quantum oscillations in a magnetic two-dimensional electron gas

Magneto-transport measurements of Shubnikov-de Haas (SdH) oscillations have been performed on two-dimensional electron gases (2DEGs) confined in CdTe and CdMnTe quantum wells. The quantum oscillations in CdMnTe, where the 2DEG interacts with magnetic Mn ions, can be described by incorporating the electron-Mn exchange interaction into the traditional Lifshitz-Kosevich formalism. The modified spin splitting leads to characteristic beating pattern in the SdH oscillations, the study of which indicates the formation of Mn clusters resulting in direct anti-ferromagnetic Mn-Mn interaction. The Landau level broadening in this system shows a peculiar decrease with increasing temperature, which could be related to statistical fluctuations of the Mn concentration.Comment: 8 pages, 6 figure

Nucleosomal arrangement affects single-molecule transcription dynamics.

In eukaryotes, gene expression depends on chromatin organization. However, how chromatin affects the transcription dynamics of individual RNA polymerases has remained elusive. Here, we use dual trap optical tweezers to study single yeast RNA polymerase II (Pol II) molecules transcribing along a DNA template with two nucleosomes. The slowdown and the changes in pausing behavior within the nucleosomal region allow us to determine a drift coefficient, χ, which characterizes the ability of the enzyme to recover from a nucleosomal backtrack. Notably, χ can be used to predict the probability to pass the first nucleosome. Importantly, the presence of a second nucleosome changes χ in a manner that depends on the spacing between the two nucleosomes, as well as on their rotational arrangement on the helical DNA molecule. Our results indicate that the ability of Pol II to pass the first nucleosome is increased when the next nucleosome is turned away from the first one to face the opposite side of the DNA template. These findings help to rationalize how chromatin arrangement affects Pol II transcription dynamics

Alginate Microencapsulation of Human Islets Does Not Increase Susceptibility to Acute Hypoxia

Islet transplantation in diabetes is hampered by the need of life-long immunosuppression. Encapsulation provides partial immunoprotection but could possibly limit oxygen supply, a factor that may enhance hypoxia-induced beta cell death in the early posttransplantation period. Here we tested susceptibility of alginate microencapsulated human islets to experimental hypoxia (0.1–0.3% O2 for 8 h, followed by reoxygenation) on viability and functional parameters. Hypoxia reduced viability as measured by MTT by 33.8±3.5% in encapsulated and 42.9±5.2% in nonencapsulated islets (P<0.2). Nonencapsulated islets released 37.7% (median) more HMGB1 compared to encapsulated islets after hypoxic culture conditions (P<0.001). Glucose-induced insulin release was marginally affected by hypoxia. Basal oxygen consumption was equally reduced in encapsulated and nonencapsulated islets, by 22.0±6.1% versus 24.8±5.7%. Among 27 tested cytokines/chemokines, hypoxia increased the secretion of IL-6 and IL-8/CXCL8 in both groups of islets, whereas an increase of MCP-1/CCL2 was seen only with nonencapsulated islets. Conclusion. Alginate microencapsulation of human islets does not increase susceptibility to acute hypoxia. This is a positive finding in relation to potential use of encapsulation for islet transplantation

Lamellar and «club-shaped» corpuscular nerve endings in human gingival mucosa. A light and electron microscopic study

A study on the presence of corpuscular nerve endings in human gingival mucosa was performed using both light and transmission electron microscopic (TEM) techniques. Both round and oval lamellar corpuscles were detected by light microscopy. They were located either subepithelially, close to the basement membrane, or within the papillae, deeply invaginated into the overlying epithelium. TEM techniques showed convoluted structures with unmyelinated fibre arborizations leading to an afferent fibre supported by the so called lamellar cells. The presence of blood vessels, collagenous fibrils, desmosome-like junctions, cytoplasmic organelles, as well as the similarity with some previously described mechanoreceptors, suggested the role of such corpuscular nerve endings in transmitting a nervous impulse induced by mechanical stimulation. Other simpler structures were also observed and named «club-shaped» corpuscles: they could support the more complex ones in responding to the strengths and the movements directly influencing the gingival mucosa.La présence de terminaisons nerveuses corpusculaires dans la muqueuse gingivale humaine a été observée tant en microscopie optique qu’en microscopie électronique à transmission. En microscopie optique on a remarqué des corpuscules lamellaires ronds et ovalaires, qui étaient localisés tant au dessous de l’épithélium, tout près de la membrane basale, qu’au dedans des papilles, profondément insérés dans l’épithélium.En microscopie électronique on a observé des structures convolutées pourvues d’arborisations de fibres nerveuses sans myéline qui vont se réunir dans une fibre afférente supportée par des cellules dites lamellaires. La présence de vaisseaux, de fibrilles collagènes, de jonctions telles que desmoses, d’inclusions cytoplasmiques autant que la ressemblance avec quelques mécanorécepteurs décrits en littérature, suggérait un rôle de ces terminaisons nerveuses corpusculaires en envoyant un impulse nerveux induit par une stimulation mécanique. On a aussi observé des corpuscules plus simples appelés «club-shaped» qui pourraient supporter les plus complexes dans la réponse aux forces et aux mouvements qui influencent directement la muqueuse gingivale

Effects of Whole Body Vibration Therapy and Classic Physiotherapy on Postural Stability in People With Back Pain: A Randomized Trial

STUDY DESIGN: This 2-step prospective randomized parallel trial evaluated postural stability in 65 back pain participants (61.6+/-7.9 y) and 50 nonback pain participants (61.2+/-8.6 y) in a first step using the MFT-S3-Check. In a second step, postural stability and questionnaires were evaluated in back pain participants before and after therapy with either whole body vibration therapy or classic physiotherapy. OBJECTIVE: The first aim was to investigate whether the MFT-S3-Check is suitable to evaluate differences in postural stability in back pain and nonback pain participants. The second aim was to evaluate the effect of whole body vibration therapy and classic physiotherapy on postural stability and the influence of depressive symptoms and pain. SUMMARY OF BACKGROUND DATA: Objective bodily measurement values in chronic back pain are rare; therefore, the evaluation of effectiveness of different therapies is difficult. METHODS: Postural stability was investigated using stability-, sensorimotor-, and symmetry indexes, in standing and seated positions with the MFT-S3-Check. The following standard questionnaires were used to investigate pain and depressive symptoms: HADS, ODI, NASS, SF-36. RESULTS: No significant difference in postural stability was found between back pain participants and the nonback pain group. None of the two training concepts in back pain participants was superior, concerning postural stability and pain. Both treatments showed positive effects, with significant improvements in postural stability in the classic physiotherapy group. Depressive symptoms had a significant correlation with pain intensity in back pain participants. CONCLUSIONS: The MFT-S3-Check could not find a significant difference in postural stability between the back pain and nonback pain group in the study setting. Postural stability improved after treatment

Activation of PKC-ε counteracts maturation and apoptosis of HL-60 myeloid leukemic cells in response to TNF family members

Protein kinase C (PKC)-ε, a component of the serine/threo-nine PKC family, has been shown to influence the survival and differentiation pathways of normal hematopoietic cells. Here, we have modulated the activity of PKC-ε with specific small molecule activator or inhibitor peptides. PKC-ε inhibitor and activator peptides showed modest effects on HL-60 maturation when added alone, but PKC-ε activator peptide significantly counteracted the pro-maturative activity of tumor necrosis factor (TNF)-α towards the monocytic/macrophagic lineage, as evaluated in terms of CD14 surface expression and morphological analyses. Moreover, while PKC-ε inhibitor peptide showed a reproducible increase of TNF-related apoptosis inducing ligand (TRAIL)-induced apoptosis, PKC-ε activator peptide potently counteracted the pro-apoptotic activity of TRAIL. Taken together, the anti-maturative and anti-apoptotic activities of PKC-ε envision a potentially important proleukemic role of this PKC family member

Signals of climate change in butterfly communities in a Mediterranean protected area.

Journal ArticleResearch Support, Non-U.S. Gov'tCopyright: © 2014 Zografou et al.The European protected-area network will cease to be efficient for biodiversity conservation, particularly in the Mediterranean region, if species are driven out of protected areas by climate warming. Yet, no empirical evidence of how climate change influences ecological communities in Mediterranean nature reserves really exists. Here, we examine long-term (1998-2011/2012) and short-term (2011-2012) changes in the butterfly fauna of Dadia National Park (Greece) by revisiting 21 and 18 transects in 2011 and 2012 respectively, that were initially surveyed in 1998. We evaluate the temperature trend for the study area for a 22-year-period (1990-2012) in which all three butterfly surveys are included. We also assess changes in community composition and species richness in butterfly communities using information on (a) species' elevational distributions in Greece and (b) Community Temperature Index (calculated from the average temperature of species' geographical ranges in Europe, weighted by species' abundance per transect and year). Despite the protected status of Dadia NP and the subsequent stability of land use regimes, we found a marked change in butterfly community composition over a 13 year period, concomitant with an increase of annual average temperature of 0.95°C. Our analysis gave no evidence of significant year-to-year (2011-2012) variability in butterfly community composition, suggesting that the community composition change we recorded is likely the consequence of long-term environmental change, such as climate warming. We observe an increased abundance of low-elevation species whereas species mainly occurring at higher elevations in the region declined. The Community Temperature Index was found to increase in all habitats except agricultural areas. If equivalent changes occur in other protected areas and taxonomic groups across Mediterranean Europe, new conservation options and approaches for increasing species' resilience may have to be devised.ESFGreek national funds (NSRF