Small coelomic epithelial cells of the starfish Asterias rubens L. that are able to proliferate in vivo and in vitro

Echinoderms, due to their outstanding potential for regeneration, are widely used as experimental models for research in regenerative biology. One of the main problems in this field concerns identification and characterization of cells responsible for the restoration of lost body parts and organs in adult animals. In this study, we analyze the probable candidates for this role in the starfish Asterias rubens L., namely, small coelomic epithelial cells with a high nuclear–cytoplasmic ratio that have the ability to proliferate. These cells are one of several cell types common to the coelomic epithelium (CE) and coelomic fluid (CF). They are analyzed with respect to morphology, proportion in the total cell pool, dynamics after injury and distribution between CE and CF. The results of whole-mount and scanning electron microscopy provide evidence that these small cells occupy a boundary position between CE and CF. Moreover, a novel subpopulation of CE cells is identified that is enriched (up to 50 %) with small epitheliocytes capable of migrating from CE into the CF. As shown in experiments with BrdU incorporation and anti-phospho-histone H3 antibody staining, small epitheliocytes cultured on laminin retain proliferative activity for at least 1 month and can form colony-like aggregates. Two types of small proliferating cells are distinguished by their behavior in culture: some cells remain attached to the substrate and form aggregates, while others detach from the substrate during culturing. The morphology of small epitheliocytes, their proliferative activity in vivo and in vitro and the ability to migrate suggest that they possess certain properties characteristic of stem cells.     

Core and symbiotic genes reveal nine Mesorhizobium genospecies and three symbiotic lineages among the rhizobia nodulating Cicer canariense in its natural habitat (La Palma,Canary Islands)

Cicer canariense is a threatened perennial wild chickpea endemic to the Canary Islands. In this study, rhizobia that nodulate this species in its natural habitats on La Palma (Canary Islands) were characterised. The genetic diversity and phylogeny were estimated by RAPD profiles, 16S-RFLP analysis and sequencing of the rrs, recA, glnII and nodC genes. 16S-RFLP grouped the isolates within the Mesorhizobium genus and distinguished nine different ribotypes. Four branches included minority ribotypes (3–5 isolates), whereas another five contained the predominant ribotypes that clustered with reference strains of M. tianshanense/M. gobiense/M. metallidurans, M. caraganae, M. opportunistum, M. ciceri and M. tamadayense. The sequences confirmed the RFLP groupings but resolved additional internal divergence within the M. caraganae group and outlined several potential novel species. The RAPD profiles showed a high diversity at the infraspecific level, except in the M. ciceri group. The nodC phylogeny resolved three symbiotic lineages. A small group of isolates had sequences identical to those of symbiovar ciceri and were only detected in M. ciceri isolates. Another group of sequences represented a novel symbiotic lineage that was associated with two particular chromosomal backgrounds. However, nodC sequences closely related to symbiovar loti predominated in most isolates, and they were detected in several chromosomal backgrounds corresponding to up to nine Mesorhizobium lineages. The results indicated that C. canariense is a promiscuous legume that can be nodulated by several rhizobial species and symbiotypes, which means it will be important to determine the combination of core and symbiotic genes that produce the most effective symbiosis.     

Synthesis of magneto-sensitive iron-containing nanoparticles by yeasts

Industrial production of magneto-sensitive nanoparticles, which can be used in the production of target drug delivery carriers, is a subject of interest for biotechnology and microbiology. Synthesis of these nanoparticles by microorganisms has been described only for bacterial species. At the same time, it is well known that yeasts can form various metal-containing nanoparticles used, for instance, in semiconductors, etc. This paper describes the first results of the biosynthesis of magneto-sensitive nanoparticles by yeasts. The organisms we used—Saccharomyces cerevisiae and Cryptococcus humicola—represented two different genera. Magneto-sensitive nanoparticles were synthesized at room temperature in bench-scale experiments. The study included transmission electron microscopy of the yeast cells and their energy dispersive spectrum analyses and revealed the presence of iron-containing nanoparticles. Both yeast cultures synthesized nanoparticles at high concentrations of dissolved iron. Electron microscopy showed that nanoparticles were associated mainly with the yeast cell wall. Formation of magneto-sensitive nanoparticles was studied under conditions of applied magnetic fields; a possible stimulating role of magnetic field is suggested. On the whole, the paper reports a novel approach to green biosynthesis of magneto-sensitive nanoparticles.     

Patterns and drivers of Araucaria araucana forest growth along a biophysical gradient in the northern Patagonian Andes: Linking tree rings with satellite observations of soil moisture

Araucaria araucana (Araucaria) is a long‐lived conifer growing along a sharp west–east biophysical gradient in the Patagonian Andes. The patterns and climate drivers of Araucaria growth have typically been documented on the driest part of the gradient relying on correlations with meteorological records, but the lack of in situ soil moisture observations has precluded an assessment of the growth responses to soil moisture variability. Here, we use a network of 21 tree‐ring width chronologies to investigate the spatiotemporal patterns of tree growth through the entire gradient and evaluate their linkages with regional climate and satellite‐observed surface soil moisture variability. We found that temporal variations in tree growth are remarkably similar throughout the gradient and largely driven by soil moisture variability. The regional spatiotemporal pattern of tree growth was positively correlated with precipitation (r = 0.35 for January 1920–1974; P < 0.01) and predominantly negatively correlated with temperature (r = ?0.38 for January–March 1920–1974; P < 0.01) during the previous growing season. These correlations suggest a temporally lagged growth response to summer moisture that could be associated with known physiological carry‐over processes in conifers and to a response to moisture variability at deeper layers of the rooting zone. Notably, satellite observations revealed a previously unobserved response of Araucaria growth to summer surface soil moisture during the current rather than the previous growing season (r = 0.65 for 1979–2000; P < 0.05). This new response has a large spatial footprint across the mid‐latitudes of the South American continent (35°–45°S) and highlights the potential of Araucaria tree rings for palaeoclimatic applications. The strong moisture constraint on tree growth revealed by satellite observations suggests that projected summer drying during the coming decades may result in regional growth declines in Araucaria forests and other water‐limited ecosystems in the Patagonian Andes.     

Shc depletion stimulates brown fat activity in vivo and in vitro

Adipose tissue is an important metabolic organ that integrates a wide array of homeostatic processes and is crucial for whole‐body insulin sensitivity and energy metabolism. Brown adipose tissue (BAT) is a key thermogenic tissue with a well‐established role in energy expenditure. BAT dissipates energy and protects against both hypothermia and obesity. Thus, BAT stimulation therapy is a rational strategy for the looming pandemic of obesity, whose consequences and comorbidities have a huge impact on the aged. Shc‐deficient mice (ShcKO) were previously shown to be lean, insulin sensitive, and resistant to high‐fat diet and obesity. We investigated the contribution of BAT to this phenotype. Insulin‐dependent BAT glucose uptake was higher in ShcKO mice. Primary ShcKO BAT cells exhibited increased mitochondrial respiration; increased expression of several mitochondrial and lipid‐oxidative enzymes was observed in ShcKO BAT. Levels of brown fat‐specific markers of differentiation, UCP1, PRDM16, ELOVL3, and Cox8b, were higher in ShcKO BAT. In vitro, Shc knockdown in BAT cell line increased insulin sensitivity and metabolic activity. In vivo, pharmacological stimulation of ShcKO BAT resulted in higher energy expenditure. Conversely, pharmacological inhibition of BAT abolished the improved metabolic parameters, that is the increased insulin sensitivity and glucose tolerance of ShcKO mice. Similarly, in vitro Shc knockdown in BAT cell lines increased their expression of UCP1 and metabolic activity. These data suggest increased BAT activity significantly contributes to the improved metabolic phenotype of ShcKO mice.     

GAGA protein is essential for male germ cell development in Drosophila

The Drosophila Trithorax‐like (Trl) gene encodes a GAGA factor which regulates a number of developmentally important genes. In this study, we identify a new function for Drosophila GAGA factor in male germ cell development. Trl mutants carrying strong hypomorphic alleles display loss of primordial germ cells during their migration in embryogenesis and severe disruption in mitochondria structure during early spermatogenesis. The mutation resulted in small testes formation, a deficit of germ cells, abnormal mitochondrial morphogenesis, spermatocyte death through autophagy, and partial or complete male sterility. Pleiotropic mutation effects can be explained by the misexpression of GAGA factor target genes, the products of which are required for germ cell progression into mature sperm. genesis 52:738–751, 2014. © 2014 Wiley Periodicals, Inc.     

Luminescent complexes of terbium ion for molecular recognition of ibuprofen

The complexation behavior and luminescent properties of terbium (Tb³⁺) complexes containing bi‐dental ligands were studied: nitrogen – 1,10‐phenanthroline, and oxygen – trifluoroacetylacetone as well as acetylacetone ligands with ibuprofen (Ibu; a non‐steroidal anti‐inflammatory drug). Aqueous and aqueous alcohol microheterogeneous solutions were used as media. The effects of solubilization by various micellar solutions, pH and ligand type on luminescent properties of Tb³⁺ complexes were investigated. Sensitized luminescence of mixed ligand complex Tb(1,10‐phenanthroline)‐Ibu and dynamic quenching effect in complex Tb(trifluoroacetylacetone)₃‐Ibu allow Ibu determination with the limit of detection 5.3 × 10^–8 mol/L and 1.26 × 10^–6 mol/L, respectively. Copyright © 2013 John Wiley & Sons, Ltd.     

Human factors and pathways essential for mediating epigenetic gene silencing

Cellular identity in both normal and disease processes is determined by programmed epigenetic activation or silencing of specific gene subsets. Here, we have used human cells harboring epigenetically silent GFP-reporter genes to perform a genome-wide siRNA knockdown screen for the identification of cellular factors that are required to maintain epigenetic gene silencing. This unbiased screen interrogated 21,121 genes, and we identified and validated a set of 128 protein factors. This set showed enrichment for functional categories, and protein-protein interactions. Among this set were known epigenetic silencing factors, factors with no previously identified role in epigenetic gene silencing, as well as unstudied factors. The set included non-nuclear factors, for example, components of the integrin-adhesome. A key finding was that the E1 and E2 enzymes of the small ubiquitin-like modifier (SUMO) pathway (SAE1, SAE2/UBA2, UBC9/UBE2I) are essential for maintenance of epigenetic silencing. This work provides the first genome-wide functional view of human factors that mediate epigenetic gene silencing. The screen output identifies novel epigenetic factors, networks, and mechanisms, and provides a set of candidate targets for epigenetic therapy and cellular reprogramming.     

Effect of photodynamic therapy on the skin using the ultrashort laser ablation

Photodynamic Therapy (PDT) with 5‐aminolevulinic acid (ALA) is known to be limited for applications in tumours of large volume mainly due to the limited penetration of topical photosensitization. The results show that micro‐holes created using a femtosecond laser before PDT significantly increased the depth of PDT effect in the healthy tissue. The combination of ultrashort laser ablation technique with PDT showed an important scientific breakthrough related to transportation and delivery of drugs into the deeper regions of the tissue. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)