Search

PURPOSE To investigate the dose-response of an aquatic microcosm exposed to gamma-rays and to test the suitability of microcosms for elucidation of the mechanisms that account for such ecological effects. MATERIALS AND METHODS The microcosm used in this study consisted of algae Euglena gracilis Z as a producer, protozoa Tetrahymena thermophila B as a consumer and bacteria Escherichia coli DH5alpha as a decomposer. After the steady-state microcosm was irradiated with 60Co gamma-rays at various dose levels, the population densities of each species were measured. RESULTS Irradiation at up to 100 Gy did not affect the population of the microcosm except for a temporary decrease of E. coli just after irradiation. At 500 or 1000Gy, E. coli died out just after irradiation. Only Eu. gracilis and T. thermophila could survive. Their populations, however, decreased compared with that of each control, except for a temporary increase of T. thermophila after 1000 Gy irradiation. These population changes were attributable to the extinction of E. coli in addition to the direct effects of radiation. Irradiation at 5000 Gy extinguished all species in the microcosm. CONCLUSIONS The response of the microcosm to radiation was dose-dependent over a range of high doses. The microcosm was also shown to be suitable for examining not only direct effects but also secondary effects.

Lampreys are representatives of an ancient vertebrate lineage that diverged from our own ~500 million years ago. By virtue of this deeply shared ancestry, the sea lamprey (P. marinus) genome is uniquely poised to provide insight into the ancestry of vertebrate genomes and the underlying principles of vertebrate biology. Here, we present the first lamprey whole-genome sequence and assembly. We note challenges faced owing to its high content of repetitive elements and GC bases, as well as the absence of broad-scale sequence information from closely related species. Analyses of the assembly indicate that two whole-genome duplications likely occurred before the divergence of ancestral lamprey and gnathostome lineages. Moreover, the results help define key evolutionary events within vertebrate lineages, including the origin of myelin-associated proteins and the development of appendages. The lamprey genome provides an important resource for reconstructing vertebrate origins and the evolutionary events that have shaped the genomes of extant organisms.

In 2001, we reported linkage of an autosomal dominant form of limb-girdle muscular dystrophy, limb-girdle muscular dystrophy 1F, to chromosome 7q32.1-32.2, but the identity of the mutant gene was elusive. Here, using a whole genome sequencing strategy, we identified the causative mutation of limb-girdle muscular dystrophy 1F, a heterozygous single nucleotide deletion (c.2771del) in the termination codon of transportin 3 (TNPO3). This gene is situated within the chromosomal region linked to the disease and encodes a nuclear membrane protein belonging to the importin beta family. TNPO3 transports serine/arginine-rich proteins into the nucleus, and has been identified as a key factor in the HIV-import process into the nucleus. The mutation is predicted to generate a 15-amino acid extension of the C-terminus of the protein, segregates with the clinical phenotype, and is absent in genomic sequence databases and a set of >200 control alleles. In skeletal muscle of affected individuals, expression of the mutant messenger RNA and histological abnormalities of nuclei and TNPO3 indicate altered TNPO3 function. Our results demonstrate that the TNPO3 mutation is the cause of limb-girdle muscular dystrophy 1F, expand our knowledge of the molecular basis of muscular dystrophies and bolster the importance of defects of nuclear envelope proteins as causes of inherited myopathies.

We demonstrate the successful transmission of 10 channels with 224-Gb/s POLMUX-16QAM modulation (28 GBaud) on a 37.5-GHz wavelength grid. Using large-Aeff pure-silica-core fibers we show a 656-km transmission distance with a spectral efficiency of 5.6 b/s/Hz. We report a back-to-back performance penalty of 3.5 dB compared to theoretical limits at the forward-error correction (FEC) limit (bit-error rate of 3.8·10-3), and a margin of 0.5 dB in Q-factor with respect to the FEC-limit after 656 km of transmission.

Mammal adipose tissues require mitochondrial activity for proper development and differentiation. The components of the mitochondrial respiratory chain/oxidative phosphorylation system (OXPHOS) are encoded by both mitochondrial and nuclear genomes. The maintenance of mitochondrial DNA (mtDNA) is a key element for a functional mitochondrial oxidative activity in mammalian cells. To ascertain the role of mtDNA levels in adipose tissue, we have analyzed the alterations in white (WAT) and brown (BAT) adipose tissues in thymidine kinase 2 (Tk2) H126N knockin mice, a model of TK2 deficiency-induced mtDNA depletion. We observed respectively severe and moderate mtDNA depletion in TK2-deficient BAT and WAT, showing both tissues moderate hypotrophy and reduced fat accumulation. Electron microscopy revealed altered mitochondrial morphology in brown but not in white adipocytes from TK2-deficient mice. Although significant reduction in mtDNA-encoded transcripts was observed both in WAT and BAT, protein levels from distinct OXPHOS complexes were significantly reduced only in TK2-deficient BAT. Accordingly, the activity of cytochrome c oxidase was significantly lowered only in BAT from TK2-deficient mice. The analysis of transcripts encoding up to fourteen components of specific adipose tissue functions revealed that, in both TK2-deficient WAT and BAT, there was a consistent reduction of thermogenesis related gene expression and a severe reduction in leptin mRNA. Reduced levels of resistin mRNA were found in BAT from TK2-deficient mice. Analysis of serum indicated a dramatic reduction in circulating levels of leptin and resistin. In summary, our present study establishes that mtDNA depletion leads to a moderate impairment in mitochondrial respiratory function, especially in BAT, causes substantial alterations in WAT and BAT development, and has a profound impact in the endocrine properties of adipose tissues. © 2011 Villarroya et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

The relationship between antiferromagnetic (AF) fluctuation and superconductivity was investigated in the La1111 series, LaFeAsO_{1−x}F_{x} (x=0, 0.05, 0.08, 0.10, and 0.14) by examining nuclear relaxation rates (1/T1) at both ambient pressure and 3.0 GPa. The results show that the critical doping level at which low-frequency AF fluctuation vanishes is around the optimally doped regime (x∼0.10). Although the AF fluctuation is enhanced by applying pressure in the underdoped regime (0.05≤x

It has been known that electron doped 12CaO x 7Al2O3 (C12A7:e-, electride) single crystals, which are composed of a closed-packed periodic quantum dot structure, may be prepared by strong reduction of the precursor C12A7:O2-, but direct single crystal growth of the C12A7:e- from the melt state has never been achieved to date. We report the melt state of polycrystalline electride in pure dry Ar atmosphere at temperatures of 1290 approximately 1500 degrees C, which leads to the direct single crystal growth of the C12A7:e- from the melt. The electride single crystals with a diameter of 7 mm and a length of 43 mm have been grown by a floating zone method, where a polycrystalline electride feed and an electride single crystal seed rod were employed. The electron concentration in the crystal increased up to approximately 1.0 x 10(20) cm(-3) as the growth proceeded. The present findings suggest that electron-entrapped local structure may exist in the melt and the electrons may act as a template for the formation of C12A7 electride in the solidification process of the C12A7 lattice.

Avaliou se o crescimento micelial de 12 isolados monospóricos de Colletotrichum gossypii var. cephalosporiodes provenientes dos Estados de São Paulo, Mato Grosso e Mato Grosso do Sul. Os isolados foram incubados em meio de cultura BDA a 25°C por 7 dias, sendo o tamanho das colônias avaliado diariamente. Ao final do período de avaliação, a área das colônias foi aferida através de programa de análises de imagens. O delineamento experimental utilizado foi o inteiramente casualizado, com arranjo em fatorial 12 x 7, com 5 repetições, onde cada unidade amostral foi representada por uma placa de Petri. Constatou-se significância ao nível de 0,01% do modelo, dos isolados, do período de incubação e de sua interação. Não foi verificada correlação entre a origem geográfica dos isolados e padrão de crescimento dos mesmos. Comparando-se o padrão de crescimento destes isolados com os níveis de patogenicidade descritos por Andrade et ai. (Anais Congresso Paulista de Fitopatologia, 2003, resumo n° 174), verificou-se também ausência de correlação entre as variáveis. Tal fato torna evidente a existência de polimorfismo entre os isolados, convergindo com os resultados citados na literatura para fungos do gênero. (Texte intégral)

Avaliou-se a morfologia conidial de 12 isolados monospóricos de C. gossypii var. cephalosporiodes dos Estados de São Paulo, Mato Grosso e Mato Grosso do Sul. Os isolados foram incubados em BIDA a 25°C por 15 dias, onde se retirou três discos de micélio (5 mm de o), na da região central da colônia. Tais discos foram transferidos para tubos de ensaio contendo 10 mL de água + Tween 20, seguido de agitação por 30 segundos. Em seguida foi retirada uma alíquota de 0,1 mL, onde foram microfotogrados 25 conídios (aumento 1000x). As imagens foram transferidas para um programa de análise de imagens, sendo aferido área, perímetro, comprimento(C), largura(L) e determinada a relação C/L. Usou-se o delineamento inteiramente casualizado, com 25 repetições, cuja unidade amostral foi um conídio. Constatou-se significância (p= 0,001) dos isolados para todas variáveis. Não ocorreu correlação entre a origem geográfica dos isolados e variáveis analisadas, o mesmo foi observado quando se comparou com níveis de patogenicidade (Andrade et al., Anais Congresso Paulista de Fitopatologia, 2003, resumo 174). Tal fato demonstra a existência de polimorfismo entre os isolados, convergindo com os resultados da literatura para fungos do gênero. (Texte intégral)

Round-robin studies on relative sensitivity factors (RSFs) in secondary ion mass spectrometry (SIMS) were conducted using bulk GaAs samples uniformly doped with various impurity elements. A total of 31 laboratories participated in two round-robins. More than 30 sets of relative ion intensities were obtained for B, Si, Cr, Mn, Fe, Cu, Zn, In and Te in GaAs. The RSFs for both positive and negative ions were derived for several types of SIMS instruments. The effect of primary ion incident angle was examined using quadrupole-based instruments and found to be the determining factor of the instrumental dependence of RSF.