The ich1 gene of the mushroom Coprinus cinereus is essential for pileus formation in fruiting

The formation of the pileus in homobasidiomycete fungi is essential for sexual reproduction, because the pileus bears the hymenium, a layer of cells that includes the specialised basidia in which nuclear fusion, meiosis and sporulation occur. The developmental mutant ichijiku of Coprinus cinereus fails to develop a differentiated pileus at the apex of the primordial shaft, which is the basal part of the fruit-body primordia and formed in an early stage of fruit-body differentiation. Genetic analysis indicates that this phenotype is caused by a recessive mutation in a single gene (ich1). The ich1 gene was mapped to chromosome XII using restriction fragment length polymorphism markers and the marker chromosome method, and cloned by complementation using a chromosome-XII-specific cosmid library. The ich1 gene encodes a novel protein of 1,353 amino acids. The Ich1 amino-acid sequence contains nuclear targeting signals, suggesting that the Ich1 protein would function in the nucleus. Northern blot analysis indicates that the ich1 gene is specifically expressed in the pileus of the wild-type fruit-body. No ich1 mRNA was detected in the ichijiku mutant, consistent with loss of the promoter region of ich1 in the mutant genome. These data demonstrate that the ick1 gene product is essential for pileus formation.</p

Identification of side population cells in mouse primordial germ cells and prenatal testis

In mammals, the stem cells of spermatogenesis are derived from an embryonic cell population called primordial germ cells (PGCs). Spermatogonial stem cells displaying the "side population" (SP) phenotype have been identified in the immature and adult mouse testis, but noting is known about the expression of the SP phenotype during prenatal development of germ cells. The SP phenotype, defined as the ability of cells to efflux fluorescent dyes such as Hoechst, is common to several stem/progenitor cell types. In the present study, we analyzed and characterized the Hoechst SP via cytofluorimetric analysis of disaggregated gonads at different time points during embryonic development in mice. To directly test the hypothesis that the SP phenotype is a feature of germ cell lineage, experiments were performed on transgenic animals expressing enhanced green fluorescent protein (EGFP) under the control of the Oct4 promoter, to identify early germ cells up to PGCs. We found that prenatal gonads contain a fraction of SP cells at each stage analyzed, and the percentage of cells in the SP fraction decreases as development proceeds. Surprisingly, more than 50% of the PGCs displayed the SP phenotype at 11.5 dpc (days post coitum). The percentage of germ cells with the SP phenotype decreased steadily with development, to less than 1% at 18.5 dpc. Cytofluorimetric analysis along with immunocytochemistry performed on sorted cells indicated that the SP fraction of prenatal gonads, as in the adult testis, was heterogeneous, being composed of both somatic and germ cells. Both cell types expressed the ABC transporters Abcg2, Abcb1a, Abcb1b and Abcc1. These findings provide evidence that the SP phenotype is a common feature of PGCs and identifies a subpopulation of fetal testis cells including prospermatogonia whose differentiation fate remains to be investigated. © 2011 UBC Press

Complex Response Function of Magnetic Resonance Spectrometers

A vectorial analysis of magnetic resonance spectrometers, based on traveling wave resonators and including the reference arm and the automatic control of frequency, has been developed. The proposed model, valid also for stationary wave resonators, gives the response function of the spectrometer for any working condition, including scalar detectors with arbitrary response law and arbitrary excitation frequency. The purely dispersive and purely absorptive linear responses are discussed in detail for different scalar detectors. The developed approach allows for optimizing the performances of the spectrometer and for obtaining the intrinsic lineshape of the sample in a very broad range of working conditions. More complex setups can be modeled following the proposed scheme.Comment: PDF Acrobat 4.0 file, 15 pages, 2 figures, revised version with added reference and corrected typo

Disfunção endotelial na Obesidade: o papel da adiponectina

Um estilo de vida sedentário e uma dieta rica em hidratos de carbono e gorduras são as principais causas para o aumento do número de casos de obesidade, tornando a síndrome metabólica num problema de saúde mundial. A síndrome metabólica carateriza-se por uma combinação de alterações que incluem a obesidade abdominal, a dislipidemia, a hipertensão arterial e a insulino-resistência (IR) as quais em conjunto, aumentam significativamente o risco de diabetes tipo 2 e doença cardiovascular. A obesidade e a IR estão associadas a disfunção endotelial, que desempenha um papel fundamental na patologia cardiovascular. Os mecanismos que associam a obesidade, a IR e a disfunção endotelial são numerosos e complexos. A obesidade geralmente envolve a gordura visceral, o que conduz a um desequilíbrio de produtos metabólicos, hormonais e adipocitocinas como os ácidos gordos livres em circulação, o tumor necrosis factor alpha (TNF-α) e a adiponectina. A adiponectina é uma adipocitocina maioritariamente produzida pelo tecido adiposo que circula em níveis relativamente elevados na corrente sanguínea. Exibe potentes efeitos anti-inflamatórios e ateroprotetores no tecido vascular, além da sua ação sensibilizadora para a insulina nos tecidos periféricos. Os níveis séricos de adiponectina diminuem em estados de obesidade e demonstrou-se uma associação entre os níveis de adiponectina circulante e a função endotelial. No entanto, os mecanismos subjacentes ao efeito benéfico da adiponectina na função endotelial não estão completamente esclarecidos. O objetivo deste estudo é investigar os efeitos da adiponectina na disfunção endotelial associada à síndrome metabólica, e caraterizar alguns dos principais mecanismos de ação associados. Assim, os potenciais benefícios terapêuticos desta adipocitocina no endotélio vascular serão avaliados após administração de adiponectina a modelos animais obesos. A síndrome metabólica será analisada em modelos animais obesos, nos quais a obesidade é induzida com uma dieta rica em gordura (DIO). Serão avaliados os benefícios terapêuticos da adiponectina em diferentes marcadores de stress oxidativo sistémicos e na parede das artérias e os níveis de expressão de diferentes proteínas associadas ao processo aterosclerótico. Avaliaremos o impacto da administração de adiponectina nos níveis de diferentes biomarcadores metabólicos, hormonais e inflamatórios. É esperado que na presença deste composto seja normalizada a disfunção endotelial e substancialmente reduzida a IR e o stress oxidativo

Expression of interleukin 2 receptors on activated human B cells.

Using anti-Tac, a monoclonal anti-interleukin 2 (IL-2) receptor antibody, we have explored the possibility that certain activated B cells display receptors for IL-2. Resting normal B cells and unselected B cell lines established from normal individuals were Tac antigen negative. In contrast, the cell surface Tac antigen expression was demonstrable on 6 of 10 B cell lines from patients with Burkitt's lymphoma, 5 of 6 B cell lines derived from patients with HTLV-I-associated adult T cell leukemia (including all four that had integrated HTLV-I into their genome), and on certain normal B cells activated with pokeweed mitogen. Furthermore, cloned Epstein-Barr virus-transformed B cell lines derived from Tac-positive normal B cells continued to express the Tac antigen in long-term cultures and manifested high affinity IL-2 receptors identified in binding studies with purified radiolabeled IL-2. The line 5B4 developed in the present study could be induced with purified JURKAT-derived or recombinant IL-2 to express a larger number of IL-2 receptors. Furthermore, the addition of IL-2 to the 5B4 B cell line augmented IgM synthesis, which could be blocked by the addition of anti-Tac. The size of the IL-2 receptors expressed on the cloned normal B cell lines was similar (53,000-57,000 daltons) to that of receptors on phytohemagglutinin-stimulated T cell lymphoblasts. Thus, certain malignant and activated normal B cells display the Tac antigen and manifest high affinity receptors for IL-2. These data suggest that IL-2 may play a role in the differentiation of activated B cells into immunoglobulin-synthesizing and -secreting cells

PCR array and protein array studies demonstrate that IL-1β (interleukin-1β) stimulates the expression and secretion of multiple cytokines and chemokines in human adipocytes

The role of IL-1β in regulating the expression and secretion of cytokines and chemokines by human adipocytes was examined. Adipocytes were incubated with human IL-1β for 4 or 24 h. The expression of a panel of 84 cytokine/chemokine genes was probed using PCR arrays. IL-1β stimulated the expression of >30 cytokine/chemokine genes on the arrays; 15 showed >100-fold increases in mRNA at 4 or 24 h including CSF3, CXCL1, CXCL2, CXCL12 and IL8. CSF3 exhibited a 10,000-fold increase in mRNA at 4 h. ADIPOQ was among the genes whose expression was inhibited. Protein arrays were used to examine the secretion of cytokines/chemokines from adipocytes. IL-1β stimulated the secretion of multiple cytokines/chemokines including MCP-1, IL-8, IP-10, MIP-1α and MCP-4. The most responsive was IP-10, which exhibited a 5,000-fold increase in secretion with IL-1β. IL-1β is likely to play a substantial role in stimulating the inflammatory response in human adipocytes in obesity