Adaptive response of Schizosaccharomyces pombe to hydrogen peroxide

Abstract Schizosaccharomyces pombe becomes resistant to killing by high concentration of hydrogen peroxide and other severe stresses including oxidants, high temperature and high concentration of ethanol when pretreated with nonlethal levels of hydrogen peroxide. In the presence of the protein synthesis inhibitor, cycloheximide, during hydrogen peroxide pretreatment, the cell obtained partial resistance to a higher level of hydrogen peroxide. The partial resistance to hydrogen peroxide in the presence of cycloheximide was acquired within 30 min of pretreatment but complete resistance obtained with de novo protein synthesis was not attained before 45 min of pretreatment. During adaptation to hydrogen peroxide, at least 15 polypeptides are induced, as analyzed by two-dimensional gel electrophoresis. Catalase activity is induced eight-fold by treatment with a nonlethal level of hydrogen peroxide.     

Morphological mutation of Lentinula edodes mycelium, particularly detectable in the dikaryotic state

A morphological mutation particularly detectable in the dikaryotic state was found in Lentinula edodes. The mutant dikaryon was readily distinguishable from the normal dikaryon by the irregularly branched short hyphae, very slow hyphal growth, and sparse aerial hyphae. Genetic analysis revealed that expression of this mutation was controlled by a single recessive gene, mor-13. Linkage analysis showed that the mor-13 was not linked to either the incompatibility factors (A and B) or the five kinds of mor genes that were segregated independently of each other in a previous study. Contribution no. 380 from the Tottori Mycological Institute     

Prospectively Isolated Cancer-Associated CD10+ Fibroblasts Have Stronger Interactions with CD133+ Colon Cancer Cells than with CD133? Cancer Cells

Although CD133 has been reported to be a promising colon cancer stem cell marker, the biological functions of CD133⁺ colon cancer cells remain controversial. In the present study, we investigated the biological differences between CD133⁺ and CD133⁻ colon cancer cells, with a particular focus on their interactions with cancer-associated fibroblasts, especially CD10⁺ fibroblasts. We used 19 primary colon cancer tissues, 30 primary cultures of fibroblasts derived from colon cancer tissues and 6 colon cancer cell lines. We isolated CD133⁺ and CD133⁻ subpopulations from the colon cancer tissues and cultured cells. In vitro analyses revealed that the two populations showed similar biological behaviors in their proliferation and chemosensitivity. In vivo analyses revealed that CD133⁺ cells showed significantly greater tumor growth than CD133⁻ cells (P = 0.007). Moreover, in cocultures with primary fibroblasts derived from colon cancer tissues, CD133⁺ cells exhibited significantly more invasive behaviors than CD133⁻ cells (P<0.001), especially in cocultures with CD10⁺ fibroblasts (P<0.0001). Further in vivo analyses revealed that CD10⁺ fibroblasts enhanced the tumor growth of CD133⁺ cells significantly more than CD10⁻ fibroblasts (P<0.05). These data demonstrate that the in vitro invasive properties and in vivo tumor growth of CD133⁺ colon cancer cells are enhanced in the presence of specific cancer-associated fibroblasts, CD10⁺ fibroblasts, suggesting that the interactions between these specific cell populations have important roles in cancer progression. Therefore, these specific interactions may be promising targets for new colon cancer therapies.     

Tetramethylthiuram disulfide or dimethyldithiocarbamate induces the synthesis of cadystins, heavy metal chelating peptides, in Schizosaccharomyces pombe.

Tetramethylthiuram disulfide (TMTD) or dimethyldithiocarbamate (DMDTC) induces the synthesis of cadystins, a family of heavy metal chelating isopeptides with the formula (gamma-Glu-Cys)n-Gly (n = 2,3,4,...), in the fission yeast Schizosaccharomyces pombe. Amount of cadystins synthesized in TMTD or DMDTC treated cells is less than that synthesized in CdCl2 treated cells but much more than that synthesized in ZnCl2 or CuSO4 treated cells.     

Substructure of the Cytoplasmic Membrane of Bacillus megaterium

The components of fractions obtained by dialyzing and differential centrifuging the “Ghost” of Bacillus megaterium were analyzed in detail. The compositions of amino acids in the main fractions (Fraction 2 and 3) of the “Ghosts”, were estimated. Fraction 2 was rich in non-polar amino acids, while Fraction 3 was scanty of them. Most of the fatty acids in Fraction 2 were 12-methyl tetradecanoic acid, while in Fraction 3 many kinds of fatty acid were detected.

As for the localization of enzymes, the three enzymes, glucose oxidase, succinic dehydrogenase and reduced nicotinamide-adenine dinucleotide oxidase, which were present in the original “Ghosts”, were mostly observed in Fraction 2, and a very little amount of them was found in the other fractions. Further, Fraction 2 could be dissolved in formic acid and dialysis of the solution brought about reaggregation to form membrane-like structure in the presence of Ca or Mg ion.     

Evolution of chromosome number in grasshoppers (Orthoptera: Caelifera: Acrididae)

Organisms Diversity & Evolution - Orthoptera have some of the largest genomes of all insects. At the same time, the architecture of their genomes remains poorly understood. Comparative...     

Toward more comprehensive environmental impact assessments: interlinked global models of LCIA and IAM applicable to this century

The International Journal of Life Cycle Assessment - Despite the long-standing demand for research on dynamic lifecycle assessment (LCA) for policymaking, only a few studies have addressed this...     

Genetic Evidence That the Non-Homologous End-Joining Repair Pathway Is Involved in LINE Retrotransposition

Long interspersed elements (LINEs) are transposable elements that proliferate within eukaryotic genomes, having a large impact on eukaryotic genome evolution. LINEs mobilize via a process called retrotransposition. Although the role of the LINE-encoded protein(s) in retrotransposition has been extensively investigated, the participation of host-encoded factors in retrotransposition remains unclear. To address this issue, we examined retrotransposition frequencies of two structurally different LINEs—zebrafish ZfL2-2 and human L1—in knockout chicken DT40 cell lines deficient in genes involved in the non-homologous end-joining (NHEJ) repair of DNA and in human HeLa cells treated with a drug that inhibits NHEJ. Deficiencies of NHEJ proteins decreased retrotransposition frequencies of both LINEs in these cells, suggesting that NHEJ is involved in LINE retrotransposition. More precise characterization of ZfL2-2 insertions in DT40 cells permitted us to consider the possibility of dual roles for NHEJ in LINE retrotransposition, namely to ensure efficient integration of LINEs and to restrict their full-length formation.     

Effect of Voltage Sensitive Fluorescent Proteins on Neuronal Excitability

Fluorescent protein voltage sensors are recombinant proteins that are designed as genetically encoded cellular probes of membrane potential using mechanisms of voltage-dependent modulation of fluorescence. Several such proteins, including VSFP2.3 and VSFP3.1, were recently reported with reliable function in mammalian cells. They were designed as molecular fusions of the voltage sensor of Ciona intestinalis voltage sensor containing phosphatase with a fluorescence reporter domain. Expression of these proteins in cell membranes is accompanied by additional dynamic membrane capacitance, or “sensing capacitance”, with feedback effect on the native electro-responsiveness of targeted cells. We used recordings of sensing currents and fluorescence responses of VSFP2.3 and of VSFP3.1 to derive kinetic models of the voltage-dependent signaling of these proteins. Using computational neuron simulations, we quantitatively investigated the perturbing effects of sensing capacitance on the input/output relationship in two central neuron models, a cerebellar Purkinje and a layer 5 pyramidal neuron. Probe-induced sensing capacitance manifested as time shifts of action potentials and increased synaptic input thresholds for somatic action potential initiation with linear dependence on the membrane density of the probe. Whereas the fluorescence signal/noise grows with the square root of the surface density of the probe, the growth of sensing capacitance is linear. We analyzed the trade-off between minimization of sensing capacitance and signal/noise of the optical read-out depending on kinetic properties and cellular distribution of the probe. The simulation results suggest ways to reduce capacitive effects at a given level of signal/noise. Yet, the simulations indicate that significant improvement of existing probes will still be required to report action potentials in individual neurons in mammalian brain tissue in single trials.     

Reduced responsiveness is an essential feature of chronic fatigue syndrome: A fMRI study

Background  

Although the neural mechanism of chronic fatigue syndrome has been investigated by a number of researchers, it remains poorly understood.