Mating pheromones promote cellular differentiation and fusion of yeast cells with those of the opposite mating type. In the absence of a suitable partner, high concentrations of mating pheromones induced rapid cell death in ϳ25% of the population of clonal cultures independent of cell age. Rapid cell death required Fig1, a transmembrane protein homologous to PMP-22/EMP/MP20/Claudin proteins, but did not require its Ca 2؉ influx activity. Rapid cell death also required cell wall degradation, which was inhibited in some surviving cells by the activation of a negative feedback loop involving the MAP kinase Slt2/Mpk1. Mutants lacking Slt2/Mpk1 or its upstream regulators also underwent a second slower wave of cell death that was independent of Fig1 and dependent on much lower concentrations of pheromones. A third wave of cell death that was independent of Fig1 and Slt2/Mpk1 was observed in mutants and conditions that eliminate calcineurin signaling. All three waves of cell death appeared independent of the caspase-like protein Mca1 and lacked certain "hallmarks" of apoptosis. Though all three waves of cell death were preceded by accumulation of reactive oxygen species, mitochondrial respiration was only required for the slowest wave in calcineurin-deficient cells. These findings suggest that yeast cells can die by necrosis-like mechanisms during the response to mating pheromones if essential response pathways are lacking or if mating is attempted in the absence of a partner. INTRODUCTIONProgrammed cell death (PCD) occurs in metazoans as a means of eliminating unwanted cells during development and removing damaged, weak, infected, or malignant cells from the organism to avoid potentially harmful consequences (Danial and Korsmeyer, 2004). PCD is highly coordinated and regulated at multiple levels. Inputs from a variety of sources can impact on a core set of enzymes that coordinate destruction of key cellular components necessary for cell survival. Apoptosis, one form of PCD, typically requires activation of cysteine-aspartyl proteases (caspases) by signaling factors derived from mitochondria or the plasma membrane. Conservation of PCD factors among all animals (Koonin and Aravind, 2002) is consistent with a very early origin of the PCD mechanism, potentially even before the divergence of animals and fungi.The occurrence of PCD in fungi has received support from numerous studies using the budding yeast Saccharomyces cerevisiae (reviewed in Madeo et al., 2002(reviewed in Madeo et al., , 2004Longo et al., 2005). Several so-called "hallmarks" of apoptosis can be observed in populations of yeast cells that have been mortally wounded by environmental stresses such as high heat, high salt, hypertonic shock, DNA damaging agents, food preservatives, and hydrogen peroxide. Starvation and aging also seem to induce apoptosis-like cell death in a minority of cells in the dying population (reviewed in Longo et al., 2005). Expression of mammalian Bax in yeast also leads to mitochondrial dysfunction, accumulation of reactive oxygen s...

Based on information technology adoption theories and considering Chinese cultural characteristics, this article proposes a user centric IT/IS evaluation model composed of three determinants, namely perceived usefulness, perceived ease of use, and perceived fit, for investigating the e-government systems application and management in China. By empirically validating the model with survey data, it is demonstrated that the perceived fit has significant impacts on the end users’ evaluation towards e-government systems, due to the special element of Hexie in the Chinese culture. The results also indicate that the reasons for failures in e-government systems application in China largely lie in the lack of fit, which may root in the long power distance characteristic of the Far Eastern culture. The findings will provide scholars and practitioners with better understanding of the user evaluation regarding e-government systems in a Chinese cultural context.

The combustion properties, flame retardant property, thermal degradation and component of pyrolysis products of calcium alginate fibers were investigated in this paper. The limiting oxygen index value of calcium alginate fibers was 34.4 showing no combustion in the air. The fiber extinguishes instantly when it is moved away from the fire. During the combustion process, the heat release rates (HRR), effective heat combustion (EHC) and total heat release (THR) of calcium alginate fibers were lower than those of cotton fibers, but higher than those of sodium alginate. The carbon dioxide yield rate of calcium alginate fibers was higher than that of cotton fibers but lower than that of sodium alginate. Calcium carbonate and calcium hydroxide, which are beneficial to hamper fibers combustion and diffusion of heat and oxygen, were formed during thermal degradation of calcium alginate fibers. There were 15 kinds of pyrolysis products in gas phase of calcium alginate fibers at 350°C and 45 kinds at 700 °C, while there were 26 kinds of pyrolysis products of sodium alginate at 350°C and 26 kinds at 700°C. Based on a series of study, the flame retardant mechanism of calcium alginate fibers was analyzed.

Based on anisometric noble-metal nanocrystals, a universal fabrication protocol for preparing 3D supercrystals with controlled orientation on a chip has been developed. A comparison of the surface-enhanced Raman scattering (SERS) behavior of 3D nanorod supercrystals aligned vertically and parallel to the chip indicates that the SERS-enhancing ability and reproducibility of the former is superior to the latter. The 3D nanorod supercrystals aligned vertically to the chip have been utilized as highly sensitive SERS substrates for the label-free discrimination of Gram-positive and -negative bacteria. Furthermore, to strengthen the stability of the supercrystal substrate for assays of bacteria in biosamples, a coating of the antibiotic vancomycin can dramatically increase adhesion of bacteria on a nanointerface and simultaneously improve the SERS response of bacteria to achieve a layer-by-layer assembled, stable, and reliable biosensor for bacteria.

Considering the various loads combination and durability,pile’s diameter,embedded depth,anchor’s rod, anchorage length need to be strengthened in the permanent supporting foundation engineering.Based on Chengdu Museum foundation project, the influencing factors such as pile’s diameter,embedded depth,anchor’s pretentioned force are discussed.With comparasion of calculated data and monitoring data, this paper generalized influence of pile diameter, embedded depth, anchor pretensioned force on permanent pars mechanics properties.