The role of Saccharomyces cerevisiae coronin in the actin and microtubule cytoskeletons

Coronin was originally identified as a cortical protein associated with the actin cytoskeleton in Dictyostelium [1]. More recent studies have revealed that coronin is involved in actin-based motility, cytokinesis and phagocytosis [2,3]. Here, we describe the identification of a single homolog of coronin in Saccharomyces cerevisiae, which we show localizes to cortical actin patches in an actin-dependent manner. Unlike Dictyostelium mutants that lack coronin, yeast strains lacking coronin had no detectable defects in actin-based processes. This may reflect differences in the functions of the actin cytoskeleton in these two organisms. Previous studies have shown that cortical actin may mediate astral microtubule-based movements of the mitotic spindle in S. cerevisiae [4,5] and that, during mitosis in Dictyostelium, the regions of the cell cortex that overlap with astral microtubules become enriched in actin and coronin [6]. We therefore examined whether yeast lacking coronin had defects in the microtubule cytoskeleton. The mutant strains had increased sensitivity to the microtubule-destabilizing drug benomyl and an increased number of large-budded cells with short spindles. Further examination of microtubule-related processes, including spindle formation, migration of the mitotic spindle to the bud neck, spindle elongation, and translocation of the elongating spindle through the bud neck, failed to reveal any defects in the coronin mutant. Taken together, these results suggest that S. cerevisiae coronin is a component of the actin cytoskeleton that may interact with the microtubule cytoskeleton.     

The morphological characteristics of the lung lesions in straighteners working with brass-bronze alloys

Morphologic study of lung specimens obtained during diagnostic thoractomy in 6 workers engaged in smelting brass-bronze alloys showed changes typical of exogenous fibrosing alveolitis, namely, terminal bronchiolitis with pseudopolypous growth in the submucous layer, vasculitis (predominantly arteritis) paralleled by secondary recalibration of vessels, arteriolar and venular shunting, and microcirculatory disorders.     

Effect of polyene antibiotics on isolated dog kidney nuclei

Effect of amphotericin B and nistation on caryoplasmic proteins, nuclear membrane-bound chromatin (DNPm) and soluble DNP (DNP0) from dog kidney isolated nuclei is studied in vitro. The yield of caryoplasmic proteins from nuclei is found to be increased during incubation with amphotericin B and nistatin, the content of some fraction in caryoplasmic proteins being decreased while their qualitative composition being unchanged. It is found that the treatment of nuclei with amphotericin B contributes the association of DNP particles with nuclear membrane and the increase of protein/DNA and RNA/DNA ratios in DNPm. No such effects are observed in the presence of nistatin. Both antibiotics do not affect protein/DNA and RNA/DNA ratios in DNP0 fraction. Polyene antibiotics are shown to change considerably the composition of acid soluble proteins in DNP0 and DNPm and in non-histone proteins in DNP0, and not to affect the content of lipids and their fatty acid composition in DNPm. The data obtained are of certain value for explanation of the mechanism of toxic effect of polyene antibiotics on animal cells.     

Thy-1, a novel marker for angiogenesis upregulated by inflammatory cytokines

We identified the cell surface glycoprotein Thy-1 on the endothelium of newly formed blood vessels in four models of angiogenesis in adult rats. Anti-Thy-1 staining showed that Thy-1 was upregulated in adventitial blood vessels after balloon injury to the carotid artery. Preabsorption with a rat Thy-1-Ig fusion construct eliminated all immunoreactivity and thus confirmed the specificity of the Thy-1 staining. Thy-1 was also expressed in the endothelium of small blood vessels formed after tumor implantation in the cornea, in periureteral vessels formed after ligation of the renal artery, and in small blood vessels of the uterus formed during pregnancy. In contrast with its expression during adult angiogenesis, Thy-1 was not expressed in the endothelium of blood vessels during embryonic angiogenesis. In vitro, the inflammatory cytokines interleukin-1beta and tumor necrosis factor-alpha upregulated Thy-1 mRNA by 8- and 14-fold, respectively. Vascular endothelial growth factor, basic fibroblast growth factor, transforming growth factor-beta, and platelet-derived growth factor-BB had no effect on Thy-1 mRNA. Thus, Thy-1 appears to be a marker of adult but not embryonic angiogenesis. The upregulation of Thy-1 by cytokines but not growth factors indicates the importance of inflammation in the pathogenesis of adult angiogenesis.     

The design and implementation of a three-phase active power filterbased on sliding mode control

This paper presents an active power filter for three-phase power systems. The work is motivated by the need for active filtration in a current-source excitation system for a variable-reluctance generator. The active filter is comprised of a six-switch three-phase inverter, a DC bus capacitor, and an isolation transformer. The isolation transformer is required by the application. The leakage inductance associated with each phase of the isolation transformer is used as the series impedance with each phase, by which the inverter is able to actively shape the phase currents in order to compensate for the nonlinearities of all loads within the point of common coupling. The active filter is controlled through two control loops. The inner current regulation loop uses sliding-mode control by virtue of its ease of implementation. The outer voltage loop regulates the average voltage on the DC bus capacitor. The outer voltage loop is responsible for correctly setting the commanded magnitude of the phase currents. This paper presents the analysis, design, and operation of the active filter. Experimental results are provided for the active filter compensating a phase-controlled rectifier which is drawing 10.4 kW     

Urea release from silicate- and polymer-coated urea in water and a simulated wetland soil

Urea release rates in water (38°C) and in a simulated wetland soil system under greenhouse conditions from silicate- and polymer-coated urea (SPCU) materials have been studied. The SPCU materials were prepared by the Korea Advanced Institute of Science and Technology (KAIST), Seoul, Korea, in cooperation with the International Fertilizer Development Center (IFDC). Average urea release ( \(\overline {UR} \) ) in water was mainly a diffusion-controlled, concentration-gradient dependent process. It was markedly influenced by the extent of swelling of the coatings of granules. Under unrestricted swelling condition, \(\overline {UR} \) versus time gave an s-shaped curve with three distinct periods: namely, a delayed period, a maximum-rate period, and slow-rate period. \(\overline {UR} \) versus time curves for SPCU after placement at 0- to 2-, 5- to 10- and 10- to 15-cm depth in a simulated wetland soil system were, in general, sigmoidal but different from those in water. They were influenced by placement depths of SPCU granules in the soil, and the order of \(\overline {UR} \) at the soil depths studied was: 0–2 cm, < 5–15 cm ? 10–15 cm.