Synergistic fungicidal activity of Cu2+ and allicin, an allyl sulfur compound from garlic, and its relation to the role of alkyl hydroperoxide reductase 1 as a cell surface defense in Saccharomyces cerevisiae

Toxicology ◽  
2005 ◽  
Vol 215 (3) ◽  
pp. 205-213 ◽  
Author(s):  
Akira Ogita ◽  
Kiyoo Hirooka ◽  
Yoshihiro Yamamoto ◽  
Nobuo Tsutsui ◽  
Ken-ichi Fujita ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Surface ◽  
Fungicidal Activity ◽  
Sulfur Compound ◽  
Alkyl Hydroperoxide Reductase ◽  
Alkyl Hydroperoxide ◽  
A Cell

Role of cations in the flocculation of Saccharomyces cerevisiae and discrimination of the corresponding proteins

1991 ◽  
Vol 37 (5) ◽  
pp. 397-403 ◽  
Author(s):  
Hiroshi Kuriyama ◽  
Itaru Umeda ◽  
Harumi Kobayashi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Surface ◽  
Inhibitory Effect ◽  
Surface Proteins ◽  
Promoting Effect ◽  
Yeast Strains ◽  
Yeast Flocculation ◽  
Different Types ◽  
Anionic Groups

Asexual yeast flocculation was studied using strong flocculents of Saccharomyces cerevisiae. The inhibitory effect of cations on flocculation is considered to be caused by competition between those cations and Ca2+ at the binding site of the Ca2+-requiring protein that is involved in flocculation. Inhibition of flocculation by various cations occurred in the following order: La3+, Sr2+, Ba2+, Mn2+, Al3+, and Na+. Cations such as Mg2+, Co2+, and K+ promoted flocculation. This promoting effect may be based on the reduction of electrostatic repulsive force between cells caused by binding of these cations anionic groups present on the cell surface. In flocculation induced by these cations, trace amounts of Ca2+ excreted on the cell surface may activate the corresponding protein. The ratio of Sr2+/Ca2+ below which cells flocculated varied among strains: for strains having the FLO5 gene, it was 400 to 500; for strains having the FLO1 gene, about 150; and for two alcohol yeast strains, 40 to 50. This suggests that there are several different types of cell surface proteins involved in flocculation in different yeast strains. Key words: yeast, flocculation, protein, cation, calcium.

Lipid Rafts in Protein Sorting and Cell Polarity in Budding Yeast Saccharomyces cerevisiae

2002 ◽  
Vol 383 (10) ◽  
pp. 1475-1480 ◽  
Author(s):  
M. Bagnat ◽  
K. Simons
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Surface ◽  
Lipid Rafts ◽  
Cell Polarity ◽  
Budding Yeast ◽  
Protein Sorting ◽  
Yeast Saccharomyces Cerevisiae ◽  
Functional Consequences ◽  
Acyl Chains

Abstract Cellular membranes contain many types and species of lipids. One of the most important functional consequences of this heterogeneity is the existence of microdomains within the plane of the membrane. Sphingolipid acyl chains have the ability of forming tightly packed platforms together with sterols. These platforms or lipid rafts constitute segregation and sorting devices into which proteins specifically associate. In budding yeast, Saccharomyces cerevisiae, lipid rafts serve as sorting platforms for proteins destined to the cell surface. The segregation capacity of rafts also provides the basis for the polarization of proteins at the cell surface during mating. Here we discuss some recent findings that stress the role of lipid rafts as key players in yeast protein sorting and cell polarity.

scholarly journals Neisseria gonorrhoeae Porin P1.B Induces Endosome Exocytosis and a Redistribution of Lamp1 to the Plasma Membrane

2002 ◽  
Vol 70 (11) ◽  
pp. 5965-5971 ◽  
Author(s):  
Patricia Ayala ◽  
Brandi Vasquez ◽  
Lee Wetzler ◽  
Magdalene So
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Cell Surface ◽  
Neisseria Gonorrhoeae ◽  
Bacterial Infection ◽  
Immunoglobulin A ◽  
Late Endosomes ◽  
A Cell ◽  
Iga Protease

ABSTRACT The immunoglobulin A (IgA) protease secreted by pathogenic Neisseria spp. cleaves Lamp1, thereby altering lysosomes in a cell and promoting bacterial intracellular survival. We sought to determine how the IgA protease gains access to cellular Lamp1 in order to better understand the role of this cleavage event in bacterial infection. In a previous report, we demonstrated that the pilus-induced Ca2+ transient triggers lysosome exocytosis in human epithelial cells. This, in turn, increases the level of Lamp1 at the plasma membrane, where it can be cleaved by IgA protease. Here, we show that porin also induces a Ca2+ flux in epithelial cells. This transient is similar in nature to that observed in phagocytes exposed to porin. In contrast to the pilus-induced Ca2+ transient, the porin-induced event does not trigger lysosome exocytosis. Instead, it stimulates exocytosis of early and late endosomes and increases Lamp1 on the cell surface. These results indicate that Neisseria pili and porin perturb Lamp1 trafficking in epithelial cells by triggering separate and distinct Ca2+-dependent exocytic events, bringing Lamp1 to the cell surface, where it can be cleaved by IgA protease.

scholarly journals Role of the Alkyl Hydroperoxide Reductase (ahpCF) Gene in Oxidative Stress Defense of the Obligate Anaerobe Bacteroides fragilis

1999 ◽  
Vol 181 (18) ◽  
pp. 5701-5710 ◽  
Author(s):  
Edson R. Rocha ◽  
C. Jeffrey Smith
Keyword(s):  
Fusidic Acid ◽  
Resistant Strain ◽  
Parent Strain ◽  
Bacteroides Fragilis ◽  
Northern Blot Hybridization ◽  
Obligate Anaerobe ◽  
Alkyl Hydroperoxide Reductase ◽  
Oxygen Exposure ◽  
Alkyl Hydroperoxide

ABSTRACT In this study we report the identification and role of the alkyl hydroperoxide reductase (ahp) gene in Bacteroides fragilis. The two components of ahp,ahpC, and ahpF, are organized in an operon, and the deduced amino acid sequences revealed that B. fragilisAhpCF shares approximately 60% identity to orthologues in other gram-positive and gram-negative bacteria. Northern blot hybridization analysis of total RNA showed that the ahpCF genes were transcribed as a polycistronic 2.4-kb mRNA and that ahpCalso was present as a 0.6-kb monocistronic mRNA. ahpC andahpCF mRNAs were induced approximately 60-fold following H2O2 treatment or oxygen exposure of the parent strain but were constitutive in a peroxide-resistant strain. Further investigation using an ahpCF′::β-xylosidase gene transcriptional fusion confirmed that ahpCF had lost normal regulation in the peroxide-resistant strain compared to the parent. The ahpCF mutant was more sensitive to growth inhibition and mutagenesis by organic peroxides than the parent strain, as determined by disk inhibition assays and the frequency of mutation to fusidic acid resistance. This finding suggests that theahp genes play an important role in peroxide resistance inB. fragilis. Under anaerobic conditions, we observed increases in the number of spontaneous fusidic acid-resistant mutants of five- and sevenfold in ahpCF and ahpF strain backgrounds, respectively, and eightfold in the ahpCF katBdouble mutant strain compared to the parent and katBstrains. In addition, ahpCF, ahpF, andahpCF katB mutants were slightly more sensitive to oxygen exposure than the parent strain. Moreover, the isolation of a strain with enhanced aerotolerance and high-level resistance to alkyl hydroperoxides from an ahpCF katB parent suggests that the physiological responses to peroxide toxicity and to the toxic effects of molecular oxygen are overlapping and complex in this obligate anaerobe.

scholarly journals Genetic Characterization of a Cell Envelope-Associated Proteinase from Lactobacillus helveticus CNRZ32

1999 ◽  
Vol 181 (15) ◽  
pp. 4592-4597 ◽  
Author(s):  
Jeffrey A. Pederson ◽  
Gerald J. Mileski ◽  
Bart C. Weimer ◽  
James L. Steele
Keyword(s):  
Cell Surface ◽  
Deletion Mutant ◽  
Cell Envelope ◽  
Physiological Role ◽  
Lactobacillus Helveticus ◽  
Whole Cells ◽  
A Cell ◽  
Hydrolysis Of

ABSTRACT A cell envelope-associated proteinase gene (prtH) was identified in Lactobacillus helveticus CNRZ32. TheprtH gene encodes a protein of 1,849 amino acids and with a predicted molecular mass of 204 kDa. The deduced amino acid sequence of the prtH product has significant identity (45%) to that of the lactococcal PrtP proteinases. Southern blot analysis indicates thatprtH is not broadly distributed within L. helveticus. A prtH deletion mutant of CNRZ32 was constructed to evaluate the physiological role of PrtH. PrtH is not required for rapid growth or fast acid production in milk by CNRZ32. Cell surface proteinase activity and specificity were determined by hydrolysis of αs1-casein fragment 1-23 by whole cells. A comparison of CNRZ32 and its prtH deletion mutant indicates that CNRZ32 has at least two cell surface proteinases that differ in substrate specificity.

Phyllotaxis Turns over a New Leaf – A Review

2019 ◽  
Author(s):  
Derek T Lamport ◽  
Li Tan ◽  
Michael Held ◽  
Marcia Kieliszewski
Keyword(s):  
Cell Surface ◽  
Calcium Binding ◽  
Wall Stress ◽  
Protein Chemistry ◽  
Computer Prediction ◽  
Cell Wall Stress ◽  
A Cell ◽  
Ancient Problem ◽  
General Explanation

Sixty years ago in the lab adjacent to Fred Sanger (1958 Nobel Prize for protein chemistry), I discovered the cell surface hydroxyproline-rich glycoproteins. Nature keeps some of her secrets longer than others. It has taken many years to dissect the molecular function and biological role of extensins and arabinogalactan proteins (AGPs). Extensins template the formation of new cell walls. AGPs remained baffling and enigmatic until a Eureka moment when computer prediction of AGP calcium binding depicted paired glucuronic acid residues and thus the likely role of a cell surface AGP-Ca2+capacitor: In conjunction with the auxin-activated proton pump that releases bound Ca2+ it led us to formulate the Hechtian Growth Oscillator as A Global Paradigm with a pivotal role in Ca2+ homeostasis. The ramifications are profound. They cannot be shrugged off with sceptical disdain but demand critical reappraisal of current dogma. Phyllotaxis is an ancient problem; it involves an essential role for auxin and the auxin efflux “PIN” proteins together with mechanotransduction of stress-strain as phyllotactic determinants. However, a general explanation remains elusive despite much effort, particularly by mathematicians. Here we propose a novel biochemical algorithm: Hechtian oscillator transduction of cell wall stress generates phyllotactic patterns quite independent of a mathematical approach. Plants simply use different rules and follow a different route.

Cell surface specific immunoglobulin inhibits α factor mediated morphogenesis in Saccharomyces cerevisiae

1987 ◽  
Vol 33 (4) ◽  
pp. 331-335
Author(s):  
Glenn J. Merkel ◽  
Charles L. Phelps ◽  
Roger W. Roeske
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Surface ◽  
Mating Type ◽  
Cell Envelope ◽  
Whole Cells ◽  
Cycle Arrest ◽  
Immunoglobulin Preparations ◽  
Specific Immunoglobulin ◽  
A Cell ◽  
Immunoglobulin Binding

Immunoglobulins raised from Saccharomyces cerevisiae a and α mating type cell envelope preparations inhibited α factor mediated morphogenesis of the a cell without inhibiting normal cell division. The Ig responsible for this inhibition was absorbed to both a and α whole cells and heat-killed cells, indicating that the immunoglobulin binding sites were exposed on the cell surface and not mating type specific. Additionally, α factor mediated cell cycle arrest was not affected by the immunoglobulin preparations, implying that the immunoglobulin was not preventing α factor from binding to its receptor.

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