L'influence de la carence en pyridoxine sur la morphologie et l'ultrastructure cellulaire de Ceratocystis ulmi

1983 ◽  
Vol 61 (8) ◽  
pp. 2079-2084 ◽  
Author(s):  
Y. Dalpé
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Comparative Study ◽  
Synthetic Medium ◽  
Filamentous Growth ◽  
Yeast Cells ◽  
Growth Morphology ◽  
The Comparative Study

Deficiency in pyridoxine of a synthetic medium induces yeastlike growth of Ceratocystis ulmi. The addition of pyridoxine allows the organism, incubated 1 to 12 days in the absence of the vitamin, to recover in 24 h its filamentous growth morphology. The comparative study of the ultrastructure of mycelial and yeast cells reveals for the latter a thickening of the cell wall, a quantitative cytoplasmic impoverishment in endoplasmic reticulum and ribosomes, and an accumulation of lipidic and osmiophilic bodies.

scholarly journals Cantharidin alters GPI-anchored protein sorting by targeting Cdc1 mediated remodeling in Endoplasmic Reticulum

2018 ◽  
Author(s):  
Pushpendra Kumar Sahu ◽  
Raghuvir Singh Tomar
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Genetic Interaction ◽  
Protein Sorting ◽  
Model Organism ◽  
Cell Wall Integrity ◽  
Yeast Cells ◽  
Growth Media ◽  
Gpi Anchor ◽  
Associated Functions

ABSTRACTCantharidin (CTD) is a potent anticancer small molecule produced by several species of blister beetle. It has been a traditional medicine for the treatment of warts and tumors for many decades. CTD suppresses the tumor growth by inducing apoptosis, cell cycle arrest, and DNA damage. It is a known inhibitor of PP2A and PP1. In this study, we identified new molecular targets of CTD usingSaccharomyces cerevisiaeas a model organism which expresses a Cantharidin Resistance Gene (CRG1).CRG1encodes a SAM-dependent methyltransferase that inactivates CTD by methylation. CTD alters lipid homeostasis, cell wall integrity, endocytosis, adhesion, and invasion in yeast cells. We found that CTD specifically affects the phosphatidylethanolamine (PE) associated functions which can be rescued by supplementation of ethanolamine (ETA) in the growth media. CTD also perturbed ER homeostasis and cell wall integrity by altering the GPI-anchored protein sorting. The CTD dependent genetic interaction profile ofCRG1revealed that Cdc1 activity in GPI-anchor remodeling is the key target of CTD, which we found to be independent of PP2A and PP1. Furthermore, our experiments with human cells suggest that CTD functions through a conserved mechanism in higher eukaryotes as well. Altogether, we conclude that CTD induces cytotoxicity by targeting Cdc1 activity in GPI-anchor remodeling in the endoplasmic reticulum (ER).

scholarly journals Hyperactive TORC1 sensitizes yeast cells to endoplasmic reticulum stress by compromising cell wall integrity

2019 ◽  
Author(s):  
Khadija Ahmed ◽  
David E. Carter ◽  
Patrick Lajoie
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Endoplasmic Reticulum Stress ◽  
Er Stress ◽  
Fungal Infections ◽  
Pathogenic Fungi ◽  
Stress Sensitivity ◽  
Antifungal Drugs ◽  
Cell Wall Integrity ◽  
Yeast Cells

ABSTRACTThe disruption of protein folding homeostasis in the endoplasmic reticulum (ER) results in an accumulation of toxic misfolded proteins and activates a network of signaling events collectively known as the unfolded protein response (UPR). While UPR activation upon ER stress is well characterized, how other signaling pathways integrate into the ER proteostasis network is unclear. Here, we sought to investigate how the target of rapamycin complex 1 (TORC1) signaling cascade acts in parallel with the UPR to regulate ER stress sensitivity. Using S. cerevisiae, we found that TORC1 signaling is attenuated during ER stress and constitutive activation of TORC1 increases sensitivity to ER stressors such as tunicamycin and inositol deprivation. This phenotype is independent of the UPR. Transcriptome analysis revealed that TORC1 hyperactivation results in cell wall remodelling. Conversely, hyperactive TORC1 sensitizes cells to cell wall stressors, including the antifungal caspofungin. Elucidating the crosstalk between the UPR, cell wall integrity, and TORC1 signaling may uncover new paradigms through which the response to protein misfolding is regulated, and thus have crucial implications for the development of novel therapeutics against pathogenic fungal infections.IMPORTANCEThe prevalence of pathogenic fungal infections, coupled with the emergence of new fungal pathogens, has brought these diseases to the forefront of global health problems. While antifungal treatments have advanced over the last decade, patient outcomes have not substantially improved. These shortcomings are largely attributed to the evolutionary similarity between fungi and humans, which limits the scope of drug development. As such, there is a pressing need to understand the unique cellular mechanisms that govern fungal viability. Given that Saccharomyces cerevisiae is evolutionarily related to a number of pathogenic fungi, and in particular to the Candida species, most genes from S. cerevisiae are highly conserved in pathogenic fungal strains. Here we show that hyperactivation of TORC1 signaling sensitizes S. cerevisiae cells to both endoplasmic reticulum stress and cell wall stressors by compromising cell wall integrity. Therefore, targeting TORC1 signaling and endoplasmic reticulum stress pathways may be useful in developing novel targets for antifungal drugs.

scholarly journals Endoplasmic Reticulum α-Glycosidases of Candida albicans Are Required for N Glycosylation, Cell Wall Integrity, and Normal Host-Fungus Interaction

2007 ◽  
Vol 6 (12) ◽  
pp. 2184-2193 ◽  
Author(s):  
Héctor M. Mora-Montes ◽  
Steven Bates ◽  
Mihai G. Netea ◽  
Diana F. Díaz-Jiménez ◽  
Everardo López-Romero ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Candida Albicans ◽  
Systemic Infection ◽  
Cell Wall Integrity ◽  
Yeast Cells ◽  
Chain Elongation ◽  
Cell Wall Integrity Pathway ◽  
Oligosaccharide Processing ◽  
Host Fungus

ABSTRACT The cell surface of Candida albicans is enriched in highly glycosylated mannoproteins that are involved in the interaction with the host tissues. N glycosylation is a posttranslational modification that is initiated in the endoplasmic reticulum (ER), where the Glc3Man9GlcNAc2 N-glycan is processed by α-glucosidases I and II and α1,2-mannosidase to generate Man8GlcNAc2. This N-oligosaccharide is then elaborated in the Golgi to form N-glycans with highly branched outer chains rich in mannose. In Saccharomyces cerevisiae, CWH41, ROT2, and MNS1 encode for α-glucosidase I, α-glucosidase II catalytic subunit, and α1,2-mannosidase, respectively. We disrupted the C. albicans CWH41, ROT2, and MNS1 homologs to determine the importance of N-oligosaccharide processing on the N-glycan outer-chain elongation and the host-fungus interaction. Yeast cells of Cacwh41Δ, Carot2Δ, and Camns1Δ null mutants tended to aggregate, displayed reduced growth rates, had a lower content of cell wall phosphomannan and other changes in cell wall composition, underglycosylated β-N-acetylhexosaminidase, and had a constitutively activated PKC-Mkc1 cell wall integrity pathway. They were also attenuated in virulence in a murine model of systemic infection and stimulated an altered pro- and anti-inflammatory cytokine profile from human monocytes. Therefore, N-oligosaccharide processing by ER glycosidases is required for cell wall integrity and for host-fungus interactions.

Heterogeneity of Size and Distribution of Intramembrane Particles in the Plasma Membrane of Yeast

1977 ◽  
Vol 35 ◽  
pp. 596-597
Author(s):  
E. Keyhani
Keyword(s):  
Plasma Membrane ◽  
Candida Utilis ◽  
Synthetic Medium ◽  
Freeze Fracture ◽  
Translational Diffusion ◽  
Yeast Cells ◽  
Distilled Water ◽  
Intramembrane Particles ◽  
The Matrix ◽  
Water Cell

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).

Pandhawa Gubah sebagai Representasi Interaksi Metafisik Manusia Jawa dan Perbandingannya dengan Cheritera Pandawa Lima

Manuskripta ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 67
Author(s):  
Novarina Novarina
Keyword(s):  
Comparative Study ◽  
Literary Theory ◽  
Research Method ◽  
Descriptive Analysis ◽  
Literary Study ◽  
Analysis Method ◽  
Research Objects ◽  
Similarities And Differences ◽  
The Difference ◽  
The Comparative Study

Abstract: This research is a comparative literary study that uses Malay and Javanese versions of Mahabarata text sources. The research objects used were the text edition of Pandhawa Gubah (PG) by Sudibjo Z. Hadisutjipto and the text of Cheritera Pandawa Lima (CPL) by Khalid Hussain. The research method used is descriptive-analysis method. In the comparative study used a comparative literary theory proposed by Endraswara (2011). The results of the text comparison reveal the similarities and differences in the image of Bima figures in the Javanese and Malay versions. The equation as a whole is that both texts contain the same heroic storyline and heroic character, Bima. In addition, Indian influence is still evident in the two texts seen from the nuances of Hinduism that exist in both texts. While the difference is seen in the events that accompany Bima's struggle in achieving his victory. Based on these similarities and differences, it can be seen that the authors attempt to represent the concept of metaphysical interactions vertically and horizontally expressed through PG text. --- Abstrak: Penelitian ini adalah satu kajian sastra bandingan yang menggunakan sumber teks Mahabarata versi Melayu dan Jawa. Objek penelitian yang digunakan adalah edisi teks Pandhawa Gubah (PG) karya Sudibjo Z. Hadisutjipto dan teks Cheritera Pandawa Lima (CPL) karya Khalid Hussain. Metode penelitian yang digunakan adalah metode deskriptif-analisis. Dalam telaah perbandingan digunakan teori sastra bandingan yang dikemukakan Endraswara (2011). Hasil perbandingan teks mengungkapkan adanya persamaan dan perbedaan citra tokoh Bima dalam versi Jawa maupun versi Melayu. Persamaan secara keseluruhan adalah kedua teks tersebut mengandung alur cerita kepahlawanan dan tokoh pahlawan yang sama yaitu Bima. Selain itu, pengaruh India masih tampak dalam kedua teks tersebut dilihat dari nuansa Hinduisme yang ada dalam kedua teks. Sementara perbedaannya tampak pada peristiwa-peristiwa yang menyertai perjuangan Bima dalam mencapai kemenangannya. Berdasarkan persamaan dan perbedaan tersebut tampak adanya upaya penulis untuk merepresentasikan konsep interaksi metafisik secara vertikal dan horizontal yang diungkapkan melalui teks PG.

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