scholarly journals Mechanism of Antifungal Activity of Terpenoid Phenols Resembles Calcium Stress and Inhibition of the TOR Pathway

2010 ◽  
Vol 54 (12) ◽  
pp. 5062-5069 ◽  
Author(s):  
Anjana Rao ◽  
Yongqiang Zhang ◽  
Sabina Muend ◽  
Rajini Rao
Keyword(s):  
Antifungal Activity ◽  
Cellular Response ◽  
Ribosome Biogenesis ◽  
Ion Homeostasis ◽  
Model Organism ◽  
Nutrient Sensing ◽  
Cellular Interaction ◽  
Tor Pathway ◽  
Calcium Stress ◽  
Wide Range

ABSTRACT Terpenoid phenols, including carvacrol, are components of oregano and other plant essential oils that exhibit potent antifungal activity against a wide range of pathogens, including Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa. To gain a mechanistic view of the cellular response to terpenoid phenols, we used Saccharomyces cerevisiae as a model organism and monitored temporal changes in metabolic activity, cytosolic and vacuolar pH, and Ca2+ transients. Using a panel of related compounds, we observed dose-dependent Ca2+ bursts that correlated with antifungal efficacy. Changes in pH were long lasting and followed the Ca2+ transients. A vma mutant lacking functional vacuolar H+-ATPase (V-ATPase) and defective in ion homeostasis was hypersensitive to carvacrol toxicity, consistent with a role for ionic disruptions in mediating cell death. Genomic profiling within 15 min of exposure revealed a robust transcriptional response to carvacrol, closely resembling that of calcium stress. Genes involved in alternate metabolic and energy pathways, stress response, autophagy, and drug efflux were prominently upregulated, whereas repressed genes mediated ribosome biogenesis and RNA metabolism. These responses were strongly reminiscent of the effects of rapamycin, the inhibitor of the TOR pathway of nutrient sensing. The results point to the activation of specific signaling pathways downstream of cellular interaction with carvacrol rather than a nonspecific lesion of membranes, as has been previously proposed.

scholarly journals Yeast chronological lifespan and proteotoxic stress: is autophagy good or bad?

2011 ◽  
Vol 39 (5) ◽  
pp. 1466-1470 ◽  
Author(s):  
Belém Sampaio-Marques ◽  
Carolina Felgueiras ◽  
Alexandra Silva ◽  
Fernando Rodrigues ◽  
Paula Ludovico
Keyword(s):  
Cell Death ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Nutrient Sensing ◽  
Signalling Pathways ◽  
Aging Effects ◽  
Tor Pathway ◽  
Chronological Lifespan ◽  
Proteotoxic Stress ◽  
Response To Stress

Autophagy, a highly conserved proteolytic mechanism of quality control, is essential for the maintenance of metabolic and cellular homoeostasis and for an efficient cellular response to stress. Autophagy declines with aging and is believed to contribute to different aspects of the aging phenotype. The nutrient-sensing pathways PKA (protein kinase A), Sch9 and TOR (target of rapamycin), involved in the regulation of yeast lifespan, also converge on a common targeted process: autophagy. The molecular mechanisms underlying the regulation of autophagy and aging by these signalling pathways in yeast, with special attention to the TOR pathway, are discussed in the present paper. The question of whether or not autophagy could contribute to yeast cell death occurring during CLS (chronological lifespan) is discussed in the light of our findings obtained after autophagy activation promoted by proteotoxic stress. Autophagy progressively increases in cells expressing the aggregation-prone protein α-synuclein and seems to participate in the early cell death and shortening of CLS under these conditions, highlighting that autophagic activity should be maintained below physiological levels to exert its promising anti-aging effects.

scholarly journals Nutrient sensing pathways regulating adult reproductive diapause in C. elegans

2020 ◽  
Author(s):  
Moriah Eustice ◽  
Jeff M. Reece ◽  
Daniel Konzman ◽  
Salil Ghosh ◽  
Jhullian Alston ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Metabolic Pathways ◽  
Neutral Lipids ◽  
Reproductive Potential ◽  
Model Organism ◽  
Nuclear Hormone Receptor ◽  
Nutrient Sensing ◽  
Reproductive Diapause ◽  
Wide Range ◽  
Underlying Mechanisms

ABSTRACTGenetic and environmental manipulations, such as dietary restriction (DR), can improve both health span and lifespan in a wide range of organisms, including humans. Changes in nutrient intake trigger often overlapping metabolic pathways that can generate distinct or even opposite outputs depending on several factors, such as when DR occurs in the lifecycle of the organism or the nature of the changes in nutrients. Due to the complexity of metabolic pathways and the diversity in outputs, the underlying mechanisms regulating diet-associated pro-longevity are not yet well understood. Adult reproductive diapause (ARD) in the model organism Caenorhabditis elegans is a DR model that is associated with lengthened lifespan and reproductive potential (Angelo and Van Gilst 2009). As the metabolic pathways regulating ARD have not yet been explored in depth, we performed a candidate-based genetic screen analyzing select nutrient-sensing pathways to determine their contribution to the regulation of ARD. Focusing on the three phases of ARD (initiation, maintenance, and recovery), we find that ARD initiation is regulated by fatty acid metabolism, sirtuins, AMPK, and the O-linked N-acetyl glucosamine (O-GlcNAc) pathway. Although ARD maintenance was not significantly influenced by the nutrient sensors in our screen, we found that ARD recovery was modulated by energy sensing, stress response, insulin-like signaling, and the TOR pathway. We also discovered that fatty acid β-oxidation regulates ARD initiation through a pathway involving the O-GlcNAc cycling enzyme, OGT-1, acting with the nuclear hormone receptor NHR-49. Consistent with these findings, our analysis revealed a change in levels of neutral lipids associated with ARD entry defects. Our findings thus identify novel conserved genetic pathways required for ARD entry and recovery and identify new genetic interactions that provide insight into the role of OGT and OGA.

scholarly journals Dynamic transcriptional response of Saccharomyces cerevisiae cells to copper

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sebnem Oc ◽  
Serpil Eraslan ◽  
Betul Kirdar
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Clustering Algorithms ◽  
Ion Homeostasis ◽  
Model Organism ◽  
Transcriptional Response ◽  
Homozygous Deletion ◽  
Suitable Model ◽  
Mitochondrial Respiratory Chain Complex

Abstract Copper is a crucial trace element for all living systems and any deficiency in copper homeostasis leads to the development of severe diseases in humans. The observation of extensive evolutionary conservation in copper homeostatic systems between human and Saccharomyces cerevisiae made this organism a suitable model organism for elucidating molecular mechanisms of copper transport and homeostasis. In this study, the dynamic transcriptional response of both the reference strain and homozygous deletion mutant strain of CCC2, which encodes a Cu2+-transporting P-type ATPase, were investigated following the introduction of copper impulse to reach a copper concentration which was shown to improve the respiration capacity of CCC2 deletion mutants. The analysis of data by using different clustering algorithms revealed significantly affected processes and pathways in response to a switch from copper deficient environment to elevated copper levels. Sulfur compound, methionine and cysteine biosynthetic processes were identified as significantly affected processes for the first time in this study. Stress response, cellular response to DNA damage, iron ion homeostasis, ubiquitin dependent proteolysis, autophagy and regulation of macroautophagy, DNA repair and replication, as well as organization of mitochondrial respiratory chain complex IV, mitochondrial organization and translation were identified as significantly affected processes in only CCC2 deleted strain. The integration of the transcriptomic data with regulome revealed the differences in the extensive re-wiring of dynamic transcriptional organization and regulation in these strains.

scholarly journals Applicability of Honey on Silkworms (Bombyx mori) and Quality Improvement of Its Biomaterials

2021 ◽  
Vol 11 (10) ◽  
pp. 4613
Author(s):  
Gabriela-Maria Baci ◽  
Alexandra-Antonia Cucu ◽  
Adela Ramona Moise ◽  
Daniel Severus Dezmirean
Keyword(s):  
Quality Improvement ◽  
Bombyx Mori ◽  
Human Health ◽  
Recombinant Proteins ◽  
Therapeutic Agent ◽  
Life Sciences ◽  
Model Organism ◽  
Medical Field ◽  
Wide Range ◽  
Ancient Times

Since ancient times, honey has been considered one of the most illustrious and esteemed natural products. Honey plays two key roles; specifically, it is an appreciated nutritional product, and also exhibits a wide range of beneficial properties for human health as a therapeutic agent. Furthermore, it has been shown that honey has valuable effects on the biological and physiological features of mulberry silkworms (Bombyx mori). Bombyx mori exhibits importance not only for the economy, but it also serves as an important biotechnological bioreactor for the production of recombinant proteins that have a great impact in the medical field and beyond. It also represents an important model organism for life sciences. In view of the fact that silk fibroin serves as a natural biopolymer that displays high biocompatibility with human organisms and due to honey’s various and remarkable properties for human health, the two elements are currently used together in order to develop ideal biomaterials for a wide range of purposes. In this review, by discussing the applicability of honey on Bombyx mori and beyond, the importance of honey for life sciences and related fields is spotlighted.

scholarly journals Antifungal Activity of Propyl Disulfide from Neem (Azadirachta indica) in Vapor and Agar Diffusion Assays against Anthracnose Pathogens (Colletotrichum gloeosporioides and Colletotrichum acutatum) in Mango Fruit

2021 ◽  
Vol 9 (4) ◽  
pp. 839
Author(s):  
Muhammad Rafiullah Khan ◽  
Vanee Chonhenchob ◽  
Chongxing Huang ◽  
Panitee Suwanamornlert
Keyword(s):  
Antifungal Activity ◽  
Mycelial Growth ◽  
Colletotrichum Gloeosporioides ◽  
Colletotrichum Acutatum ◽  
Model Parameters ◽  
Pathogenicity Test ◽  
Agar Diffusion ◽  
Wide Range ◽  
Significant Difference ◽  
Diffusion Assay

Microorganisms causing anthracnose diseases have a medium to a high level of resistance to the existing fungicides. This study aimed to investigate neem plant extract (propyl disulfide, PD) as an alternative to the current fungicides against mango’s anthracnose. Microorganisms were isolated from decayed mango and identified as Colletotrichum gloeosporioides and Colletotrichum acutatum. Next, a pathogenicity test was conducted and after fulfilling Koch’s postulates, fungi were reisolated from these symptomatic fruits and we thus obtained pure cultures. Then, different concentrations of PD were used against these fungi in vapor and agar diffusion assays. Ethanol and distilled water were served as control treatments. PD significantly (p ≤ 0.05) inhibited more of the mycelial growth of these fungi than both controls. The antifungal activity of PD increased with increasing concentrations. The vapor diffusion assay was more effective in inhibiting the mycelial growth of these fungi than the agar diffusion assay. A good fit (R2, 0.950) of the experimental data in the Gompertz growth model and a significant difference in the model parameters, i.e., lag phase (λ), stationary phase (A) and mycelial growth rate, further showed the antifungal efficacy of PD. Therefore, PD could be the best antimicrobial compound against a wide range of microorganisms.

scholarly journals Shared Components of the FRQ-Less Oscillator and TOR Pathway Maintain Rhythmicity in Neurospora

2021 ◽  
pp. 074873042199994
Author(s):  
Rosa Eskandari ◽  
Lalanthi Ratnayake ◽  
Patricia L. Lakin-Thomas
Keyword(s):  
Circadian Rhythms ◽  
Clock Genes ◽  
Nutrient Sensing ◽  
Mass Spectrometry Analysis ◽  
Growth Responses ◽  
Tor Pathway ◽  
Spectrometry Analysis ◽  
Binding Partner ◽  
Binding Partners ◽  
Free Running

Molecular models for the endogenous oscillators that drive circadian rhythms in eukaryotes center on rhythmic transcription/translation of a small number of “clock genes.” Although substantial evidence supports the concept that negative and positive transcription/translation feedback loops (TTFLs) are responsible for regulating the expression of these clock genes, certain rhythms in the filamentous fungus Neurospora crassa continue even when clock genes ( frq, wc-1, and wc-2) are not rhythmically expressed. Identification of the rhythmic processes operating outside of the TTFL has been a major unresolved area in circadian biology. Our lab previously identified a mutation ( vta) that abolishes FRQ-less rhythmicity of the conidiation rhythm and also affects rhythmicity when FRQ is functional. Further studies identified the vta gene product as a component of the TOR (Target of Rapamycin) nutrient-sensing pathway that is conserved in eukaryotes. We now report the discovery of TOR pathway components including GTR2 (homologous to the yeast protein Gtr2, and RAG C/D in mammals) as binding partners of VTA through co-immunoprecipitation (IP) and mass spectrometry analysis using a VTA-FLAG strain. Reciprocal IP with GTR2-FLAG found VTA as a binding partner. A Δ gtr2 strain was deficient in growth responses to amino acids. Free-running conidiation rhythms in a FRQ-less strain were abolished in Δ gtr2. Entrainment of a FRQ-less strain to cycles of heat pulses demonstrated that Δ gtr2 is defective in entrainment. In all of these assays, Δ gtr2 is similar to Δ vta. In addition, expression of GTR2 protein was found to be rhythmic across two circadian cycles, and functional VTA was required for GTR2 rhythmicity. FRQ protein exhibited the expected rhythm in the presence of GTR2 but the rhythmic level of FRQ dampened in the absence of GTR2. These results establish association of VTA with GTR2, and their role in maintaining functional circadian rhythms through the TOR pathway.

scholarly journals Antimicrobial and antioxidant potentials of non-cytotoxic extracts of corticolous lichens sampled in Armenia

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Razmik Sargsyan ◽  
Arsen Gasparyan ◽  
Gohar Tadevosyan ◽  
Hovik Panosyan
Keyword(s):  
Antifungal Activity ◽  
Methanol Extract ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Cytotoxic Activities ◽  
Bacterial Strains ◽  
Evernia Prunastri ◽  
Wide Range ◽  
Antibacterial And Antifungal ◽  
Acetone Extracts

AbstractDue to wide range of secondary metabolites, lichens were used from antiquity as sources of colorants, perfumes and medicaments. This research focuses on exploring the antioxidant, antimicrobial and cytotoxic activities of methanol, ethanol, acetone extracts and aqueous infusions of corticolous lichens sampled from Armenia. Methanol, ethanol and acetone extracts from all tested lichens were active against Gram-positive bacterial strains. The most effective solvent to retrieve antimicrobial compounds was methanol. Aqueous infusions of tested lichens didn’t show any significant antibacterial and antifungal activity. The highest antimicrobial activity was observed for methanol extract of Ramalina sinensis. The minimum inhibitory concentration of methanol extract of Ramalina sinensis were 0.9–1.8 mg mL− 1. Pseudevernia furfuracea demonstrated antifungal activity (Ø 12 mm). Methanol extract of Parmelia sulcata demonstrated largest 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging activity (71 %). The cytotoxicity was measured on human HeLa (cervical carcinoma) cell lines using microculture tetrazolium test assay. The IC50 values estimated for methanol extracts of Peltigera praetextata, Evernia prunastri, Ramalina sinensis and Ramalina farinacea species in HeLa cell line were within 1.8–2.8 mg mL− 1 and considered as non-cytotoxic. Obtained results suggest that studied lichens can be prospective in biotechnologies as alternative sources of antimicrobial and antioxidant substances.

scholarly journals The TOR Signal Transduction Cascade Controls Cellular Differentiation in Response to Nutrients

2001 ◽  
Vol 12 (12) ◽  
pp. 4103-4113 ◽  
Author(s):  
N. Shane Cutler ◽  
Xuewen Pan ◽  
Joseph Heitman ◽  
Maria E. Cardenas
Keyword(s):  
Signal Transduction ◽  
Protein Kinases ◽  
Protein Phosphatase ◽  
Nutrient Sensing ◽  
Yeast Cells ◽  
Regulatory Subunit ◽  
Growth Defect ◽  
Tor Pathway ◽  
Pseudohyphal Growth ◽  
Pseudohyphal Differentiation

Rapamycin binds and inhibits the Tor protein kinases, which function in a nutrient-sensing signal transduction pathway that has been conserved from the yeast Saccharomyces cerevisiaeto humans. In yeast cells, the Tor pathway has been implicated in regulating cellular responses to nutrients, including proliferation, translation, transcription, autophagy, and ribosome biogenesis. We report here that rapamycin inhibits pseudohyphal filamentous differentiation of S. cerevisiae in response to nitrogen limitation. Overexpression of Tap42, a protein phosphatase regulatory subunit, restored pseudohyphal growth in cells exposed to rapamycin. The tap42-11 mutation compromised pseudohyphal differentiation and rendered it resistant to rapamycin. Cells lacking the Tap42-regulated protein phosphatase Sit4 exhibited a pseudohyphal growth defect and were markedly hypersensitive to rapamycin. Mutations in other Tap42-regulated phosphatases had no effect on pseudohyphal differentiation. Our findings support a model in which pseudohyphal differentiation is controlled by a nutrient-sensing pathway involving the Tor protein kinases and the Tap42–Sit4 protein phosphatase. Activation of the MAP kinase or cAMP pathways, or mutation of the Sok2 repressor, restored filamentation in rapamycin treated cells, supporting models in which the Tor pathway acts in parallel with these known pathways. Filamentous differentiation of diverse fungi was also blocked by rapamycin, demonstrating that the Tor signaling cascade plays a conserved role in regulating filamentous differentiation in response to nutrients.

scholarly journals A toolbox of Stable Integration Vectors (SIV) in the fission yeast Schizosaccharomyces pombe

2019 ◽  
Author(s):  
Aleksandar Vještica ◽  
Magdalena Marek ◽  
Pedro N’kosi ◽  
Laura Merlini ◽  
Gaowen Liu ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Model Organism ◽  
Experimental System ◽  
Single Copy ◽  
Cell Physiology ◽  
Large Set ◽  
Stable Integration ◽  
Wide Range ◽  
Fluorescent Tags

AbstractSchizosaccharomyces pombe is a widely used model organism that resembles higher eukaryotes in many aspects of cell physiology. Its popularity as an experimental system partially stems from the ease of genetic manipulations, where the innate homology-targeted repair is exploited to precisely edit the genome. While vectors to incorporate exogenous sequences into the chromosomes are available, most are poorly characterized. Here we show that commonly used fission yeast vectors, which upon integration produce repetitive genomic regions, yield unstable genomic loci. We overcome this problem by designing a new series of Stable Integration Vectors (SIV) that target four different prototrophy genes. SIV produce non-repetitive, stable genomic loci and integrate predominantly as single copy. Additionally, we develop a set of complementary auxotrophic alleles that preclude false-positive integration events. We expand the vector series to include antibiotic resistance markers, promoters, fluorescent tags and terminators, and build a highly modular toolbox to introduce heterologous sequences. Finally, as proof of concept, we generate a large set of ready-to-use, fluorescent probes to mark organelles and cellular processes with a wide range of applications in fission yeast research.

scholarly journals Establishing Probiotic Saccharomyces boulardii as a Model Organism for Synthesis and Delivery of Biomolecules

2020 ◽  
Author(s):  
Deniz Durmusoglu ◽  
Ibrahim Al’Abri ◽  
Scott P. Collins ◽  
Chase Beisel ◽  
Nathan Crook
Keyword(s):  
Gene Expression ◽  
Copy Number ◽  
Model Organism ◽  
Saccharomyces Boulardii ◽  
Gastrointestinal Disorders ◽  
Control Of Gene Expression ◽  
Germ Free ◽  
Gut Colonization ◽  
Wide Range ◽  
Dosing Strategy

AbstractSaccharomyces boulardii is a widely used yeast probiotic which can counteract various gastrointestinal disorders1. As a relative of Saccharomyces cerevisiae, S. boulardii exhibits rapid growth and is easy to transform2 and thus represents a promising chassis for the engineered secretion of biomolecules. To establish S. boulardii as a platform for delivery of biomolecules to the mammalian gut, we measured the amount and variance in protein expression enabled by promoters, terminators, selective markers, and copy number control elements in this organism. These genetic elements were characterized in plasmidic and genomic contexts, revealing strategies for tunable control of gene expression and CRISPR-mediated genome editing in this strain. We then leveraged this set of genetic parts to combinatorially assemble pathways enabling a wide range of drug and vitamin titers. Finally, we measured S. boulardii’s residence time in the gastrointestinal tracts of germ-free and antibiotic-treated mice, revealing the relationships between dosing strategy and colonization level. This work establishes S. boulardii as a genetically tractable commensal fungus and provides a set of strategies for engineering S. boulardii to synthesize and deliver biomolecules during gut colonization.

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