scholarly journals Exceptional Solvent Tolerance inYarrowia lipolyticaIs Enhanced by Sterols

2018 ◽  
Author(s):  
Caleb Walker ◽  
Seunghyun Ryu ◽  
Cong T. Trinh
Keyword(s):  
Cell Wall ◽  
Organic Solvents ◽  
Membrane Damage ◽  
Solvent Tolerance ◽  
Wall Structure ◽  
Membrane Composition ◽  
Adaptive Laboratory Evolution ◽  
Fuels And Chemicals ◽  
High Concentrations ◽  
Manufacturing Platform

AbstractMicrobial biocatalysis in organic solvents such as ionic liquids (ILs) is attractive for making fuels and chemicals from complex substrates including lignocellulosic biomass. However, low IL concentrations of 0.5-1.0 % (v/v) can drastically inhibit microbial activity. In this study, we engineered an exceptionally robust oleaginous yeastYarrowia lipolytica, YlCW001, by adaptive laboratory evolution (ALE). The mutant YlWC001 shows robust growth in up to 18% (v/v) 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), which makes it the most IL-tolerant microorganism published to our knowledge. Remarkably, YlCW001 exhibits broad tolerance in most commonly used hydrophilic ILs beyond [EMIM][OAc]. Scanning electron microscopy revealed that ILs significantly damage cell wall and/or membrane of wildtypeY. lipolyticawith observed cavities, dents, and wrinkles while YlCW001 maintains healthy morphology even in high concentrations of ILs up to 18% (v/v). By performing comprehensive metabolomics, lipidomics, and transcriptomics to elucidate this unique phenotype, we discovered that both wildtypeY. lipolyticaand YlCW001 reconfigured membrane composition (e.g., glycerophospholipids and sterols) and cell wall structure (e.g., chitin) under IL-stressful environments. By probing the steroid pathway at transcriptomic, enzymatic, and metabolic levels, we validated that sterols (i.e., ergosterol) are a key component of the cell membrane that enablesY. lipolyticato resist IL-responsive membrane damage and hence tolerate high IL concentrations. This study provides a better understanding of exceptional robustness ofY. lipolyticathat can be potentially harnessed as a microbial manufacturing platform for production of fuels and chemicals in organic solvents.

scholarly journals Membranes and bile formation. Composition of several mammalian biles and their membrane-damaging properties

1979 ◽  
Vol 178 (1) ◽  
pp. 201-208 ◽  
Author(s):  
R Coleman ◽  
S Iqbal ◽  
P P Godfrey ◽  
D Billington
Keyword(s):  
Guinea Pig ◽  
Bile Salts ◽  
Cell Damage ◽  
Membrane Damage ◽  
Total Content ◽  
Hepatic Cell ◽  
Membrane Composition ◽  
Bile Formation ◽  
Composition And Structure ◽  
High Concentrations

The total content and profile of bile salts and phospholipids are reported for several mammalian biles. Rabbit and guinea-pig biles are characterized by high proportions of conjugated dihydroxy bile salts with respect to trihydroxy bile salts, but contain relatively little phospholipid. Both rabbit and guinea-pig biles exhibit little evidence of hepatic cell damage, even though they are able to cause membrane damage (as evidenced by lysis of human erythrocytes) at low (2–3 mM) concentrations of bile salts; this lytic behaviour is also a property of their predominant bile salts. Addition of phosphatidylcholine to the bile or bile salt is able to decrease the lytic behaviour. Perhaps the most significant observation is that these biles, and their predominant bile salts, are dramatically less lytic towards sheep erythrocytes, indicating that some factor(s) in membrane composition and structure may partly explain the resistance of membranes of the biliary tract to the presence of high concentrations of potentially membrane-damaging bile salts.

Bacterial Peptidoglycan Stapling with Functionalized D-Amino Acids

2019 ◽  
Author(s):  
Sylvia L. Rivera ◽  
Akbar Espaillat ◽  
Arjun K. Aditham ◽  
Peyton Shieh ◽  
Chris Muriel-Mundo ◽  
...  
Keyword(s):  
Cell Wall ◽  
Clinical Success ◽  
Bacterial Species ◽  
Enzymatic Reaction ◽  
Amino Acid Derivative ◽  
Wall Structure ◽  
Live Bacteria ◽  
Cross Links ◽  
Osmotic Lysis ◽  
Bacterial Peptidoglycan

Transpeptidation reinforces the structure of cell wall peptidoglycan, an extracellular heteropolymer that protects bacteria from osmotic lysis. The clinical success of transpeptidase-inhibiting β-lactam antibiotics illustrates the essentiality of these cross-linkages for cell wall integrity, but the presence of multiple, seemingly redundant transpeptidases in many bacterial species makes it challenging to determine cross-link function precisely. Here we present a technique to covalently link peptide strands by chemical rather than enzymatic reaction. We employ bio-compatible click chemistry to induce triazole formation between azido- and alkynyl-D-alanine residues that are metabolically installed in the cell walls of Gram-positive and Gram-negative bacteria. Synthetic triazole cross-links can be visualized by substituting azido-D-alanine with azidocoumarin-D-alanine, an amino acid derivative that undergoes fluorescent enhancement upon reaction with terminal alkynes. Cell wall stapling protects the model bacterium Escherichia coli from β-lactam treatment. Chemical control of cell wall structure in live bacteria can provide functional insights that are orthogonal to those obtained by genetics.<br>

Antifungal Activity Directed Toward the Cell Wall by 2-Cyclohexylidenhydrazo- 4-Phenyl-Thiazole Against Candida albicans

2019 ◽  
Vol 19 (4) ◽  
pp. 428-438 ◽  
Author(s):  
Nívea P. de Sá ◽  
Ana P. Pôssa ◽  
Pilar Perez ◽  
Jaqueline M.S. Ferreira ◽  
Nayara C. Fonseca ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Antifungal Activity ◽  
Mammalian Cells ◽  
C Elegans ◽  
Buccal Epithelial Cells ◽  
Mutant Strains ◽  
Low Toxicity ◽  
High Concentrations ◽  
Mic Value

<p>Background: The increasing incidence of invasive forms of candidiasis and resistance to antifungal therapy leads us to seek new and more effective antifungal compounds. </P><P> Objective: To investigate the antifungal activity and toxicity as well as to evaluate the potential targets of 2- cyclohexylidenhydrazo-4-phenyl-thiazole (CPT) in Candida albicans. </P><P> Methods: The antifungal activity of CPT against the survival of C. albicans was investigated in Caenorhabditis elegans. Additionally, we determined the effect of CPT on the inhibition of C. albicans adhesion capacity to buccal epithelial cells (BECs), the toxicity of CPT in mammalian cells, and the potential targets of CPT in C. albicans. </P><P> Results: CPT exhibited a minimum inhibitory concentration (MIC) value of 0.4-1.9 µg/mL. Furthermore, CPT at high concentrations (>60 x MIC) showed no or low toxicity in HepG2 cells and <1% haemolysis in human erythrocytes. In addition, CPT decreased the adhesion capacity of yeasts to the BECs and prolonged the survival of C. elegans infected with C. albicans. Analysis of CPT-treated cells showed that their cell wall was thinner than that of untreated cells, especially the glucan layer. We found that there was a significantly lower quantity of 1,3-β-D-glucan present in CPT-treated cells than that in untreated cells. Assays performed on several mutant strains showed that the MIC value of CPT was high for its antifungal activity on yeasts with defective 1,3-β-glucan synthase. </P><P> Conclusion: In conclusion, CPT appears to target the cell wall of C. albicans, exhibits low toxicity in mammalian cells, and prolongs the survival of C. elegans infected with C. albicans.</p>

Recent Developments in the Downstream Processing of Phycobiliproteins from Algae: A Review

2021 ◽  
Vol 06 ◽  
Author(s):  
Ayekpam Chandralekha Devi ◽  
G. K. Hamsavi ◽  
Simran Sahota ◽  
Rochak Mittal ◽  
Hrishikesh A. Tavanandi ◽  
...  
Keyword(s):  
Cell Wall ◽  
Large Scale ◽  
Downstream Processing ◽  
Review Article ◽  
Current Status ◽  
Wall Structure ◽  
Scale Production ◽  
Cell Wall Disruption ◽  
Recent Developments ◽  
Macro Algae

Abstract: Algae (both micro and macro) have gained huge attention in the recent past for their high commercial value products. They are the source of various biomolecules of commercial applications ranging from nutraceuticals to fuels. Phycobiliproteins are one such high value low volume compounds which are mainly obtained from micro and macro algae. In order to tap the bioresource, a significant amount of work has been carried out for large scale production of algal biomass. However, work on downstream processing aspects of phycobiliproteins (PBPs) from algae is scarce, especially in case of macroalgae. There are several difficulties in cell wall disruption of both micro and macro algae because of their cell wall structure and compositions. At the same time, there are several challenges in the purification of phycobiliproteins. The current review article focuses on the recent developments in downstream processing of phycobiliproteins (mainly phycocyanins and phycoerythrins) from micro and macroalgae. The current status, the recent advancements and potential technologies (that are under development) are summarised in this review article besides providing future directions for the present research area.

scholarly journals A Metzincin and TIMP-Like Protein Pair of a Phage Origin Sensitize Listeria monocytogenes to Phage Lysins and Other Cell Wall Targeting Agents

2021 ◽  
Vol 9 (6) ◽  
pp. 1323
Author(s):  
Etai Boichis ◽  
Nadejda Sigal ◽  
Ilya Borovok ◽  
Anat A. Herskovits
Keyword(s):  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Mammalian Cells ◽  
Protein Pair ◽  
Growth Conditions ◽  
Wall Structure ◽  
Antibiotic Resistant ◽  
Extracellular Milieu ◽  
Virion Release ◽  
Genes Encoding

Infection of mammalian cells by Listeria monocytogenes (Lm) was shown to be facilitated by its phage elements. In a search for additional phage remnants that play a role in Lm’s lifecycle, we identified a conserved locus containing two XRE regulators and a pair of genes encoding a secreted metzincin protease and a lipoprotein structurally similar to a TIMP-family metzincin inhibitor. We found that the XRE regulators act as a classic CI/Cro regulatory switch that regulates the expression of the metzincin and TIMP-like genes under intracellular growth conditions. We established that when these genes are expressed, their products alter Lm morphology and increase its sensitivity to phage mediated lysis, thereby enhancing virion release. Expression of these proteins also sensitized the bacteria to cell wall targeting compounds, implying that they modulate the cell wall structure. Our data indicate that these effects are mediated by the cleavage of the TIMP-like protein by the metzincin, and its subsequent release to the extracellular milieu. While the importance of this locus to Lm pathogenicity remains unclear, the observation that this phage-associated protein pair act upon the bacterial cell wall may hold promise in the field of antibiotic potentiation to combat antibiotic resistant bacterial pathogens.

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