Bacterial Peptidoglycan Stapling with Functionalized D-Amino Acids

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>

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Three-Dimensional Imaging of Plant Cell Wall Deconstruction Using Fluorescence Confocal Microscopy

Sustainable Chemistry ◽

10.3390/suschem1020007 ◽

2020 ◽

Vol 1 (2) ◽

pp. 75-85

Author(s):

Aya Zoghlami ◽

Yassin Refahi ◽

Christine Terryn ◽

Gabriel Paës

Keyword(s):

Cell Wall ◽

Enzymatic Hydrolysis ◽

Plant Cell Wall ◽

Enzymatic Reaction ◽

Time Lapse ◽

Quantitative Information ◽

Image Resolution ◽

Wall Structure ◽

Hydrolysis Time ◽

Fluorescence Confocal Microscopy

Lignocellulosic biomass (LB) is recalcitrant to enzymatic hydrolysis due to its compact and complex cell wall structure. To identify the parameters behind LB recalcitrance, experimental data over hydrolysis time must be collected. Here, we describe a novel method to collect time-lapse images during cell wall deconstruction by enzymatic hydrolysis. The protocol includes instructions for sample preparation, layout of a custom designed incubation chamber and instructions for confocal time lapse acquisition. The protocol sets out a detailed plan where cross-sections of untreated and pretreated poplar samples are mounted in a sealed frame containing a buffer and an enzymatic cocktail. The sealed frame is then placed into an incubator to maintain the sample at a constant temperature of 50 °C, which is optimal for enzymatic reaction while avoiding enzymatic cocktail evaporation. Using lignin natural autofluorescence, confocal z-stacks of untreated and pretreated samples were acquired at regular time intervals during enzymatic hydrolysis for 24 h. Acquisition parameters were optimized to compromise between image resolution and reduced photo-bleaching. The acquired image might then be processed by further development of algorithms to extract precise quantitative information on cell wall deconstruction. This protocol is an important first step towards elucidating the underlying parameters of LB recalcitrance by allowing the acquisition of high-quality images of LB hydrolysis for extracting quantitative data on LB deconstruction.

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Effects of low-molecular weight alcohols on bacterial viability

Revista Romana de Medicina de Laborator ◽

10.1515/rrlm-2017-0028 ◽

2017 ◽

Vol 25 (4) ◽

pp. 335-343 ◽

Cited By ~ 7

Author(s):

Adrian Man ◽

Andrei Şerban Gâz ◽

Anca Delia Mare ◽

Lavinia Berţa

Keyword(s):

Cell Wall ◽

Ethylene Glycol ◽

Bacterial Species ◽

Inhibitory Effect ◽

Butyl Alcohol ◽

Cell Wall Structure ◽

Good Effect ◽

Wall Structure ◽

Gram Positive ◽

Microdilution Method

Abstract Alcohol based solutions are among the most convenient and wide spread aid in the prevention of nosocomial infections. The current study followed the efficacy of several types and isomers of alcohols on different bacterial species. Seven alcohols (ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl alcohol, and ethylene glycol) were used to evaluate their minimal inhibitory and bactericidal effects by microdilution method on bacteria that express many phenotypical characteristics: different cell-wall structure (Gram positive/negative bacteria), capsule production (Klebsiella pneumoniae), antibiotic resistance (MRSA vs MSSA) or high environmental adaptability (Pseudomonas aeruginosa). Results: The best inhibitory effect was noticed for n-propyl, followed by iso-propyl, n-butyl, and iso-butyl alcohols with equal values. Ethylene glycol was the most inefficient alcohol on all bacteria. In K. pneumoniae and P. aeruginosa, the bactericidal concentrations were higher than the inhibitory one, and to a level similar to that encountered for most of the Gram-positive bacteria. Among Gram-positive cocci, E. faecalis presented the lowest susceptibility to alcohols. Conclusions: All alcohols presented good effect on bacteria, even in low concentrations. Compared to ethanol as standard, there are better alternatives that can be used as antimicrobials, namely longer-chain alcohols such as propyl or butyric alcohols and their iso- isomers. Ethylene glycol should be avoided, due to its toxicity hazard and low antimicrobial efficacy. Bacterial phenotype (highly adaptable bacteria, biofilm formation) and structure (cell wall structure, presence of capsule) may drastically affect the responsiveness to the antimicrobial activity of alcohols, leading to higher bactericidal than inhibitory concentrations.

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Faculty Opinions recommendation of Wood cell-wall structure requires local 2D-microtubule disassembly by a novel plasma membrane-anchored protein.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.4116957.3896055 ◽

2010 ◽

Author(s):

Clive Lloyd

Keyword(s):

Cell Wall ◽

Plasma Membrane ◽

Wood Cell Wall ◽

Cell Wall Structure ◽

Wall Structure

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Forage Cell Wall Structure and Digestibility

10.2134/1993.foragecellwall ◽

1993 ◽

Cited By ~ 113

Keyword(s):

Cell Wall ◽

Cell Wall Structure ◽

Wall Structure

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

Current Biochemical Engineering ◽

10.2174/2212711906999210101230613 ◽

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.

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Recent findings in plant cell wall structure and metabolism: future challenges and potential implications for softening

Stewart Postharvest Review ◽

10.2212/spr.2006.2.9 ◽

2006 ◽

Vol 2 (2) ◽

pp. 1-8

Keyword(s):

Cell Wall ◽

Plant Cell ◽

Plant Cell Wall ◽

Cell Wall Structure ◽

Wall Structure ◽

Future Challenges ◽

Structure And Metabolism

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

Microorganisms ◽

10.3390/microorganisms9061323 ◽

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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