Ethambutol, a cell wall inhibitor of Mycobacterium tuberculosis, elicits l-glutamate efflux of Corynebacterium glutamicum

Microbiology ◽  
2005 ◽  
Vol 151 (5) ◽  
pp. 1359-1368 ◽  
Author(s):  
Eva Radmacher ◽  
Kathrin C. Stansen ◽  
Gurdyal S. Besra ◽  
Luke J. Alderwick ◽  
William N. Maughan ◽  
...  
Keyword(s):  
Cell Wall ◽  
Mycobacterium Tuberculosis ◽  
Corynebacterium Glutamicum ◽  
Cellular Response ◽  
Large Scale ◽  
Dna Microarrays ◽  
Cell Envelope ◽  
Scale Production ◽  
Biochemical Analyses ◽  
Glutamate Efflux

Corynebacterium glutamicum is used for the large-scale production of l-glutamate, but the efflux of this amino acid is poorly understood. This study shows that addition of ethambutol (EMB) to growing cultures of C. glutamicum causes l-glutamate efflux at rates of up to 15 nmol min−1 (mg dry wt)−1, whereas in the absence of EMB, no efflux occurs. EMB is used for the treatment of Mycobacterium tuberculosis, and at a molecular level it targets a series of arabinosyltransferases (EmbCAB). The single arabinosyltransferase-encoding emb gene of C. glutamicum was placed under the control of a Tet repressor (TetR). Experiments with this strain, as well as with an emb-overexpressing strain, coupled with biochemical analyses showed that: (i) emb expression was correlated with l-glutamate efflux, (ii) emb overexpression increased EMB resistance, (iii) EMB caused less arabinan deposition in cell wall arabinogalactan, and (iv) EMB caused a reduced content of cell-wall-bound mycolic acids. Thus EMB addition resulted in a marked disordering of the cell envelope, which was also discernible by examining cellular morphology. In order to further characterize the cellular response to EMB addition, genome-wide expression profiling was performed using DNA microarrays. This identified 76 differentially expressed genes, with 18 of them upregulated more than eightfold. Among these were the cell-wall-related genes ftsE and mepA (encoding a secreted metalloprotease); however, genes of central metabolism were largely absent. Given that an altered lipid composition of the plasma membrane of C. glutamicum can result in l-glutamate efflux, we speculate that major structural alterations of the cell envelope are transmitted to the membrane, which in turn activates an export system, perhaps via increased membrane tension.

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 The thick waxy coat of mycobacteria, a protective layer against antibiotics and the host's immune system

2020 ◽  
Vol 477 (10) ◽  
pp. 1983-2006 ◽  
Author(s):  
Sarah M. Batt ◽  
David E. Minnikin ◽  
Gurdyal S. Besra
Keyword(s):  
Infectious Disease ◽  
Cell Wall ◽  
Mycobacterium Tuberculosis ◽  
Immune System ◽  
Mortality Rate ◽  
Cell Envelope ◽  
Protective Layer ◽  
Structure And Function ◽  
Complex Lipids ◽  
And Function

Tuberculosis, caused by the pathogenic bacterium Mycobacterium tuberculosis (Mtb), is the leading cause of death from an infectious disease, with a mortality rate of over a million people per year. This pathogen's remarkable resilience and infectivity is largely due to its unique waxy cell envelope, 40% of which comprises complex lipids. Therefore, an understanding of the structure and function of the cell wall lipids is of huge indirect clinical significance. This review provides a synopsis of the cell envelope and the major lipids contained within, including structure, biosynthesis and roles in pathogenesis.

scholarly journals AraR, an l-Arabinose-Responsive Transcriptional Regulator in Corynebacterium glutamicum ATCC 31831, Exerts Different Degrees of Repression Depending on the Location of Its Binding Sites within the Three Target Promoter Regions

2015 ◽  
Vol 197 (24) ◽  
pp. 3788-3796 ◽  
Author(s):  
Takayuki Kuge ◽  
Haruhiko Teramoto ◽  
Masayuki Inui
Keyword(s):  
Corynebacterium Glutamicum ◽  
Binding Sites ◽  
Large Scale ◽  
Transcriptional Regulator ◽  
Scale Production ◽  
Primary Role ◽  
Promoter Regions ◽  
Independent Manner ◽  
Content Type

ABSTRACTInCorynebacterium glutamicumATCC 31831, a LacI-type transcriptional regulator AraR, represses the expression ofl-arabinose catabolism (araBDA), uptake (araE), and the regulator (araR) genes clustered on the chromosome. AraR binds to three sites: one (BSB) between the divergent operons (araBDAandgalM-araR) and two (BSE1and BSE2) upstream ofaraE.l-Arabinose acts as an inducer of the AraR-mediated regulation. Here, we examined the roles of these AraR-binding sites in the expression of the AraR regulon. BSBmutation resulted in derepression of botharaBDAandgalM-araRoperons. The effects of BSE1and/or BSE2mutation onaraEexpression revealed that the two sites independently function as theciselements, but BSE1plays the primary role. However, AraR was shown to bind to these sites with almost the same affinityin vitro. Taken together, the expression ofaraBDAandaraEis strongly repressed by binding of AraR to a single site immediately downstream of the respective transcriptional start sites, whereas the binding site overlapping the −10 or −35 region of thegalM-araRandaraEpromoters is less effective in repression. Furthermore, downregulation ofaraBDAandaraEdependent onl-arabinose catabolism observed in the BSBmutant and the AraR-independentaraRpromoter identified withingalM-araRadd complexity to regulation of the AraR regulon derepressed byl-arabinose.IMPORTANCECorynebacterium glutamicumhas a long history as an industrial workhorse for large-scale production of amino acids. An important aspect of industrial microorganisms is the utilization of the broad range of sugars for cell growth and production process. MostC. glutamicumstrains are unable to use a pentose sugarl-arabinose as a carbon source. However, genes forl-arabinose utilization and its regulation have been recently identified inC. glutamicumATCC 31831. This study elucidates the roles of the multiple binding sites of the transcriptional repressor AraR in the derepression byl-arabinose and thereby highlights the complex regulatory feedback loops in combination withl-arabinose catabolism-dependent repression of the AraR regulon in an AraR-independent manner.

Design and optimization of a recombinant system for large-scale production of the MPT64 antigen from Mycobacterium tuberculosis

2006 ◽  
Vol 46 (1) ◽  
pp. 64-72 ◽  
Author(s):  
Brian V. Geisbrecht ◽  
Boris Nikonenko ◽  
Rowena Samala ◽  
Reiko Nakamura ◽  
Carol A. Nacy ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Large Scale ◽  
Scale Production ◽  
Design And Optimization ◽  
Large Scale Production

scholarly journals Two Accessory Proteins Govern MmpL3 Mycolic Acid Transport in Mycobacteria

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Allison Fay ◽  
Nadine Czudnochowski ◽  
Jeremy M. Rock ◽  
Jeffrey R. Johnson ◽  
Nevan J. Krogan ◽  
...  
Keyword(s):  
Cell Wall ◽  
Mycobacterium Tuberculosis ◽  
Cell Envelope ◽  
Complex Structure ◽  
Mycolic Acid ◽  
Accessory Proteins ◽  
Acid Transport ◽  
Content Type ◽  
Mycolic Acids ◽  
Antibiotic Target

ABSTRACT Mycolic acids are the signature lipid of mycobacteria and constitute an important physical component of the cell wall, a target of mycobacterium-specific antibiotics and a mediator of Mycobacterium tuberculosis pathogenesis. Mycolic acids are synthesized in the cytoplasm and are thought to be transported to the cell wall as a trehalose ester by the MmpL3 transporter, an antibiotic target for M. tuberculosis. However, the mechanism by which mycolate synthesis is coupled to transport, and the full MmpL3 transport machinery, is unknown. Here, we identify two new components of the MmpL3 transport machinery in mycobacteria. The protein encoded by MSMEG_0736/Rv0383c is essential for growth of Mycobacterium smegmatis and M. tuberculosis and is anchored to the cytoplasmic membrane, physically interacts with and colocalizes with MmpL3 in growing cells, and is required for trehalose monomycolate (TMM) transport to the cell wall. In light of these findings, we propose MSMEG_0736/Rv0383c be named “TMM transport factor A”, TtfA. The protein encoded by MSMEG_5308 also interacts with the MmpL3 complex but is nonessential for growth or TMM transport. However, MSMEG_5308 accumulates with inhibition of MmpL3-mediated TMM transport and stabilizes the MmpL3/TtfA complex, indicating that it may stabilize the transport system during stress. These studies identify two new components of the mycobacterial mycolate transport machinery, an emerging antibiotic target in M. tuberculosis. IMPORTANCE The cell envelope of Mycobacterium tuberculosis, the bacterium that causes the disease tuberculosis, is a complex structure composed of abundant lipids and glycolipids, including the signature lipid of these bacteria, mycolic acids. In this study, we identified two new components of the transport machinery that constructs this complex cell wall. These two accessory proteins are in a complex with the MmpL3 transporter. One of these proteins, TtfA, is required for mycolic acid transport and cell viability, whereas the other stabilizes the MmpL3 complex. These studies identify two new components of the essential cell envelope biosynthetic machinery in mycobacteria.

scholarly journals Proteomic Analysis of the Intestinal Epithelial Cell Response to EnteropathogenicEscherichia coli

2004 ◽  
Vol 279 (19) ◽  
pp. 20127-20136 ◽  
Author(s):  
Philip R. Hardwidge ◽  
Isabel Rodriguez-Escudero ◽  
David Goode ◽  
Sam Donohoe ◽  
Jimmy Eng ◽  
...  
Keyword(s):  
Proteomic Analysis ◽  
Cellular Response ◽  
Large Scale ◽  
Cell Types ◽  
Effector Proteins ◽  
Intestinal Epithelial ◽  
Host Proteins ◽  
Epithelial Monolayers ◽  
Childhood Morbidity ◽  
Biochemical Analyses

We present the first large scale proteomic analysis of a human cellular response to a pathogen. EnteropathogenicEscherichia coli(EPEC) is an enteric human pathogen responsible for much childhood morbidity and mortality worldwide. EPEC uses a type III secretion system (TTSS) to inject bacterial proteins into the cytosol of intestinal epithelial cells, resulting in diarrhea. We analyzed the host response to TTSS-delivered EPEC effector proteins by infecting polarized intestinal epithelial monolayers with either wild-type or TTSS-deficient EPEC. Host proteins were isolated and subjected to quantitative profiling using isotope-coded affinity tagging (ICAT) combined with electrospray ionization tandem mass spectrometry. We identified over 2000 unique proteins from infected Caco-2 monolayers, of which ∼13% are expressed differentially in the presence of TTSS-delivered EPEC effector proteins. We validated these datain silicoand through immunoblotting and immunofluorescence microscopy. The identified changes extend cytoskeletal observations made in less relevant cell types and generate testable hypotheses with regard to host proteins potentially involved in EPEC-induced diarrhea. These data provide a framework for future biochemical analyses of host-pathogen interactions.

Bioprocess Optimization of L-Lysine Production by Using RSM and Artificial Neural Networks from Corynebacterium glutamicum ATCC13032

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Vanasi Bhushanam ◽  
Ramesh Malothu
Keyword(s):  
Neural Network ◽  
Amino Acid ◽  
Corynebacterium Glutamicum ◽  
Large Scale ◽  
Incubation Temperature ◽  
Scale Production ◽  
Feed Forward Neural Network ◽  
Lysine Production ◽  
Important Amino Acid ◽  
Artificial Neural

AbstractL-Lysine is one of the important amino acid required for humans and animals. It has a high commercial market. Large scale production of this amino acid is essential to meet the commercial demands. Typically, L-lysine is produced by batch fermentation. In the present study, the important process, as well as nutrient parameters such as glucose concentration (g/L), rpm, incubation temperature (°C), pH and incubation time for L-lysine production by Corynebacterium glutamicum ATCC13032, were optimized by a combined approach of response surface methodology (RSM) with artificial neural network (ANN) method. Initially, 32 runs face central composite design was employed. In the first step, the data was analyzed by the RSM and the optimum conditions for L-lysine production were determined. In the second step, the same data was used to train the neural network. A feed-forward neural network with error backpropagation was used. The best network was obtained by optimizing the no of neurons in the hidden layer. From the best network, the optimized weights and predicted responses were used to optimize the conditions of the selected parameters by genetic algorithm (GA). Overall with the combination of RSM-ANN-GA onefold of L-lysine production from Corynebacterium glutamicum ATCC 13032 was improved.

scholarly journals Impact of LytR-CpsA-Psr Proteins on Cell Wall Biosynthesis in Corynebacterium glutamicum

2016 ◽  
Vol 198 (22) ◽  
pp. 3045-3059 ◽  
Author(s):  
Meike Baumgart ◽  
Karin Schubert ◽  
Marc Bramkamp ◽  
Julia Frunzke
Keyword(s):  
Cell Wall ◽  
Mycobacterium Tuberculosis ◽  
Corynebacterium Glutamicum ◽  
Morphological Changes ◽  
Cell Wall Biosynthesis ◽  
Special Focus ◽  
Content Type ◽  
Cell Wall Biogenesis ◽  
Exact Function ◽  
The Impact

ABSTRACT Proteins of the LCP (LytR, CpsA, Psr) family have been shown to inherit important roles in bacterial cell wall biosynthesis. However, their exact function in the formation of the complex cell wall structures of the Corynebacteriales , including the prominent pathogens Mycobacterium tuberculosis and Corynebacterium diphtheriae , remains unclear. Here, we analyzed the role of the LCP proteins LcpA and LcpB of Corynebacterium glutamicum , both of which localize at regions of nascent cell wall biosynthesis. A strain lacking lcpB did not show any growth-related or morphological phenotype under the tested conditions. In contrast, conditional silencing of the essential lcpA gene resulted in severe growth defects and drastic morphological changes. Compared to the wild-type cell wall, the cell wall of this mutant contained significantly less mycolic acids and a reduced amount of arabinogalactan. In particular, rhamnose, a specific sugar component of the linker that connects arabinogalactan and peptidoglycan, was decreased. Complementation studies of the lcpA -silencing strain with several mutated and truncated LcpA variants suggested that both periplasmic domains are essential for function whereas the cytoplasmic N-terminal part is dispensable. Successful complementation experiments with proteins of M. tuberculosis and C. diphtheriae revealed a conserved function of LCP proteins in these species. Finally, pyrophosphatase activity of LcpA was shown in an in vitro assay. Taken together, our results suggest that LCP proteins are responsible for the transfer of arabinogalactan onto peptidoglycan in actinobacterial species and support a crucial function of a so-far-uncharacterized C-terminal domain (LytR_C domain) which is frequently found at the C terminus of the LCP domain in this prokaryotic phylum. IMPORTANCE About one-third of the world's population is infected with Mycobacterium tuberculosis , and multiple-antibiotic resistance provokes the demand for novel antibiotics. The special cell wall architecture of Corynebacteriales is critical for treatments because it is either a direct target or a barrier that the drug has to cross. Here, we present the analysis of LcpA and LcpB of the closely related Corynebacterium glutamicum , the first of which is an essential protein involved in cell wall biogenesis. Our work provides a comprehensive characterization of the impact of LCP proteins on cell wall biogenesis in this medically and biotechnologically important class of bacteria. Special focus is set on the two periplasmic LcpA domains and their contributions to physiological function.

scholarly journals Pectin and Xylan Biosynthesis in Poplar: Implications and Opportunities for Biofuels Production

2021 ◽  
Vol 12 ◽  
Author(s):  
Joshua A. Schultz ◽  
Heather D. Coleman
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Woody Plants ◽  
Large Scale ◽  
Fossil Fuels ◽  
Potential Method ◽  
Scale Production ◽  
Large Scale Production ◽  
Xylan Biosynthesis ◽  
Wall Components

A potential method by which society's reliance on fossil fuels can be lessened is via the large-scale utilization of biofuels derived from the secondary cell walls of woody plants; however, there remain a number of technical challenges to the large-scale production of biofuels. Many of these challenges emerge from the underlying complexity of the secondary cell wall. The challenges associated with lignin have been well explored elsewhere, but the dicot cell wall components of hemicellulose and pectin also present a number of difficulties. Here, we provide an overview of the research wherein pectin and xylan biosynthesis has been altered, along with investigations on the function of irregular xylem 8 (IRX8) and glycosyltransferase 8D (GT8D), genes putatively involved in xylan and pectin synthesis. Additionally, we provide an analysis of the evidence in support of two hypotheses regarding GT8D and conclude that while there is evidence to lend credence to these hypotheses, there are still questions that require further research and examination.

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