scholarly journals Twists and Turns in the Salicylate Catabolism of Aspergillus terreus, Revealing New Roles of the 3-Hydroxyanthranilate Pathway

mSystems ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Tiago M. Martins ◽  
Celso Martins ◽  
Paula Guedes ◽  
Cristina Silva Pereira

ABSTRACT In fungi, salicylate catabolism was believed to proceed only through the catechol branch of the 3-oxoadipate pathway, as shown, e.g., in Aspergillus nidulans. However, the observation of a transient accumulation of gentisate upon the cultivation of Aspergillus terreus in salicylate medium questions this concept. To address this, we have run a comparative analysis of the transcriptome of these two species after growth in salicylate using acetate as a control condition. The results revealed the high complexity of the salicylate metabolism in A. terreus with the concomitant positive regulation of several pathways for the catabolism of aromatic compounds. This included the unexpected joint action of two pathways—3-hydroxyanthranilate and nicotinate—possibly crucial for the catabolism of aromatics in this fungus. Importantly, the 3-hydroxyanthranilate catabolic pathway in fungi is described here for the first time, whereas new genes participating in the nicotinate metabolism are also proposed. The transcriptome analysis showed also for the two species an intimate relationship between salicylate catabolism and secondary metabolism. This study emphasizes that the central pathways for the catabolism of aromatic hydrocarbons in fungi hold many mysteries yet to be discovered. IMPORTANCE Aspergilli are versatile cell factories used in industry for the production of organic acids, enzymes, and pharmaceutical drugs. To date, bio-based production of organic acids relies on food substrates. These processes are currently being challenged to switch to renewable nonfood raw materials—a reality that should inspire the use of lignin-derived aromatic monomers. In this context, aspergilli emerge at the forefront of future bio-based approaches due to their industrial relevance and recognized prolific catabolism of aromatic compounds. Notwithstanding considerable advances in the field, there are still important knowledge gaps in the central catabolism of aromatic hydrocarbons in fungi. Here, we disclose a novel central pathway, 3-hydroxyanthranilate, defying previously established ideas on the central metabolism of the aromatic amino acid tryptophan in Ascomycota. We also observe that the catabolism of the aromatic salicylate greatly activated the secondary metabolism, furthering the significance of using lignin-derived aromatic hydrocarbons as a distinctive biomass source.

2020 ◽  
Author(s):  
Tiago M. Martins ◽  
Celso Martins ◽  
Cristina Silva Pereira

ABSTRACTIn fungi, salicylate catabolism was believed to proceed only through the catechol branch of the 3-oxoadipate pathway, as shown e.g. in Aspergillus nidulans. However, the observation of a transient accumulation of gentisate upon cultivation of Aspergillus terreus in salicylate media questions this concept. To address this we have run a comparative analysis of the transcriptome of these two species after growth in salicylate using acetate as a control condition. The results revealed the high complexity of the salicylate metabolism in A. terreus with the concomitant positive regulation of several pathways for the catabolism of aromatic compounds. This included the unexpected joint action of two pathways: the nicotinate and the 3-hydroxyanthranilate, possibly crucial for the catabolism of aromatics in this fungus. New genes participating in the nicotinate metabolism are here proposed, whereas the 3-hydroxyanthranilate catabolic pathway in fungi is described for the first time. The transcriptome analysis showed also for the two species an intimate relationship between salicylate catabolism and secondary metabolism. This study emphasizes that the central pathways for the catabolism of aromatic hydrocarbons in fungi hold many mysteries yet to be discovered.IMPORTANCEAspergilli are versatile cell factories used in industry for production of organic acids, enzymes and pharmaceutical drugs. To date, organic acids bio-based production relies on food substrates. These processes are currently being challenged to switch to renewable non-food raw materials; a reality that should inspire the use of lignin derived aromatic monomers. In this context, Aspergilli emerge at the forefront of future bio-based approaches due to their industrial relevance and recognized prolific catabolism of aromatic compounds. Notwithstanding considerable advances in the field, there are still important knowledge gaps in the central catabolism of aromatic hydrocarbons in fungi. Here, we disclosed a novel central pathway, defying previous established ideas on the central metabolism of the aromatic amino acid tryptophan in Ascomycota. We also observed that the catabolism of the aromatic salicylate greatly activated the secondary metabolism, furthering the significance of using lignin derived aromatic hydrocarbons as a distinctive biomass source.


2020 ◽  
Vol 8 (4) ◽  
pp. 574 ◽  
Author(s):  
Patrick Fickers ◽  
Hairong Cheng ◽  
Carol Sze Ki Lin

Sugar alcohols and organic acids that derive from the metabolism of certain microorganisms have a panoply of applications in agro-food, chemical and pharmaceutical industries. The main challenge in their production is to reach a productivity threshold that allow the process to be profitable. This relies on the construction of efficient cell factories by metabolic engineering and on the development of low-cost production processes by using industrial wastes or cheap and widely available raw materials as feedstock. The non-conventional yeast Yarrowia lipolytica has emerged recently as a potential producer of such metabolites owing its low nutritive requirements, its ability to grow at high cell densities in a bioreactor and ease of genome edition. This review will focus on current knowledge on the synthesis of the most important sugar alcohols and organic acids in Y. lipolytica.


Author(s):  
Delia MICHIU ◽  
Maria TOFANA ◽  
Elena MUDURA ◽  
Florina MUNTEAN

Generally beer contain numerous aromatic compounds, some naturally present in the raw materials and some formed during processing. In this work were analysed beer wort flavor compounds, during primary fermentation, taking into study two beer wort types: one obtained from Pilsner malt (100%), other from a mixture of Pilsner malt (80%) and Caramel Malt (20%). An Shimadzu GC/MS-QP2010 equipment was used for samples analysis. The major compounds founded in beer wort samples, was derived from a vast array of compounds that arise from a number of sources. In this way, during fermentation and conditioning we founded different categories of secondary products: higher alcohols, esters, vicinal diketones (VDK), organic acids and aldehydes. The concentration of this aroma compounds depends on malt type and the moment of wort examination. Was noticed that some compounds disappeared and others appeared, from the day to day of primary fermentation.


2019 ◽  
Vol 17 (2) ◽  
pp. 499-508 ◽  
Author(s):  
Galina S. Pevneva ◽  
Natalya G. Voronetskaya ◽  
Nikita N. Sviridenko ◽  
Anatoly K. Golovko

AbstractThe paper presents the results of investigation of changes in the composition of hydrocarbons and sulfur-containing compounds of an atmospheric residue in the course of cracking in the presence of a tungsten carbide–nickel–chromium (WC/Ni–Cr) catalytic additive and without it. The cracking is carried out in an autoclave at 500 °C for 30 min. The addition of the WC/Ni–Cr additive promotes the deepening of reactions of destruction not only of resins and asphaltenes, but also high molecular weight naphthene-aromatic compounds of the atmospheric residue. It is shown that the content of low molecular weight C9–C17 n-alkanes and C9–C10 alkylbenzenes rose sharply in the products of cracking with addition of WC/Ni–Cr in comparison with those produced without the additive. Alkyl- and naphthene-substituted aromatic hydrocarbons of benzene, naphthalene, phenanthrene series, polyarenes, benzo- and dibenzothiophenes are identified.


2013 ◽  
Vol 116 (1) ◽  
pp. 125-141 ◽  
Author(s):  
Manoj Dora ◽  
Dirk Van Goubergen ◽  
Maneesh Kumar ◽  
Adrienn Molnar ◽  
Xavier Gellynck

Purpose – Recent literature emphasizes the application of lean manufacturing practices to food processing industries in order to improve operational efficiency and productivity. Only a very limited number of studies have focused on the implementation of lean manufacturing practices within small and medium-sized enterprises (SMEs) operating in the food sector. The majority of these studies used the case study method and concentrated on individual lean manufacturing techniques geared towards resolving efficiency issues. This paper aims to analyze the status of the lean manufacturing practices and their benefits and barriers among European food processing SMEs. Design/methodology/approach – A structured questionnaire was developed to collect data. A total of 35 SMEs' representatives, mostly CEOs and operations managers, participated in the survey. The study investigated the role of two control variables in lean implementation: size of the company and country of origin. Findings – The findings show that lean manufacturing practice deployment in food processing SMEs is generally low and still evolving. However, some lean manufacturing practices are more prevalent than others; e.g. flow, pull and statistical process control are not widely used by the food processing SMEs, whereas total productive maintenance, employee involvement, and customer association are more widespread. The key barriers encountered by food SMEs in the implementation of lean manufacturing practices result from the special characteristics of the food sector, such as highly perishable products, complicated processing, extremely variable raw materials, recipes and unpredictable demand. In addition, lack of knowledge and resources makes it difficult for food processing SMEs to embark on the lean journey. Originality/value – The gap in the literature regarding the application of lean manufacturing in the food sector is identified and addressed in this study. The originality of this paper lies in analyzing the current status of the use of lean manufacturing practices among food SMEs in Europe and identifying potential barriers.


2018 ◽  
Vol 20 (16) ◽  
pp. 10960-10977 ◽  
Author(s):  
Erik H. Hoffmann ◽  
Andreas Tilgner ◽  
Ralf Wolke ◽  
Olaf Böge ◽  
Arno Walter ◽  
...  

An aqueous-phase chemistry mechanism for the oxidation of aromatic compounds in the atmosphere is developed based on available kinetic data. Detailed model studies successfully describe the oxidation and functionalization of monoaromatic compounds in the atmosphere.


mSphere ◽  
2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Valerie J. Price ◽  
Wenwen Huo ◽  
Ardalan Sharifi ◽  
Kelli L. Palmer

ABSTRACT Enterococcus faecalis is a bacterium that normally inhabits the gastrointestinal tracts of humans and other animals. Although these bacteria are members of our native gut flora, they can cause life-threatening infections in hospitalized patients. Antibiotic resistance genes appear to be readily shared among high-risk E. faecalis strains, and multidrug resistance in these bacteria limits treatment options for infections. Here, we find that CRISPR-Cas and restriction-modification systems, which function as adaptive and innate immune systems in bacteria, significantly impact the spread of antibiotic resistance genes in E. faecalis populations. The loss of these systems in high-risk E. faecalis suggests that they are immunocompromised, a tradeoff that allows them to readily acquire new genes and adapt to new antibiotics. Enterococcus faecalis is an opportunistic pathogen and a leading cause of nosocomial infections. Conjugative pheromone-responsive plasmids are narrow-host-range mobile genetic elements (MGEs) that are rapid disseminators of antibiotic resistance in the faecalis species. Clustered regularly interspaced short palindromic repeat (CRISPR)-Cas and restriction-modification confer acquired and innate immunity, respectively, against MGE acquisition in bacteria. Most multidrug-resistant E. faecalis isolates lack CRISPR-Cas and possess an orphan locus lacking cas genes, CRISPR2, that is of unknown function. Little is known about restriction-modification defense in E. faecalis. Here, we explore the hypothesis that multidrug-resistant E. faecalis strains are immunocompromised. We assessed MGE acquisition by E. faecalis T11, a strain closely related to the multidrug-resistant hospital isolate V583 but which lacks the ~620 kb of horizontally acquired genome content that characterizes V583. T11 possesses the E. faecalis CRISPR3-cas locus and a predicted restriction-modification system, neither of which occurs in V583. We demonstrate that CRISPR-Cas and restriction-modification together confer a 4-log reduction in acquisition of the pheromone-responsive plasmid pAM714 in biofilm matings. Additionally, we show that the orphan CRISPR2 locus is functional for genome defense against another pheromone-responsive plasmid, pCF10, only in the presence of cas9 derived from the E. faecalis CRISPR1-cas locus, which most multidrug-resistant E. faecalis isolates lack. Overall, our work demonstrated that the loss of only two loci led to a dramatic reduction in genome defense against a clinically relevant MGE, highlighting the critical importance of the E. faecalis accessory genome in modulating horizontal gene transfer. Our results rationalize the development of antimicrobial strategies that capitalize upon the immunocompromised status of multidrug-resistant E. faecalis. IMPORTANCE Enterococcus faecalis is a bacterium that normally inhabits the gastrointestinal tracts of humans and other animals. Although these bacteria are members of our native gut flora, they can cause life-threatening infections in hospitalized patients. Antibiotic resistance genes appear to be readily shared among high-risk E. faecalis strains, and multidrug resistance in these bacteria limits treatment options for infections. Here, we find that CRISPR-Cas and restriction-modification systems, which function as adaptive and innate immune systems in bacteria, significantly impact the spread of antibiotic resistance genes in E. faecalis populations. The loss of these systems in high-risk E. faecalis suggests that they are immunocompromised, a tradeoff that allows them to readily acquire new genes and adapt to new antibiotics.


Significance The proposals identified areas where the euro could potentially become more dominant, such as the issuance of green bonds, digital currencies, and international trade in raw materials and energy. Ambitions to enhance the international leverage of the euro are being driven by the aim to strengthen EU strategic autonomy amid rising geopolitical risks. Impacts Developing its digital finance sector would be an opportunity for the EU to enhance its strategic autonomy in financial services. Challenging the US dollar would require the euro-area to rebalance its economy away from foreign to domestic demand. Member state division will prevent the economic reconfiguration the euro-area needed to make the euro a truly global currency.


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