Publications by authors named "Ronnie Lubbers"

Antimicrobial resistance is a major threat to human health. Basic knowledge of antimicrobial mechanism of action (MoA) is imperative for patient care and for identification of novel antimicrobials. However, the process of antimicrobial MoA identification is relatively laborious.

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Background: The aromatic compounds vanillin and vanillic acid are important fragrances used in the food, beverage, cosmetic and pharmaceutical industries. Currently, most aromatic compounds used in products are chemically synthesized, while only a small percentage is extracted from natural sources. The metabolism of vanillin and vanillic acid has been studied for decades in microorganisms and many studies have been conducted that showed that both can be produced from ferulic acid using bacteria.

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Protocatechuic acid (3,4-dihydroxybenzoic acid) is a chemical building block for polymers and plastics. In addition, protocatechuic acid has many properties of great pharmaceutical interest. Much research has been performed in creating bacterial protocatechuic acid production strains, but no protocatechuic acid-producing fungal cell factories have been described.

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Carbon catabolite repression enables fungi to utilize the most favourable carbon source in the environment, and is mediated by a key regulator, CreA, in most fungi. CreA-mediated regulation has mainly been studied at high monosaccharide concentrations, an uncommon situation in most natural biotopes. In nature, many fungi rely on plant biomass as their major carbon source by producing enzymes to degrade plant cell wall polysaccharides into metabolizable sugars.

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Salicylic acid plays an important role in the plant immune response, and its degradation is therefore important for plant-pathogenic fungi. However, many nonpathogenic microorganisms can also degrade salicylic acid. In the filamentous fungus , two salicylic acid metabolic pathways have been suggested.

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Article Synopsis
  • - Section Flavi includes both harmful (e.g., Aspergillus flavus) and beneficial (e.g., Aspergillus oryzae) species of fungi, with the latter playing a role in food fermentation and enzyme production.
  • - Researchers sequenced 19 genomes and compared them to others, finding that the closest relative of A. oryzae is not A. flavus but rather A. minisclerotigenes or A. aflatoxiformans, revealing high genetic diversity, especially near chromosome ends.
  • - Although many CAZymes and secondary metabolite genes are predicted in section Flavi, the correlation between these predictions and actual growth characteristics or polysaccharide breakdown is inconsistent, indicating a
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Cinnamic acid is an aromatic compound commonly found in plants and functions as a central intermediate in lignin synthesis. Filamentous fungi are able to degrade cinnamic acid through multiple metabolic pathways. One of the best studied pathways is the non-oxidative decarboxylation of cinnamic acid to styrene.

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Aromatic compounds derived from lignin are of great interest for renewable biotechnical applications. They can serve in many industries e.g.

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Article Synopsis
  • - The study examines how a specific organism produces enzymes (CAZymes) to break down plant biomass for sustainable fuels and chemicals, focusing on the transcriptional response to two feedstocks: corn stover and soybean hulls over different time intervals.
  • - Results showed that corn stover prompted a greater and broader CAZyme expression, while soybean hulls produced more specific enzyme types; key transcription factors (XYR1 and ARA1) were found to regulate this response based on the sugar compositions of the feedstocks.
  • - Blocking certain metabolic pathways increased CAZyme gene expression in both substrates over time, highlighting the complexity of the regulatory mechanisms involved in plant biomass degradation and the impact of feedstock composition on this process.
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In this chapter we describe a method to generate mutants of filamentous fungi using their genomic plasticity and rapid adaptability to their environment. This method is based on spontaneous mutations occurring in relation to improved growth of fungi on media by repeated inoculation resulting in adaptation of the strain to the condition. The critical aspect of this method is the design of the selective media, which will depend strongly on the phenomenon that will be studied.

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Aspergillus niger produces an arsenal of extracellular enzymes that allow synergistic degradation of plant biomass found in its environment. Pectin is a heteropolymer abundantly present in the primary cell wall of plants. The complex structure of pectin requires multiple enzymes to act together.

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D-galacturonic acid (GalA) is the most abundant monosaccharide component of pectin. Previous transcriptome analysis in the plant pathogenic fungus Botrytis cinerea identified eight GalA-inducible genes involved in pectin decomposition, GalA transport and utilization. Co-expression of these genes indicates that a specific regulatory mechanism occurs in B.

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