Citrate exporter CexA plays a key role in the production of citric acid in fungi; however, its role in intracellular metabolism has remained unclear. In this study, we comparably characterized homologous cexA genes in the white koji fungus Aspergillus luchuensis mut. kawachii and the yellow koji fungus Aspergillus oryzae, which exhibit high and low abilities, respectively, to produce citric acid. Disruption of cexA caused a significant decline of both extracellular and intracellular citric acid accumulation in Aspergillus kawachii, while overexpression of the A. kawachii cexA gene (AkcexA) into A. oryzae significantly enhanced both extracellular and intracellular citric acid accumulation in A. oryzae to a level comparable to that of A. kawachii. In addition, overexpression of two intrinsic cexA homologs (AocexA and AocexB) in A. oryzae also enhanced its extracellular and intracellular citric acid accumulation. Comprehensive analysis of intracellular metabolites from an AkcexA-overexpressing strain of A. oryzae compared with its control strain identified metabolic changes associated with intracellular citric acid accumulation via the glycolytic pathway, pentose phosphate pathway, and tricarboxylic acid cycle. Our results indicate that citric acid export enhances not only extracellular citric acid accumulation but also intracellular metabolic fluxes to generate citric acid.
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http://dx.doi.org/10.1016/j.jbiosc.2020.09.002 | DOI Listing |
Acc Chem Res
January 2025
Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
ConspectusReactions of gas phase molecules with surfaces play key roles in atmospheric and environmental chemistry. Reactive uptake coefficients (γ), the fraction of gas-surface collisions that yield a reaction, are used to quantify the kinetics in these heterogeneous and multiphase systems. Unlike rate coefficients for homogeneous gas- or liquid-phase reactions, uptake coefficients are system- and observation-dependent quantities that depend upon a multitude of underlying elementary steps.
View Article and Find Full Text PDFJ Biomed Mater Res B Appl Biomater
January 2025
Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, People's Republic of China.
In dental implant surgery, infection is identified as the primary factor contributing to the failure of bone grafts. There is an urgent need to develop bone graft materials possessing antibacterial characteristics to facilitate bone regeneration. Magnesium phosphate bone cement (MPC) is highly desirable for bone regeneration due to its favorable biocompatibility, plasticity, and osteogenic capabilities.
View Article and Find Full Text PDFJ Dairy Res
January 2025
Facultad de Ingeniería Química (FIQ-UNL), Instituto de Lactología Industrial (CONICET), Santiago del Estero 2829, Santa Fe, Argentina.
We compared the effects of two waste-based culture media (M1 and M2) on the technological properties of (L90) for its application as a secondary culture in Cremoso cheese. The following parameters were studied at different ripening times: pH (7, 20, and 40 d), microbiological counts, carbohydrates and organic acids (7 and 40 d), moisture, fat, protein and volatile compounds (40 d). The viability and the metabolic performance of the strain in cheeses were also verified along ripening.
View Article and Find Full Text PDFPhytochem Anal
January 2025
College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China.
Introduction: As a widely used Chinese herbal medicine, Mume Fructus pulp (MFP) has rich nutritional value and biological activity, but its quality control research is relatively scarce.
Objectives: The objective of the study was to evaluate the quality difference between MFPs from different origins and its adulterant apricot pulp (APP), and to identify potential quality markers.
Methods: The chemical compositions were identified by untargeted metabolomics analysis based on ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry combined with feature-based molecular networking.
Int J Food Microbiol
January 2025
College of Food Science, Sichuan Agricultural University, Ya'an, Sichuan 625014, China. Electronic address:
Acid adaptive response (AAR) is a survival mechanism that allows bacteria to develop enhanced stress tolerance. Our previous research identified AAR in Alicyclobacillus acidoterrestris, a thermo-acidophilic bacterium responsible for fruit juice spoilage. However, the roles of specific acidulants, adaptive temperatures, and acidic juice matrices in triggering AAR remain elusive.
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