Three recently isolated catalase-negative mutants of Hansenula polymorpha lost the ability to grow on methanol but grew in media containing glucose, ethanol or glycerol. Their incubation in a medium with methanol resulted in an accumulation of hydrogen peroxide and cell death. During growth of a catalase-negative mutant in chemostat on a mixture of methanol and glucose, neither H2O2 accumulation nor cell death were observed up to the molar ratio of 10:1 of the two substrates. Cytochrome-c peroxidase and NADH-peroxidase activities were detected in the cells. In methylotrophic yeasts, catalase seems to be an enzyme characteristic of the metabolism of methanol but not needed for the metabolism of multicarbon substrates. The hydrogen peroxide produced during growth of the mutants on mixed substrates is detoxified by cytochrome-c peroxidase and other peroxidases.
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mSphere
October 2023
Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA.
Co-infection with and is associated with dental caries, and their co-cultivation results in enhanced biofilm matrix production that contributes to increased virulence and caries risk. Moreover, the catalase-negative demonstrates increased oxidative stress tolerance when co-cultivated in biofilms with a catalase-producing yeast. Here, we sought to obtain mechanistic insights into the increased HO tolerance of when co-cultivated with clinical isolates of , and .
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May 2022
Department of Oral Biology, Surgery and Biomedical Engineering, University at Buffalo, 3435 Main Street, B36A Foster Hall, Buffalo, NY, 14214, USA.
Current biomaterials effectively replace biological structures but are limited by infections and long-term material failures. This study examined the molecular mechanisms of radio frequency glow discharge treatments (RFGDT) in mediating the disinfection of biomaterial surfaces and concurrently promoting cell attachment and proliferation. Dental biomaterials were subjected to RFGDT, and viability of oral microbial species, namely Streptococcus mutants (SM), Streptococcus gordonii (SG), Moraxella catarrhalis (MC), and Porphyromonas gingivalis (PG), were assessed.
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February 2022
Department of Zoology, GCU Lahore, Pakistan.
are the most common probiotics used in food and other industries because of their capability of producing bacteriocins. Bacteriocins are compounds that are used to kill pathogenic microorganisms. As most bacteria have become resistant to synthetic antibacterial tools, the importance of using probiotics as antibacterial agents has increased.
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January 2017
Department of Chemistry, Indiana University, Bloomington, Indiana, USA; Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, USA.
The catalase-negative, facultative anaerobe D39 is naturally resistant to hydrogen peroxide (HO) produced endogenously by pyruvate oxidase (SpxB). Here, we investigate the adaptive response to endogenously produced HO. We show that lactate oxidase, which converts lactate to pyruvate, positively impacts pyruvate flux through SpxB and that mutants produce significantly lower HO.
View Article and Find Full Text PDFVet Res
September 2010
Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain.
Staphylococcus aureus subsp. anaerobius, a microaerophilic and catalase-negative bacterium, is the etiological agent of abscess disease, a specific chronic condition of sheep and goats, which is characterized by formation of necrotic lesions that are located typically in superficial lymph nodes. We constructed an isogenic mutant of S.
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