13 research outputs found
Microbial Stress Responses: Antioxidants, the Plasma “Membrane, and Beyond
No full textFrontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Editorial: Microbial Stress Responses: Antioxidants, the Plasma Membrane, and Beyond
No full textOver the past decade, our understanding of the mechanisms involved in microbial responses to stressful environmental conditions have expanded greatly. We are now able to observe both microbial toxicity sensing and microbial adaptations to environmental perturbation. During stressful situations, such as extremes in pH, temperature, humidity and pressure, the microbial cell membrane is always the first target both in bacteria and fungi (Guan and Liu, 2020; Lanze et al., 2020). As the activities of cell membranes are crucial in the functioning of all cells, it is essential to study them during periods of stress, in particular, how the functioning of ATPases is disturbed, whether changes are observed in cation uptake or if membrane potentials are drastically altered. Emerging technologies, such as transcriptomics, proteomics, metabolomics, lipidomics and glycomics, can help us to understand the molecular mechanisms that interplay within the cell membrane during microbial exposure to stressful conditions. Investigation into aspects of the cell membrane, such as membrane raft structure characterization, ion homeostasis, and the role of ion transporters and antioxidants could shed valuable light on the holistic microbial response to stress. Frontiers in Microbiology took initiative in bringing out a special issue on this cutting-edge theme. In this Research Topic we collected 1 review and 9 original research articles which combined give an overview on the current status of this field
Physiological Basis for the Tolerance of Yeast Zygosaccharomyces bisporus to Salt Stress
No full textZygosaccharomyces bisporus is a moderately halotolerant yeast isolated from highly sugary and salty foods. We performed various evident biochemical and in vivo experiments as first of its kind to sketch out the possible overlay of salt tolerance mechanism in this model organism. The growth and survival curve analysis revealed that 1.0 M NaCl concentration (sublethal) enacts growth inhibitory effects with prompting immediate delay in cell division cycle; however, yeast cells adopted modified stress physiologically with further stretched stress spans which was accompanied by an upsurge in the level of cellular metabolites such as trehalose (reserve carbohydrate) and chiefly glycerol (polyols) as major compatible osmolytes, suggesting their role in defense mechanism against osmotic stress. To further elucidate the relation of osmotic stress cell physiology to salinity, thiobarbituric acid reactive substances, protein carbonyl, and reduced glutathione content were measured in salt-stressed cells demonstrating positive correlation of reactive oxygen species generation in Z. bisporus with an elevated concentration of lipid and protein oxidation, thereby damaging cell membrane and eventually causing cell death. We assessed NaCl exposure sourcing increased intracellular reactive oxygen species concentration, by an electron transfer-based colorimetric cupric-reducing antioxidant capacity assay justifying that cellular total antioxidant capacity which uses all the combined antioxidant activities present within vitamins, proteins, lipids, and glutathione reverses these deleterious stress effects. Henceforth, performance of Z. bisporus MTCC 4801 mounted because of stress regime seems to be multifactorial
Effect Of Valproic Acid On Growth And Different Stress Indicators With Hal5 Gene In <i>Saccharomyces Cerevisiae</i> Strains
No full textIn vitro anticariogenic effect of gallic acid against Streptococcus mutans
No full text445-451Involvement of Streptococcus mutans in the pathogenesis of dental caries among human populations is well established. Here, we studied the effect of gallic acid, a naturally occurring polyphenol on certain cariogenic activities of S. mutans. Gallic acid inhibited the glycosyltransferase activity, a key enzyme of sucrose metabolism by 27-36% in S. mutans. Minimal inhibitory concentration (MIC) of gallic acid (136 μg/mL) inhibited the growth of S.mutans by 50%. About 0.4 mM of the polyphenol reduced biofilm formation by 40%, hydrophobicity 60% and acid production 36% by the organism under in vitro growth conditions. Fluorescence microscopy revealed that in absence of gallic acid, the cells were present as clumps, however in the presence of gallic acid (68 µg/mL), they were well segregated due to the inhibition of biofilm formation. The present findings suggest that gallic acid has cariostatic activity against S. mutans, which may have potential application in prevention of dental caries
FTIR spectroscopy and biochemical investigation of ethanol stressed yeast Pachysolen tannophilus
No full textInhibition Analysis Of Tris-Like Compounds On Trehalase Activity In <i>Aspergillus Niger</i>
No full textUptake of inorganic phosphate is a limiting factor for Saccharomyces cerevisiae during growth at low temperatures
No full textThe fermenting ability of Saccharomyces at low temperatures is crucial for the development of alcoholic beverages, but the key factors for the cold tolerance of yeast are not well known. In this report, we present the results of a screening for genes able to confer cold tolerance by overexpression in a laboratory yeast strain auxotrophic for tryptophan. We identified genes of tryptophan permeases (TAT1 and TAT2), suggesting that the first limiting factor in the growth of tryptophan auxotrophic yeast at low temperatures is tryptophan uptake. This fact is of little relevance to industrial strains which are prototrophic for tryptophan. Then, we screened for genes able to confer growth at low temperatures in tryptophan-rich media and found several genes related to phosphate uptake (PHO84, PHO87, PHO90 and GTR1). This suggests that without tryptophan limitation, uptake of inorganic phosphate becomes the limiting factor. We have found that overexpression of the previously uncharacterized ORF YCR015c/CTO1 increases the uptake of inorganic phosphate. Also, genes involved in ergosterol biosynthesis (NSG2) cause improvement of growth at 10°C, dependent on tryptophan uptake, while the gluconeogenesis gene PCK1 and the proline biosynthesis gene PRO2 cause an improvement in growth at 10°C, independent of tryptophan and phosphate uptake.I. Vicent was a recipient of a FPI fellowship from the Generalitat Valenciana. This work was supported by Grant AGL2003-03757 from the Spanish Ministry of Science and Technology and by Grant ACOMP06/66 from Generalitat Valenciana (both awarded to A.N.), and funded by Universidad Politecnica de Valencia (Grants PPI2742/2002 and PPI5621-05-04) awarded to A.N. and R.S.Vicent González, IE.; Navarro Marzal, AL.; Mulet Salort, JM.; Sharma, SC.; Serrano Salom, R. (2015). Uptake of inorganic phosphate is a limiting factor for Saccharomyces cerevisiae during growth at low temperatures. FEMS Yeast Research. 15(3):1-13. https://doi.org/10.1093/femsyr/fov008S11315
Bioconjugation of InGaP quantum dots for molecular sensing
No full textFluorescence-based molecular sensing and cellular imaging are commonly carried out with the application of organic dyes. Quantum dots (QDs) are now recognized as better tools because they are brighter, size tunable, and more photostable than dyes. Most of the proposed QD-based biosensing systems involve elements of known toxicity. The present work reports the functionalization of biocompatible InGaPanS core-shell QDs with anti-bovine serum albumin (anti-BSA) to exploit them as fluorescent probes for antigen detection. Successful bioconjugation was characterized with the absorption and emission spectra showing blue shifts of around 40 and 30 nm, respectively. Gel electrophoresis and particle size distribution studies further confirmed the mass increment of QDs after their functionalization with anti-BSA. Surface plasmon resonance spectrometry has been used to study the affinity of QD-(anti-BSA) probes for bovine serum albumin (BSA). Photoluminescence quenching of the developed probe is observed in the presence of BSA. (C) 2011 Elsevier Inc. All rights reserved
