Search results for "Overproduction"
showing 10 items of 16 documents
Anhydrobiosis in yeasts: Glutathione synthesis by yeast Ogataea (Hansenula) polymorpha cells after their dehydration-rehydration.
2019
The possibility of using active dry microbial preparations in biotechnological processes is essential for the development of new modern industrial technologies. In this study, we show the possibility of obtaining such preparations of the genetically engineered yeast strain Ogataea (Hansenula) polymorpha with glutathione overproduction. Special pre-treatment involving the gradual rehydration of dry cells in water vapour led to the restoration/reactivation of almost 100% of dehydrated cells. Furthermore, dry cells do not lose their viability during storage at room temperatures. Application of dry cells as the inoculum provides the same levels of glutathione synthesis as that of a native yeast…
Valorisation of Persimmon and Blueberry By-Products to Obtain Functional Powders: in vitro Digestion and Fermentation by Gut Microbiota
2020
[EN] Globalization of fruit and vegetable markets generates overproduction, surpluses, and potentially valuable residues. The valorization of these byproducts constitutes a challenge, to ensure sustainability and reintroduce them into the food chain. This work focuses on blueberry and persimmon residues, rich in polyphenols and carotenoids, to obtain powders with high added value to be used as ingredients in food formulation. These powders have been characterized, and the changes in the bioactive compounds in in vitro gastrointestinal digestion have been evaluated. The results indicated that the type of residue, the drying process, as well as the content and type of fiber determine the rele…
Constitutive activation of MexT by amino acid substitutions results in MexEF-OprN overproduction in clinical isolates of Pseudomonas aeruginosa
2018
ABSTRACT When overproduced, the multidrug efflux system MexEF-OprN increases the resistance of Pseudomonas aeruginosa to fluoroquinolones, chloramphenicol, and trimethoprim. In this work, we demonstrate that gain-of-function mutations in the regulatory gene mexT result in oligomerization of the LysR regulator MexT, constitutive upregulation of the efflux pump, and increased resistance in clinical isolates.
L-carnitine protects C2C12 cells against mitochondrial superoxide overproduction and cell death.
2017
International audience; AIMTo identify and characterize the protective effect that L-carnitine exerted against an oxidative stress in C2C12 cells.METHODSMyoblastic C2C12 cells were treated with menadione, a vitamin K analog that engenders oxidative stress, and the protective effect of L-carnitine (a nutrient involved in fatty acid metabolism and the control of the oxidative process), was assessed by monitoring various parameters related to the oxidative stress, autophagy and cell death.RESULTSAssociated with its physiological function, a muscle cell metabolism is highly dependent on oxygen and may produce reactive oxygen species (ROS), especially under pathological conditions. High levels o…
Anhydrobiosis in yeast: Glutathione overproduction improves resistance to dehydration of a recombinant Ogataea (Hansenula) polymorpha strain
2018
Abstract We show for the first time that a recombinant strain of yeast Ogataea (Hansenula) polymorpha is at least as tolerant to dehydration-rehydration treatment as the wild type strain. It is believed that this unusual characteristic of this recombinant yeast strain is linked with its ability to overproduce glutathione. Based on plasma membrane permeability analysis, we hypothesise that glutathione, in addition to its powerful antioxidative protective effects on membrane lipids, may also protect membrane proteins and/or nucleic acids. The combination of yeast cell dehydration with immobilisation and subsequent preliminary slow rehydration in water vapour gave good results in terms of reco…
Left ventricular filling abnormalities and obesity-associated hypertension: relationship with overproduction of circulating transforming growth facto…
2005
This study has been designed to evaluate the relationship among transforming growth factor beta1 (TGFbeta1) and some measurements of diastolic function in a population of hypertensive subjects with normal left ventricular ejection fraction. We studied 67 hypertensive outpatients who according to their BMI levels were subdivided into three groups: lean (L), overweight (OW) and obese (OB) hypertensives (HT). Circulating TGFbeta1 and M- and B-mode echocardiography was determined. All hypertensives were further subgrouped, according to European Society of Cardiology Guidelines, into two subsets of patients with normal diastolic function or with diastolic dysfunction. Prevalence of left ventricu…
Peroxynitrite generated from constitutive nitric oxide synthase mediates the early biochemical injury in short-term cultured hepatocytes
2000
AbstractEarly loss of P450 in rat hepatocyte cultures appears directly related to nitric oxide (NO) overproduction. This study provides experimental evidence for the induction – shortly after isolation through the classical procedure – of strong oxidative stress that involves both oxygen-derived and NO-derived species. NO formation at this stage is due to the early activation of liver constitutive NO synthase (cNOS). Immunodetection of nitrated proteins provides direct evidence of endogenous peroxynitrite (PN) formation upon hepatocyte isolation. On the basis of the combined use of dihydrorhodamine 123 and NOS inhibitors, the analysis of the amount, time course and nature of the species inv…
The overproduction of 2,4-DTBP accompanying to the lack of available form of phosphorus during the biodegradative utilization of aminophosphonates by…
2014
Although information about the ability of some filamentous fungi to biodegrade organophosphonates is available, the knowledge about accompanying changes in fungal metabolism is very limited. The aim of our study was to determine the utilization of the chosen, structurally diverse aminophosphonates by Aspergillus terreus (Thom), in the context of the behaviour of this fungus while growing in unfavourable conditions, namely the lack of easily available phosphates. We found that all the studied compounds were utilized by fungus as nutritive sources of phosphorus, however, their effect on the production of fungal biomass depended on their structure. We also observed an interesting change in the…
Differential sensitivity of rat hepatocyte CYP isoforms to self-generated nitric oxide.
2001
AbstractEarly loss of P450 in rat hepatocyte cultures appears directly related to nitric oxide (NO) overproduction. This study investigates the influence of endogenously generated NO (or NO-derived species) on the relative expression of cytochrome P450 (CYP) isoforms in rat hepatocytes. Our results support the view that loss of P450 holoenzyme in culture is the ultimate consequence of a NO driven process, activated during the common hepatocyte isolation procedure, that leads to an accelerated and selective degradation of specific CYP apoproteins. Under conditions in which NO and peroxynitrite formation is operative, changes in the level of specific CYP isoforms result in a significant alter…
GroEL buffers against deleterious mutations
2002
GroEL, a heat-shock protein that acts as a molecular chaperone1, is overproduced in endosymbiotic but not in free-living bacteria2,3,4, presumably to assist in the folding of conformationally damaged proteins. Here we show that the overproduction of GroEL in Escherichia coli masks the effects of harmful mutations that have accumulated during a simulated process of vertical transmission. This molecular mechanism, which may be an adaptation to the bacterium's intracellular lifestyle, is able to rescue lineages from a progressive fitness decline resulting from the fixation of deleterious mutations under strong genetic drift5,6.