Prebiotic synthesis of purines from metabolic intermediates

It is well established that thiamine deficiency results in an excess of metabolic intermediates such as lactate and pyruvate, which is likely due to insufficient levels of cofactor for the function of thiamine-dependent enzymes. When in excess, both pyruvate and lactate can increase the stabilization of the hypoxia-inducible factor 1-alpha (HIF-1α) transcription factor, resulting in the trans-activation of HIF-1α regulated genes independent of low oxygen, termed pseudo-hypoxia. Therefore, the resulting dysfunction in cellular metabolism and accumulation of pyruvate and lactate during thiamine deficiency may facilitate a pseudo-hypoxic state. In order to investigate the possibility of a transcriptional relationship between hypoxia and thiamine deficiency, we measured alterations in metabolic intermediates, HIF-1α stabilization, and gene expression. We found an increase in intracellular pyruvate and extracellular lactate levels after thiamine deficiency exposure to the neuroblastoma cell line SK-N-BE. Similar to cells exposed to hypoxia, there was a corresponding increase in HIF-1α stabilization and activation of target gene expression during thiamine deficiency, including glucose transporter-1 (GLUT1), vascular endothelial growth factor (VEGF), and aldolase A. Both hypoxia and thiamine deficiency exposure resulted in an increase in the expression of the thiamine transporter SLC19A3. These results indicate thiamine deficiency induces HIF-1α-mediated gene expression similar to that observed in hypoxic stress, and may provide evidence for a central transcriptional response associated with the clinical manifestations of thiamine deficiency.

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β-Galactosidase-Producing Isolates in Mucoromycota: Screening, Enzyme Production, and Applications for Functional Oligosaccharide Synthesis

Journal of Fungi ◽

10.3390/jof7030229 ◽

2021 ◽

Vol 7 (3) ◽

pp. 229

Author(s):

Bettina Volford ◽

Mónika Varga ◽

András Szekeres ◽

Alexandra Kotogán ◽

Gábor Nagy ◽

...

Keyword(s):

Wheat Bran ◽

Enzyme Production ◽

Specific Activity ◽

Prebiotic Synthesis ◽

Crude Enzyme ◽

Oligosaccharide Synthesis ◽

Industrial Enzymes ◽

Chromogenic Agar ◽

Lichtheimia Ramosa ◽

Excellent Source

β-Galactosidases of Mucoromycota are rarely studied, although this group of filamentous fungi is an excellent source of many industrial enzymes. In this study, 99 isolates from the genera Lichtheimia, Mortierella, Mucor, Rhizomucor, Rhizopus and Umbelopsis, were screened for their β-galactosidase activity using a chromogenic agar approach. Ten isolates from the best producers were selected, and the activity was further investigated in submerged (SmF) and solid-state (SSF) fermentation systems containing lactose and/or wheat bran substrates as enzyme production inducers. Wheat bran proved to be efficient for the enzyme production under both SmF and SSF conditions, giving maximum specific activity yields from 32 to 12,064 U/mg protein and from 783 to 22,720 U/mg protein, respectively. Oligosaccharide synthesis tests revealed the suitability of crude β-galactosidases from Lichtheimia ramosa Szeged Microbiological Collection (SZMC) 11360 and Rhizomucor pusillus SZMC 11025 to catalyze transgalactosylation reactions. In addition, the crude enzyme extracts had transfructosylation activity, resulting in the formation of fructo-oligosaccharide molecules in a sucrose-containing environment. The maximal oligosaccharide concentration varied between 0.0158 and 2.236 g/L depending on the crude enzyme and the initial material. Some oligosaccharide-enriched mixtures supported the growth of probiotics, indicating the potential of the studied enzyme extracts in future prebiotic synthesis processes.

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Prebiotic synthesis of aminooxazoline-5′-phosphates in water by oxidative phosphorylation

Chemical Communications ◽

10.1039/c7cc02183f ◽

2017 ◽

Vol 53 (36) ◽

pp. 4919-4921 ◽

Cited By ~ 4

Author(s):

C. Fernández-García ◽

N. M. Grefenstette ◽

M. W. Powner

Keyword(s):

Amino Acids ◽

Oxidative Phosphorylation ◽

Prebiotic Synthesis ◽

Strecker Synthesis ◽

Novel Strategy

A novel strategy for aminooxazoline-5′-phosphate synthesis in water from prebiotic feedstocks, which is generationally linked to Strecker synthesis of proteinogenic amino acids.

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Mechanisms Involved in Interspecific Communication between Wine Yeasts

Foods ◽

10.3390/foods10081734 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1734

Author(s):

Ana Mencher ◽

Pilar Morales ◽

Jordi Tronchoni ◽

Ramon Gonzalez

Keyword(s):

Alcoholic Fermentation ◽

Yeast Species ◽

Interspecific Interactions ◽

Interference Competition ◽

Weighted Average ◽

Starter Cultures ◽

Simple Consequence ◽

Wine Yeasts ◽

Exploitation Competition ◽

Metabolic Intermediates

In parallel with the development of non-Saccharomyces starter cultures in oenology, a growing interest has developed around the interactions between the microorganisms involved in the transformation of grape must into wine. Nowadays, it is widely accepted that the outcome of a fermentation process involving two or more inoculated yeast species will be different from the weighted average of the corresponding individual cultures. Interspecific interactions between wine yeasts take place on several levels, including interference competition, exploitation competition, exchange of metabolic intermediates, and others. Some interactions could be a simple consequence of each yeast running its own metabolic programme in a context where metabolic intermediates and end products from other yeasts are present. However, there are clear indications, in some cases, of specific recognition between interacting yeasts. In this article we discuss the mechanisms that may be involved in the communication between wine yeasts during alcoholic fermentation.

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