0000000000453927
AUTHOR
Guillaume Lemetais
A way to follow the viability of encapsulated Bifidobacterium bifidum subjected to a freeze-drying process in order to target the colon: Interest of flow cytometry
The aim of this work was to apply flow cytometry in order to assess and compare the viability of freeze-dried entrapped bacteria with an usual technique by quantification by plate count techniques. It also aimed at studying the effect of various cryoprotectants on the viability of an entrapped Bifidobacterium bifidum subjected to freeze-drying to check their ability to be delivered all along the gastro-intestinal tract. The alginate-pectinate beads were chosen as the encapsulation matrix added with different protectants. The beads were characterized by scanning electron microscopy and the viability was checked by both methods. The best combination to improve viability of entrapped bacteria …
Ergosterol biosynthesis: a fungal pathway for life on land?
International audience; Sterols, essential lipids of most eukaryotic cells, ensure important structural and signaling functions. The selection pressure that has led to different dominant sterols in the three eukaryotic kingdoms remains unknown. Here, we investigated the influence of the progression in the different steps of the ergosterol biosynthetic pathway (EBP) on the yeast resistance to transitions from aqueous to aerial media, typical perturbations of the higher fungi habitats. Five mutants of the EBP (ergΔ), accumulating different sterol intermediates in the EBP, and the wild-type (WT) strain were exposed to drying under atmospheric air or nitrogen and wetting. Results show that the …
Industrial production of dried yeast: plasma membrane as a survival indicator of air drying process
International audience; Preservation of microorganisms by desiccationis a major industrial interest.However, study of cell survival mechanismsthat occur during desiccation is complex. In this work, the impact of the magnitude and the kinetics of dehydration on yeastsurvival wereevaluatedin either hyperosmotic liquid medium or a gaseous environment. Asame lethal magnitude of dehydration and a same lethal kinetic effect were found. As previously shown for osmotic stress, this work demonstrate that yeast survival after drying was also related to plasma membrane disorganization, suggesting a similar passive rearrangement of the membrane components.Hyperosmotic treatment in liquid medium represe…
Impact of probiotics on risk factors for cardiovascular diseases. A review.
International audience; Probiotic microorganisms have historically been used to rebalance disturbed intestinal microbiota and to diminish gastrointestinal disorders, such as diarrhea or inflammatory bowel diseases (e.g., Crohn's disease and ulcerative colitis). Recent studies explore the potential for expanded uses of probiotics on medical disorders that increase the risk of developing cardiovascular diseases and diabetes, such as obesity, hypercholesterolemia, arterial hypertension, and metabolic disturbances such as hyperhomocysteinemia and oxidative stress. This review aims at summarizing the proposed molecular and cellular mechanisms involved in probiotic-host interactions and to identi…
Drying process strongly affects probiotics viability and functionalities
International audience; Probiotic formulations are widely used and are proposed to have a variety of beneficial effects, depending on the probiotic strains present in the product. The impact of drying processes on the viability of probiotics is well documented. However, the impact of these processes on probiotics functionality remains unclear. In this work, we investigated variations in seven different bacterial markers after various desiccation processes. Markers were composed of four different viability evaluation (combining two growth abilities and two cytometric measurements) and in three in vitro functionalities: stimulation of IL-10 and IL-12 production by PBMCs (immunomodulation) and…
Data from: Ergosterol biosynthesis: a fungal pathway for life on land?
Sterols, essential lipids of most eukaryotic cells, ensure important structural and signaling functions. The selection pressure which has led to different dominant sterols in the three eukaryotic kingdoms remains unknown. Here we investigated the influence of the progression in the different steps of the ergosterol biosynthetic pathway (EBP) on the yeast resistance to transitions from aqueous to aerial media, typical perturbations of the higher fungi habitats. Five mutants of the EBP (ergΔ), accumulating different sterol intermediates in the EBP, and the WT strain were exposed to drying under atmospheric air or nitrogen and wetting. Results show that the progression in the EBP parallels an …