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Some other groups and circumstances
Published in Geoffrey P. Webb, Nutrition, 2019
In vegan diets there is no reliable source of vitamin B12. Symptoms of megaloblastic anaemia and the neurological manifestations of vitamin B12 might thus be expected to be prevalent amongst vegans. However, the human requirement for vitamin B12 is extremely small (UK RNI – 1.5 μg/day) and stores of the vitamin in the liver are large and could amount to several years supply in an omnivore. In the UK, many meat and plant-based milk substitutes are fortified with B12 as are some breakfast cereals. Many vegans take B12 supplements. Even in the absence of such alternative dietary sources, cases of clinical B12 deficiency amongst Caucasian vegans are rare. There are indirect sources of B12 even for those who consume no animal products or supplemented foods such as the following: From microorganisms and moulds contaminating plant foods. Insects or insect remains consumed with plant foods. Absorption of vitamin produced endogenously by gut bacteria although most of this is produced below the point of absorption in the ileum and is excreted in faeces. From fermented foods, nutritional yeast or yeast extract spreads. From faecal contamination of seaweed.
Optimization of Myrothecium roridum tode: fries phytotoxin production and bioactivity on water hyacinth (Eichhornia crassipes)
Published in Toxin Reviews, 2021
Wahab Oluwanisola Okunowo, Akinniyi Adediran Osuntoki, Adedotun Adeyinka Adekunle, George Olabode Gbenle, Hamed K. Abbas, Wayne Thomas Shier
The largest necrotic lesion on water hyacinth leaves was observed with medium containing glutamine as a nitrogen source, which caused a lesion about twice the size of the least effective nitrogen sources in the media, yeast extract and sodium nitrate, the normal nitrogen source in ZDB (Figure 4). The maximum phytotoxin production obtained with glutamine was not significantly different from that obtained with sodium glutamate, urea or ammonium nitrate (p > 0.05), but it was significantly greater than that obtained with sodium nitrate or yeast extract (p < 0.001). Phytotoxin concentration obtained from the second best nitrogen source, sodium glutamate, was significantly greater than that obtained with sodium nitrate, ammonium chloride or yeast extract (p < 0.001). This result suggests that an organic nitrogen source is preferred by M. roridum for phytotoxin production, although yeast extract supported the least phytotoxin production. Yeast extract was also reported to be a poor phytotoxin inducer in Bipolaris euphorbiae (Barbosa et al.2002).
From correlation to causality: the case of Subdoligranulum
Published in Gut Microbes, 2020
Matthias Van Hul, Tiphaine Le Roy, Edi Prifti, Maria Carlota Dao, Adrien Paquot, Jean-Daniel Zucker, Nathalie M. Delzenne, Giulio G. Muccioli, Karine Clément, Patrice D. Cani
Subdoligranulum variabile DSM 15176 T was obtained from the Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ). The strain was routinely cultured in yeast extract-peptone medium supplemented with glucose, raffinose and anti-oxidants (detailed composition in supplementary Table 1). Attempts to enumerate S. variabile DSM 15176 T on solid medium failed despite separate autoclaving of phosphate and agar, as well as replacement of agar by gellan gum.39,40 Thus, live and cultivable bacteria were enumerated using most probable number calculation associated to dilution to extinction method: bacterial culture was serially diluted to the appropriate concentrations according to optical density (OD) measurements at 680 nm, then 10 vials per dilution were inoculated with 1 ml of dilution. The number of vials with visible growing within the three following days allowed the calculation of the live bacteria concentration in the culture.41 For the administration to the mice, bacterial culture was centrifuged at 4000 g during 20 min at 4°C. Then supernatant was removed, and the pellet was washed twice in anoxic PBS supplemented with antioxidants and finally resuspended in glycerol (25% vol/vol) and stored at −80°C.
Brazilian red propolis reduces orange-complex periodontopathogens growing in multispecies biofilms
Published in Biofouling, 2019
Stela Lima Farias Miranda, Jennifer Toledo Damasceno, Marcelo Faveri, Luciene Figueiredo, Helio Doyle da Silva, Severino Matias de Alencar Alencar, Pedro Luiz Rosalen, Magda Feres, Bruno Bueno-Silva
Most strains (e.g., Actinomyces subsp., Streptococcus subsp., and Fusobacterium subsp.) were grown on tryptone soy agar with 5% sheep blood under anaerobic conditions (85% nitrogen, 10% carbon dioxide, and 5% hydrogen), while Eubacterium subsp. and N. mucosa were cultured on fastidious anaerobic agar with 5% ram blood. P. gingivalis and P. melaninogenica were grown on tryptone soy agar containing yeast extract enriched with 1% hemin, 5% menadione and 5% sheep blood. T. forsythia was grown on tryptone soy agar containing yeast extract enriched with 1% hemin, 5% menadione, 5% sheep blood, and 1% N-acetylmuramic acid. After 24 h, the bacterial inocula were transferred to glass tubes with BHI (Becton Dickinson, Sparks, MD, USA) supplemented with 1% hemin and allowed to grow for 24 h. The optical density (OD) of each inoculum was read at 600 nm and adjusted to 0.1, which corresponds to ∼108 CFU ml−1. Individual cell suspensions were diluted, and 100 µl aliquots of the inocula containing 106 cells were mixed with 11.8 ml of BHI broth supplemented with 1% hemin and 5% sheep blood. The final biofilm inoculum consisted of 15 ml with ∼1 × 106 cells of each bacterial strain.