scholarly journals Mosaic Patterns of B-vitamin Synthesis and Utilization in a Natural Marine Microbial Community

2018 ◽  
Author(s):  
Laura Gómez-Consarnau ◽  
Rohan Sachdeva ◽  
Scott M. Gifford ◽  
Lynda S. Cutter ◽  
Jed A. Fuhrman ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
De Novo ◽  
B Vitamins ◽  
Microbial Consortia ◽  
Vitamin B ◽  
Complex Interactions ◽  
Spatial Changes ◽  
One Year ◽  
B Vitamin

Aquatic environments contain diverse microbial communities whose complex interactions mediate the cycling of major and trace nutrients such as vitamins. B-vitamins are essential coenzymes that many organisms cannot synthesize. Thus their exchange among de-novo synthesizers and auxotrophs is expected to play an important role in the microbial consortia and explain some of the temporal and spatial changes observed in diversity. In this study, we analyzed metatranscriptomes of a natural coastal microbial community, diel sampled-quarterly over one year to try to identify the potential major B-vitamin synthesizers and consumers. Our transcriptomic data show that the best-represented taxa dominated the expression of synthesis genes for some B-vitamins but lacked transcripts for others. For instance, Rhodobacterales dominated the expression of vitamin-B12synthesis, but not of vitamin-B7, whose synthesis transcripts were mainly represented by Flavobacteria.In contrast, bacterial groups that constituted less than 4% of the community (e.g., Verrucomicrobia) accounted for most of the vitamin-B1synthesis transcripts. Furthermore, ambient vitamin-B1concentrations were higher in samples collected during the day, and were positively correlated with chlorophyll-aconcentration. Our analysis supports the hypothesis that the mosaic of metabolic interdependencies through B-vitamin synthesis and exchange are key processes that contribute to shaping microbial communities in nature.

Effects of Community Versus Single Strain Inoculants on the Biocontrol of Salmonella and Microbial Community Dynamics in Alfalfa Sprouts†

2005 ◽  
Vol 68 (1) ◽  
pp. 40-48 ◽  
Author(s):  
ANABELLE MATOS ◽  
JAY L. GARLAND
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Community Dynamics ◽  
Community Level ◽  
Microbial Consortia ◽  
Single Strain ◽  
Acridine Orange Staining ◽  
Physiological Profiles ◽  
Alfalfa Sprouts ◽  
Alfalfa Seeds

Potential biological control inoculants, Pseudomonas fluorescens 2-79 and microbial communities derived from market sprouts or laboratory-grown alfalfa sprouts, were introduced into alfalfa seeds with and without a Salmonella inoculum. We examined their ability to inhibit the growth of this foodborne pathogen and assess the relative effects of the inoculants on the alfalfa microbial community structure and function. Alfalfa seeds contaminated with a Salmonella cocktail were soaked for 2 h in bacterial suspensions from each inoculant tested. Inoculated alfalfa seeds were grown for 7 days and sampled during days 1, 3, and 7. At each sampling, alfalfa sprouts were sonicated for 7 min to recover microflora from the surface, and the resulting suspensions were diluted and plated on selective and nonselective media. Total bacterial counts were obtained using acridine orange staining, and the percentage culturability was calculated. Phenotypic potential of sprout-associated microbial communities inoculated with biocontrol treatments was assessed using community-level physiological profiles based on patterns of use of 95 separate carbon sources in Biolog plates. Community-level physiological profiles were also determined using oxygen-sensitive fluorophore in BD microtiter plates to examine functional patterns in these communities. No significant differences in total and mesophilic aerobe microbial cell density or microbial richness resulting from the introduction of inoculants on alfalfa seeds with and without Salmonella were observed. P. fluorescens 2-79 exhibited the greatest reduction in the growth of Salmonella early during alfalfa growth (4.22 log at day 1), while the market sprout inoculum had the reverse effect, resulting in a maximum log reduction (5.48) of Salmonella on day 7. Community-level physiological profiles analyses revealed that market sprout communities peaked higher and faster compared with the other inoculants tested. These results suggest that different modes of actions of single versus microbial consortia biocontrol treatments may be involved.

scholarly journals Elucidation of roles for vitamin B12 in regulation of folate, ubiquinone, and methionine metabolism

2017 ◽  
Vol 114 (7) ◽  
pp. E1205-E1214 ◽  
Author(s):  
Margaret F. Romine ◽  
Dmitry A. Rodionov ◽  
Yukari Maezato ◽  
Lindsey N. Anderson ◽  
Premchendar Nandhikonda ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Microbial Communities ◽  
Binding Proteins ◽  
De Novo ◽  
Transcriptional Regulator ◽  
Vitamin B ◽  
Methionine Metabolism ◽  
Community Metabolism ◽  
Light Sensing ◽  
Allosteric Effector

Only a small fraction of vitamin B12-requiring organisms are able to synthesize B12 de novo, making it a common commodity in microbial communities. Initially recognized as an enzyme cofactor of a few enzymes, recent studies have revealed additional B12-binding enzymes and regulatory roles for B12. Here we report the development and use of a B12-based chemical probe to identify B12-binding proteins in a nonphototrophic B12-producing bacterium. Two unexpected discoveries resulted from this study. First, we identified a light-sensing B12-binding transcriptional regulator and demonstrated that it controls folate and ubiquinone biosynthesis. Second, our probe captured proteins involved in folate, methionine, and ubiquinone metabolism, suggesting that it may play a role as an allosteric effector of these processes. These metabolic processes produce precursors for synthesis of DNA, RNA, and protein. Thereby, B12 likely modulates growth, and by limiting its availability to auxotrophs, B12-producing organisms may facilitate coordination of community metabolism.

Effects of the forage to concentrate ratio on B-vitamin concentrations in different ruminal fractions of dairy cows

2005 ◽  
Vol 85 (3) ◽  
pp. 389-399 ◽  
Author(s):  
D. E. Santschi ◽  
J. Chiquette ◽  
R. Berthiaume ◽  
R. Martineau ◽  
J. J. Matte ◽  
...  
Keyword(s):  
Dairy Cows ◽  
B Vitamins ◽  
Free Fluid ◽  
Vitamin B ◽  
Associated Bacteria ◽  
Lactating Cows ◽  
Liquid Portion ◽  
B Vitamin ◽  
High Forage ◽  
Surrounding Fluid

Two studies were undertaken to verify the effect of the forage to concentrate ratio of the diet on B-vitamin concentrations in ruminal contents. In Study 1, eight primiparous and eight multiparous cows were used in a cross-over design, and concentrations of biotin, folates and vitamin B12 were determined in ruminal fluid and plasma of cows fed a high-forage (HF; 58:42 forage to concentrate ratio; DM basis) or a low-forage (LF; 37:63 forage to concentrate ratio; DM basis) diet. In Study 2, six ruminally cannulated lactating cows were used in a cross-over design to evaluate the effects of forage to concentrate ratio (HF = 60:40; LF = 40:60; DM basis) on concentrations of seven B-vitamins in the particle-free fluid and in both liquid- and solid-associated bacteria. Results showed that B-vitamins were present mainly in the bacterial fractions of the ruminal content, while only limited amounts were found in the surrounding fluid. A change in the forage to concentrate ratio had a greater effect on vitamin concentration in the bacteria associated with the solid fraction than in those present in the liquid portion of the rumen. The most noticeable effects of a low forage diet were an increase in riboflavin, but a decrease in true vitamin B12 concentrations in solid-associated bacteria as well as a decrease in biotin concentration in particle-free fluid. In conclusion, it appears that ruminal B-vitamin concentration is altered by changes in the forage to concentrate ratio, which suggests that the supply of vitamins to dairy cows is influenced by diet composition. Key words: B-vitamins, dairy cow, ruminal fractions, forage to concentrate ratio

scholarly journals Folate and vitamin B12concentrations are associated with plasma DHA and EPA fatty acids in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study

2017 ◽  
Vol 117 (1) ◽  
pp. 124-133 ◽  
Author(s):  
I. Iglesia ◽  
I. Huybrechts ◽  
M. González-Gross ◽  
T. Mouratidou ◽  
J. Santabárbara ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Healthy Lifestyle ◽  
Blood Parameters ◽  
B Vitamins ◽  
Vitamin B ◽  
Total Homocysteine ◽  
Underlying Mechanisms ◽  
B Vitamin ◽  
Helena Study

AbstractThis study aimed to examine the association between vitamin B6, folate and vitamin B12biomarkers and plasma fatty acids in European adolescents. A subsample from the Healthy Lifestyle in Europe by Nutrition in Adolescence study with valid data on B-vitamins and fatty acid blood parameters, and all the other covariates used in the analyses such as BMI, Diet Quality Index, education of the mother and physical activity assessed by a questionnaire, was selected resulting in 674 cases (43 % males). B-vitamin biomarkers were measured by chromatography and immunoassay and fatty acids by enzymatic analyses. Linear mixed models elucidated the association between B-vitamins and fatty acid blood parameters (changes in fatty acid profiles according to change in 10 units of vitamin B biomarkers). DHA, EPA) andn-3 fatty acids showed positive associations with B-vitamin biomarkers, mainly with those corresponding to folate and vitamin B12. Contrarily, negative associations were found withn-6:n-3 ratio,trans-fatty acids and oleic:stearic ratio. With total homocysteine (tHcy), all the associations found with these parameters were opposite (for instance, an increase of 10 nmol/l in red blood cell folate or holotranscobalamin in females produces an increase of 15·85 µmol/l of EPA (Pvalue <0·01), whereas an increase of 10 nmol/l of tHcy in males produces a decrease of 2·06 µmol/l of DHA (Pvalue <0·05). Positive associations between B-vitamins and specific fatty acids might suggest underlying mechanisms between B-vitamins and CVD and it is worth the attention of public health policies.

scholarly journals Corynebacterium Comparative Genomics Reveals a Role for Cobamide Sharing in the Skin Microbiome

2020 ◽  
Author(s):  
Mary Hannah Swaney ◽  
Lindsay R Kalan
Keyword(s):  
Comparative Genomics ◽  
Microbial Communities ◽  
Community Dynamics ◽  
De Novo ◽  
Skin Barrier ◽  
Skin Microbiome ◽  
Bacterial Phyla ◽  
Host Interactions ◽  
Complex Interactions ◽  
Associated Species

ABSTRACTThe human skin microbiome is a key player in human health, with diverse functions ranging from defense against pathogens to education of the immune system. Recent studies have begun unraveling the complex interactions within skin microbial communities, shedding light on the invaluable role that skin microorganisms have in maintaining a healthy skin barrier. While the Corynebacterium genus is a dominant taxon of the skin microbiome, relatively little is known how skin-associated Corynebacteria contribute to microbe-microbe and microbe-host interactions on the skin. Here, we performed a comparative genomics analysis of 71 Corynebacterium species from diverse ecosystems, which revealed functional differences between host- and environment-associated species. In particular, host-associated species were enriched for de novo biosynthesis of cobamides, which are a class of cofactor essential for metabolism in organisms across the tree of life but are produced by a limited number of prokaryotes. Because cobamides have been hypothesized to mediate community dynamics within microbial communities, we analyzed skin metagenomes for Corynebacterium cobamide producers, which revealed a positive correlation between cobamide producer abundance and microbiome diversity, a trait associated with skin health. We also provide the first metagenome-based assessment of cobamide biosynthesis and utilization in the skin microbiome, showing that both dominant and low abundant skin taxa encode for the de novo biosynthesis pathway and that cobamide-dependent enzymes are encoded by phylogenetically diverse taxa across the major bacterial phyla on the skin. Taken together, our results support a role for cobamide sharing within skin microbial communities, which we hypothesize mediates community dynamics.

scholarly journals Vitamin B-6 Intake Is Modestly Associated with Arsenic Methylation in Uruguayan Children with Low-Level Arsenic Exposure

2020 ◽  
Vol 150 (5) ◽  
pp. 1223-1229 ◽  
Author(s):  
Gauri Desai ◽  
Marie Vahter ◽  
Elena I Queirolo ◽  
Fabiana Peregalli ◽  
Nelly Mañay ◽  
...  
Keyword(s):  
Arsenic Exposure ◽  
B Vitamins ◽  
Vitamin B ◽  
Dimethylarsinic Acid ◽  
Study Objective ◽  
Low Level ◽  
Urinary Arsenic ◽  
Vitamin Intake ◽  
Vitamin B 12 ◽  
B Vitamin

ABSTRACT Background Detoxification of inorganic arsenic (iAs) occurs when it methylates to form monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). Lower proportions of urinary iAs and MMA, and higher proportions of DMA indicate efficient methylation. The role of B-vitamins in iAs methylation in children with low-level arsenic exposure is understudied. Objectives Our study objective was to assess the association between B-vitamin intake and iAs methylation in children with low-level arsenic exposure (&lt;50 µg/L in water; urinary arsenic 5–50 µg/L). Methods We conducted a cross-sectional study in 290 ∼7-y-old children in Montevideo. Intake of thiamin, riboflavin, niacin, vitamin B-6, and vitamin B-12 was calculated by averaging 2 nonconsecutive 24-h recalls. Total urinary arsenic concentration was measured as the sum of urinary iAs, MMA, and DMA, and adjusted for urinary specific gravity; iAs methylation was measured as urinary percentage As, percentage MMA, and percentage DMA. Arsenic concentrations from household water sources were assessed. Linear regressions tested the relationships between individual energy-adjusted B-vitamins and iAs methylation. Results Median (range) arsenic concentrations in urine and water were 9.9 (2.2–48.7) and 0.45 (0.1–18.9) µg/L, respectively. The median (range) of urinary percentage iAs, percentage MMA, and percentage DMA was 10.6% (0.0–33.8), 9.7% (2.6–24.8), and 79.1% (58.5–95.4), respectively. The median (range) intake levels of thiamin, riboflavin, niacin, and vitamin B-6 were 0.81 (0.19–2.56), 1.0 (0.30–2.24), 8.6 (3.5–23.3), and 0.67 (0.25–1.73) mg/1000 kcal, respectively, whereas those of folate and vitamin B-12 were 216 (75–466) and 1.7 (0.34–8.3) µg/1000 kcal, respectively. Vitamin B-6 intake was inversely associated with urinary percentage MMA (β = −1.60; 95% CI: −3.07, −0.15). No other statistically significant associations were observed. Conclusions Although vitamin B-6 intake was inversely associated with urinary percentage MMA, our findings suggest limited support for a relation between B-vitamin intake and iAs methylation in children exposed to low-level arsenic.

scholarly journals B-vitamins and prevention of dementia

2008 ◽  
Vol 67 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Robert Clarke
Keyword(s):  
Folic Acid ◽  
Cognitive Function ◽  
Meta Analysis ◽  
B Vitamins ◽  
Vitamin Supplementation ◽  
Vitamin B ◽  
Cross Sectional ◽  
Principal Investigators ◽  
Individual Participant ◽  
B Vitamin

Elevated plasma homocysteine (Hcy) concentrations have been implicated with risk of cognitive impairment and dementia, but it is unclear whether low vitamin B12 or folate status is responsible for cognitive decline. Most studies reporting associations between cognitive function and Hcy or B-vitamins have used a cross-sectional or case–control design and have been unable to exclude the possibility that such associations are a result of the disease rather than being causal. The Hcy hypothesis of dementia has attracted considerable interest, as Hcy can be easily lowered by folic acid and vitamin B12, raising the prospect that B-vitamin supplementation could lower the risk of dementia. While some trials assessing effects on cognitive function have used folic acid alone, vitamin B12 alone or a combination, few trials have included a sufficient number of participants to provide reliable evidence. An individual-patient-data meta-analysis of all randomised trials of the effects on cognitive function and vascular risk of lowering Hcy with B-vitamins will maximise the power to assess the epidemiologically-predicted differences in risk. Among the twelve large randomised Hcy-lowering trials for prevention of vascular disease, data should be available on about 30 000 participants with cognitive function. The principal investigators of such trials have agreed to combine individual-participant data from their trials after their separate publication.

scholarly journals Suboptimal Vitamin B Intakes of Zambian Preschool Children: Evaluation of 24-Hour Dietary Recalls

2018 ◽  
Vol 39 (2) ◽  
pp. 281-289 ◽  
Author(s):  
Tyler J. Titcomb ◽  
Samantha T. Schmaelzle ◽  
Emily T. Nuss ◽  
Jesse F. Gregory ◽  
Sherry A. Tanumihardjo
Keyword(s):  
Preschool Children ◽  
Dietary Diversity ◽  
Pantothenic Acid ◽  
The United States ◽  
B Vitamins ◽  
Vitamin B ◽  
Institute Of Medicine ◽  
Mean Values ◽  
Vitamin Intake ◽  
B Vitamin

Background: Hidden hunger affects individuals who chronically consume an inadequate intake of at least 1 micronutrient and is associated with low dietary diversity. Little data are available on dietary intake or status assessment of B vitamins among preschool children in Zambia. Objectives: The aim of this study was to assess 24-hour dietary recall records obtained from Zambian children aged 3 to 7 years for B vitamin intake in relation to adequacy and change over time in the same community. Methods: Twenty-four-hour dietary recalls were collected from 2 studies that were 2 years apart in the same district of Zambia. Data were retrospectively analyzed for B vitamin intake, that is, biotin, vitamin B12, folate, niacin, pantothenic acid, vitamin B6, riboflavin, and thiamin. The estimated average requirement (EAR) cut point method was used to assess inadequacy prevalence for EARs established by the Institute of Medicine in the United States. Results: For all B vitamins, mean values were below the EARs established for children 4 to 8 years old. Relative to the EAR, children had the highest intakes of vitamin B6 with inadequacies of 77.9% and 60.1% in 2010 and 2012, respectively. The highest prevalence of inadequate intake was associated with folate, where ≥95% of the children had intakes below the EAR in both studies. Conclusions: All median vitamin B intakes were inadequate among these young children in rural Zambia. Future researchers and policy makers may need to consider B vitamin status in resource-poor areas of the country.

scholarly journals Nutritional aspects and possible pathological mechanisms of hyperhomocysteinaemia: an independent risk factor for vascular disease

2000 ◽  
Vol 59 (2) ◽  
pp. 221-237 ◽  
Author(s):  
Michelle C. McKinley
Keyword(s):  
Risk Factor ◽  
Vascular Disease ◽  
Independent Risk Factor ◽  
B Vitamins ◽  
Vitamin B ◽  
Vascular Toxicity ◽  
Vitamin Status ◽  
The Status ◽  
B Vitamin ◽  
The Relationship

Numerous case–control and prospective studies have identified elevated plasma homocysteine as a strong independent risk factor for cerebovascular, cardiovascular and peripheral vascular disease. Homocysteine is formed as a result of the breakdown of the dietary amino acid methionine. Once formed, homocysteine is either remethylated to methionine, or undergoes a trans-sulfuration reaction to form cysteine. The re-methylation of homocysteine to methionine is dependent on three B-vitamins, i.e. riboflavin, vitamin B12and folate. The second pathway of homocysteine metabolism is the trans-sulfuration pathway which requires both vitamin B6and riboflavin for its activity. Thus, up to four B-vitamins are required for intracellular homocysteine metabolism. Many studies have noted strong inverse relationships between homocysteine levels and the status of both vitamin B12and folate. However, the relationship between vitamin B6status and homocysteine is still uncertain. Similarly, numerous intervention studies have demonstrated effective lowering of homocysteine levels as a result of folate and vitamin B12supplementation, while the homocysteine-lowering ability of vitamin B6is unclear. Even though riboflavin plays a crucial role in both the trans-sulfuration and remethylation pathways of homocysteine metabolism, the relationship between riboflavin status and homocysteine levels has not been investigated. The exact mechanism that explains the vascular toxicity of elevated homocysteine levels is unknown at present, studies indicate that it is both atherogenic and thrombogenic. To date, no randomized clinical trial has demonstrated that lowering of homocysteine levels is beneficial in terms of reducing the prevalence of vascular disease. It is probable, however, that optimal B-vitamin status is important in the prevention of vascular disease.

The B-vitamin group and the activity of hepatic microsomal mixed-function oxidases of the growing Wistar rat

1978 ◽  
Vol 39 (1) ◽  
pp. 127-137 ◽  
Author(s):  
R. Miltenberger ◽  
U. Oltersdorf
Keyword(s):  
Wistar Rats ◽  
Wistar Rat ◽  
B Vitamins ◽  
Vitamin B ◽  
Microsomal Enzymes ◽  
Mixed Function Oxidases ◽  
Male Wistar Rats ◽  
B Vitamin ◽  
Hepatic Microsomal Enzymes

1. Male Wistar rats were given isoenergetic, semi-synthetic diets deficient in thiamin, riboflavin, pyrid-oxine or all the B-vitamins.2. In rats given these deficient diets the ‘sleeping time’ induced with pentobarbital (PB) and the ‘paralysis time’ with zoxazolamine (Zz) were prolonged.3. The tolerance effect against both drugs was nearly independent of the levels of B-vitamins in the diets.4. In preparations from vitamin-B deficient animals the activities of the following hepatic microsomal enzymes were reduced: the aliphatic hydroxylase of PB, the aromatic hydroxylases of aniline (EC 1.14.14.1) and of Zz, the N-demethylase of aminopyrine, the UDP glucuronyltransferase (EC 2.4.1.17) of p-nitrophenol. The reactions most influenced were those of ‘type-1’ substrates, particularly those involving the hydroxylases.5. The effects observed were caused mainly by deficiency of riboflavin and to a lesser extent of thiamin or pyridoxine.

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