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Micronutrients
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Vitamin B5 or pantothenic acid is an essential micronutrient required for the biosynthesis of coenzyme A. Coenzyme A (CoA) is a key cofactor in the citric acid cycle or the Krebs cycle, as well as in the metabolism of fatty acid. Pantothenic acid is also present at the active site of acyl carrier protein (ACP) (3, 9, 33, 43). About 85% of dietary pantothenic acid is as CoA and phosphopantetheine. All tissues are capable of forming CoA from pantothenic acid (33). Pantothenic acid is required for the synthesis of several essential molecules including sphingolipids, leucine, arginine, methionine, cholesterol, steroid hormones, vitamin A, vitamin D, and heme A. CoA provides the essential acetyl group to the neurotransmitter acetylcholine, to serotonin in its conversion to melatonin, and to the acetylated sugars present in glycoproteins and glycolipids (N-acetylglucosamine, N-acetylgalactosamine, and N-acetylneuramic acid) (33). Pantothenic acid lotion may promote healthy hair. Vitamin B5 has been suggested to aid in wound healing and to prevent acne. Vitamin B5 supplement could also reduce pain in patients with rheumatoid arthritis (33, 43). A deficiency of vitamin B5 is rare, but some benign symptoms may appear such as fatigue, insomnia, acne, dermatitis, irritability, epigastric distress with anorexia and constipation, numbness and tingling of the hands and feet, and stomach pains (3). No toxicity as a result of pantothenic acid excess has been identified at the dosages used (9, 33, 43).
Lipopolysaccharide and the Permeability of the Bacterial Outer Membrane
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
In addition, mutants seriously defective in the synthesis of multiple OM proteins, such as the mutants defective in both OmpA and the murein lipoprotein, are known to possess unstable OM that is partially defective in its barrier function to hydrophobic solutes (3,4). Other mutants supersusceptible to hydrophobic drugs include the pss mutant (defective in phosphatidylserine synthetase) (50) as well as the E. coli mutant LH530 that synthesizes reduced amounts of lipid A but probably has the primary defect in a more general step of lipid biosynthesis, since the defect can be compensated for by the gene that encodes phosphopantetheinyl transferase (51–53).
Halogenases with Potential Applications for the Synthesis of Halogenated Pharmaceuticals
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Georgette Rebollar-Pérez, Cynthia Romero-Guido, Antonino Baez, Eduardo Torres
α-Ketoglutarate halogenases, also referred to as non-heme iron halogenases, are enzymes able to exploit a radical halogen species to halogenate unactivated, aliphatic carbon centers, by radical intermediates (Jones et al., 2010). In the mechanism of non-heme iron halogenases the iron(II) in halogenases is complexed by two histidine residues, a ketoglutarate molecule and chloride ion (Fig. 16.1d). In this mechanism, the substrates are molecules tethered to the phosphopantetheinyl arm of carrier proteins (Akey et al., 2012). After the binding of the substrate and molecular oxygen, the decarboxylation of α-ketoglutarate takes place, and then reactive oxo-ferryl intermediate is produced. Hydrogen abstraction from the substrate is followed by transfer of the halide to the substrate radical (Fig. 16.1d).
Nanotoxicity of engineered nanomaterials (ENMs) to environmentally relevant beneficial soil bacteria – a critical review
Published in Nanotoxicology, 2019
Ricky W. Lewis, Paul M. Bertsch, David H. McNear
At least one study has examined the effects of TiO2 ENMs on PGPR activity in soils. In the presence or absence of TiO2 ENMs, Timmusk et al. (2018) inoculated wheat seedling roots with B. thuringiensis AZP2, Paenibacillus (Pa.) polymyxa A26, Alcaligenes (Al.) faecalis AF, and a Sfp type f-phosphopantetheinyl transferase deletion mutant, Pa. polymyxa A26Δsfp, or combinations of B. thuringiensis AZP2 and Pa. polymyxa A26 or Al. faecalis. These authors also assessed the effect of the PGPR and TiO2 ENM treatments on drought, salt, and pathogen responses. Based on shoot biomass from peat soil-grown wheat, the findings suggest that TiO2 ENMs might enhance PGPR activity when plants are co-inoculated with B. thuringiensis AZP2 and Pa. polymyxa A26 or Al. faecalis. No effect was observed by the TiO2 ENM treatment when plants were grown in sand. Additionally, the positive effect of PGPR and TiO2 ENMs on plants was greater when plants were stressed by drought, salt, or the fungal pathogen, Fusarium culmorum. Environmental scanning electron microscopy (SEM) imaging showed that TiO2 ENM treatment likely improved bacterial colonization of the root system, thereby enhancing plant growth promotion. The universality of these findings with regard to plant species, PGPR species, and ENM type is unclear; however, this study shows that PGPR–ENM interactions are complex in the soil environment and non-nutritive ENMs could be used to enhance PGPR activity.
Concurrent gut transcriptome and microbiota profiling following chronic ethanol consumption in nonhuman primates
Published in Gut Microbes, 2018
Tasha Barr, Suhas Sureshchandra, Paul Ruegger, Jingfei Zhang, Wenxiu Ma, James Borneman, Kathleen Grant, Ilhem Messaoudi
In the duodenum, we uncovered a positive correlation between ethanol consumption and several OTU associated with inflammation such as Porphyromonadaceae.53 We also identified many OTU associated with inflammation that positively correlated with ethanol consumption in the ileum including major Prevotella species (P. copri, P. stercorea, and P. loescheii). Similarly, the frequency of opportunistic pathogens such as Prevotella copri, P. stercorea, P. loescheii, Clostridium perfrigens, C. celatum, C. clostridioforme, and Streptococcus suis were increased with daily ethanol dose in the colon. In contrast, chronic heavy ethanol consumption decreased putatively beneficial bacteria such as Blautia species in jejunum and Ruminococcus species in ileum. Interestingly, an expansion of P. copri in mice has been shown to exacerbate colitis.54 We also observed an increase in the genus Porphyromonas in the colon with heavy ethanol drinking compared to controls. Porphyromonas have been identified as a strong biomarker for CRC in humans.55 Decreases in Porphyromonadaceae have also been associated with inflammation in colorectal tumor-bearing mice.53 In the colon, we also found a positive correlation between ethanol consumption and frequency of Peptostreptococcaceae bacterium and Haemophilus parainfluenzae, which are enriched in CRC patients39 and associated with colorectal carcinoma-in-adenoma.41 Furthermore, Selenomonas dianae, which is enriched in proximal colon tumors,40 was also increased with ethanol consumption. These findings are particularly interesting given the increased incidence of CRC with AUD.56 Additionally, the abundance of Flexispira species, which are usually dominant in healthy macaques,57 was reduced with heavy ethanol consumption suggestive of a loss in commensal bacteria. Furthermore, PICRUSt analyses revealed several putative bacterial genes that positively correlated with ethanol consumption are involved in carbohydrate metabolism. We also uncovered a negative correlation between ethanol consumption and the putative bacterial gene 4′-phosphopantetheinyl transferase, which is involved in vitamin production and metabolism, a potential mechanism of alcohol-mediated malabsorption/malnutrition.
Bifidobacterium animalis: the missing link for the cancer-preventive effect of Gynostemma pentaphyllum
Published in Gut Microbes, 2021
Weilin Liao, Imran Khan, Guoxin Huang, Shengshuang Chen, Liang Liu, Wai Kit Leong, Xiao Ang Li, Jianlin Wu, W. L. Wendy Hsiao
To further investigate whether GpS treatment could alter the biosynthesis and metabolism of the bacteria, we looked into the transcriptome of B. animalis in the presence and absence of GpS using RNAseq analysis. By comparing to the Ctrl, we identified 25 genes uniquely expressed in the GpS-treated culture of B. animalis. These genes are mapped to various biosynthesis pathways using the KEGG Mapper (Figure 5b). For instance, on the map, hisB, hisH, and hisI are part of the 10-gene cluster encode steps in the histidine biosynthetic pathway.34ArgJ encodes duel enzymes for arginine biosynthesis. MetF encodes 5,10-methylenetetrahydrofolate reductase, responsible for converting dUMP to dTMP for de novo synthesis. PyrB is mapped to pyrimidine biosynthesis; and miaA, tadA, tsaB, ybeY encode enzymes for RNA editing and synthesis.35 Besides playing the roles in biogenesis and biosynthesis as described above, some of the genes have different unique functions; for instance, recR encodes RecR protein, together with RecF and RecO proteins, forms the RecFOR complex which functions in RecA-mediated replication and homologous recombination. The recA, F, and O genes are all upregulated in GpS-cultures (Figure 5c). Another interesting gene, ruvA, encores part of RuvA-B DNA helicase for DNA repair and recombination.36 RuvB is also found upregulated on our gene list (Figure 5c and Table S2). Both the RuvA-B complex and the RecR are critical to bacterial DNA repair. The yajC gene encodes the smaller subunit of the preprotein translocase complex, which interacts with membrane protein SecD and SecF to coordinate protein transport and secretion across the cytoplasmic membrane in Escherichia coli.37PstA encodes the subunit of the ABC transporter, and the gatC gene encodes a translation factor. The coaD encodes phosphopantetheine adenyltransferase, which is involved in coenzyme-A biosynthesis. The coaD gene is also a frequent target for antibacterial drug discovery.38 The 4.5 RNA encoded by the ffs gene is the RNA component of the signal recognition particle (SRP) ribonucleoprotein complex that binds to the ribosome. SRP complex involves co-translational protein secretion and requires for cell viability. Deficiency of the gene causes a dramatic loss in protein synthesis, and eventual cell death.39 The rpmH encodes ribosomal 50S ribosomal subunit protein L34. It is worth mentioning that good numbers of upregulated genes in GpS-culture are the genes encoding 50S and 30S ribosomal subunit proteins (Figure 5c and Table S2). Transcription of rRNA is an essential step in ribosome biogenesis, which is highly regulated by the external supply of nutrients or external stimuli. In our case, GpS is well served as the growth stimulus to B. animalis through the activations of a series of genes encoding for rRNA and various biogenesis protein molecules, as illustrated above.