China
Africa
Explore chapters and articles related to this topic
Basic Microbiology
Published in Philip A. Geis, Cosmetic Microbiology, 2020
Facultative anaerobes have evolved mechanisms to produce ATP (although in smaller amounts) by breaking down sugars when O2 is absent. Collectively referred to as fermentation, these mechanisms produce ATP along with a number of interesting byproducts depending on the species. Many of these byproducts are important commercially. The mechanisms of fermentation are categorized based on the major acid or alcohol byproducts that are produced. Homolactic fermentation—Produces lactic acid exclusively as a byproduct of fermentation.Heterolactic fermentation—Produces lactic acid in addition to ethanol and CO2.Alcoholic fermentation—In this mechanism, ethanol is the primary byproduct in addition to CO2.Mixed acid fermentation—Produces multiple byproducts including acetic acid, lactic acid, succinic acid, and formic acids as well as ethanol.Butanediol fermentation—In this mechanism, butanediol and ethanol are produced in large amounts along with lactic acid.
Biology of microbes
Published in Philip A. Geis, Cosmetic Microbiology, 2006
Escherichia. This organism, like Serratia, belongs to the Enterobacteriaceae. It utilizes a mixed acid fermentation pathway to produce lactate, acetate, succinate, and either formate or hydrogen, carbon dioxide gas, and ethanol. E. coli is perhaps the most studied and experimentally used bacterium. It is a major inhabitant of the human gut and is a presumptive positive for the presence of fecal contamination in water. Some strains cause gastroenteritis or urinary tract infections. E. coli can grow in the gut, producing enterotoxins that cause the hypersecretion of chloride and water in the small intestine; this is colloquially referred to as “traveler’s diarrhea.”
The duodenal mucosa associated microbiome, visceral sensory function, immune activation and psychological comorbidities in functional gastrointestinal disorders with and without self-reported non-celiac wheat sensitivity
Published in Gut Microbes, 2022
Ayesha Shah, Seungha Kang, Nicholas J Talley, Anh Do, Marjorie M Walker, Erin R Shanahan, Natasha A Koloski, Michael P Jones, Simon Keely, Mark Morrison, Gerald J Holtmann
In this study, we have compared all the FGID subjects with the controls using three distinct statistical approaches: edgeR, sPLS-DA (ASV-level), and factor analysis (genus-level). One or more of these approaches identified specific ASVs representing Prevotella, Alloprevotella, Neisseria, Veillonella, Peptostreptococcus, and Leptotrichia to be increased for the FGID patients compared to the control group. These differences are likely to support a mixed acid fermentation including succinate and propionate production, which in turn provides substrates that can support the growth of asaccharolytic Veillonella spp. and Neisseria spp.,41 respectively. As such, these alterations in the d-MAM profiles of FGID patients without SR-NCWS are microbiologically intuitive and aligned with other findings. Indeed, a previous study focussing on IBS patients observed in the small intestine significantly increased the abundance of Prevotella spp, and Prevotella and Veillonella spp. abundance was significantly correlated.42
Dietary Isoflavones Alter Gut Microbiota and Lipopolysaccharide Biosynthesis to Reduce Inflammation
Published in Gut Microbes, 2022
Sudeep Ghimire, Nicole M. Cady, Peter Lehman, Stephanie R. Peterson, Shailesh K. Shahi, Faraz Rashid, Shailendra Giri, Ashutosh K. Mangalam
While we found no significant functional differences in the microbial communities after the diet switch from ISO to PF and PF to ISO when comparing D0 and D28 separately (Figure S3a S3b) there were significant differences between D0 and D28 over time for both diet changes (Figure S3c S3d). Functionally on D0 the ISO diet had significant enrichment of mixed acid fermentation and TCA cycle VI pathways suggesting a higher abundance of short-chain fatty acid pathways (Figure 5a). The folate transformation pathway was only significantly enriched in mice on a PF diet. However on D28 the diet change from PF to ISO had significant enrichment of chorismate biosynthesis pathways and L-lysine biosynthesis VI pathway (Figure 5b). The lysine biosynthesis pathway VI is crucial as it produces an important metabolite meso-diaminopimelate which is a constituent of the bacterial cell wall peptidoglycan. The chorismite biosynthesis pathways produce chorismite which is an important intermediate leading to the synthesis of essential metabolites such as L-phenylalanine L-tyrosine L-tryptophan vitamins E and K ubiquinone and certain siderophores. Especially these amino acids act as substrates for the production of secondary metabolites from alkaloids flavonoids lignin coumarin and other phenolic compounds implying that a diet switch to PF from ISO but not ISO from PF enhances secondary metabolite production from dietary flavonoids.
Human vaginal pH and microbiota: an update
Published in Gynecological Endocrinology, 2018
Keshav Godha, Kelly M. Tucker, Colton Biehl, David F. Archer, Sebastian Mirkin
The pH of the vagina has been an ongoing area of interest in the understanding of vaginal physiology, disease, and drug development. More than a century ago, in 1892, Albert Döderlein, a German obstetrician and gynecologist, was the first to describe a Gram-positive bacterium from the vagina, Döderlein’s bacillus (Lactobacilli genus), that was characterized by its ability to produce lactic acid through glycogen fermentation [2]. The resulting acidic pH of a healthy human vagina (normal range of 3.8–4.5) was found to provide protection against urinary tract infections (UTI) vaginitis, and deterring the overgrowth of pathogenic microbes [3]. Since then, other non-Lactobacillus species have been discovered that contribute to the acidic pH through homolactic and mixed acid fermentation [4]. Döderlein’s discovery brought awareness to the microorganisms that colonize the human vagina, currently defined as the vaginal microbiota.