Actinomycetota

Phylum Actinomycetota / Actinobacteria comprises aerobic , anaerobic , Gram-positive bacteria with high guanine and cytosine nucleotide contents in their genomic DNA
Manzo & Bhatt 2015
Kim et al. 2017 Immunol Rev. 279(1): 90-105
Shah et al. 2021e Int. J. Mol. Sci. 22: 6597

Actinomycetota / Actinobacteria are very rich in Bacterial natural products
Kalkreuter et al. 2020 Trends in Pharmacological Sciences 41: 13

Actinobacteria were the most abundant phylum in younger children
Khan Mirzaei et al. 2020

Actinobacteria are regularly present in the colon, but in low abundance (1.8%) in the Gut microbiota of healthy adult people (Kim et al. 2017 Immunol Rev. 279(1): 90-105 ; King et al. 2019) and belong to the healthy colonic microbiota
Flint et al. 2015

These organisms are commonly associated with the production of secondary metabolites (Manzo & Bhatt 2015) with powerful enzymes encoded in their biosynthetic gene clusters (BGCs)
Mike 2019

They are replaced during child development by Firmicutes and Bacteroidetes following the dietary transition from milk to solid food
Monira et al. 2011 Front. Microbiol. 2: 228
Robertson et al. 2019 Trends Microbiol. 27: 131–147

Fiber diet stimulates actinobacteria to produce propionate and butyrate and to stimulate the intestinal gluconeogenesis. That decreases the metabolic syndrome
Zmora et al. 2019 Nat Rev Gastroenterology & Hepatology 16: 35

The GOS-Lu (galactooligosaccharides derived from lactulose) prebiotic preparation increased the abundance of Actinobacteria mainly due to an increment in the Bifidobacteriaceae family and reduces significantly populations of pro-inflammatory bacteria families and species
Fernandez et al. 2018

Relative abundance of Actinomycetota / Actinobacteria in the ecosystem

• Soil: 13.0%


• Plant leaf: 0.0%


• Air: 4.6%


• Ocean: 2.6%


• Freshwater: 15.8%


• Human gut: 2.2%

Shin et al. 2015 Trends Biotechnol 33: 496

A major microbial biotransformation of bile acids is the generation of oxo- (or keto-) bile acids by oxidation of hydroxyl groups at ring position 3, 7, or 12 that are catalyzed by bacteria with Hydroxysteroid Dehydrogenases (HSDHS) (HSDHs), which are present in Actinobacteria
Kisiela et al. 2012 J. Steroid Biochem. Mol. Biol. 129: 31–46.

Actinobacteria are one of the producers of the important microbial metabolite tryptophan. Isoflavones and lignans, represent plant-derived chemicals that are metabolized by a diverse array of gut bacteria such as Actinobacteria to molecules that bind estrogen receptors and may evoke mammacarcinoma protective effects
Adlercreutz 2007 Critical Reviews in Clinical Laboratory Sciences 44(5–6): 483-525
Lampe 2009
Patisaul & Jefferson 2010

Moreover, Actinomycetota produce metabolites used as antibiotics, Anticancer drugs, antihelminthics, and Immunosuppressants / Immunosuppressive drugs
Willey et al. 2023 McGraw Hill, USA, ISBN 978-1-265-12303-1

Dietary fructan can result in expansion of Actinobacteria
Menne et al. 2000 The Journal of nutrition. 130:1197–1199
Kolida et al. 2007
Ramirez-Farias et al. 2009

Two known genera belong to the core OTUs (>47% of healthy humans) in the healthy human gut:
• Bifidobacterium
• Collinsella
Tap et al. 2009 Environ Microbiol 11: 2574-2584

see also:
Childhood / Child & Development of Gut Microbiota