Impact of Probiotics on Human Gut Microbiota and the Relationship with Obesity
Marcela Albuquerque Cavalcanti de Albuquerque, Alejandra de Moreno de LeBlanc, Jean Guy LeBlanc, Raquel Bedani in Lactic Acid Bacteria, 2020
In the literature, the gut microbiota is referred to as a “separate organ” (Possemiers et al. 2011) or “forgotten organ” (O’Hara and Shanahan 2006, Clemente et al. 2012) because of the exorbitant number of microorganisms inhabiting this location. The gut microbiota is composed of both anaerobic and aerobic microbial communities although the vast majority are strictly anaerobic and difficult to be cultured in vitro (Dave et al. 2012). The gut microbiota consists of more than 1,500 species distributed in at least seven different phyla (Dave et al. 2012, Alonso and Guarner 2013). The most dominant bacterial phyla found in the human gut are Firmicutes (including for example the genera Lactobacillus, Ruminococcus, Clostridium, and Eubacteria) and Bacteroidetes (including genera Bacteroides, Porphyromonas, Prevotella among others), followed by Proteobacteria (including genera Klebsiella, Enterobacter, Succinivibrio) and Actinobacteria (including, genera Bifidobacterium and Coreobacteria). Other phyla can be found in minor proportions such as Fusobacteria, Verrucomicrobia, Tenericutes, Cyanobacteria, Spirochaetes, and Synergistetes with less than 2% (Gill et al. 2006, Robles-Alonso and Guarner 2013, Caesar et al. 2015). All these microorganisms interact with each other and with their host, exerting influence on its physiology and health (Dave et al. 2012).
Commensal microbiota and its relationship to homeostasis and disease
Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald in Principles of Mucosal Immunology, 2020
The mucosa of the lower respiratory tract is minimally colonized by microbiota, although this assessment may change when it comes under study using culture-independent metagenomic analysis. In contrast, the microbiota of the nasal passage (nares) contains a rich, complex microbiome. The majority is derived from just two bacterial phyla, Actinobacteria and Firmicutes. A minor contribution is made by Proteobacteria, Bacteroidetes, and four other rare phyla. As expected, the nares microbiome is characteristic and is more similar between individuals than it is to other anatomic sites within the same individual. However, interindividual variation is also a feature, representing a relatively stable trait. Because aspects of the microbial fingerprint are shared among couples living together, the composition of this microbiome is likely to reflect a shared residential environment.
An Overview of Parasite Diversity
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2023
About 30 major groups of bacteria called phyla (singular, phylum) are recognized, for which at least some members of each can be cultured in the lab. There are at least 20 more “candidate phyla” identified, members of which are recognized for their genetic distinctiveness but thus far are unculturable. The number of bacterial phyla may someday climb to as high as 1,000. Of 16 relatively well-known bacterial lineages, 8 are particularly prominent with respect to containing human pathogens. Among them are bacteria causing many prominent human diseases, including tuberculosis, cholera, plague, syphilis, anthrax, Lyme disease and leprosy. Some prominent bacterial lineages such as Chlamydia and Rickettsia consist exclusively of intracellular parasites. Other groups, such as the Spirochaetes, not only have prominent parasitic representatives but also include many free-living species. Several bacterial lineages are predominantly free-living but contain a few parasitic representatives. It is clear that bacteria have readily adopted parasitism on several occasions. It is also clear that HGT has played an important role in the history of parasitism in bacteria. The first evidence for this process was the documentation of the transfer of drug resistance or virulence genes on plasmids from one bacterium to another unrelated bacterial species.
Subgingival microbiome of experimental gingivitis: shifts associated with the use of chlorhexidine and N-acetyl cysteine mouthwashes
Published in Journal of Oral Microbiology, 2019
Ahlam Al-Kamel, Divyashri Baraniya, Wadhah Abdulnaser Al-Hajj, Esam Halboub, Saleem Abdulrab, Tsute Chen, Nezar Noor Al-Hebshi
A total of 785 species – 34 of which potentially novel – belonging to 219 genera and 11 bacterial phyla were identified overall. The relative abundances and detection frequencies of taxa at the three taxonomic levels for each sample/group in the two sub-studies are provided in Supplementary files 2–7. The number of taxa per sample ranged from 39 to 84 genera and from 70 to 284 species. The relative abundances of bacterial phyla with >1% abundance (which together constituted more than 99% of all identified phyla), the 10 most abundant genera, and the 15 most abundant species are presented in Figures 3 and 4. Overall, Fusobacterium, Streptococcus, Leptotrichia, Veillonella, Propionibacterium, and Actinomyces were among the most abundant genera regardless of the time points or interventions; at the species levels were F. nucleatum, the Veillonella parvula group, Propionibacterium propionicum, and Granulicatella adiacens.
Prevention of enteric bacterial infections and modulation of gut microbiota with conjugated linoleic acids producing Lactobacillus in mice
Published in Gut Microbes, 2020
Mengfei Peng, Zajeba Tabashsum, Puja Patel, Cassandra Bernhardt, Chitrine Biswas, Jianghong Meng, Debabrata Biswas
The majority of human gut epithelial surfaces are colonized and safeguarded by a tremendous number of microorganisms including bacteria, viruses, fungi, and protozoans which are known as common gut microflora; each of them is crucial in forming and balancing a complex ecosystem with microbial diversity.1 These large number of microorganisms build up a microbial genetic repertoire approximately 100 times greater than that of the human host.2 Diversity of these microbes, specifically number of diverse bacterial species, is essential for good health and immunity of host.3,4 According to recent reports, human distal gastrointestinal (GI) tract can house more than 1000 distinct bacterial species, and the total number was estimated to be larger than 1014 CFU/gm of fecal material.5 Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria are the prevalent bacterial phyla in human gut microbiota and each of these phyla contains dozens of bacterial genus and hundreds of species.6–8
Gut microbiota in mucosa and feces of newly diagnosed, treatment-naïve adult inflammatory bowel disease and irritable bowel syndrome patients
Published in Gut Microbes, 2022
Hana Čipčić Paljetak, Anja Barešić, Marina Panek, Mihaela Perić, Mario Matijašić, Ivana Lojkić, Ana Barišić, Darija Vranešić Bender, Dina Ljubas Kelečić, Marko Brinar, Mirjana Kalauz, Marija Miličević, Dora Grgić, Nikša Turk, Irena Karas, Silvija Čuković-Čavka, Željko Krznarić, Donatella Verbanac
The intricate symbiotic relationship of the host and resident gut microbiota community provides the host with multiple essential functions and plays a crucial role in the maintenance of health. High inter-individual differences, as well as quantitative variation in the gut microbiota composition under the influence of a large number of host and environmental factors (including food intake, medication, geographical location, age, etc.),10–12 present a challenge in defining what constitutes a “normal” human microbiome. The most dominant bacterial phyla found in a healthy human gut are Bacteroidetes, Firmicutes, and Actinobacteria.13,14 This complex landscape can be stratified into reproducible patterns of variation of major taxa (i.e. Bacteroides, Prevotella, and Ruminococcus) in fecal metagenomes termed enterotypes.15 Recognizing compositional patterns and separating the human population across these three possible configurations can help in understanding human health and disease conditions.16
Related Knowledge Centers
- Bacteria
- Monophyly
- 16S Ribosomal Rna
- Candidate Division
- Microgenomates
- Gracilibacteria
- Pseudomonadota
- Chlamydiota
- Lentisphaerota
- Planctomycetota