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An Overview of Parasite Diversity
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
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.
Exopolysaccharide Production from Marine Bacteria and Its Applications
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Prashakha J. Shukla, Shivang B. Vhora, Ankita G. Murnal, Unnati B. Yagnik, Maheshwari Patadiya
As a survival strategy, marine bacteria secrete several secondary metabolites (De Carvalho and Fernandes, 2010). These secondary metabolites help in their protection and survival (Jensen and Fenical, 1996). The first compound was an “antibiotic” produced by a marine actinomycete Chainiapurpurogena in 1975 (Okazaki et al., 1975). Bioactive natural products with unique characteristics (“anti-tumor and anti-cancer” properties) were obtained from marine organisms, such as sponges and algae. From 1997 to 2008, 659 compounds have been isolated from five major marine bacterial phyla, namely, Bacteroidetes, Firmicutes, Proteobacteria, Cyanobacteria and Actinobacteria (Proksch et al., 2002; Williams, 2009).
Human Gut Microbiota–Transplanted Gn Pig Models for HRV Infection
Published in Lijuan Yuan, Vaccine Efficacy Evaluation, 2022
A total of 5,616,353 non-chimeric high-quality sequences from the feces of the human donor and the recipient pigs were analyzed with QIIME. We analyzed the sequences at the operational taxonomic unit (OTU) level (Schloss and Handelsman, 2005). The recipient pigs carried microbiota that is similar to the human donor's microbiota (Figure 11.1A), despite that all pigs had received the attenuated HRV vaccine. Two bacterial phyla, Firmicutes and Proteobacteria, representing over 98% of total bacterial sequences in each subject, dominated the microbiota of both the human donor (delivered by C-section) and the recipient pigs. The most abundant genera within Firmicutes were Streptococcus, Enterococcus, Veillonella, and Staphylococcus (Figure 11.1A). The rank abundance curve showed that the gut microbiota of the human donor and pigs had a long tail of rare OTUs (data not shown). For example, around 900 OTUs (species rank from 100 to 1,000) each accounted only 0.01% (10–4) to well below 0.001% (10–5) of total bacteria.
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
AST-120 Treatment Alters the Gut Microbiota Composition and Suppresses Hepatic Triglyceride Levels in Obese Mice
Published in Endocrine Research, 2021
Yuki Hiraga, Tetsuya Kubota, Makoto Katoh, Yasushi Horai, Hiroyuki Suzuki, Yusuke Yamashita, Rieko Hirata, Masao Moroi
The bacterial phyla Bacteroidetes and Firmicutes are known to account for the majority of the gut microbiota in humans.3 NAFLD has been reported to be associated with a decrease in the relative abundance of some species of Firmicutes in the gut microbiota.4 Wang et al. reported an increase in the number of Bacteroidetes and decrease in the number of Firmicutes in patients with NAFLD as compared to the observations in non-NAFLD patients.5 Another study reported that the relative abundance of Bacteroidetes tended to be higher in patients with nonalcoholic steatohepatitis (NASH). The Bacteroidetes/Firmicutes (B/F) ratio has been reported to be significantly increased in patients with NASH.6,7 These reports provide evidence to suggest that changes of the gut microbiota composition are closely associated with the development and improvement of NAFLD.
An integrated workflow for enhanced taxonomic and functional coverage of the mouse fecal metaproteome
Published in Gut Microbes, 2021
Nicolas Nalpas, Lesley Hoyles, Viktoria Anselm, Tariq Ganief, Laura Martinez-Gili, Cristina Grau, Irina Droste-Borel, Laetitia Davidovic, Xavier Altafaj, Marc-Emmanuel Dumas, Boris Macek
Further investigation into taxonomic composition between LSC and nLSC revealed broad changes already at the phylum level. Notably, Bacteroidetes and Verrucomicrobia were enriched within LSC-prepared samples, whereas Firmicutes, Actinobacteria and Deferribacteres phyla were over-represented in nLSC samples. Such depletion or enrichment of several major bacterial phyla have previously been reported by Tanca and colleagues.24 While Verrucomicrobia was found enriched by LSC in ours as well as Tanca’s study, Bacteroidetes, Firmicutes and Actinobacteria were enriched by opposite methods. Several reasons may explain these discrepancies, such as the host organism under study (i.e. Mus musculus versus Homo sapiens), different protein sequence database construction (i.e. mouse microbiome catalog versus UniProtKB custom microbiome) and minimal biological variability (i.e. three biological sample here versus one in Tanca’s study).