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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 contrast to members of the Enterobacteriaceae family, Pseudomonas aeruginosa, and many other gram-negative bacteria, certain other gram-negatives show high intrinsic susceptibility to hydrophobic inhibitors. These include Neisseria gonorrhoeae (13), Brucella spp., (39), Vibrio cholerae (40), Comamonas testosteroni (12), Pseudomonas acidovorans (12), Acinetobacter calcoaceticus (12), as well as Sphingomonas paucimobilis (M. Vaara, unpublished observations). In an elegant series of assays, Plesiat and Nikaido determined the OM permeability rates for hydrophobic steroid probes in various gram-negatives and showed that the rates were significantly (up to more than 20-fold) higher in C. testosteroni, P. acidovorans, and A. calcoaceticus than in P. aeruginosa, P. putida, E. coli, and S. typhimurium (12). The molecular mechanism underlying this difference was not studied. It would be interesting to assay whether the permeable species expose phospholipids in the outer leaflet of the OM, as does V. cholerae (40). In any case, increased permeability of hydrophobic molecules could be advantagenous for gram-negative bacteria in certain environmental habitats, both terrestrial and aquatic, in order to facilitate the uptake of hydrophobic nutrients.
Effect of Nutraceuticals on Gut Microbiota—What Is the Deal in Cancer?
Published in Sheeba Varghese Gupta, Yashwant V. Pathak, Advances in Nutraceutical Applications in Cancer, 2019
Andréa Burgess, Asra Sami, Sheeba Varghese Gupta
During gut dysbiosis, the number of Proeobacteria, Lentisphaerae, Bacteroides, and Parabacteroides species in the gut decrease (Rea et al., 2018). This reduction impacts the gut’s ability to directly metabolize chemotherapeutic medication and produce secondary toxic metabolites (Pouncey et al., 2018). Garcia-Gonzalez and colleagues used a Caenorhabditis elegans (C. elegans) worm model to investigate how the administration of different bacterial strains would influence chemotherapeutic medication potency. The worms fed with E. coli were “two orders of magnitude more sensitive to the sterilizing effect” of 5-fluoro-2′-deoxyuridine (FUDR) in comparison to worms fed with Comamonas bacteria. It was determined that the RNA metabolism capabilities of inoculated bacteria was essential for the observed enhanced cytotoxic effects (Garcia-Gonzalez et al., 2017).
Identification of clinical specimens isolated from neonates
Published in Elida Zairina, Junaidi Khotib, Chrismawan Ardianto, Syed Azhar Syed Sulaiman, Charles D. Sands, Timothy E. Welty, Unity in Diversity and the Standardisation of Clinical Pharmacy Services, 2017
M. Djunaedi, S.A.S. Sulaiman, A. Sarriff, N.B.A. Aziz, Habsah
The common Gram-negative bacteria isolated in 2003 and 2004 included Enterobacter sp. (26% and 5%), Klebsiella pneumoniae (23% and 47%), Acinetobacter sp. (14% and 12%), Pseudomonas aeruginosa (13% and 13%), and Escherichia coli (8% and 6%, respectively). The other Gram-negative bacteria are Citrobacter sp., Burkholderia pseudomallei, Serratia rubidaea, Haemophilus parainfluenzae, Pseudomonas putida, Serratia marcescens, Pantoea (Enterobacter) agglomerans, Comamonas testosteroni, Stenotrophomonas (Xantho) maltophilia, Pantoea sp., Proteus vulgaris, Burkholderia (Pseudo.) cepacia, Salmonella sp., Serratia ficaria, Escherichia vulneris, Serratia liquefaciens, enteropathogenic bacteria, Acinetobacter baumannii (anitratus), Alcaligenes xylosoxidans ss. xyloso, and Acinetobacter lwoffii.
Intraguild predation between Pristionchus pacificus and Caenorhabditis elegans: a complex interaction with the potential for aggressive behaviour
Published in Journal of Neurogenetics, 2020
Kathleen T. Quach, Sreekanth H. Chalasani
C. elegans has been cultivated in the laboratory setting with E. coli, OP50 since its debut as a model organism (Brenner, 1974). However, like P. pacificus, C. elegans is found in nature with a variety of other bacteria species, with Enterobacteriaceae and Acetobacteraceae species associated with high proliferation (Dirksen et al., 2016; Samuel et al., 2016; Schulenburg & Félix, 2017). Caenorhabditis elegans also displays a preference for bacterial species other than E. coli OP50, particularly if the other bacteria is higher quality food, as measured by growth rate (Shtonda & Avery, 2006). Furthermore, C. elegans raised on higher-quality bacteria leave mediocre bacteria more often (Shtonda & Avery, 2006). One such high-quality bacterial strain is Comamonas sp., which was isolated from a soil environment (Avery & Shtonda, 2003). Interestingly, the list of bacteria naturally found with and preferred by P. pacificus also includes the Comamonadaceae family (Akduman et al., 2018; Koneru et al., 2016). Additionally, a Comamonas sp. DA1877 diet has been shown to increase surplus killing in P. pacificus via increased the same B12 mechanism as in a Novosphingobium L76 diet (Akduman et al., 2019). Therefore, Comamonas sp. may be useful in mutually exacerbating competition between P. pacificus and C. elegans.
The gut microbiome of COVID-19 recovered patients returns to uninfected status in a minority-dominated United States cohort
Published in Gut Microbes, 2021
Rachel C. Newsome, Josee Gauthier, Maria C. Hernandez, George E. Abraham, Tanya O. Robinson, Haley B. Williams, Meredith Sloan, Anna Owings, Hannah Laird, Taylor Christian, Yilianys Pride, Kenneth J. Wilson, Mohammad Hasan, Adam Parker, Michal Senitko, Sarah C. Glover, Raad Z. Gharaibeh, Christian Jobin
To determine if the presence or absence of viral RNA in patient feces results in differences the gut microbiome, each COVID-19 patient’s fecal RNA was isolated and assayed via qPCR for the presence of COVID-19 viral RNA. 24 of the 50 COVID-19 patients (48%) tested positive, and 26 (52%) tested negative (Table 1). We examined the microbial community between qPCR positive and negative patient samples using PERMANOVA and found significant difference between these groups (Figure 5a, PERMANOVA FDR-P = .03). This difference was also observed in antibiotic treated subjects only (PERMANOVA FDR-P = .02). Consistent with previous observations, the Shannon diversity index or observed species richness between qPCR positive and negative COVID-19 patients is not different (Figure 5b, gls FDR P = .78, Supplementary Figure S1D). The microbial taxa enriched in the qPCR positive versus negative samples were then analyzed, revealing that the top three enriched genera in the positive samples were Comamonas, Sphaerochaeta, and Synergistes (Figure 5c). Also enriched in these positive samples were Klebsiella and Agathobacter, which were found earlier to be enriched in control and COVID-19-recovered patients compared to COVID-19-infected, respectively. The top three genera enriched in qPCR-negative fecal samples were Pseudoclavibacter, Cutibacterium and Mycoplasma. Phocea was also enriched in the negative versus positive samples, which was also the genera most associated with COVID-19 recovered patients versus control patients, indicating a possible connection between presence of this bacteria and recovery from COVID-19.
Completion of the gut microbial epi-bile acid pathway
Published in Gut Microbes, 2021
Heidi L. Doden, Patricia G. Wolf, H. Rex Gaskins, Karthik Anantharaman, João M. P. Alves, Jason M. Ridlon
The sequence WP_007678535.1 from Novosphingobium sp. AP12, whose recombinant enzyme product did not exhibit bile acid 12β-HSDH activity with the substrates tested, may be specific for aerobic bile acid degradation products. Environmental microorganisms, such as Comamonas testosteroni TA441 and Pseudomonas sp. strain Chol1, encode a CA degradation pathway involving conversion of a 12-oxo-intermediate to 7α,12β-dihydroxy-androsta-1,4-diene-3,17-dione (12β-DHADD).63,64 Thus, sequences in the extension of the subtree may have 12β-HSDH activity, but with specificity for side-chain cleaved steroids rather than bile acids.