The recA operon: A novel stress response gene cluster in Bacteroides fragilis

Nicholson, Samantha; Smalley, Darren; Smith, C. Jeffrey; Abratt, Valerie R.

doi:10.1016/j.resmic.2014.03.005

Cited by 11 publications

(5 citation statements)

References 42 publications

(79 reference statements)

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“…116 Studies with Bfr by Nicholson et al suggested that the bacterioferritin co-migratory protein, encoded within the recA operon, may play a role in maintaining metabolic fitness and genomic integrity in response to oxidative stress. 117 This may be accomplished by assisting in the reduction of hydroperoxides, thereby preventing lipid oxidation and DNA damage during oxidative stress.…”

Section: Oxidative Stress Responses As Virulence Factors and Protectimentioning

confidence: 99%

Gut Bacteroides species in health and disease

2021

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The functional diversity of the mammalian intestinal microbiome far exceeds that of the host organism, and microbial genes contribute substantially to the well-being of the host. However, beneficial gut organisms can also be pathogenic when present in the gut or other locations in the body. Among dominant beneficial bacteria are several species of Bacteroides, which metabolize polysaccharides and oligosaccharides, providing nutrition and vitamins to the host and other intestinal microbial residents. These topics and the specific organismal and molecular interactions that are known to be responsible for the beneficial and detrimental effects of Bacteroides species in humans comprise the focus of this review. The complexity of these interactions will be revealed.

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Section: Oxidative Stress Responses As Virulence Factors and Protectimentioning

confidence: 99%

Gut Bacteroides species in health and disease

2021

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“…Repair proteins such as MutS (EMQU_2803) conferring DNA mismatch repair and its protection from oxidative stress are slightly upregulated). So is the recA (EMQU_2752: 2 folds in the foregut) operon that was shown to be upregulated during oxidative stress (38); recF for recombination repair (39), whose general role is maintenance of DNA is upregulated (2 and 3 folds in fore- and hindguts, respectively) (40).…”

Section: Resultsmentioning

confidence: 99%

Survival strategies ofEnterococcus mundtiiin the gut ofSpodoptera littoralis: a live report

Mazumdar

Teh

Murali

et al. 2020

Preprint

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21The complex interaction between a higher organism and its resident gut flora is a subject of 22 immense interest in the field of symbiosis. Many insects harbor a complex community of 23 microorganisms in their gut. Larvae of Spodoptera littoralis, a lepidopteran pest which is 24 prevalent in tropical and subtropical regions of the world, have a tube-like gut structure 25 containing a simple bacterial community. This community varies both spatially (along the 26 length of the gut) and temporally (during the life cycle of the insect). 27To monitor the dynamics and rapid adaptation of microbes to the gut conditions, a GFP-tagged 28 reporter E. mundtii was constructed. After feeding to early instar S. littoralis larvae, the tagged-29 microbes recovered from the fore and hind guts by flow cytometry. The fluorescent reporter 30 confirmed the persistence of E. mundtii in the gut. RNA-sequencing of the sorted bacteria 31 highlighted various strategies that the symbiont employs to survive, including upregulated 32 pathways for tolerating alkaline stress, forming biofilms and two-component signaling systems, 33 resisting oxidative stress and quorum sensing. Although these symbionts depend on the host for 34 amino acid and fatty acids, differential regulation among various metabolic pathways points to 35 an enriched lysine synthesis pathway in the hindgut of the larvae. 36 37 animals, pests or pollinators of food crops, and as cyclers of carbon and nitrogen during the 43 decomposition of plant biomass (1) 44 There are several factors that determine the gut bacterial composition in insects. The gut can be 45 compartmentalized, resulting in structures that vary according to the complexity of the microbial 46 communities. Insects with a straight, tube-like gut usually possess a less diverse microbial 47 population compared to species with invaginations and deep pouches (1). Other factors that 48 shape the gut population include the following: oxygen level, gut pH, the presence of digestive 49 enzymes, antimicrobial compounds, and insect diet (2, 3). Although most bacteria have an 50 affinity for neutral pH, several acidophiles and alkalophiles have adapted to extreme pH 51 conditions. 52 Gut microbes can be either vertically or horizontally transmitted. Vertical transmission allows 53 bacterial transfer (from the ovaries to the egg shells) to the next generation (4), whereas 54 horizontal transmission occurs over the course of the life cycle, through diet and social behavior. 55 Regardless of how bacteria are transmitted, microbial populations may be unstable during early 56 developmental stages (5, 6). For example, in holometabolous insects, a complete metamorphosis 57 of the gut occurs in the larva, through pupal and adult stages, resulting in microbial turnover and 58 variable microbial counts (5).59 Insects are helped by their bacterial and fungal symbionts with functions relating to the digestion 60 of complex plant carbohydrates and amino acids, the assimilation of vitamins and the 61 development of defensive str...

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“…We also investigated the functional potential of susceptible microbiota and found genes regulating mRNA stability as a predictor of susceptibility. Response to stress caused by antibiotics involves changes in the transcriptional state of the bacteria [44], particularly elevated synthesis of selected stress response proteins [45,46]. To achieve this regulation, it is thought that keeping a low general mRNA abundance allows crucial mRNA encoding stress-related proteins to gain access to ribosomes for translation [47,48] short chain fatty acids [38], which have numerous health benefits for the host [55,56].…”

Section: Discussionmentioning

confidence: 99%

A mouse model of occult intestinal colonization demonstrating antibiotic-induced outgrowth of carbapenem-resistantEnterobacteriaceae

Sim

Kashaf

Conlan

et al. 2021

Preprint

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The human intestinal microbiome is a complex community that contributes to host health and disease. In addition to normal microbiota, pathogens like carbapenem-resistant Enterobacteriaceae may be asymptomatically present. When these bacteria are present at very low levels, they are often undetectable in hospital surveillance cultures, known as occult or subclinical colonization. Through the use of antibiotics, these subclinical pathogens can increase to sufficiently high levels to become detectable, in a process called outgrowth. However, little is known about the interaction between gut microbiota and Enterobacteriaceae during occult colonization and outgrowth. We developed a clinically relevant mouse model for studying occult colonization. Conventional wild-type mice without antibiotic pre-treatment were exposed to K. pneumoniae but rapidly tested negative for colonization. This occult colonization was found to perturb the microbiome as detected by both 16S rRNA amplicon and shotgun metagenomic sequencing. Outgrowth of occult K. pneumoniae was induced either by a four-antibiotic cocktail or by individual receipt of ampicillin, vancomycin or azithromycin, which all reduced overall microbial diversity. Notably, vancomycin was shown to trigger K. pneumoniae outgrowth in only a subset of exposed animals (outgrowth-susceptible). To identify factors that underlie outgrowth susceptibility, we analyzed microbiome-encoded gene functions and were able to classify outgrowth-susceptible microbiomes using pathways associated with mRNA stability. Lastly, an evolutionary approach illuminated the importance of xylose metabolism in K. pneumoniae colonization, supporting xylose abundance as a second susceptibility indicator. We showed that our model is generalizable to other pathogens, including carbapenem-resistant Escherichia coli and Enterobacter cloacae. This study suggests that microbiota mRNA and small-molecule metabolites may be used to predict outgrowth-susceptibility. Our modeling of occult colonization and outgrowth could help the development of strategies to mitigate the risk of subsequent infection and transmission in medical facilities and the wider community.

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The recA operon: A novel stress response gene cluster in Bacteroides fragilis

Cited by 11 publications

References 42 publications

Gut Bacteroides species in health and disease

Gut Bacteroides species in health and disease

Survival strategies ofEnterococcus mundtiiin the gut ofSpodoptera littoralis: a live report

A mouse model of occult intestinal colonization demonstrating antibiotic-induced outgrowth of carbapenem-resistantEnterobacteriaceae

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