Toxicity of Methylated Bismuth Compounds Produced by Intestinal Microorganisms toBacteroides thetaiotaomicron, a Member of the Physiological Intestinal Microbiota

Methanoarchaea have an outstanding capability to methylate numerous metal(loid)s therefore producing toxic and highly mobile derivatives. Here, we report that the production of methylated bismuth species by the methanoarchaeumMethanobrevibacter smithii, a common member of the human intestine, impairs the growth of members of the beneficial intestinal microbiota at low concentrations. The bacteriumBacteroides thetaiotaomicron, which is of great importance for the welfare of the host due to its versatile digestive abilities and its protective function for the intestine, is highly sensitive against methylated, but not against inorganic, bismuth species. The level of methylated bismuth species produced by the methanoarchaeumM. smithiiin a coculture experiment causes a reduction of the maximum cell density ofB. thetaiotaomicron. This observation suggests that the production of methylated organometal(loid) species in the human intestine, caused by the activity of methanoarchaea, may affect the health of the host. The impact of the species to reduce the number of the physiological intestinal microbiota brings an additional focus on the potentially harmful role of methanoarchaea in the intestine of a higher organism.

Download Full-text

Interphotoreceptor coupling: an evolutionary perspective

Pflügers Archiv - European Journal of Physiology ◽

10.1007/s00424-021-02572-9 ◽

2021 ◽

Author(s):

Lorenzo Cangiano ◽

Sabrina Asteriti

Keyword(s):

Visual Information ◽

Signal To Noise Ratio ◽

Electrical Coupling ◽

Physiological Role ◽

Cellular Processes ◽

Contact Points ◽

Highly Sensitive ◽

The Many ◽

The Impact

AbstractIn the vertebrate retina, signals generated by cones of different spectral preference and by highly sensitive rod photoreceptors interact at various levels to extract salient visual information. The first opportunity for such interaction is offered by electrical coupling of the photoreceptors themselves, which is mediated by gap junctions located at the contact points of specialised cellular processes: synaptic terminals, telodendria and radial fins. Here, we examine the evolutionary pressures for and against interphotoreceptor coupling, which are likely to have shaped how coupling is deployed in different species. The impact of coupling on signal to noise ratio, spatial acuity, contrast sensitivity, absolute and increment threshold, retinal signal flow and colour discrimination is discussed while emphasising available data from a variety of vertebrate models spanning from lampreys to primates. We highlight the many gaps in our knowledge, persisting discrepancies in the literature, as well as some major unanswered questions on the actual extent and physiological role of cone-cone, rod-cone and rod-rod communication. Lastly, we point toward limited but intriguing evidence suggestive of the ancestral form of coupling among ciliary photoreceptors.

Download Full-text

Irf4-dependent CD103+CD11b+dendritic cells and the intestinal microbiome regulate monocyte and macrophage activation and intestinal peristalsis in postoperative ileus

Gut ◽

10.1136/gutjnl-2017-313856 ◽

2017 ◽

Vol 66 (12) ◽

pp. 2110-2120 ◽

Cited By ~ 18

Author(s):

Judith-Mira Pohl ◽

Sebastian Gutweiler ◽

Stephanie Thiebes ◽

Julia K Volke ◽

Ludger Klein-Hitpass ◽

...

Keyword(s):

Dendritic Cells ◽

Antibiotic Treatment ◽

Intestinal Microbiota ◽

Postoperative Ileus ◽

Intestinal Microbiome ◽

Oral Antibiotic ◽

Monocytes And Macrophages ◽

Intestinal Peristalsis ◽

The Impact

ObjectivePostoperative ileus (POI), the most frequent complication after intestinal surgery, depends on dendritic cells (DCs) and macrophages. Here, we have investigated the mechanism that activates these cells and the contribution of the intestinal microbiota for POI induction.DesignPOI was induced by manipulating the intestine of mice, which selectively lack DCs, monocytes or macrophages. The disease severity in the small and large intestine was analysed by determining the distribution of orally applied fluorescein isothiocyanate-dextran and by measuring the excretion time of a retrogradely inserted glass ball. The impact of the microbiota on intestinal peristalsis was evaluated after oral antibiotic treatment.ResultsWe found thatCd11c-Cre+Irf4flox/floxmice lack CD103+CD11b+DCs, a DC subset unique to the intestine whose function is poorly understood. Their absence in the intestinal muscularis reduced pathogenic inducible nitric oxide synthase (iNOS) production by monocytes and macrophages and ameliorated POI. Pathogenic iNOS was produced in the jejunum by resident Ly6C–macrophages and infiltrating chemokine receptor 2-dependent Ly6C+monocytes, but in the colon only by the latter demonstrating differential tolerance mechanisms along the intestinal tract. Consistently, depletion of both cell subsets reduced small intestinal POI, whereas the depletion of Ly6C+monocytes alone was sufficient to prevent large intestinal POI. The differential role of monocytes and macrophages in small and large intestinal POI suggested a potential role of the intestinal microbiota. Indeed, antibiotic treatment reduced iNOS levels and ameliorated POI.ConclusionsOur findings reveal that CD103+CD11b+DCs and the intestinal microbiome are a prerequisite for the activation of intestinal monocytes and macrophages and for dysregulating intestinal motility in POI.

Download Full-text

Maternal Microbiota Transfer Programs Offspring Eating Behavior

Frontiers in Microbiology ◽

10.3389/fmicb.2021.672224 ◽

2021 ◽

Vol 12 ◽

Author(s):

Anne-Lise Pocheron ◽

Gwenola Le Dréan ◽

Helene Billard ◽

Thomas Moyon ◽

Anthony Pagniez ◽

...

Keyword(s):

Eating Behavior ◽

Intestinal Microbiota ◽

Caloric Intake ◽

Microbiota Composition ◽

Sprague Dawley ◽

Family Culture ◽

Gut Colonization ◽

Main Determinants ◽

The Impact

Understanding the link between mother’s obesity and regulation of the child’s appetite is a prerequisite for the design of successful preventive strategies. Beyond the possible contributions of genetic heritage, family culture, and hormonal and metabolic environment during pregnancy, we investigate in the present paper the causal role of the transmission of the maternal microbiotas in obesity as microbiotas differ between lean and obese mothers, maternal microbiotas are the main determinants of a baby’s gut colonization, and the intestinal microbiota resulting from the early colonization could impact the feeding behavior of the offspring with short- and long-term consequences on body weight. We thus investigated the potential role of vertical transfers of maternal microbiotas in programming the eating behavior of the offspring. Selectively bred obese-prone (OP)/obese-resistant (OR) Sprague-Dawley dams were used since differences in the cecal microbiota have been evidenced from males of that strain. Microbiota collected from vagina (at the end of gestation), feces, and milk (at postnatal days 1, 5, 10, and 15) of OP/OR dams were orally inoculated to conventional Fischer F344 recipient pups from birth to 15 days of age to create three groups of pups: F-OP, F-OR, and F-Sham group (that received the vehicle). We first checked microbiotal differences between inoculas. We then assessed the impact of transfer (from birth to adulthood) onto the intestinal microbiota of recipients rats, their growth, and their eating behavior by measuring their caloric intake, their anticipatory food reward responses, their preference for sweet and fat tastes in solutions, and the sensations that extend after food ingestion. Finally, we searched for correlation between microbiota composition and food intake parameters. We found that maternal transfer of microbiota differing in composition led to alterations in pups’ gut microbiota composition that did not last until adulthood but were associated with specific eating behavior characteristics that were predisposing F-OP rats to higher risk of over consuming at subsequent periods of their life. These findings support the view that neonatal gut microbiotal transfer can program eating behavior, even without a significant long-lasting impact on adulthood microbiota composition.

Download Full-text

Intestinal microbiota during early life – impact on health and disease

Proceedings of The Nutrition Society ◽

10.1017/s0029665114000627 ◽

2014 ◽

Vol 73 (4) ◽

pp. 457-469 ◽

Cited By ~ 29

Author(s):

Lotta Nylund ◽

Reetta Satokari ◽

Seppo Salminen ◽

Willem M. de Vos

Keyword(s):

Intestinal Microbiota ◽

Early Life ◽

Later Life ◽

Related Factors ◽

Life Impact ◽

Health And Disease ◽

And Function ◽

The Impact

In the first years after birth, the intestinal microbiota develops rapidly both in diversity and complexity while being relatively stable in healthy adults. Different life-style-related factors as well as medical practices have an influence on the early-life intestinal colonisation. We address the impact of some of these factors on the consecutive microbiota development and later health. An overview is presented of the microbial colonisation steps and the role of the host in that process. Moreover, new early biomarkers are discussed with examples that include the association of microbiota and atopic diseases, the correlation of colic and early development and the impact of the use of antibiotics in early life. Our understanding of the development and function of the intestinal microbiota is constantly improving but the long-term influence of early-life microbiota on later life health deserves careful clinical studies.

Download Full-text

The Intestinal Microbiota Interferes with the microRNA Response upon Oral Listeria Infection

mBio ◽

10.1128/mbio.00707-13 ◽

2013 ◽

Vol 4 (6) ◽

Cited By ~ 51

Author(s):

Cristel Archambaud ◽

Odile Sismeiro ◽

Joern Toedling ◽

Guillaume Soubigou ◽

Christophe Bécavin ◽

...

Keyword(s):

Bacterial Infection ◽

Intestinal Microbiota ◽

Mirna Expression ◽

Target Genes ◽

Host Protein ◽

Protein Coding ◽

Content Type ◽

Protein Coding Genes ◽

The Impact

ABSTRACT The intestinal tract is the largest reservoir of microbes in the human body. The intestinal microbiota is thought to be able to modulate alterations of the gut induced by enteropathogens, thereby maintaining homeostasis. Listeria monocytogenes is the agent of listeriosis, an infection transmitted to humans upon ingestion of contaminated food. Crossing of the intestinal barrier is a critical step of the infection before dissemination into deeper organs. Here, we investigated the role of the intestinal microbiota in the regulation of host protein-coding genes and microRNA (miRNA or miR) expression during Listeria infection. We first established the intestinal miRNA signatures corresponding to the 10 most highly expressed miRNAs in the murine ileum of conventional and germfree mice, noninfected and infected with Listeria. Next, we identified 6 miRNAs whose expression decreased upon Listeria infection in conventional mice. Strikingly, five of these miRNA expression variations (in miR-143, miR-148a, miR-200b, miR-200c, and miR-378) were dependent on the presence of the microbiota. In addition, as is already known, protein-coding genes were highly affected by infection in both conventional and germfree mice. By crossing bioinformatically the predicted targets of the miRNAs to our whole-genome transcriptomic data, we revealed an miRNA-mRNA network that suggested miRNA-mediated global regulation during intestinal infection. Other recent studies have revealed an miRNA response to either bacterial pathogens or commensal bacteria. In contrast, our work provides an unprecedented insight into the impact of the intestinal microbiota on host transcriptional reprogramming during infection by a human pathogen. IMPORTANCE While the crucial role of miRNAs in regulating the host response to bacterial infection is increasingly recognized, the involvement of the intestinal microbiota in the regulation of miRNA expression has not been explored in detail. Here, we investigated the impact of the intestinal microbiota on the regulation of protein-coding genes and miRNA expression in a host infected by L. monocytogenes, a food-borne pathogen. We show that the microbiota interferes with the microRNA response upon oral Listeria infection and identify several protein-coding target genes whose expression correlates inversely with that of the miRNA. Further investigations of the regulatory networks involving miR-143, miR-148a, miR-200b, miR-200c, and miR-378 will provide new insights into the impact of the intestinal microbiota on the host upon bacterial infection.

Download Full-text

Reactive oxygen species: influence on cerebral vascular tone

Journal of Applied Physiology ◽

10.1152/japplphysiol.01044.2005 ◽

2006 ◽

Vol 100 (2) ◽

pp. 739-743 ◽

Cited By ~ 120

Author(s):

Frank M. Faraci

Keyword(s):

Reactive Oxygen Species ◽

Vascular Tone ◽

Reactive Oxygen ◽

Vascular Biology ◽

Oxygen Species ◽

Low Concentrations ◽

The Impact ◽

Endothelium Dependent Relaxation ◽

Cerebral Vascular

Reactive oxygen species have multiple effects on vascular cells. Defining the sources and the impact of the various reactive oxygen species within the vessel wall has emerged as a major area of study in vascular biology. This review will focus on recent findings related to effects of reactive oxygen species on cerebral vascular tone. Effects of superoxide radical, hydrogen peroxide, and the reactive nitrogen species peroxynitrite are summarized. Although higher concentrations may be important for cerebral vascular biology in disease, relatively low concentrations of reactive oxygen species may function as signaling molecules involved with normal regulation of cerebral vascular tone. The mechanisms by which reactive oxygen species affect vascular tone may be quite complex, and our understanding of these processes is increasing. Additionally, the role of reactive oxygen species as mediators of endothelium-dependent relaxation is addressed. Finally, the consequences of the molecular interactions of superoxide with nitric oxide and arachidonic acid are discussed.

Download Full-text

Evidences for a Nutritional Role of Iodine in Plants

Frontiers in Plant Science ◽

10.3389/fpls.2021.616868 ◽

2021 ◽

Vol 12 ◽

Author(s):

Claudia Kiferle ◽

Marco Martinelli ◽

Anna Maria Salzano ◽

Silvia Gonzali ◽

Sara Beltrami ◽

...

Keyword(s):

Plant Defence ◽

Biomass Accumulation ◽

Bioinformatic Analysis ◽

Biotic And Abiotic Stress ◽

Proteomic Data ◽

Low Concentrations ◽

Functional Involvement ◽

The Impact ◽

Plant Defence Response

Little is known about the role of iodine in plant physiology. We evaluated the impact of low concentrations of iodine on the phenotype, transcriptome and proteome of Arabidopsis thaliana. Our experiments showed that removal of iodine from the nutrition solution compromises plant growth, and restoring it in micromolar concentrations is beneficial for biomass accumulation and leads to early flowering. In addition, iodine treatments specifically regulate the expression of several genes, mostly involved in the plant defence response, suggesting that iodine may protect against both biotic and abiotic stress. Finally, we demonstrated iodine organification in proteins. Our bioinformatic analysis of proteomic data revealed that iodinated proteins identified in the shoots are mainly associated with the chloroplast and are functionally involved in photosynthetic processes, whereas those in the roots mostly belong and/or are related to the action of various peroxidases. These results suggest the functional involvement of iodine in plant nutrition.

Download Full-text

Evidences for a nutritional role of iodine in plants

10.1101/2020.09.16.300079 ◽

2020 ◽

Author(s):

Claudia Kiferle ◽

Marco Martinelli ◽

Anna Maria Salzano ◽

Silvia Gonzali ◽

Sara Beltrami ◽

...

Keyword(s):

Plant Defence ◽

Biomass Accumulation ◽

Bioinformatic Analysis ◽

Plant Nutrient ◽

Biotic And Abiotic Stress ◽

Proteomic Data ◽

Low Concentrations ◽

The Impact ◽

Plant Defence Response

ABSTRACTLittle is known about the role of iodine in plant physiology. We evaluated the impact of low concentrations of iodine on the phenotype, transcriptome and proteome of Arabidopsis thaliana. Our experiments showed that removal of iodine from the nutrition solution compromises plant growth, and restoring it in micromolar concentrations is beneficial for biomass accumulation and leads to early flowering. In addition, iodine treatments specifically regulate the expression of several genes, mostly involved in the plant defence response, suggesting that iodine may protect against both biotic and abiotic stress. Finally, we demonstrated iodine organification in proteins. Our bioinformatic analysis of proteomic data revealed that iodinated proteins identified in the shoots are mainly associated with the chloroplast and are functionally involved in photosynthetic processes, whereas those in the roots mostly belong and/or are related to the action of various peroxidases. These results suggest that iodine should be considered as a plant nutrient.

Download Full-text

The Anti-Methicillin-Resistant Staphylococcus aureus Quinolone WCK 771 Has Potent Activity against Sequentially Selected Mutants, Has a Narrow Mutant Selection Window against Quinolone-Resistant Staphylococcus aureus, and Preferentially Targets DNA Gyrase

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00641-06 ◽

2006 ◽

Vol 50 (11) ◽

pp. 3568-3579 ◽

Cited By ~ 21

Author(s):

Sachin S. Bhagwat ◽

Lakshmi A. Mundkur ◽

Shrikant V. Gupte ◽

Mahesh V. Patel ◽

Habil F. Khorakiwala

Keyword(s):

Staphylococcus Aureus ◽

Dna Gyrase ◽

Primary Target ◽

Topoisomerase Iv ◽

Mutant Selection ◽

Low Concentrations ◽

Selection Window ◽

High Level ◽

The Impact

ABSTRACT WCK 771 is a broad-spectrum fluoroquinolone with enhanced activity against quinolone-resistant staphylococci. To understand the impact of the target-level interactions of WCK 771 on its antistaphylococcal pharmacodynamic properties, we determined the MICs for genetically defined mutants and studied the mutant prevention concentrations (MPCs), the frequency of mutation, and the cidality against the wild type and double mutants. There was a twofold increase in the MICs of WCK 771 for single gyrA mutants, indicating that DNA gyrase is its primary target. All first- and second-step mutants selected by WCK 771 revealed gyrA and grlA mutations, respectively. The MICs of WCK 771 and clinafloxacin were found to be superior to those of other quinolones against strains with double and triple mutations. WCK 771 was also cidal for high-density double mutants at low concentrations. WCK 771 and clinafloxacin showed narrow mutant selection windows compared to those of the other quinolones. Against a panel of 50 high-level quinolone-resistant clinical isolates of staphylococci (ciprofloxacin MIC ≥ 16 μg/ml), the WCK 771 MPCs were ≤2 μg/ml for 68% of the strains and ≤4 μg/ml for 28% of the strains. Our results demonstrate that gyrA is the primary target of WCK 771 and that it has pharmacodynamic properties remarkably different from those of quinolones with dual targets (garenoxacin and moxifloxacin) and topoisomerase IV-specific quinolones (trovafloxacin). WCK 771 displayed an activity profile comparable to that of clinafloxacin, a dual-acting quinolone with a high affinity to DNA gyrase. Overall, the findings signify the key role of DNA gyrase in determining the optimal antistaphylococcal features of quinolones.

Download Full-text

Liver cirrosis and complication risk management

Terapevticheskii arkhiv ◽

10.26442/00403660.2021.08.200917 ◽

2021 ◽

Vol 93 (8) ◽

pp. 963-968

Author(s):

Igor G. Bakulin ◽

Inna A. Oganezova ◽

Maria I. Skalinskaya ◽

Ekaterina V. Skazyvaeva

Keyword(s):

Risk Management ◽

Liver Cirrhosis ◽

Gut Microbiota ◽

Intestinal Permeability ◽

Intestinal Microbiota ◽

Digestive System ◽

Complication Risk ◽

Meta Analyses ◽

The Impact

Liver cirrhosis (LC) takes the main place in the structure of the pathology of the digestive system in terms of the frequency of mortality, as well as in the development of fatal and poorly controlled complications, which requires the search for effective methods for preventing the progression of the disease and the development of complications. The article provides updated information on the role of the intestinal microbiota, as well as endotoxemia and increased intestinal permeability syndromes in the pathophysiology of LC and its complications. The results of recent meta-analyses of the impact of dysbiotic disorders on the prognosis of the LC and the options for their correction are presented. Understanding of the significance of involvement of gut microbiota in the pathogenesis of LC has become one of the levers of management of the risks of complications of LC. In this case, the livergut axis can be considered to be the leading link to the formation of most of the main complications of LC.

Download Full-text