scholarly journals Intraoral Microbial Metabolism and Association with Host Taste Perception

2020 ◽  
Vol 99 (6) ◽  
pp. 739-745 ◽  
Author(s):  
A. Gardner ◽  
P.W. So ◽  
G.H. Carpenter
Keyword(s):  
Current Knowledge ◽  
Microbial Metabolism ◽  
Sweet Taste ◽  
Salivary Protein ◽  
Oral Bacteria ◽  
Oral Microbiome ◽  
Taste Perception ◽  
Resonance Spectroscopy ◽  
High Concentrations

Metabolomics has been identified as a means of functionally assessing the net biological activity of a particular microbial community. Considering the oral microbiome, such an approach remains largely underused. While the current knowledge of the oral microbiome is constantly expanding, there are several deficits in knowledge particularly relating to their interactions with their host. This work uses nuclear magnetic resonance spectroscopy to investigate metabolic differences between oral microbial metabolism of endogenous (i.e., salivary protein) and exogenous (i.e., dietary carbohydrates) substrates. It also investigated whether microbial generation of different metabolites may be associated with host taste perception. This work found that in the absence of exogenous substrate, oral bacteria readily catabolize salivary protein and generate metabolic profiles similar to those seen in vivo. Important metabolites such as acetate, butyrate, and propionate are generated at relatively high concentrations. Higher concentrations of metabolites were generated by tongue biofilm compared to planktonic salivary bacteria. Thus, as has been postulated, metabolite production in proximity to taste receptors could reach relatively high concentrations. In the presence of 0.25 M exogenous sucrose, increased catabolism was observed with increased concentrations of a range of metabolites relating to glycolysis (lactate, pyruvate, succinate). Additional pyruvate-derived molecules such as acetoin and alanine were also increased. Furthermore, there was evidence that individual taste sensitivity to sucrose was related to differences in the metabolic fate of sucrose in the mouth. High-sensitivity perceivers appeared more inclined toward continual citric acid cycle activity postsucrose, whereas low-sensitivity perceivers had a more efficient conversion of pyruvate to lactate. This work collectively indicates that the oral microbiome exists in a complex balance with the host, with fluctuating metabolic activity depending on nutrient availability. There is preliminary evidence of an association between host behavior (sweet taste perception) and oral catabolism of sugar.

scholarly journals Single-Cell Genomics and the Oral Microbiome

2020 ◽  
Vol 99 (6) ◽  
pp. 613-620 ◽  
Author(s):  
M. Balachandran ◽  
K.L. Cross ◽  
M. Podar
Keyword(s):  
Microbial Community ◽  
Single Cell ◽  
Single Cells ◽  
Oral Bacteria ◽  
Oral Microbiome ◽  
Oral Microbiota ◽  
Oral Diseases ◽  
Interspecies Interactions ◽  
Single Cell Genomics

The human oral cavity is one of the first environments where microbes have been discovered and studied since the dawn of microbiology. Nevertheless, approximately 200 types of bacteria from the oral microbiota have remained uncultured in the laboratory. Some are associated with a healthy oral microbial community, while others are linked to oral diseases, from dental caries to gum disease. Single-cell genomics has enabled inferences on the physiology, virulence, and evolution of such uncultured microorganisms and has further enabled isolation and cultivation of several novel oral bacteria, including the discovery of novel interspecies interactions. This review summarizes some of the more recent advances in this field, which is rapidly moving toward physiologic characterization of single cells and ultimately cultivation of the yet uncultured. A combination of traditional microbiological approaches with genomic-based physiologic predictions and isolation strategies may lead to the oral microbiome being the first complex microbial community to have all its members cultivable in the laboratory. Studying the biology of the individual microbes when in association with other members of the community, in controlled laboratory conditions and in vivo, should lead to a better understanding of oral dysbiosis and its prevention and reversion.

scholarly journals Exploring Associations between Interindividual Differences in Taste Perception, Oral Microbiota Composition, and Reported Food Intake

Nutrients ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1167 ◽  
Author(s):  
Camilla Cattaneo ◽  
Patrizia Riso ◽  
Monica Laureati ◽  
Giorgio Gargari ◽  
Ella Pagliarini
Keyword(s):  
Food Intake ◽  
Eating Habits ◽  
Saturated Fat ◽  
Sweet Taste ◽  
Oral Microbiome ◽  
Taste Perception ◽  
Oral Microbiota ◽  
Microbiota Composition

The role of taste perception, its relationship with oral microbiota composition, and their putative link with eating habits and food intake were the focus of the present study. A sample of 59 reportedly healthy adults (27 male, 32 female; age: 23.3 ± 2.6 years) were recruited for the study and taste thresholds for basic tastes, food intake, and oral microbiota composition were evaluated. Differences in taste perception were associated with different habitual food consumption (i.e., frequency) and actual intake. Subjects who were orally hyposensitive to salty taste reported consuming more bakery and salty baked products, saturated-fat-rich products, and soft drinks than hypersensitive subjects. Subjects hyposensitive to sweet taste reported consuming more frequently sweets and desserts than the hypersensitive group. Moreover, subjects hypersensitive to bitter taste showed higher total energy and carbohydrate intakes compared to those who perceived the solution as less bitter. Some bacterial taxa on tongue dorsum were associated with gustatory functions and with vegetable-rich (e.g., Prevotella) or protein/fat-rich diets (e.g., Clostridia). Future studies will be pivotal to confirm the hypothesis and the potential exploitation of oral microbiome as biomarker of long-term consumption of healthy or unhealthy diets.

scholarly journals Characterization of Oral Microbiome and Exploration of Potential Biomarkers in Patients with Pancreatic Cancer

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Haiyang Sun ◽  
Xia Zhao ◽  
Yanxia Zhou ◽  
Jun Wang ◽  
Rui Ma ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Bacterial Community ◽  
High Throughput Sequencing ◽  
Pancreatic Disease ◽  
Good Prognosis ◽  
Oral Bacteria ◽  
Oral Microbiome ◽  
Linear Discriminant ◽  
Neisseria Mucosa ◽  
High Concentrations

Pancreatic cancer (PC) is highly malignant and lacks an effective therapeutic schedule, hence that early diagnosis is of great importance to achieve a good prognosis. Oral bacteria have been proved to be associated with pancreatic cancer, but the specific mechanism has not been comprehensively illustrated. In our study, thirty-seven saliva samples in total were collected with ten from PC patients, seventeen from benign pancreatic disease (BPD) patients, and ten from healthy controls (HC). The oral bacterial community of HC, PC, and BPD groups was profiled by 16S rDNA high-throughput sequencing and bioinformatic methods. As shown by Simpson, Inverse Simpson, Shannon and Heip, oral microbiome diversity of HC, BPD and PC groups is in increasing order with the BPD and PC groups significantly higher than the HC group. Principal coordinate analysis (PCoA) suggested that grouping by PC, BPD and HC was statistically significant. The linear discriminant analysis effect size (LEfSe) identified high concentrations of Fusobacterium periodonticum and low concentrations of Neisseria mucosa as specific risk factors for PC. Furthermore, predicted functions showed changes such as RNA processing and modification as well as the pathway of NOD-like receptor signaling occurred in both PC and HC groups. Conclusively, our findings have confirmed the destruction of oral bacterial community balance among patients with PC and BPD and indicated the potential of Fusobacterium periodonticum and Neisseria mucosa as diagnostic biomarkers of PC.

scholarly journals Saccharibacteria (TM7) in the Human Oral Microbiome

2019 ◽  
Vol 98 (5) ◽  
pp. 500-509 ◽  
Author(s):  
B. Bor ◽  
J.K. Bedree ◽  
W. Shi ◽  
J.S. McLean ◽  
X. He
Keyword(s):  
Oral Cavity ◽  
Relative Abundance ◽  
Current Knowledge ◽  
Growth Dynamics ◽  
Oral Bacteria ◽  
Oral Microbiome ◽  
Mammalian Host ◽  
Host Bacterium ◽  
Direct Killing ◽  
16S Rrna Diversity

Bacteria from the Saccharibacteria phylum (formerly known as TM7) are ubiquitous members of the human oral microbiome and are part of the Candidate Phyla Radiation. Recent studies have revealed remarkable 16S rRNA diversity in environmental and mammalian host-associated members across this phylum, and their association with oral mucosal infectious diseases has been reported. However, due to their recalcitrance to conventional cultivation, TM7’s physiology, lifestyle, and role in health and diseases remain elusive. The recent cultivation and characterization of Nanosynbacter lyticus type strain TM7x (HMT_952)—the first Saccharibacteria strain coisolated as an ultrasmall obligate parasite with its bacterial host from the human oral cavity—provide a rare glimpse into the novel symbiotic lifestyle of these enigmatic human-associated bacteria. TM7x is unique among all bacteria: it has an ultrasmall size and lives on the surface of its host bacterium. With a highly reduced genome, it lacks the ability to synthesize any of its own amino acids, vitamins, or cell wall precursors and must parasitize other oral bacteria. TM7x displays a highly dynamic interaction with its bacterial hosts, as reflected by the reciprocal morphologic and physiologic changes in both partners. Furthermore, depending on environmental conditions, TM7x can exhibit virulent killing of its host bacterium. Thus, Saccharibacteria potentially affect oral microbial ecology by modulating the oral microbiome structure hierarchy and functionality through affecting the bacterial host’s physiology, inhibiting the host’s growth dynamics, or affecting the relative abundance of the host via direct killing. At this time, several other uncharacterized members of this phylum have been detected in various human body sites at high prevalence. In the oral cavity alone, at least 6 distinct groups vary widely in relative abundance across anatomic sites. Here, we review the current knowledge on the diversity and unique biology of this recently uncovered group of ultrasmall bacteria.

scholarly journals Assessing Cerebral Metabolism in the Immature Rodent: From Extracts to Real-Time Assessments

2018 ◽  
Vol 40 (5-6) ◽  
pp. 463-474
Author(s):  
Alkisti Mikrogeorgiou ◽  
Duan Xu ◽  
Donna M. Ferriero ◽  
Susan J. Vannucci
Keyword(s):  
Ketone Bodies ◽  
Current Knowledge ◽  
Cerebral Metabolism ◽  
High Energy ◽  
Resonance Spectroscopy ◽  
Neurodevelopmental Outcomes ◽  
1H Mrs ◽  
13C Mrs ◽  
The Brain

Brain development is an energy-expensive process. Although glucose is irreplaceable, the developing brain utilizes a variety of substrates such as lactate and the ketone bodies, β-hydroxybutyrate and acetoacetate, to produce energy and synthesize the structural components necessary for cerebral maturation. When oxygen and nutrient supplies to the brain are restricted, as in neonatal hypoxia-ischemia (HI), cerebral energy metabolism undergoes alterations in substrate use to preserve the production of adenosine triphosphate. These changes have been studied by in situ biochemical methods that yielded valuable quantitative information about high-energy and glycolytic metabolites and established a temporal profile of the cerebral metabolic response to hypoxia and HI. However, these analyses relied on terminal experiments and averaging values from several animals at each time point as well as challenging requirements for accurate tissue processing.More recent methodologies have focused on in vivo longitudinal analyses in individual animals. The emerging field of metabolomics provides a new investigative tool for studying cerebral metabolism. Magnetic resonance spectroscopy (MRS) has enabled the acquisition of a snapshot of the metabolic status of the brain as quantifiable spectra of various intracellular metabolites. Proton (1H) MRS has been used extensively as an experimental and diagnostic tool of HI in the pursuit of markers of long-term neurodevelopmental outcomes. Still, the interpretation of the metabolite spectra acquired with 1H MRS has proven challenging, due to discrepancies among studies, regarding calculations and timing of measurements. As a result, the predictive utility of such studies is not clear. 13C MRS is methodologically more challenging, but it provides a unique window on living tissue metabolism via measurements of the incorporation of 13C label from substrates into brain metabolites and the localized determination of various metabolic fluxes. The newly developed hyperpolarized 13C MRS is an exciting method for assessing cerebral metabolism in vivo, that bears the advantages of conventional 13C MRS but with a huge gain in signal intensity and much shorter acquisition times. The first part of this review article provides a brief description of the findings of biochemical and imaging methods over the years as well as a discussion of their associated strengths and pitfalls. The second part summarizes the current knowledge on cerebral metabolism during development and HI brain injury.

scholarly journals The Oral Microbiome in Pediatric IBD: A Source of Pathobionts or Biomarkers?

2021 ◽  
Vol 8 ◽  
Author(s):  
Khalid Elmaghrawy ◽  
Séamus Hussey ◽  
Gary P. Moran
Keyword(s):  
Potential Role ◽  
Inflammatory Responses ◽  
Current Knowledge ◽  
Oral Bacteria ◽  
Oral Microbiome ◽  
Gi Tract ◽  
Clinical Indicator ◽  
Microbial Dysbiosis ◽  
Oral Microbes

The oral cavity is continuous with the gastrointestinal tract and in children, oral health may be closely linked with the overall health of the GI tract. In the case of pediatric Crohn's disease (CD), oral manifestations are an important clinical indicator of intestinal disease. Recent studies of the microbiome in IBD suggest that translocation of oral microbes to the gut may be a common feature of the microbial dysbiosis which is a signature of both CD and ulcerative colitis (UC). Murine studies suggest that translocation of oral bacteria and yeasts to the lower GI tract may trigger inflammation in susceptible hosts, providing a mechanistic link to the development of IBD. Conversely, some studies have shown that dysbiosis of the oral microbiome may occur, possibly as a result of inflammatory responses and could represent a useful source of biomarkers of GI health. This review summarizes our current knowledge of the oral microbiome in IBD and presents current hypotheses on the potential role of this community in the pathogenesis of these diseases.

Spectroscopic imaging of human disease

1996 ◽  
Vol 54 ◽  
pp. 884-885
Author(s):  
D.J. Meyerhoff
Keyword(s):  
Magnetic Field ◽  
Magnetic Resonance ◽  
Field Gradient ◽  
Human Disease ◽  
Morphological Changes ◽  
Magnetic Field Gradient ◽  
Spectroscopic Imaging ◽  
Resonance Spectroscopy ◽  
Tissue Water

Magnetic Resonance Imaging (MRI) observes tissue water in the presence of a magnetic field gradient to study morphological changes such as tissue volume loss and signal hyperintensities in human disease. These changes are mostly non-specific and do not appear to be correlated with the range of severity of a certain disease. In contrast, Magnetic Resonance Spectroscopy (MRS), which measures many different chemicals and tissue metabolites in the millimolar concentration range in the absence of a magnetic field gradient, has been shown to reveal characteristic metabolite patterns which are often correlated with the severity of a disease. In-vivo MRS studies are performed on widely available MRI scanners without any “sample preparation” or invasive procedures and are therefore widely used in clinical research. Hydrogen (H) MRS and MR Spectroscopic Imaging (MRSI, conceptionally a combination of MRI and MRS) measure N-acetylaspartate (a putative marker of neurons), creatine-containing metabolites (involved in energy processes in the cell), choline-containing metabolites (involved in membrane metabolism and, possibly, inflammatory processes),

Hair cell changes after cationic stimulation of corti's organ

1989 ◽  
Vol 47 ◽  
pp. 798-799
Author(s):  
Cesar D. Fermin ◽  
Hans-Peter Zenner
Keyword(s):  
Organ Of Corti ◽  
Cross Sectional ◽  
Surface Areas ◽  
High K ◽  
Anatomical Arrangement ◽  
Cell Cytosol ◽  
High Concentrations ◽  
K Concentration ◽  
Cell Changes

Contraction of outer and inner hair cells (OHC&IHC) in the Organ of Corti (OC) of the inner ear is necessary for sound transduction. Getting at HC in vivo preparations is difficult. Thus, isolated HCs have been used to study OHC properties. Even though viability has been shown in isolated (iOHC) preparations by good responses to current and cationic stimulation, the contribution of adjoining cells can not be explained with iOHC preparations. This study was undertaken to examine changes in the OHC after expossure of the OHC to high concentrations of potassium (K) and sodium (Na), by carefully immersing the OC in either artifical endolymph or perilymph. After K and Na exposure, OCs were fixed with 3% glutaraldehyde, post-fixed in osmium, separated into base, middle and apex and embedded in Araldite™. One μm thick sections were prepared for analysis with the light and E.M. Cross sectional areas were measured with Bioquant™ software.Potassium and sodium both cause isolated guinea pig OHC to contract. In vivo high K concentration may cause uncontrolled and sustained contractions that could contribute to Meniere's disease. The behavior of OHC in the vivo setting might be very different from that of iOHC. We show here changes of the cell cytosol and cisterns caused by K and Na to OHC in situs. The table below shows results from cross sectional area measurements of OHC from OC that were exposed to either K or Na. As one would expect, from the anatomical arrangement of the OC, OHC#l that are supported by rigid tissue would probably be displaced (move) less than those OHC located away from the pillar. Surprisingly, cells in the middle turn of the cochlea changed their surface areas more than those at either end of the cochlea. Moreover, changes in surface area do not seem to differ between K and Na treated OCs.

STEROID METABOLISM IN THE PERFUSED HUMAN PLACENTA

1978 ◽  
Vol 87 (1) ◽  
pp. 181-191 ◽  
Author(s):  
Alfred S. Wolf ◽  
Klaus A. Musch ◽  
Werner Speidel ◽  
Jürgen R. Strecker ◽  
Christian Lauritzen
Keyword(s):  
Venous Blood ◽  
Placental Lactogen ◽  
Dehydroepiandrosterone Sulphate ◽  
Metabolic Capacity ◽  
Loading Test ◽  
Lower Range ◽  
Group I ◽  
High Concentrations ◽  
Steroid Precursor

ABSTRACT A new model for the perfusion of human term-placentas has been developed for studies on the placental biogenesis of C-18 and C-19 steroids. For viability criteria, the glucose- and oxygen-consumption, regional perfusion control by dye-infusions or scanning after injection of 99Tc-labelled macroparticles, and the histological qualification were chosen. The recycled perfusate was investigated for the steroids oestrone (Oe1), oestradiol-17β (Oe2), oestriol (Oe3), 4-androstene-3,17-dione (A), testosterone (T), and human placental lactogen (HPL) by radioimmunoassay in controls and perfusions with the foetal steroid precursor dehydroepiandrosterone sulphate (DHA-S). In control perfusions, steroid hormones were found in constant ratios (Oe1:Oe2:Oe3:T:A = 30:1.5:100:0.35:1). Following the administration of 10 mg DHA-S for testing the metabolic capacity of the organ, high concentrations of Oe1 (90–720 ng/ml = 250–3970 % as compared to 100% pre-injection values) were found, shortly preceded by a rapid increase of A (66–1000 ng/ml = 100–16 000 %). A typical surge of T (5.3–147 ng/ml = 265–4640 %) preceded the normally slower increment of Oe2 (22–220 ng/ml = 1570–4330 %). The concentrations of Oe3 and HPL remained nearly unchanged. From different steroid patterns after DHA-S-load, two distinct responses of term-placentas could be differentiated: Group I (n=12) showed high concentrations of Oe1 (3200 ± 940 %), a small increase of T (1020 ± 500%), as well as low and delayed values of Oe2 (1660 ± 450%). In Group II (n = 5), values were high for T (3160 ± 1020%) and Oe2 (3300 ± 1110%), whereas Oe1 was found in a lower range (508 ± 302%). In contrast to in vivo findings in maternal venous blood after DHS-S injection to the mother, oestrone was found in perfusions as the main oestrogen fraction from DHA-S. Thus, the analysis of such metabolic differences might be of help in the interpretation of complex results from the DHA-S-loading test.

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