scholarly journals Fecal short-chain fatty acids are not predictive of colonic tumor status and cannot be predicted based on bacterial community structure

2019 ◽  
Author(s):  
Marc A. Sze ◽  
Begüm D. Topçuoğlu ◽  
Nicholas A. Lesniak ◽  
Mack T. Ruffin ◽  
Patrick D. Schloss
Keyword(s):  
Colorectal Cancer ◽  
Fatty Acids ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Sequence Data ◽  
Short Chain Fatty Acids ◽  
Tumor Burden ◽  
Short Chain ◽  
Rrna Gene ◽  
Chain Fatty Acids

AbstractColonic bacterial populations are thought to have a role in the development of colorectal cancer with some protecting against inflammation and others exacerbating inflammation. Short-chain fatty acids (SCFAs) have been shown to have anti-inflammatory properties and are produced in large quantities by colonic bacteria which produce SCFAs by fermenting fiber. We assessed whether there was an association between fecal SCFA concentrations and the presence of colonic adenomas or carcinomas in a cohort of individuals using 16S rRNA gene and metagenomic shotgun sequence data. We measured the fecal concentrations of acetate, propionate, and butyrate within the cohort and found that there were no significant associations between SCFA concentration and tumor status. When we incorporated these concentrations into random forest classification models trained to differentiate between people with normal colons and those with adenomas or carcinomas, we found that they did not significantly improve the ability of 16S rRNA gene or metagenomic gene sequence-based models to classify individuals. Finally, we generated random forest regression models trained to predict the concentration of each SCFA based on 16S rRNA gene or metagenomic gene sequence data from the same samples. These models performed poorly and were able to explain at most 14% of the observed variation in the SCFA concentrations. These results support the broader epidemiological data that questions the value of fiber consumption for reducing the risks of colorectal cancer. Although other bacterial metabolites may serve as biomarkers to detect adenomas or carcinomas, fecal SCFA concentrations have limited predictive power.ImportanceConsidering colorectal cancer is the third leading cancer-related cause of death within the United States, it is important to detect colorectal tumors early and to prevent the formation of tumors. Short-chain fatty acids (SCFAs) are often used as a surrogate for measuring gut health and for being anti-carcinogenic because of their anti-inflammatory properties. We evaluated the fecal SCFA concentration of a cohort of individuals with varying colonic tumor burden who were previously analyzed to identify microbiome-based biomarkers of tumors. We were unable to find an association between SCFA concentration and tumor burden or use SCFAs to improve our microbiome-based models of classifying people based on their tumor status. Furthermore, we were unable to find an association between the fecal community structure and SCFA concentrations. Our results indicate that the association between fecal SCFAs, the gut microbiome, and tumor burden is weak.

scholarly journals Fecal Short-Chain Fatty Acids Are Not Predictive of Colonic Tumor Status and Cannot Be Predicted Based on Bacterial Community Structure

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Marc A. Sze ◽  
Begüm D. Topçuoğlu ◽  
Nicholas A. Lesniak ◽  
Mack T. Ruffin ◽  
Patrick D. Schloss
Keyword(s):  
Colorectal Cancer ◽  
Fatty Acids ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Sequence Data ◽  
Short Chain Fatty Acids ◽  
Tumor Burden ◽  
Short Chain ◽  
Rrna Gene ◽  
Chain Fatty Acids

ABSTRACT Colonic bacterial populations are thought to have a role in the development of colorectal cancer with some protecting against inflammation and others exacerbating inflammation. Short-chain fatty acids (SCFAs) have been shown to have anti-inflammatory properties and are produced in large quantities by colonic bacteria that produce SCFAs by fermenting fiber. We assessed whether there was an association between fecal SCFA concentrations and the presence of colonic adenomas or carcinomas in a cohort of individuals using 16S rRNA gene and metagenomic shotgun sequence data. We measured the fecal concentrations of acetate, propionate, and butyrate within the cohort and found that there were no significant associations between SCFA concentration and tumor status. When we incorporated these concentrations into random forest classification models trained to differentiate between people with healthy colons and those with adenomas or carcinomas, we found that they did not significantly improve the ability of 16S rRNA gene or metagenomic gene sequence-based models to classify individuals. Finally, we generated random forest regression models trained to predict the concentration of each SCFA based on 16S rRNA gene or metagenomic gene sequence data from the same samples. These models performed poorly and were able to explain at most 14% of the observed variation in the SCFA concentrations. These results support the broader epidemiological data that questions the value of fiber consumption for reducing the risks of colorectal cancer. Although other bacterial metabolites may serve as biomarkers to detect adenomas or carcinomas, fecal SCFA concentrations have limited predictive power. IMPORTANCE Considering that colorectal cancer is the third leading cancer-related cause of death within the United States, it is important to detect colorectal tumors early and to prevent the formation of tumors. Short-chain fatty acids (SCFAs) are often used as a surrogate for measuring gut health and for being anticarcinogenic because of their anti-inflammatory properties. We evaluated the fecal SCFA concentrations of a cohort of individuals with different colonic tumor burdens who were previously analyzed to identify microbiome-based biomarkers of tumors. We were unable to find an association between SCFA concentration and tumor burden or use SCFAs to improve our microbiome-based models of classifying people based on their tumor status. Furthermore, we were unable to find an association between the fecal community structure and SCFA concentrations. Our results indicate that the association between fecal SCFAs, the gut microbiome, and tumor burden is weak.

scholarly journals Bacillus asahii sp. nov., a novel bacterium isolated from soil with the ability to deodorize the bad smell generated from short-chain fatty acids

2004 ◽  
Vol 54 (6) ◽  
pp. 1997-2001 ◽  
Author(s):  
Isao Yumoto ◽  
Kikue Hirota ◽  
Shingo Yamaga ◽  
Yoshinobu Nodasaka ◽  
Tsuneshirou Kawasaki ◽  
...  
Keyword(s):  
Fatty Acids ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequencing ◽  
16S Rrna Gene Sequencing ◽  
Short Chain Fatty Acids ◽  
Rrna Gene ◽  
Fatty Acids Profile ◽  
Rrna Gene Sequencing ◽  
Chain Fatty Acids

In a screening campaign to isolate strains with the ability to remove the bad smell associated with animal faeces, strain MA001T was isolated from a soil sample obtained from Shizuoka prefecture, Japan. The isolate grew at pH 6–9 but not at pH 10. Cells were Gram-positive, straight rods with peritrichous flagella and produced ellipsoidal spores. The isolate was positive for catalase and oxidase tests but negative for indole production, deamination of phenylalanine and H2S production. The isolate did not produce acid from any carbohydrates tested and could not grow in more than 2 % NaCl. The DNA G+C content was 39·4 mol%. The cellular fatty acids profile consisted of significant amount of C15 branched-chain fatty acids, iso-C15 : 0 and anteiso-C15 : 0. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that strain MA001T was closely related to Bacillus simplex and Bacillus psychrosaccharolyticus. DNA–DNA hybridization revealed a low relatedness of the isolate to several phylogenetically close neighbours (less than 9 %). On the basis of the phenotypic characteristics observed, phylogenetic data based on 16S rRNA gene sequencing and DNA–DNA relatedness data, it is concluded that the isolate should be classified as representing a novel species, for which the name Bacillus asahii is proposed. The type strain is MA001T (=JCM 12112T=NCIMB 13969T).

scholarly journals Response of Gut Microbiota to Fasting and Hibernation in Syrian Hamsters

2009 ◽  
Vol 75 (20) ◽  
pp. 6451-6456 ◽  
Author(s):  
Kei Sonoyama ◽  
Reiko Fujiwara ◽  
Naoki Takemura ◽  
Toru Ogasawara ◽  
Jun Watanabe ◽  
...  
Keyword(s):  
Fatty Acids ◽  
16S Rrna ◽  
Gut Microbiota ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Short Chain Fatty Acids ◽  
Short Chain ◽  
Rrna Gene ◽  
Syrian Hamsters ◽  
Real Time Quantitative Pcr ◽  
Chain Fatty Acids

ABSTRACT Although hibernating mammals wake occasionally to eat during torpor, this period represents a state of fasting. Fasting is known to alter the gut microbiota in nonhibernating mammals; therefore, hibernation may also affect the gut microbiota. However, there are few reports of gut microbiota in hibernating mammals. The present study aimed to compare the gut microbiota in hibernating torpid Syrian hamsters with that in active counterparts by using culture-independent analyses. Hamsters were allocated to either torpid, fed active, or fasted active groups. Hibernation was successfully induced by maintaining darkness at 4°C. Flow cytometry analysis of cecal bacteria showed that 96-h fasting reduced the total gut bacteria. This period of fasting also reduced the concentrations of short chain fatty acids in the cecal contents. In contrast, total bacterial numbers and concentrations of short chain fatty acids were unaffected by hibernation. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments indicated that fasting and hibernation modulated the cecal microbiota. Analysis of 16S rRNA clone library and species-specific real-time quantitative PCR showed that the class Clostridia predominated in both active and torpid hamsters and that populations of Akkermansia muciniphila, a mucin degrader, were increased by fasting but not by hibernation. From these results, we conclude that the gut microbiota responds differently to fasting and hibernation in Syrian hamsters.

scholarly journals Associations between disordered gut microbiota and changes of neurotransmitters and short-chain fatty acids in depressed mice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Min Wu ◽  
Tian Tian ◽  
Qiang Mao ◽  
Tao Zou ◽  
Chan-juan Zhou ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Gut Microbiota ◽  
Molecular Mechanisms ◽  
Short Chain Fatty Acids ◽  
Short Chain ◽  
Rrna Gene ◽  
Microbial Composition ◽  
Fecal Samples ◽  
Chain Fatty Acids

Abstract Mounting evidence suggests that gut microbiota can play an important role in pathophysiology of depression, but its specific molecular mechanisms are still unclear. This study was conducted to explore the associations between changes in neurotransmitters and short-chain fatty acids (SCFAs) and altered gut microbiota in depressed mice. Here, the chronic restraint stress (CRS) model of depression was built. The classical behavioral tests were conducted to assess the depressive-like behaviors of mice. The 16S rRNA gene sequence extracted from fecal samples was used to assess the gut microbial composition. Liquid and gas chromatography mass spectroscopy were used to identify neurotransmitters in hypothalamus and SCFAs in fecal samples, respectively. Finally, 29 differential bacteria taxa between depressed mice and control mice were identified, and the most differentially abundant bacteria taxa were genus Allobaculum and family Ruminococcaceae between the two groups. The acetic acid, propionic acid, pentanoic acid, norepinephrine, 5-HIAA and 5-HT were significantly decreased in depressed mice compared to control mice. Genus Allobaculum was found to be significantly positively correlated with acetic acid and 5-HT. Taken together, these results provided novel microbial and metabolic frameworks for understanding the role of microbiota-gut-brain axis in depression, and suggested new insights to pave the way for novel therapeutic methods.

Changes of the Intestinal Microbiota, Short Chain Fatty Acids, and Fecal pH in Patients with Colorectal Cancer

2013 ◽  
Vol 58 (6) ◽  
pp. 1717-1726 ◽  
Author(s):  
Seiji Ohigashi ◽  
Kazuki Sudo ◽  
Daiki Kobayashi ◽  
Osamu Takahashi ◽  
Takuya Takahashi ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Fatty Acids ◽  
Intestinal Microbiota ◽  
Short Chain Fatty Acids ◽  
Short Chain ◽  
Fecal Ph ◽  
Chain Fatty Acids
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