scholarly journals Influence of 2′-Fucosyllactose on the Microbiota Composition and Metabolic Activity of Fecal Cultures from Breastfed and Formula-Fed Infants at Two Months of Age

2021 ◽  
Vol 9 (7) ◽  
pp. 1478
Author(s):  
Alicja M. Nogacka ◽  
Silvia Arboleya ◽  
Naghmeh Nikpoor ◽  
Jeremie Auger ◽  
Nuria Salazar ◽  
...  

Although breast milk is considered the gold standard of nutrition for infant feeding, some circumstances may make breastfeeding difficult. Several commercial milk preparations include synthetic human milk oligosaccharides (HMOs) in their composition. However, the effect of HMOs on the establishment of the intestinal microbiota remains incompletely understood. Independent batch fermentations were performed with feces from six full-term infant donors of two months of age (three breastfed and three formula-fed, exclusively) in the presence of 2′fucosyllactose (2′FL), one of the most abundant HMOs in human milk. Microbiota composition was analyzed by 16S rRNA gene sequencing at baseline and at 24 h of incubation. The 2′FL consumption, gas accumulation, and levels of different metabolites were determined by chromatography. Microbiota profiles at baseline were clearly influenced by the mode of feeding and by the intrinsic ability of microbiotas to degrade 2′FL. The 2′FL degradation rate clustered fecal cultures into slow and fast degraders, regardless of feeding type, this being a determinant factor influencing the evolution of the microbiota during incubation, although the low number of donors precludes drawing sound conclusions. More studies are needed to decipher the extent to which the early intervention with HMOs could influence the microbiota as a function of its ability to utilize 2′FL.

Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4445
Author(s):  
Lisa F. Stinson ◽  
Michelle L. Trevenen ◽  
Donna T. Geddes

Bacteria in human milk contribute to the establishment of the infant gut microbiome. As such, numerous studies have characterized the human milk microbiome using DNA sequencing technologies, particularly 16S rRNA gene sequencing. However, such methods are not able to differentiate between DNA from viable and non-viable bacteria. The extent to which bacterial DNA detected in human milk represents living, biologically active cells is therefore unclear. Here, we characterized both the viable bacterial content and the total bacterial DNA content (derived from viable and non-viable cells) of fresh human milk (n = 10). In order to differentiate the living from the dead, a combination of propidium monoazide (PMA) and full-length 16S rRNA gene sequencing was used. Our results demonstrate that the majority of OTUs recovered from fresh human milk samples (67.3%) reflected DNA from non-viable organisms. PMA-treated samples differed significantly in their bacterial composition compared to untreated samples (PERMANOVA p < 0.0001). Additionally, an OTU mapping to Cutibacterium acnes had a significantly higher relative abundance in PMA-treated (viable) samples. These results demonstrate that the total bacterial DNA content of human milk is not representative of the viable human milk microbiome. Our findings raise questions about the validity of conclusions drawn from previous studies in which viability testing was not used, and have broad implications for the design of future work in this field.


2019 ◽  
Author(s):  
Wanfeng Wu ◽  
Yihang Sun ◽  
Shaowu Cheng ◽  
Ning Luo ◽  
Cheng Cheng ◽  
...  

Abstract BackgroundIschemic stroke (IS) is a common type of stroke with high rates of morbidity, mortality, and disability. Despite accumulating evidence that the gut microbiome and metabolome are associated with human diseases, whether they contribute to the pathophysiological mechanism of IS and whether microbial communities affect metabolic phenotype and function are unclear. ResultsIn this study, we integrated 16S rRNA gene sequencing and LC-MS-based metabolomics to explore the roles and underlying mechanisms of the gut microbiome and metabolome in a rat model of IS. Microbiota composition and diversity in IS and control rats were significantly different at the phylum and genus levels. The relative abundance of the phylum Firmicutes was significantly decreased, whereas Proteobacteria and Deferribacteres were markedly increased in IS rats compared with abundance levels in controls. In addition, the metabolic profiles of IS rats were significantly different from those of control rats. We detected 308 significantly dysregulated metabolites, including 155 up-regulated and 153 down-regulated, that best distinguished the IS and control groups. Furthermore, correlation analysis revealed that dysbiosis of the gut microbiota was strongly correlated with dysregulated metabolites. Overall, our results showed that IS is characterized by significant alterations in gut microbiota composition and diversity as well as metabolic phenotype. ConclusionThese results demonstrate that dysbiosis of gut microbiota and perturbations of gut microflora-related metabolites are involved in the development of IS and may serve as potential biomarkers of ischemic stroke.


2020 ◽  
Vol 117 ◽  
pp. 104776
Author(s):  
Fabiana de Melo ◽  
Fernanda Carpes Milanesi ◽  
Patrícia Daniela Melchiors Angst ◽  
Rui Vicente Oppermann

PLoS ONE ◽  
2014 ◽  
Vol 9 (2) ◽  
pp. e88982 ◽  
Author(s):  
Nicholas A. Kennedy ◽  
Alan W. Walker ◽  
Susan H. Berry ◽  
Sylvia H. Duncan ◽  
Freda M. Farquarson ◽  
...  

2019 ◽  
Vol 13 (1) ◽  
pp. 90-101
Author(s):  
Sanju Kumari ◽  
Utkarshini Sharma ◽  
Rohit Krishna ◽  
Kanak Sinha ◽  
Santosh Kumar

Background: Cellulolysis is of considerable economic importance in laundry detergents, textile and pulp and paper industries and in fermentation of biomass into biofuels. Objective: The aim was to screen cellulase producing actinobacteria from the fruit orchard because of its requirement in several chemical reactions. Methods: Strains of actinobacteria were isolated on Sabouraud’s agar medium. Similarities in cultural and biochemical characterization by growing the strains on ISP medium and dissimilarities among them perpetuated to recognise nine groups of actinobacteria. Cellulase activity was measured by the diameter of clear zone around colonies on CMC agar and the amount of reducing sugar liberated from carboxymethyl cellulose in the supernatant of the CMC broth. Further, 16S rRNA gene sequencing and molecular characterization were placed before NCBI for obtaining recognition with accession numbers. Results: Prominent clear zones on spraying Congo Red were found around the cultures of strains of three groups SK703, SK706, SK708 on CMC agar plates. The enzyme assay for carboxymethylcellulase displayed extra cellulase activity in broth: 0.14, 0.82 and 0.66 &#181;mol mL-1 min-1, respectively at optimum conditions of 35°C, pH 7.3 and 96 h of incubation. However, the specific cellulase activities per 1 mg of protein did not differ that way. It was 1.55, 1.71 and 1.83 μmol mL-1 min-1. The growing mycelia possessed short compact chains of 10-20 conidia on aerial branches. These morphological and biochemical characteristics, followed by their verification by Bergey’s Manual, categorically allowed the strains to be placed under actinobacteria. Further, 16S rRNA gene sequencing, molecular characterization and their evolutionary relationship through phylogenetics also confirmed the putative cellulase producing isolates of SK706 and SK708 subgroups to be the strains of Streptomyces. These strains on getting NCBI recognition were christened as Streptomyces glaucescens strain SK91L (KF527284) and Streptomyces rochei strain SK78L (KF515951), respectively. Conclusion: Conclusive evidence on the basis of different parameters established the presence of cellulase producing actinobacteria in the litchi orchard which can convert cellulose into fermentable sugar.


Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Janis R. Bedarf ◽  
Naiara Beraza ◽  
Hassan Khazneh ◽  
Ezgi Özkurt ◽  
David Baker ◽  
...  

Abstract Background Recent studies suggested the existence of (poly-)microbial infections in human brains. These have been described either as putative pathogens linked to the neuro-inflammatory changes seen in Parkinson’s disease (PD) and Alzheimer’s disease (AD) or as a “brain microbiome” in the context of healthy patients’ brain samples. Methods Using 16S rRNA gene sequencing, we tested the hypothesis that there is a bacterial brain microbiome. We evaluated brain samples from healthy human subjects and individuals suffering from PD (olfactory bulb and pre-frontal cortex), as well as murine brains. In line with state-of-the-art recommendations, we included several negative and positive controls in our analysis and estimated total bacterial biomass by 16S rRNA gene qPCR. Results Amplicon sequencing did detect bacterial signals in both human and murine samples, but estimated bacterial biomass was extremely low in all samples. Stringent reanalyses implied bacterial signals being explained by a combination of exogenous DNA contamination (54.8%) and false positive amplification of host DNA (34.2%, off-target amplicons). Several seemingly brain-enriched microbes in our dataset turned out to be false-positive signals upon closer examination. We identified off-target amplification as a major confounding factor in low-bacterial/high-host-DNA scenarios. These amplified human or mouse DNA sequences were clustered and falsely assigned to bacterial taxa in the majority of tested amplicon sequencing pipelines. Off-target amplicons seemed to be related to the tissue’s sterility and could also be found in independent brain 16S rRNA gene sequences. Conclusions Taxonomic signals obtained from (extremely) low biomass samples by 16S rRNA gene sequencing must be scrutinized closely to exclude the possibility of off-target amplifications, amplicons that can only appear enriched in biological samples, but are sometimes assigned to bacterial taxa. Sequences must be explicitly matched against any possible background genomes present in large quantities (i.e., the host genome). Using close scrutiny in our approach, we find no evidence supporting the hypothetical presence of either a brain microbiome or a bacterial infection in PD brains.


2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Musa Saheed Ibrahim ◽  
Beckley Ikhajiagbe

Abstract Background Rice forms a significant portion of food consumed in most household worldwide. Rice production has been hampered by soil factors such as ferruginousity which has limited phosphorus availability; an important mineral component for the growth and yield of rice. The presence of phosphate-solubilizing bacteria (PSB) in soils has been reported to enhance phosphate availability. In view of this, the present study employed three bacteria species (BCAC2, EMBF2 and BCAF1) that were previously isolated and proved P solubilization capacities as inocula to investigate the growth response of rice germinants in an in vitro setup. The bacteria isolates were first identified using 16S rRNA gene sequencing and then applied as inoculum. The inolula were prepared in three concentrations (10, 7.5 and 5.0 ml) following McFarland standard. Viable rice (var. FARO 44) seeds were sown in petri dishes and then inoculated with the three inocula at the different concentrations. The setup was studied for 28 days. Results 16S rRNA gene sequencing identified the isolates as: isolate BCAC2= Bacillus cereus strain GGBSU-1, isolate BCAF1= Proteus mirabilis strain TL14-1 and isolate EMBF2= Klebsiella variicola strain AUH-KAM-9. Significant improvement in rice germination, morphology, physiology and biomass parameters in the bacteria-inoculated setups was observed compared to the control. Germination percentage after 4 days was 100 % in the inoculated rice germinants compared to 65% in the control (NiS). Similarly, inoculation with the test isolates enhanced water-use efficiency by over 40%. The rice seedlings inoculated with Bacillus cereus strain GGBSU-1 (BiS) showed no signs of chlorosis and necrosis throughout the study period as against those inoculated with Proteus mirabilis strain TL14-1 (PiS) and Klebsiella variicola strain AUH-KAM-9 (KiS). Significant increase in chlorophyll-a, chlorophyll-b and alpha amylase was observed in the rice seedlings inoculated with BiS as against the NiS. Conclusion Inoculating rice seeds with Bacillus cereus strain GGBSU-1, Proteus mirabilis strain TL14-1 and Klebsiella variicola strain AUH-KAM-9 in an in vitro media significantly improved growth parameters of the test plant. Bacillus cereus strain GGBSU-1 showed higher efficiency due to a more improved growth properties observed.


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