Genotyping and plant-derived glycan utilization analysis of Bifidobacterium strains from mother-infant pairs

The Effect of Mono- and Di-Saccharides on the Microbiome of Dairy Cow Manure and Its Odor

In a previous experiment, we showed that the odor of Bos taurus manure slurries could be improved by anaerobic incubation with the sugars glucose, lactose, and sucrose. This improvement was due to reductions in the concentrations of malodorants, including dimethyl disulfide, p-cresol, p-ethylphenol, indole, and skatole, and a shift to the production of fruity esters, including ethyl butyrate and propyl propanoate. Due to large concentrations of lactic acid produced by the sugar-amended manure slurries, we inferred that lactic acid bacteria were involved in improving the manure slurry odor. Here, through 16S rRNA amplicon sequencing for microbiome analysis, we show that lactic acid bacterial growth was promoted by the addition of all three sugars. Lactobacillus buchneri and an unknown Lactobacillus sp. were the most prominent lactic acid bacteria stimulated by sugar addition. Lactobacillales were found only in trace abundances in unamended manure slurries. The relative abundance of orders such as Clostridiales, Bifidobacteriales, and Erysipelotrichales were not noticeably affected by sugar amendment. However, the disaccharides lactose and sucrose seemed to increase the relative abundance of Bifidobacterium, whereas the monosaccharide glucose did not. We conclude that lactic acid bacteria are the primary bacteria involved in improving odor in dairy cow manure slurries and present strategies to enhance their abundance in animal wastes.

Limosilactobacillus allomucosae sp. nov., a novel species isolated from wild boar faecal samples as a potential probiotic for domestic pigs

Six strains, WILCCON 0050, WILCCON 0051, WILCCON 0052, WILCCON 0053, WILCCON 0054, WILCCON 0055T, were isolated from four different faecal samples of wild boars on Pulau Ubin, Singapore, Singapore. Based on core genome phylogenetic analysis, the six strains formed a distinct clade within the genus Limosilactobacillus (Lm.), with the most closely related type strain being Lm. mucosae DSM 13345T. The minimum ANI, dDDH, and AAI values within these six strains were 97.8%, 78.8%, and 98.6%, respectively. In contrast, the ANI, dDDH, and AAI values with Lm. mucosae DSM 13345T were lower, ranging between 94.8-95.1%, 57.1-59.0%, and 95.9-97.0%, respectively. While ANI and AAI were close to the thresholds of 95% and 97% for bacterial species delineation, respectively, dDDH was significantly lower than the threshold value of 70%. Based on our phylogenomic, phenotypic and chemotaxonomic analyses, we propose a novel species with the name Limosilactobacillus allomucosae sp. nov., with WILCCON 0055T (DSM 117632T = LMG 33563T) as the designated type strain. In vitro investigations revealed the strains' ability to break down raffinose-family oligosaccharides, and to utilize prebiotics such as xylo-oligosaccharides and galacturonic acid, thereby enhancing fibre digestion and nutrient absorption. Moreover, strong auto-aggregation properties, as well as resistance to low pH and porcine bile were observed, suggesting their potential survival and persistence during passage through the gut. The high bile tolerance of these strains appears to be attributed to their ability to deconjugate a wide range of conjugated bile compounds. In silico analysis indicated a strong potential for mucin-binding activity, which aids their colonization in the gut. These characteristics indicate the potential suitability of strains of Lm. allomucosae as probiotics for domestic pigs.

Effects of maternal advanced lipoxidation end products diet on the glycolipid metabolism and gut microbiota in offspring mice

Introduction

Dietary advanced lipoxidation end products (ALEs), which are abundant in heat-processed foods, could induce lipid metabolism disorders. However, limited studies have examined the relationship between maternal ALEs diet and offspring health.

Methods

To investigate the transgenerational effects of ALEs, a cross-generation mouse model was developed. The C57BL/6J mice were fed with dietary ALEs during preconception, pregnancy and lactation. Then, the changes of glycolipid metabolism and gut microbiota of the offspring mice were analyzed.

Results

Maternal ALEs diet not only affected the metabolic homeostasis of dams, but also induced hepatic glycolipid accumulation, abnormal liver function, and disturbance of metabolism parameters in offspring. Furthermore, maternal ALEs diet significantly upregulated the expression of TLR4, TRIF and TNF-α proteins through the AMPK/mTOR/PPARα signaling pathway, leading to dysfunctional glycolipid metabolism in offspring. In addition, 16S rRNA analysis showed that maternal ALEs diet was capable of altered microbiota composition of offspring, and increased the Firmicutes/Bacteroidetes ratio.

Discussion

This study has for the first time demonstrated the transgenerational effects of maternal ALEs diet on the glycolipid metabolism and gut microbiota in offspring mice, and may help to better understand the adverse effects of dietary ALEs.

Cross-feeding of bifidobacteria promotes intestinal homeostasis: a lifelong perspective on the host health

Throughout the life span of a host, bifidobacteria have shown superior colonization and glycan abilities. Complex glycans, such as human milk oligosaccharides and plant glycans, that reach the colon are directly internalized by the transport system of bifidobacteria, cleaved into simple structures by extracellular glycosyl hydrolase, and transported to cells for fermentation. The glycan utilization of bifidobacteria introduces cross-feeding activities between bifidobacterial strains and other microbiota, which are influenced by host nutrition and regulate gut homeostasis. This review discusses bifidobacterial glycan utilization strategies, focusing on the cross-feeding involved in bifidobacteria and its potential health benefits. Furthermore, the impact of cross-feeding on the gut trophic niche of bifidobacteria and host health is also highlighted. This review provides novel insights into the interactions between microbe-microbe and host-microbe.

Whole-genome resequencing and transcriptional profiling association analysis revealed the intraspecies difference response to oligosaccharides utilization in Bifidobacterium animalis subsp. lactis

Introduction

As prebiotics, oligosaccharides are frequently combined with Bifidobacterium to develop synbiotic products. However, a highly diverse gene repertoire of Bifidobacterium is involved in sugar catabolism, and even phylogenetically close species may differ in their sugar utilization capabilities. To further explore the mechanism underlying the differences in Bifidobacterium animalis subsp. lactis oligosaccharide metabolism.

Methods

This study screened strains with differential oligosaccharide metabolism. Subsequently, these strains were subjected to genome-wide resequencing and RT-qPCR.

Results

The resequencing results indicated that the subspecies of B. animalis subsp. lactis had a high genome similarity. The RT-qPCR results revealed that glycosidase genes exhibited consistency in the phenotype of metabolism at the transcriptional level; the better the growth of the strains on the oligosaccharides, the higher was the expression of glycosidase genes related to the oligosaccharides. Our results suggested that the differences in the gene transcription levels led to intraspecies differences in the ability of the strains to metabolize oligosaccharides even when they belonged to the same subspecies.

Discussion

Future studies with more sample size could generalizable the conclusion to all B. animalis subsp. lactis strains, thus would lay the theoretical foundation for the utilization of the B. animalis subsp. lactis strain as probiotics and the development of synbiotic products.

Sialic acid-based probiotic intervention in lactating mothers improves the neonatal gut microbiota and immune responses by regulating sialylated milk oligosaccharide synthesis via the gut-breast axis

Human milk oligosaccharides (HMOs) are vital milk carbohydrates that help promote the microbiota-dependent growth and immunity of infants. Sialic acid (SA) is a crucial component of sialylated milk oligosaccharides (S-MOs); however, the effects of SA supplementation in lactating mothers on S-MO biosynthesis and their breastfed infants are unknown. Probiotic intervention during pregnancy or lactation demonstrates promise for modulating the milk glycobiome. Here, we evaluated whether SA and a probiotic (Pro) mixture could increase S-MO synthesis in lactating mothers and promote the microbiota development of their breastfed neonates. The results showed that SA+Pro intervention modulated the gut microbiota and 6'-SL contents in milk of maternal rats more than the SA intervention, which promoted Lactobacillus reuteri colonization in neonates and immune development. Deficient 6'-SL in the maternal rat milk of St6gal1 knockouts (St6gal1-/-) disturbed intestinal microbial structures in their offspring, thereby impeding immune tolerance development. SA+Pro intervention in lactating St6gal1± rats compromised the allergic responses of neonates by promoting 6'-SL synthesis and the neonatal gut microbiota. Our findings from human mammary epithelial cells (MCF-10A) indicated that the GPR41-PI3K-Akt-PPAR pathway helped regulate 6'-SL synthesis in mammary glands after SA+Pro intervention through the gut - breast axis. We further validated our findings using a human-cohort study, confirming that providing SA+Pro to lactating Chinese mothers increased S-MO contents in their breast milk and promoted gut Bifidobacterium spp. and Lactobacillus spp. colonization in infants, which may help enhance immune responses. Collectively, our findings may help alter the routine supplementation practices of lactating mothers to modulate milk HMOs and promote the development of early-life gut microbiota and immunity.

Preferential sugar utilization by bifidobacterial species

Aim: Bifidobacteria benefit host health and homeostasis by breaking down diet- and host-derived carbohydrates to produce organic acids in the intestine. However, the sugar utilization preference of bifidobacterial species is poorly understood. Thus, this study aimed to investigate the sugar utilization preference (i.e., glucose or lactose) of various bifidobacterial species. Methods: Strains belonging to 40 bifidobacterial species/subspecies were cultured on a modified MRS medium supplemented with glucose and/or lactose, and their preferential sugar utilization was assessed using high-performance thin-layer chromatography. Comparative genomic analysis was conducted with a focus on genes involved in lactose and glucose uptake and genes encoding for carbohydrate-active enzymes. Results: Strains that preferentially utilized glucose or lactose were identified. Almost all the lactose-preferring strains harbored the lactose symporter lacS gene. However, the comparative genomic analysis could not explain all their differences in sugar utilization preference. Analysis based on isolate source revealed that all 10 strains isolated from humans preferentially utilized lactose, whereas all four strains isolated from insects preferentially utilized glucose. In addition, bifidobacterial species isolated from hosts whose milk contained higher lactose amounts preferentially utilized lactose. Lactose was also detected in the feces of human infants, suggesting that lactose serves as a carbon source not only for infants but also for gut microbes in vivo. Conclusion: The different sugar preference phenotypes of Bifidobacterium species may be ascribed to the residential environment affected by the dietary habits of their host. This study is the first to systematically evaluate the sugar uptake preference of various bifidobacterial species.