Su, J.-Q. | bioRxiv Science

bioRxiv2024

Activated carbon ameliorates type 2 diabetes via metabolic remodeling of the gut microbiota

Type 2 diabetes (T2D) is a major public health concern worldwide and there has been increasing attention on the role of natural dietary drugs in diabetes therapy. However, the effects of these drugs on gut microbial composition, functional potentials and metabolisms remain unclear. Here, we conducted integrated 16S rRNA sequencing and metabolomic analyses in T2D GK rats and healthy Wistar rats that exposed to four natural dietary drugs (highly porous activated carbon, wheatgrass, dandelion and corn stigma). Oral administration of activated carbon and dandelion decreased the body weight gain in both high-fat diet (HFD) GK rats and Wistar rats. Significantly lower level of blood glucose was observed in GK rats with activated carbon intervention. A group of beneficial bacteria and metabolites were promoted, and the endotoxin-producing bacteria were inhibited by dietary drugs, especially for the activated carbon diet. Oral administration of activated carbon resulted in metabolic changes and anti-inflammatory effects that decreased both high-fat diet-induced obesity and diabetes. The beneficial effects of increased positive responders are related to improved carbohydrate and amino acid metabolism, regulated inflammatory mediators, with simultaneous reduction of detrimental compounds such as lipopolysaccharide (LPS) synthesis and modification of the gut microbiome. These findings highlight the effectiveness of natural dietary drugs, with a particular emphasis on activated carbon, and establish a foundation for tailoring the use of these drugs in T2D therapy. ImportanceOur findings highlight the significant hypoglycemic effect of activated carbon, demonstrating its potential to remodel the gut microbiota, improve carbohydrate and amino acid metabolism, regulate inflammatory mediators, and reduce detrimental compounds such as lipopolysaccharide (LPS). These results suggest that dietary intervention with activated carbon could be a noninvasive and accessible method for improving diabetes management, providing novel insights into the role of natural dietary drugs in metabolic health and diabetes therapy.

microbiology↗

bioRxiv2023

Microbiome Analysis of the Eastern Oyster As a Function of Ploidy and Seasons

Shellfish, such as the eastern oysters (Crassostrea virginica) are not only valued as seafood but also for the ecosystem services they provide, including improving water quality and reducing eutrophication. Excess N causes eutrophication, harmful algal blooms, fish kills and overall decline of estuarine ecosystems resulting in economic losses. Oyster reefs sequester N and enhance denitrification processes, however, information on the N cycling oyster microbiome is scarce with most studies focusing on random grab samples or on pathogens, such as Vibrio spp. Further, triploid oysters are often used for aquaculture, as they grow faster than diploids, but there is little information on potential microbiome differences with ploidy. To address these knowledge gaps, diploid and triploid farmed oysters were collected at monthly intervals over one year and analyzed using a coupled approach encompassing shotgun metagenomics and quantitative microbial elemental cycling (QMEC) qPCR assays. Overall, the genus Psychrobacter dominated the core microbiome across all samples, regardless of season or ploidy, followed by Synechococcus, Pseudomonas, Pseudoalteromonas and Clostridium. Psychrobacter abundances increased significantly in the colder months; the same trend was also observed in the alpha and beta diversity. However, warmer months had increased bacterial diversity relative to colder months. Gene functional profiles were similar among seasons and ploidy, with respiration and metabolism of carbohydrates, RNA, and proteins as dominant functions. There were strong positive correlations between abundance of the "core" microbiome taxa and gene functions associated with central metabolism, DNA and carbohydrate metabolism, strongly suggesting the functional role of Psychrobacter in the microbiome. Metagenome assembly was performed to characterize dominant species, followed by phylogenetic analysis of select MAGs (metagenome-assembled genomes), further supporting the presence of multiple Psychrobacter spp. Sequence-based identification of denitrification genes in the Pyschrobacter MAGs indicated the presence of norB, narH, narI, nirK, and norB. QMEC analysis indicated C and N cycling genes were most abundant, with no discernable patterns due to seasons or ploidy. Among N cycling genes, the nosZII clade was dominant, which is likely responsible for the eastern oysters potential for bioextraction and enhancing water quality via denitrification.

microbiology↗