Comparative Analyses of the Transport Proteins Encoded within the Genomes of nine Bifidobacterium Species

The modulatory effect of pea resistant starch on hyperlipidemia in high fat diet-induced obese mice is related to their supramolecular structural features

BACKGROUND

Resistant starch (RS) has gained attention for its potential in managing metabolic disorders. This study aimed to compare the supramolecular structure and anti-hyperlipidemia effects of RS isolated from native pea starch (NP-RS) and autoclaved pea starch (AP-RS) in high-fat diet (HFD)-induced obese mice. The structural characteristics of NP-RS and AP-RS were analyzed, and their impacts on obesity-related conditions, gene expression, and gut microbiota were evaluated.

RESULTS

The crystalline polymorph of AP-RS shifted from a C-type to a B-type, with significantly higher long- and short-range crystallinity and double helix levels compared to NP-RS, as determined by X-ray diffraction and solid-state carbon-13 nuclear magnetic resonance (13C-NMR) analyses. Small-angle X-ray scattering analysis demonstrated a higher α value for AP-RS, suggested enhanced structural compactness. In vivo experiments revealed that both NP-RS and AP-RS alleviated obesity-related conditions, including body weight control, oxidative stress inhibition, inflammatory response alleviation, and liver function regulation, with AP-RS exhibiting more pronounced effects. These effects were associated with the down-regulation of gene expression levels of liver type glycogen synthase-2 (GYS2), enzyme glycogenin-1 (GYG1), sterol regulatory element binding protein-1 (SREBP-1), fatty acid synthase (FAS) and the up-regulation of insulin induced gene-1 (Insig-1), Insig-2, and acetyl-CoA oxidase 1 (Acox1). Additionally, 16S rDNA sequencing analysis indicated that both NP-RS and AP-RS mitigated HFD-induced gut dysbiosis by increasing the abundance of beneficial bacteria, such as Allobaculum and Bifidobacterium.

CONCLUSION

The resistant characteristics of AP-RS, marked by increased crystallinity and a higher content of double helices, exhibit greater stability. This stability likely leads to differences in accessibility and fermentability between NP-RS and AP-RS substrates in vivo across various intestinal segments, resulting in different physiological responses in obese mice. These findings highlight the potential for designing novel RS-based supplements with tailored metabolic effects to promote health benefits. © 2025 Society of Chemical Industry.

An Insider's Perspective about the Pathogenic Relevance of Gut Bacterial Transportomes

BACKGROUND

The gut microbiome is integral to host health, hosting complex interactions between the host and numerous microbial species in the gastrointestinal tract. Key among the molecular mechanisms employed by gut bacteria are transportomes, consisting of diverse transport proteins crucial for bacterial adaptation to the dynamic, nutrient-rich environment of the mammalian gut. These transportomes facilitate the movement of a wide array of molecules, impacting both the host and the microbial community.

SUMMARY

This communication explores the significance of transportomes in gut bacteria, focusing on their role in nutrient acquisition, competitive interactions among microbes, and potential pathogenicity. It delves into the transportomes of key gut bacterial species like E. coli, Salmonella, Bacteroides, Lactobacillus, Clostridia, and Bifidobacterium, examining the functions of predicted transport proteins. The overview synthesizes recent research efforts, highlighting how these transportomes influence host-microbe interactions and contribute to the microbial ecology of the gut.

KEY MESSAGES

Transportomes are vital for the survival and adaptation of bacteria in the gut, enabling the import and export of various nutrients and molecules. The complex interplay of transport proteins not only supports bacterial growth and competition but also has implications for host health, potentially contributing to pathogenic processes. Understanding the pathogenic potential of transportomes in major gut bacterial species provides insights into gut health and disease, offering avenues for future research and therapeutic strategies.

The Emerging Concept of Transportome: State of the Art

The array of ion channels and transporters expressed in cell membranes, collectively referred to as the transportome, is a complex and multifunctional molecular machinery; in particular, at the plasma membrane level it finely tunes the exchange of biomolecules and ions, acting as a functionally adaptive interface that accounts for dynamic plasticity in the response to environmental fluctuations and stressors. The transportome is responsible for the definition of membrane potential and its variations, participates in the transduction of extracellular signals, and acts as a filter for most of the substances entering and leaving the cell, thus enabling the homeostasis of many cellular parameters. For all these reasons, physiologists have long been interested in the expression and functionality of ion channels and transporters, in both physiological and pathological settings and across the different domains of life. Today, thanks to the high-throughput technologies of the postgenomic era, the omics approach to the study of the transportome is becoming increasingly popular in different areas of biomedical research, allowing for a more comprehensive, integrated, and functional perspective of this complex cellular apparatus. This article represents a first effort for a systematic review of the scientific literature on this topic. Here we provide a brief overview of all those studies, both primary and meta-analyses, that looked at the transportome as a whole, regardless of the biological problem or the models they used. A subsequent section is devoted to the methodological aspect by reviewing the most important public databases annotating ion channels and transporters, along with the tools they provide to retrieve such information. Before conclusions, limitations and future perspectives are also discussed.