The Marine Fish Gut Microbiome as a Source of Novel Bacteriocins.

The marine environment is the largest ecological habitat on Earth, albeit one of the least explored, particularly in terms of its microbial inhabitants. The marine fish gut is host to a diverse microbial community from which diverse bioactive molecules can be sourced. Due to the unique environmental pressures these microbial communities experience, the bioactive molecules they produce often evolve unique adaptations that give them diverse structures and activities, differentiating them from terrestrial homologues. Of particular interest, due to their structural and functional diversity, are the ribosomally-synthesized antimicrobial peptides (bacteriocins). With increasing pressure from emerging antibiotic-resistant disease and industrial demand for novel therapeutics, the marine fish gut microbiome represents a relatively untapped resource of novel bacteriocins that could prove beneficial to human health and aquaculture. This review presents an overview of the marine fish gut microbiome and explores its potential as a source of bacteriocins for human health with considerations for applications and future research in this area.

Maternal high-fat diet-induced microbiota changes are associated with alterations in embryonic brain metabolites and adolescent behaviour.

The developing central nervous system is highly sensitive to nutrient changes during the perinatal period, emphasising the potential impact of alterations of maternal diet on offspring brain development and behaviour. A growing body of research implicates the gut microbiota in neurodevelopment and behaviour. Maternal overweight and obesity during the perinatal period has been linked to changes in neurodevelopment, plasticity and affective disorders in the offspring, with implications for microbial signals from the maternal gut. Here we investigate the impact of maternal high-fat diet (mHFD)-induced changes in microbial signals on offspring brain development, and neuroimmune signals, and the enduring effects on behaviour into adolescence. We first demonstrate that maternal caecal microbiota composition at term pregnancy (embryonic day 18: E18) differs significantly in response to maternal diet. Moreover, mHFD resulted in the upregulation of microbial genes in the maternal intestinal tissue linked to alterations in quinolinic acid synthesis and elevated kynurenine levels in the maternal plasma, both neuronal plasticity mediators related to glutamate metabolism. Metabolomics of mHFD embryonic brains at E18 also detected molecules linked to glutamate-glutamine cycle, including glutamic acid, glutathione disulphide and kynurenine. During adolescence, the mHFD offspring exhibited increased locomotor activity and anxiety-like behaviour in a sex-dependent manner, along with upregulation of glutamate-related genes compared to controls. Overall, our results demonstrate that maternal exposure to high-fat diet results in microbiota changes, behavioural imprinting, altered brain metabolism and glutamate signalling during critical developmental windows during the perinatal period.

The interplay between diet and the gut microbiome: implications for health and disease.

Diet has a pivotal role in shaping the composition, function and diversity of the gut microbiome, with various diets having a profound impact on the stability, functionality and diversity of the microbial community within our gut. Understanding the profound impact of varied diets on the microbiome is crucial, as it will enable us not only to make well-informed dietary decisions for better metabolic and intestinal health, but also to prevent and slow the onset of specific diet-related diseases that stem from suboptimal diets. In this Review, we explore how geographical location affects the gut microbiome and how different diets shape its composition and function. We examine the mechanisms by which whole dietary regimes, such as the Mediterranean diet, high-fibre diet, plant-based diet, high-protein diet, ketogenic diet and Western diet, influence the gut microbiome. Furthermore, we underscore the need for exhaustive studies to better understand the causal relationship between diet, host and microorganisms for the development of precision nutrition and microbiome-based therapies.

Interplay between microbial-derived GABA and host GABA receptor signaling collectively influence the tumorigenic function of GABA in colon cancer.

Although classically recognized as a neurotransmitter, gamma aminobutyric acid (GABA) has also been identified in colonic tumors. Moreover, the gut microbiome represents another potential source of GABA. Both GABAA and GABAB receptors have been implicated in contributing to the effects of GABA in colorectal cancer, with both pro- and anti-tumorigenic functions identified. However, their subunit composition is often overlooked. Studies to date have not addressed whether the GABA-producing potential of the microbiome changes over the course of colon tumor development or whether receptor subunit expression patterns are altered in colon cancer. Therefore, we investigated the clusters of orthologous group frequencies of glutamate decarboxylase (GAD) in feces from two murine models of colon cancer and found that the frequency of microbial GAD was significantly decreased early in the tumorigenic process. We also determined that microbial-derived GABA inhibited proliferation of colon cancer cells in vitro and that this effect of GABA on SW480 cells involved both GABAA and GABAB receptors. GABA also inhibited prostaglandin E2 (PGE2)-induced proliferation and interleukin-6 (IL-6) expression in these cells. Gene expression correlations were assessed using the "Cancer Exploration" suite of the TIMER2.0 web tool and identified that GABA receptor subunits were differentially expressed in human colon cancer. Moreover, GABAA receptor subunits were predominantly positively associated with PGE2 synthase, cyclooxygenase-2 and IL-6. Collectively, these data demonstrate decreased potential of the microbiome to produce GABA during tumorigenesis, a novel anti-tumorigenic pathway for GABA, and that GABA receptor subunit expression adds a further layer of complexity to GABAergic signaling in colon cancer.

Gut microbiota signatures of vulnerability to food addiction in mice and humans.

OBJECTIVE: Food addiction is a multifactorial disorder characterised by a loss of control over food intake that may promote obesity and alter gut microbiota composition. We have investigated the potential involvement of the gut microbiota in the mechanisms underlying food addiction. DESIGN: We used the Yale Food Addiction Scale (YFAS) 2.0 criteria to classify extreme food addiction in mouse and human subpopulations to identify gut microbiota signatures associated with vulnerability to this disorder. RESULTS: Both animal and human cohorts showed important similarities in the gut microbiota signatures linked to food addiction. The signatures suggested possible non-beneficial effects of bacteria belonging to the Proteobacteria phylum and potential protective effects of Actinobacteria against the development of food addiction in both cohorts of humans and mice. A decreased relative abundance of the species Blautia wexlerae was observed in addicted humans and of Blautia genus in addicted mice. Administration of the non-digestible carbohydrates, lactulose and rhamnose, known to favour Blautia growth, led to increased relative abundance of Blautia in mice faeces in parallel with dramatic improvements in food addiction. A similar improvement was revealed after oral administration of Blautia wexlerae as a beneficial microbe. CONCLUSION: By understanding the crosstalk between this behavioural alteration and gut microbiota, these findings constitute a step forward to future treatments for food addiction and related eating disorders.

Bifidobacterium longum subsp. infantis regulates Th1/Th2 balance through the JAK-STAT pathway in growing mice.

Objectives: Bifidobacterium longum subsp. infantis is a dominant bacterium in infant gut, which plays a critical role in maintaining the health and development of infants. This study investigated the abilities of eight different strains of B. longum subsp. infantis to regulate the T helper (Th)1/Th2 balance. Methods: Eight B. longum subsp. infantis strains, including I2MI (FJSWXI2MIM1), I4MI [FJSWXI4MI (CCFM1270)], I4MNI (FJSWXI4MNIM1), I5TI (FJSWXI5TIM1), I6TI (FJSWXI6TIM1), I8TI [FJSWXI8TI (CCFM1271)], I10TI [FJSWXI10TI (CCFM1272)], and B6MNI [BJSWXB6MNIM1 (CCFM1269)], were gavaged to BALB/C pups in both female (n = 8) and male (n = 8) mice starting from 1 to 3 weeks old (1 × 109 CFU/day/mice). Selected immune cells were assessed by immunofluorescence and flow cytometry. Cytokines and immunoglobulins were determined by ELISA. Bacterial and bifidobacterial communities were determined by 16S rRNA gene sequencing and bifidobacterial groEL sequencing. Results: B. longum subsp. infantis I4MI and I8TI were shown to increase the ration of colonic IgG2a/IgE in male mice (P < 0.05). B6MNI was demonstrated to significantly increase the levels of colonic IFN-γ and IgG2a, as well as the ratio of IgG2a/IgE in female mice (P < 0.05). It was also shown to significantly increase the ratio of colonic IgG2a/IgE (P < 0.05) and reduce the level of colonic IL-4 in male mice (P < 0.05). Furthermore, B6MNI was demonstrated to regulate colonic JAK/STAT pathway in both male and female mice. I4MI, I5TI, and B6MNI were shown to increase the relative abundance of Bifidobacterium and B. longum subsp. infantis in both male and female mice, whereas I8TI was only shown to increase the relative abundance of Bifidobacterium and B. longum subsp. infantis in male mice (P < 0.05). Conclusion: These results indicated supplementation with B. longum subsp. infantis in early infancy may regulate the Th1/Th2 immune balance, which may prevent the development of related diseases.

Genome plasticity shapes the ecology and evolution of Phocaeicola dorei and Phocaeicola vulgatus.

Phocaeicola dorei and Phocaeicola vulgatus are very common and abundant members of the human gut microbiome and play an important role in the infant gut microbiome. These species are closely related and often confused for one another; yet, their genome comparison, interspecific diversity, and evolutionary relationships have not been studied in detail so far. Here, we perform phylogenetic analysis and comparative genomic analyses of these two Phocaeicola species. We report that P. dorei has a larger genome yet a smaller pan-genome than P. vulgatus. We found that this is likely because P. vulgatus is more plastic than P. dorei, with a larger repertoire of genetic mobile elements and fewer anti-phage defense systems. We also found that P. dorei directly descends from a clade of P. vulgatus¸ and experienced genome expansion through genetic drift and horizontal gene transfer. Overall, P. dorei and P. vulgatus have very different functional and carbohydrate utilisation profiles, hinting at different ecological strategies, yet they present similar antimicrobial resistance profiles.

Probiotic intervention improves metabolic outcomes in gestational diabetes mellitus: A meta-analysis of randomized controlled trials.

AIMS: To conduct a randomized controlled trial meta-analysis and provide concise and specific recommendations for clinical practice optimization of gestational diabetes for probiotics. METHODS: Up until May 2023, we conducted a thorough, systematic search of PubMed, Cochrane Central Controlled Trials, and Embase. Stata software was used to merge the resulting data from the original studies. Cochran's Q and the I2 statistics were used to evaluate and quantify heterogeneity. The GRADE method was used to evaluate the overall quality of the evidence. Sources of heterogeneity were analyzed through a leave-one-out meta-analysis, a Galbraith plot, and a subgroup analysis. RESULTS: A meta-analysis of 11 randomized controlled trials with a total of 713 participants was finally conducted. Our findings indicated the administration of probiotics at a median dosage of 6 × 109 CFU/day led to a substantial improvement in fasting glucose levels (MD: -4.16 mg/dL [95% CI: -6.78, -1.54]; P < 0.001), fasting insulin levels (MD: -3.33 µIU/ml [95% CI: -4.92, -1.74]; P < 0.001), homeostatic model assessment for insulin resistance (HOMA-IR) (MD: -0.71 [95% CI: -0.97, -0.45]; P < 0.001), and quantitative insulin sensitivity check index (QUICKI) (MD: 0.01 [95% CI: 0.01, 0.02]; P < 0.001). Subgroup analysis indicated that probiotic intervention exerted a more significant reduction in fasting blood glucose in patients with higher baseline BMI and glucose levels, and reduced fasting insulin more markedly in those with elevated baseline insulin. According to the GRADE assessment, the quality of evidence for fasting blood glucose and QUICKI was rated as "high", while the quality for fasting insulin and HOMA-IR was rated as "moderate". CONCLUSIONS: Probiotic intervention has been shown to significantly decrease levels of fasting blood glucose, fasting insulin, and HOMA-IR, while elevating QUICKI levels in patients with GDM, underscoring the potential utility of probiotics in the adjunctive management of GDM.

Bifidobacterium longum Subsp. infantis Promotes IgA Level of Growing Mice in a Strain-Specific and Intestinal Niche-Dependent Manner.

Throughout infancy, IgA is crucial for maintaining gut mucosal immunity. This study aims to determine whether supplementing newborn mice with eight different strains of Bifidobacterium longum subsp. infantis might regulate their IgA levels. The strains were gavaged to BALB/C female (n = 8) and male (n = 8) dams at 1-3 weeks old. Eight strains of B. longum subsp. infantis had strain-specific effects in the regulation of intestinal mucosal barriers. B6MNI, I4MI, and I10TI can increase the colonic IgA level in females and males. I8TI can increase the colonic IgA level in males. B6MNI was also able to significantly increase the colonic sIgA level in females. B6MNI, I4MI, I8TI, and I10TI regulated colonic and Peyer's patch IgA synthesis genes but had no significant effect on IgA synthesis pathway genes in the jejunum and ileum. Moreover, the variety of sIgA-coated bacteria in male mice was changed by I4MI, I5TI, I8TI, and B6MNI. These strains also can decrease the relative abundance of Escherichia coli. These results indicate that B. longum subsp. infantis can promote IgA levels but show strain specificity. Different dietary habits with different strains of Bifidobacterium may have varying effects on IgA levels when supplemented in early infancy.

Planococcus notacanthi sp. nov., isolated from the skin of a deep-sea snub-nosed spiny eel.

A novel bacterial strain, APC 4016T, was previously isolated from the skin of a snub-nosed spiny eel, Notacanthus chemnitzii, from a depth of 1000 m in the northern Atlantic Ocean. Cells were aerobic, cocci, motile, Gram-positive to Gram-variable staining, and gave rise to orange-pigmented colonies. Growth occurred at 4-40 °C (optimum, 25-28 °C), pH 5.5-12 (optimum, pH 7-7.5), and 0-12 % (w/v) NaCl (optimum, 1 %). 16S rRNA gene phylogenetic analysis confirmed that strain APC 4016T belonged to the genus Planococcus and was most closely related to Planococcus okeanokoites IFO 12536T (98.98 % 16S similarity). However, digital DNA-DNA hybridization and average nucleotide identity values between these two strains were low, at 20.1 and 83.8 %, respectively. Major (>10 %) cellular fatty acids of strain APC 4016T were iso-C14 : 0, anteiso-C15 : 0 and C16 : 1-ω-Alc. The predominant respiratory quinones were menaquinones 5, 6, 7 and 8. The major cellular polar lipids were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine, and three unknown lipids were also present. The draft genome sequence is 3.6 Mb with a G+C content of 45.25 mol%. This strain was previously shown to have antimicrobial activity and to encode bacteriocin and secondary metabolite biosynthetic gene clusters. Based on the phylogenetic analysis and its distinct phenotypic characteristics, strain APC 4016T is deemed to represent a novel species of the genus Planococcus, and for which the name Planococcus notacanthi sp. nov. is proposed. The type strain of this species is APC 4016T (=DSM 115753T=NCIMB 15463T).

Exopolysaccharides Produced by Bifidobacterium longum subsp. longum YS108R Ameliorates DSS-Induced Ulcerative Colitis in Mice by Improving the Gut Barrier and Regulating the Gut Microbiota.

Ulcerative colitis (UC) is a major disease that has endangered human health. Our previous study demonstrated that Bifidobacterium longum subsp. longum YS108R, a ropy exopolysaccharide (EPS)-producing bacterium, could alleviate UC in mice, but it is unclear whether EPS is the key substance responsible for its action. In this study, we proposed to investigate the remitting effect of EPS from B. longum subsp. longum YS108R on UC in a DSS-induced UC mouse model. Water extraction and alcohol precipitation were applied to extract EPS from the supernatant of B. longum subsp. longum YS108R culture. Then the animal trial was performed, and the results indicated that YS108R EPS ameliorated colonic pathological damage and the intestinal barrier. YS108R EPS suppressed inflammation via NF-κB signaling pathway inhibition and attenuated oxidative stress via the Nrf2 signaling pathway activation. Remarkably, YS108R EPS regulated gut microbiota, as evidenced by an increase in short-chain fatty acid (SCFA)-producing bacteria and a decline in Gram-negative bacteria, resulting in an increase of propionate and butyrate and a reduction of lipopolysaccharide (LPS). Collectively, YS108R EPS manipulated the intestinal microbiota and its metabolites, which further improved the intestinal barrier and inhibited inflammation and oxidative stress, thereby alleviating UC.

A metagenomic catalog of the early-life human gut virome.

Early-life human gut microbiome is a pivotal driver of gut homeostasis and infant health. However, the viral component (known as "virome") remains mostly unexplored. Here, we establish the Early-Life Gut Virome (ELGV), a catalog of 160,478 non-redundant DNA and RNA viral sequences from 8130 gut virus-like particles (VLPs) enriched or bulk metagenomes in the first three years of life. By clustering, 82,141 viral species are identified, 68.3% of which are absent in existing databases built mainly from adults, and 64 and 8 viral species based on VLPs-enriched and bulk metagenomes, respectively, exhibit potentials as biomarkers to distinguish infants from adults. With the largest longitudinal population of infants profiled by either VLPs-enriched or bulk metagenomic sequencing, we track the inherent instability and temporal development of the early-life human gut virome, and identify differential viruses associated with multiple clinical factors. The mother-infant shared virome and interactions between gut virome and bacteriome early in life are further expanded. Together, the ELGV catalog provides the most comprehensive and complete metagenomic blueprint of the early-life human gut virome, facilitating the discovery of pediatric disease-virome associations in future.

Harnessing the endogenous Type I-C CRISPR-Cas system for genome editing in Bifidobacterium breve.

Bifidobacterium breve, one of the main bifidobacterial species colonizing the human gastrointestinal tract in early life, has received extensive attention for its purported beneficial effects on human health. However, exploration of the mode of action of such beneficial effects exerted by B. breve is cumbersome due to the lack of effective genetic tools, which limits its synthetic biology application. The widespread presence of CRISPR-Cas systems in the B. breve genome makes endogenous CRISPR-based gene editing toolkits a promising tool. This study revealed that Type I-C CRISPR-Cas systems in B. breve can be divided into two groups based on the amino acid sequences encoded by cas gene clusters. Deletion of the gene coding uracil phosphoribosyl-transferase (upp) was achieved in five B. breve strains from both groups using this system. In addition, translational termination of uracil phosphoribosyl-transferase was successfully achieved in B. breve FJSWX38M7 by single-base substitution of the upp gene and insertion of three stop codons. The gene encoding linoleic acid isomerase (bbi) in B. breve, being a characteristic trait, was deleted after plasmid curing, which rendered it unable to convert linoleic acid into conjugated linoleic acid, demonstrating the feasibility of successive editing. This study expands the toolkit for gene manipulation in B. breve and provides a new approach toward functional genome editing and analysis of B. breve strains.IMPORTANCEThe lack of effective genetic tools for Bifidobacterium breve is an obstacle to studying the molecular mechanisms of its health-promoting effects, hindering the development of next-generation probiotics. Here, we introduce a gene editing method based on the endogenous CRISPR-Cas system, which can achieve gene deletion, single-base substitution, gene insertion, and successive gene editing in B. breve. This study will facilitate discovery of functional genes and elucidation of molecular mechanisms of B. breve pertaining to health-associated benefits.

Early life exposure of infants to benzylpenicillin and gentamicin is associated with a persistent amplification of the gut resistome.

BACKGROUND: Infant gut microbiota is highly malleable, but the long-term longitudinal impact of antibiotic exposure in early life, together with the mode of delivery on infant gut microbiota and resistome, is not extensively studied. METHODS: Two hundred and eight samples from 45 infants collected from birth until 2 years of age over five time points (week 1, 4, 8, 24, year 2) were analysed. Based on shotgun metagenomics, the gut microbial composition and resistome profile were compared in the early life of infants divided into three groups: vaginal delivery/no-antibiotic in the first 4 days of life, C-section/no-antibiotic in the first 4 days of life, and C-section/antibiotic exposed in first 4 days of life. Gentamycin and benzylpenicillin were the most commonly administered antibiotics during this cohort's first week of life. RESULTS: Newborn gut microbial composition differed in all three groups, with higher diversity and stable composition seen at 2 years of age, compared to week 1. An increase in microbial diversity from week 1 to week 4 only in the C-section/antibiotic-exposed group reflects the effect of antibiotic use in the first 4 days of life, with a gradual increase thereafter. Overall, a relative abundance of Actinobacteria and Bacteroides was significantly higher in vaginal delivery/no-antibiotic while Proteobacteria was higher in C-section/antibiotic-exposed infants. Strains from species belonging to Bifidobacterium and Bacteroidetes were generally persistent colonisers, with Bifidobacterium breve and Bifidobacterium bifidum species being the major persistent colonisers in all three groups. Bacteroides persistence was dominant in the vaginal delivery/no-antibiotic group, with species Bacteroides ovatus and Phocaeicola vulgatus found to be persistent colonisers in the no-antibiotic groups. Most strains carrying antibiotic-resistance genes belonged to phyla Proteobacteria and Firmicutes, with the C-section/antibiotic-exposed group presenting a higher frequency of antibiotic-resistance genes (ARGs). CONCLUSION: These data show that antibiotic exposure has an immediate and persistent effect on the gut microbiome in early life. As such, the two antibiotics used in the study selected for strains (mainly Proteobacteria) which were multiple drug-resistant (MDR), presumably a reflection of their evolutionary lineage of historical exposures-leading to what can be an extensive and diverse resistome. Video Abstract.

Production, Composition and Nutritional Properties of Organic Milk: A Critical Review.

Milk is one of the most valuable products in the food industry with most milk production throughout the world being carried out using conventional management, which includes intensive and traditional systems. The intensive use of fertilizers, antibiotics, pesticides and concerns regarding animal health and the environment have given increasing importance to organic dairy and dairy products in the last two decades. This review aims to compare the production, nutritional, and compositional properties of milk produced by conventional and organic dairy management systems. We also shed light on the health benefits of milk and the worldwide scenario of the organic dairy production system. Most reports suggest milk has beneficial health effects with very few, if any, adverse effects reported. Organic milk is reported to confer additional benefits due to its lower omega-6-omega-3 ratio, which is due to the difference in feeding practices, with organic cows predominantly pasture fed. Despite the testified animal, host, and environmental benefits, organic milk production is difficult in several regions due to the cost-intensive process and geographical conditions. Finally, we offer perspectives for a better future and highlight knowledge gaps in the organic dairy management system.

Influence of age, socioeconomic status, and location on the infant gut resistome across populations.

Antibiotic resistance is a growing global concern, with many ecological niches showing a high abundance of antibiotic resistance genes (ARGs), including the human gut. With increasing indications of ARGs in infants, this study aims to investigate the gut resistome profile during early life at a wider geographic level. To achieve this objective, we utilized stool samples data from 26 studies involving subjects aged up to 3 years from different geographical locations. The 32,277 Metagenome Assembled Genomes (MAGs) previously generated from shotgun sequencing reads from these studies were used for resistome analysis using RGI with the CARD database. This analysis showed that the distribution of ARGs across the countries in our study differed in alpha diversity and compositionally. In particular, the abundance of ARGs was found to vary by socioeconomic status and healthcare access and quality (HAQ) index. Surprisingly, countries having lower socioeconomic status and HAQ indices showed lower ARG abundance, which was contradictory to previous reports. Gram-negative genera, including Escherichia, Enterobacter, Citrobacter, and Klebsiella harbored a particularly rich set of ARGs, which included antibiotics that belong to the Reserve, Access or Watch category, such as glycopeptides, fluoroquinolones, sulfonamides, macrolides, and tetracyclines. We showed that ARG abundance exponentially decreased with time during the first 3 years of life. Many highly ARG-abundant species including Escherichia, Klebsiella, Citrobacter species that we observed are well-known pathobionts found in the infant gut in early life. High abundance of these species and a diverse range of ARGs in their genomes point toward the infant gut, acting as an ARG reservoir. This is a concern and further studies are needed to examine the causal effect and its consequences on long-term health.

Alleviative effects of exopolysaccharides from Limosilactobacillus mucosae CCFM1273 against ulcerative colitis via modulation of gut microbiota and inhibition of Fas/Fasl and TLR4/NF-κB pathways.

Ulcerative colitis (UC) has become a public health challenge as its global prevalence increases annually. The use of prebiotics in healthcare has grown in recent years. Thus, the present study was designed to explore the alleviating effects and mechanisms of exopolysaccharides (EPS) produced by Limosilactobacillus mucosae CCFM1273 on UC. The results indicated that CCFM1273 EPS mitigated the disease symptoms and colonic pathologic damage in DSS-induced colitis mice. Moreover, CCFM1273 EPS improved the intestinal barrier by restoring goblet cell numbers and MUC2 production, enhancing intercellular junctions, and inhibiting epithelial cell apoptosis. In addition, CCFM1273 EPS inhibited colonic inflammation and oxidative stress. Importantly, CCFM1273 EPS augmented short-chain fatty acid (SCFA) producers, leading to increased levels of SCFAs (especially propionic acid), which inhibited the Fas/Fasl pathway and consequently inhibited epithelial apoptosis, and diminished Gram-negative bacteria, further decreasing lipopolysaccharides (LPS), which suppressed the TLR4/NF-κB pathway and consequently suppressed colonic inflammation, eventually relieving UC in mice. This study provides theoretical support for the use of prebiotics in clinical practice for UC.

Advances in research on microbial conjugated linoleic acid bioconversion.

Conjugated linoleic acid (CLA) is a functional food ingredient with prebiotic properties that provides health benefits for various human pathologies and disorders. However, limited natural CLA sources in animals and plants have led microorganisms like Lactobacillus and Bifidobacterium to emerge as new CLA sources. Microbial conversion of linoleic acid to CLA is mediated by linoleic acid isomerase and multicomponent enzymatic systems, with CLA production efficiency dependent on microbial species and strains. Additionally, complex factors like LA concentration, growth status, culture substrates, precursor type, prebiotic additives, and co-cultured microbe identity strongly influence CLA production and isomer composition. This review summarizes advances in the past decade regarding microbial CLA production, including bacteria and fungi. We highlight CLA production and potential regulatory mechanisms and discuss using microorganisms to enhance CLA content and nutritional value of fermented products. We also identify primary microbial CLA production bottlenecks and provide strategies to address these challenges and enhance production through functional gene and enzyme mining and downstream processing. This review aims to provide a reference for microbial CLA production and broaden the understanding of the potential probiotic role of microbial CLA producers.