Distribution, cholesterol-lowering and immunomodulation effects of lactic acid bacteria from fermented mussel (Hoi-dong)

Evaluating the safety and efficacy of Lacticaseibacillus paracasei TISTR 2593 as a therapeutic probiotic for obesity prevention

Several recent studies have reported the potential of probiotics in reducing body weight and fat mass and improving glucose and lipid metabolism. Therefore, probiotic administration is considered an alternative approach for treating obesity. The objective of this study was to evaluate the probiotic properties and antiadipogenic potential of the strain TISTR 2593. Through whole-genome sequence analysis, the strain TISTR 2593 was identified as Lacticaseibacillus paracasei. L. paracasei TISTR 2593 exhibited γ-hemolytic activity (nonhemolysis) and demonstrated susceptibility to antibiotics, indicating that it is generally safe for consumption. Additionally, this strain displayed desirable probiotic properties, including tolerance to artificial gastric juice and bile salts, adhesion to Caco-2 cells, and the ability to inhibit pathogens. Furthermore, L. paracasei TISTR 2593 exhibited cholesterol-reducing capability and demonstrated antiadipogenic activity. In 3T3-L1 adipocytes, treatment with 10% (w/v) heated L. paracasei TISTR 2593 cells resulted in an approximately 50% reduction in lipid accumulation, similar to the positive control (quercetin). Moreover, L. paracasei TISTR 2593 heat-killed cells dose-dependently decreased the expression levels of CCAAT/enhancer-binding protein-α and peroxisome proliferator-activated receptor-γ, two vital transcription factors involved in the early stage of adipocyte differentiation. These findings suggest that L. paracasei TISTR 2593 possesses probiotic and functional properties, including antiadipogenic activity, supporting its potential as a therapeutic probiotic supplement for preventing obesity. Overall, the results of this study indicate that L. paracasei TISTR 2593 exhibits promising probiotic characteristics and beneficial effects on adipogenesis modulation, reinforcing its potential as a therapeutic option in obesity prevention.

Pathogenic mechanisms of Enterocytozoon hepatopenaei through the parasite-gut microbiome-shrimp ( Litopenaeus vannamei) physiology axis

The progressive impact of Enterocytozoon hepatopenaei (EHP) infection on gut microbial function in Litopenaeus vannamei remains poorly understood beyond static comparisons between healthy and infected individuals. To close this knowledge gap, metagenomic sequencing was used to characterize the gut microbiomes of normal, long, medium, and short-sized adult shrimp categorized by increasing severity of infection. EHP infection suppressed digestive activity while inducing immune responses compared with healthy shrimp. Increasing infection severity was associated with a gradual decline in gut α-diversity and an expansion of potential pathogens and virulence factors (VFs). In addition, dysbiosis in gut microbiota composition and function, as well as reduced network stability among differential species, intensified with infection severity. Accordingly, we identified 24 EHP-discriminatory species that contributed an overall 83.3% accuracy in diagnosing infection severity without false negatives. Functional pathway analysis revealed significant suppression of metabolic, degradative, and biosynthetic processes in EHP-infected shrimp compared with healthy controls. Among them, map00630 glyoxylate and dicarboxylate metabolism and map00280 valine, leucine and isoleucine degradation were consistently depleted in infected individuals, thereby impairing their digestive function and anti-inflammatory responses. Additionally, EHP infection diversified VFs directly affecting shrimp gut microbiome. These findings support a conceptual model linking EHP pathogenesis to the parasite-gut microbiome-shrimp physiology axis.

Potentially probiotic NPL 1334 strain of Enterococcus durans benefits rats with diet-induced hypercholesterolemia

PURPOSE

To study the potential of a candidate probiotic strain belonging to the Enterococcus durans species in alleviating hypercholesterolemia and improving the microbial milieu of rat gut.

METHODS

A previously isolated and characterized E. durans strain NPL 1334 was further screened in vitro for its bile salt hydrolyzation and cholesterol assimilation ability. An in vivo trial using diet-induced hypercholesterolemic rats was conducted to evaluate the effects of the administered test probiotic strain on the animal's blood biochemical parameters such as total cholesterol (TC), high-density lipopolysaccharides (HDL), low-density lipopolysaccharides (LDL), triglycerides (TG), on body weight, oxidative stress markers, and its impact on intestinal and fecal microbiota as well as a histopathological examination of the test animal's livers.

RESULTS

E. durans strain showed good bile salt hydrolyzing ability and ample cholesterol assimilation in vitro. Probiotic-fed hypercholesterolemic rats showed significantly lowered cholesterol, triglyceride and LDL levels. The body weight of probiotic-fed rats was reduced as compared to the control. E. durans also stimulated the growth of beneficial LAB in the intestine of experimental rats and did not harm the liver of the experimental rats.

CONCLUSION

E. durans can be a natural therapeutic alternative to manage diet-induced hypercholesterolemia and may eventually enhance anti-cholesterolemic therapies.

Anaerobic flora, Selenomonas ruminis sp. nov., and the bacteriocinogenic Ligilactobacillus salivarius strain MP3 from crossbred-lactating goats

This study aimed to examine the distribution of anaerobic bacteria in the rumen fluid of Thai crossbred goats and to screen potential probiotic strains capable of producing antimicrobial compounds and inhibiting bacteria that cause milk fat depression. Thirty-four strains of bacteria from the rumen fluid were divided into 13 groups within 12 genera based on 16S rRNA gene sequences. The RF1-5 and RF5-12 were identified as Streptococcus luteliensis and Bacillus licheniformis, respectively, and demonstrated non-ropy exopolysaccharide. Furthermore, mPRGC5T was closely related to Selenomonas caprae JCM 33725 T (97.8% similarity) based on 16S rRNA gene sequences. It exhibited low average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values with related type strains ranging from 84.9 to 86.0%, 21.3 to 21.8%, and 73.8 to 76.1%, respectively. The genotypic and phenotypic characteristics of mPRGC5T strongly support this strain as a new species of the genus Selenomonas for which the name Selenomonas ruminis mPRGC5T was proposed. The type strain is mPRGC5T (= JCM 33724 T = KCTC 25177 T). Ligilactobacillus salivarius MP3 showed antibacterial activity against Cutibacterium acnes subsp. acnes DSM 1897 T and Kocuria rhizophila MIII. The enterolysin A cluster gene was identified in its genome. The auto-aggregation of L. salivarius MP3 was 93.6 ± 0.2%. Additionally, co-aggregation of L. salivarius MP3 with C. acnes DSM 1897 T and K. rhizophila MIII had 92.2 ± 3.4% and 87.3 ± 4.5%, respectively. The adhesion capacity of strain MP3 was 76.11 ± 2.2%. Probiogenomic analysis revealed that L. salivarius MP3 was nonhazardous to animal supplementation and included acid- and bile-tolerant ability. However, strain MP3 contained three antibiotic resistance genes. Thus, the supplementation of L. salivarius MP3 could increase the milk fat content by suppressing C. acnes DSM 1897 T with antibiotic resistance gene horizontal transfer awareness.

Functional genome analysis and anti-Helicobacter pylori activity of a novel bacteriocinogenic Lactococcus sp. NH2-7C from Thai fermented pork (Nham)

Helicobacter pylori, linked to gastric diseases, is targeted for probiotic treatment through bacteriocin production. Bacteriocins have gained recognition for their non-toxic effects on host cells and their ability to combat a wide range of pathogens. This study aimed to taxonomically characterize and evaluate the safety and probiotic properties of the novel species of Lactococcus sp. NH2-7C isolated from fermented pork, as well as its bacteriocin NH2-7C, both in vitro and in silico. Comparative genotypic analysis revealed an average nucleotide identity of 94.96%, an average amino acid identity of 94.29%, and a digital DNA-DNA hybridization value of 63.80% when compared to Lactococcus lactis subsp. lactis JCM 5805T. These findings suggest that strain NH2-7C represents a novel species within the genus Lactococcus. In silico assessments confirmed the non-pathogenic nature of strain NH2-7C and the absence of genes associated with virulence and biogenic amine formation. Whole-genome analysis revealed the presence of the nisA gene responsible for nisin A production, indicating its potential as a beneficial compound with anti-Helicobacter pylori activity and non-toxic characteristics. Probiotic assessments indicated bile salt hydrolase and cholesterol assimilation activities, along with the modulation of interleukin-6 and tumour necrosis factor-α secretion. Strain NH2-7C demonstrated gastrointestinal tolerance and the ability to adhere to Caco-2 cells, affirming its safety and probiotic potential. Additionally, its ability to produce bacteriocins supports its suitability as a functional probiotic strain with therapeutic potential. However, further in vitro and in vivo investigations are crucial to ensure its safety and explore potential applications for Lactococcus sp. NH2-7C as a probiotic agent.