Cornflower Extract and Its Active Components Alleviate Dexamethasone-Induced Muscle Wasting by Targeting Cannabinoid Receptors and Modulating Gut Microbiota.

Sarcopenia, a decline in muscle mass and strength, can be triggered by aging or medications like glucocorticoids. This study investigated cornflower (Centaurea cyanus) water extract (CC) as a potential protective agent against DEX-induced muscle wasting in vitro and in vivo. CC and its isolated compounds mitigated oxidative stress, promoted myofiber growth, and boosted ATP production in C2C12 myotubes. Mechanistically, CC reduced protein degradation markers, increased mitochondrial content, and activated protein synthesis signaling. Docking analysis suggested cannabinoid receptors (CB) 1 and 2 as potential targets of CC compounds. Specifically, graveobioside A from CC inhibited CB1 and upregulated CB2, subsequently stimulating protein synthesis and suppressing degradation. In vivo, CC treatment attenuated DEX-induced muscle wasting, as evidenced by enhanced grip strength, exercise performance, and modulation of muscle gene expression related to differentiation, protein turnover, and exercise performance. Moreover, CC enriched gut microbial diversity, and the abundance of Clostridium sensu stricto 1 positively correlated with muscle mass. These findings suggest a multifaceted mode of action for CC: (1) direct modulation of the muscle cannabinoid receptor system favoring anabolic processes and (2) indirect modulation of muscle health through the gut microbiome. Overall, CC presents a promising therapeutic strategy for preventing and treating muscle atrophy.

Gut microbiota modulation via short-term administration of potential probiotic kefir yeast Kluyveromyces marxianus A4 and A5 in BALB/c mice.

Kefir yeast, Kluyveromyces marxianus, has been evaluated for its potential probiotic properties-survivability, non-pathogenicity, and antioxidant and anti-microbial activities. However, host gut microbiota modulation of kefir yeasts remains unclear. Here, we compared kefir yeast strains K. marxianus A4 (Km A4) and K. marxianus A5 (Km A5) with Saccharomyces boulardii ATCC MYA-796 (Sb MYA-796) by investigating their adherence to colorectal adenocarcinoma (Caco-2) cells and gut microbiota modulation in BALB/c mice. The kefir yeast strains exhibited higher intestinal cell adhesion than Sb MYA-796 (p < 0.05). Bacteroidetes, Bacteroidales, and Bacteroides were more abundant in the 1 × 108 CFU/mL of Km A4 treatment group than in the control group (p < 0.05). Moreover, 1 × 108 CFU/mL of Km A5 increased Corynebacteriales and Corynebacterium compared to the 1 × 108 CFU/mL of Km A4 treatment group (p < 0.01). The results showed that Km A4 and Km A5 had good Caco-2 cell adhesion ability and modulated gut microbiota upon short-term administration in healthy mice. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01268-3.

A Combined In Vitro and In Vivo Assessment of the Safety of the Yeast Strains Kluyveromyces marxianus A4 and A5 Isolated from Korean Kefir.

Kefir is a traditional fermented milk containing beneficial bacteria and yeasts. Despite Kluyveromyces marxianus, isolated from kefir, gaining increasing attention as a potential probiotic yeast owing to its biological function, Saccharomyces boulardii is the only species considered as a probiotic yeast. We evaluated the safety of K. marxianus strains A4 and A5, isolated from Korean kefir, in comparison with that of S. boulardii. Virulence attributes were preliminarily assessed in vitro including their ability of gelatin hydrolysis, pseudohyphae formation, and hemolysis. To evaluate in vivo safety, the strains were challenged in a healthy animal model, four-week-old female BALB/c mice. Mice were orally administered 0.2 mL of 0.9% sterilized saline (NC_S; n = 6), S. boulardii ATCC MYA-796 (high concentration, S.b_H; low concentration, S.b_L; n = 6 for each), K. marxianus A4 (high concentration, A4_H; low concentration, A4_L; n = 6 for each), or K. marxianus A5 (high concentration, A5_H; low concentration, A5_L; n = 6 for each) for 2 weeks. At study end, body weight, spleen and liver weights, and blood parameters were assessed. K. marxianus A4 and A5 were tested negative for gelatinase and hemolysis. Overall, hematological, plasma biochemical, and cytokine (interleukin-1ß and tumor necrosis factor-α) parameters were comparable between the experimental and negative control (NC) groups. Notably, the interleukin-6 level of the A5_H group was significantly lower than that of the NC group (p < 0.05), suggesting anti-inflammatory potential of K. marxianus A5.

Effect of postbiotics derived from kefir lactic acid bacteria-mediated bioconversion of citrus pomace extract and whey on high-fat diet-induced obesity and gut dysbiosis.

The objective of this study was to develop a highly bioactive postbiotic for weight management by bioconversion of whey (WHE) and polyphenol-rich citrus pomace extract (CPX) using kefir lactic acid bacteria (LAB). WHE and CPX bioconverted by kefir LAB (CPB) were fed to C57BL/6J mice on high-fat diets for five weeks and compared with oral administrations of saline (CON), WHE, CPX, and kefir LAB. Hesperetin, a potential therapeutic agent for obesity, was increased in the CPB after bioconversion from an inactive precursor. Compared with the CON group, the CPB group showed significantly reduced body weight gain, adipose tissue weight/body weight ratio, hypertriglyceridemia, and adipocyte diameter along with increased gene expression related to energy expenditure in adipose tissue (p < 0.05). Interestingly, the abundance of gut microbiota related to butyrate production was significantly altered in the CPB group compared with the CON group. There was a significant correlation between obesogenic biomarkers and the abundance of butyrate-producing and obesogenic gut microbiota. In conclusion, kefir LAB-derived bioconversion of WHE and CPX may be effective in combating obesity and obesity-related diseases.

Prevalence and Virulence Characteristics of Enterococcus faecalis and Enterococcus faecium in Bovine Mastitis Milk Compared to Bovine Normal Raw Milk in South Korea.

Enterococcus spp. are pathogens that cause environmental mastitis and are difficult to eliminate owing to their resistance to antibiotics. To compare the virulence characteristics of isolates from bovine mastitis milk (BMM) and bovine normal raw milk (NRM), we isolated Enterococcus spp. from 39 dairy farms in South Korea from 2015−2020. A total of 122 Enterococcus spp. were identified, with Enterococcus faecalis (73.8%) accounting for the majority, followed by Enterococcus faecium (26.2%). E. faecalis isolated from BMM harbored gelE, asa1, esp, and cylA genes with a prevalence of 85.7, 71.4, 54.3, and 30.0%, respectively. These genes were significantly more abundant in BMM than in NRM, except for asa1 (p < 0.0001). Interestingly, strong biofilm and gelatinase formation was predominately observed for BMM isolates and this was significantly correlated to the presence of esp and gelE genes (p < 0.05). BMM isolates demonstrated higher resistance to tetracycline (59.3%), followed by chloramphenicol (21.0%), rifampicin (18.5%), doxycycline (4.9%), ciprofloxacin (1.2%), and nitrofurantoin (1.2%), than those from NRM. E. faecalis harboring esp, gelE, and cylA may be causative agents for bovine mastitis and act as a reservoir for the transmission of virulence factors to humans.

Isolation and Characterization of Halophilic Kocuria salsicia Strains from Cheese Brine.

Kocuria salsicia can survive in extreme environments and cause infections, including catheter-related bacteremia, in humans. Here, we investigated and evaluated the characteristics of nine K. salsicia strains (KS1-KS9) isolated from cheese brine from a farmstead cheese-manufacturing plant in Korea from June to December, 2020. Staphylococcus aureus American Type Culture Collection (ATCC) 29213 was used as a positive control in the growth curve analysis and biofilm-formation assays. All K. salsicia isolates showed growth at 15% salt concentration and temperatures of 15°C, 25°C, 30°C, 37°C, and 42°C. KS6 and KS8 showed growth at 5°C, suggesting that they are potential psychrotrophs. In the biofilm-formation analysis via crystal violet staining, KS6 exhibited the highest biofilm-forming ability at various temperatures and media [phosphate buffered saline, nutrient broth (NB), and NB containing 15% sodium chloride]. At 25°C and 30°C, KS3, KS6, and KS8 showed higher biofilm-forming ability than S. aureus ATCC 29213. The antimicrobial resistance of the isolates was evaluated using the VITEK® 2 system; most isolates were resistant to marbofloxacin and nitrofurantoin (both 9/9, 100%), followed by enrofloxacin (7/9, 77.8%). Five of the nine isolates (5/9, 55.6%) showed multidrug resistance. Our study reports the abilities of K. salsicia to grow in the presence of high salt concentrations and at relatively low temperatures, along with its multidrug resistance and tendency to form biofilms.

Survivability of Kluyveromyces marxianus Isolated From Korean Kefir in a Simulated Gastrointestinal Environment.

Kluyveromyces marxianus accounts for > 90% of the yeast population of kefir, and recently, its probiotic potential has been actively explored with a focus on its health benefits and safety. Herein, the survivability of five kefir-isolated K. marxianus strains (Km A1-A5) in a simulated gastrointestinal (GI) environment was evaluated and compared with those of commercial probiotic yeast, Saccharomyces boulardii MYA-796. To further explore the potential to survive in the host GI tract, biochemical activities, hydrophobicity assay, biofilm formation, auto-aggregation analysis, and phenol tolerance of the strains were assessed. K. marxianus A4 exhibited the best survivability among all tested strains, including the clinically proven probiotic yeast strain S. boulardii MYA-796 (p = 0.014) in the artificial GI tract ranging from pH 2.0 to 7.5. In addition, the five K. marxianus strains and S. boulardii MYA-796 displayed different assimilation of lactose, xylitol, D-sorbitol, and DL-lactate, indicating that K. marxianus metabolized a wide range of substances and, thus, might be more feasible to nourish themselves in the host GI tract for survival. K. marxianus strains showed a greater hydrophobicity of cell surface, abilities to biofilm formation and auto-aggregation, and phenol tolerance than S. boulardii MYA-796, suggesting greater potential for survival in the host GI tract.