A new Leuconostoc citreum strain discovered in the traditional sweet potato sour liquid fermentation as a novel bioflocculant for highly efficient starch production

Dynamic development of gut microbiota and metabolism during and after weaning of kittens

BACKGROUND

As the pet population grows, there is increasing attention on the health and well-being of companion animals. Weaning, a common challenge for young mammals, often leads to issues such as diarrhea, growth retardation, and in severe cases, even mortality. However, the specific changes in gut microbiota and metabolites in kittens following weaning remain unclear. In this study, we conducted a comprehensive investigation of the dynamic changes in the gut microbiota, serum metabolism, antioxidant capacity, and immune function of kittens at various time points: days 0, 4, and 30 post-weaning.

RESULTS

Significant changes in the immune response and gut microbiota were observed in kittens following weaning. Specifically, IgM levels increased significantly (P < 0.01, n = 20), while IgA and IgG levels showed a sustained elevation. Weaning also disrupted the intestinal microbiota, leading to notable changes in serum metabolism. On day 4 post-weaning, there was a decrease in beneficial bacteria such as Bacteroides vulgatus, Fusobacterium nucleatum, Anaerostipes caccae, and Butyricico-ccaceae. However, by day 30, beneficial bacteria including Candidatus Arthro-mitus, Holdemanella, and Bifidobacterium had increased (P < 0.05, n = 20). Serum metabolites showed clear separation across time points, with day 0 and day 4 exhibiting similar patterns. A total of 45 significantly altered metabolites (P < 0.05, n = 20) were identified, primarily related to vitamins, steroids, peptides, organic acids, lipids, and carbohydrates. Pathway analysis revealed significant enrichment in eight metabolic pathways, with key changes in arginine metabolism and biosynthesis. Additionally, bacteria such as Bacteroides fragilis, Bacteroides stercoris, Leuconostoc citreum, and Bifidobacterium adolescentis were positively correlated with serum metabolic changes, emphasizing the link between gut microbiota and systemic metabolism (P < 0.05, n = 20).

CONCLUSION

Our study demonstrated that the composition and function of intestinal microorganisms as well as serum metabolic profiles of weaned kittens presented dynamic changes. These findings not only deepen our understanding of the effects of weaning on kitten health, but also provide valuable insights into post-weaning nutritional regulation strategies for kittens.

Coagulation/flocculation-flotation harvest of Microcystis aeruginosa by cationic hydroxyethyl cellulose and Agrobacterium mucopolysaccharides

Efficient biocoagulants/bioflocculants are desired for removal of Microcystis aeruginosa, the dominant harmful bloom-forming cyanobacterium. Herein, we reported cationic hydroxyethyl cellulose (CHEC) inactivated M. aeruginosa cells after forming coagulates and floating-flocculated them with aid of Agrobacterium mucopolysaccharides (AMP) and surfactant. CHEC exhibited cyanocidal activity at 20 mg/L, coagulating 85% of M. aeruginosa biomass within 9 h and decreasing 41% of chlorophyll a after 72 h. AMP acted as an adhesive flocculation aid that accelerated and strengthened the formation of flocs, approaching a maximum in 10 min. Flocs of M. aeruginosa were floated after foaming with cocoamidopropyl betaine (CAB), which facilitated the subsequent filter harvest. 82% of M. aeruginosa biomass was suspended on water surface after treated with the coagulation/flocculation-flotation (CFF) agents containing CHEC (25 mg/L), AMP (177 mg/L) and CAB (0.1 mg/L). All components in CFF agents at the applied concentrations did not inhibit acetylcholinesterase or Vibrio fischeri. Our findings provide new insights in developing bio-based materials for sustainable control of cyanobacterial blooms.

Genomic analysis of Leuconostoc citreum TR116 with metabolic reconstruction and the effects of fructose on gene expression for mannitol production

The species Leuconostoc citreum is often isolated from grain and vegetable fermentations such as sourdough, sauerkraut and kimchi. Lc. citreum has seen an increase in its use as a starter culture for various fermentations and food applications. The strain Lc. citreum TR116 has been applied previously in this laboratory aimed at sugar depletion through metabolism resulting in the reduction of fructose to mannitol, a polyol considered as a sweet carbohydrate. Besides reducing sugar, TR116 showed flavour modulating characteristics and contributes to the extension of microbial shelf life. In order to obtain a better understanding of this strain and to fully use its set of abilities, the genome of Lc. citreum TR116 was sequenced using the Illumina MiSeq, assembly with SPAdes and annotated by the Prokaryotic Genome Annotation Pipeline. Metabolic reconstruction was employed to elucidate carbohydrate, organic acid and amino acid metabolism in the strain. Of particular interest was the gene expression analysis ascertained the influence of fructose on the genes mdh and manX involved in the uptake of fructose and its conversion to mannitol. This investigation, the first in Lc. citreum, illustrates the metabolic processes involved in fermentation used by this strain and demonstrates that in the presence of fructose, expression of the genes mdh and manX is increased. The resulting transparency of the skill set of TR116 contributes highly to future functionalisation of food systems and food ingredients.