Antagonistic Activity against Ascosphaera apis and Functional Properties of Lactobacillus kunkeei Strains

Abstract

Lactic acid bacteria (LAB) are an important group of honeybee gut microbiota. These bacteria are involved in food digestion, stimulate the immune system, and may antagonize undesirable microorganisms in the gastrointestinal tract. Lactobacillus kunkeei is a fructophilic lactic acid bacterium (FLAB) most frequently found in the gastrointestinal tracts of honeybees. Ascosphaera apis is an important pathogenic fungus of honeybee larvae; it can colonize the intestine, especially in conditions of nutritional or environmental stress that cause microbial dysbiosis. In this work, some functional properties of nine selected L. kunkeei strains were evaluated. The study focused on the antifungal activity of these strains against A. apis DSM 3116, using different matrices: cell lysate, broth culture, cell-free supernatant, and cell pellet. The cell lysate showed the highest antifungal activity. Moreover, the strains were shown to possess good cell-surface properties (hydrophobicity, auto-aggregation, and biofilm production) and a good resistance to high sugar concentrations. These L. kunkeei strains were demonstrated to be functional for use in “probiotic syrup”, useful to restore the symbiotic communities of the intestine in case of dysbiosis and to exert a prophylactic action against A. apis.

Antimicrobial Activity against Paenibacillus larvae and Functional Properties of Lactiplantibacillus plantarum Strains: Potential Benefits for Honeybee Health

“…To assess osmotic tolerance, a test was performed according to Iorizzo et al [ 44 ], with some modifications. L. plantarum strains were grown in MRS broth at 37 °C and after 24 h the cells were harvested using centrifugation at 8000 rpm for 10 min at 4 °C.…”

“…To assess osmotic tolerance, a test was performed according to Iorizzo et al [44], with some modifications. L. plantarum strains were grown in MRS broth at 37 • C and after 24 h the cells were harvested using centrifugation at 8000 rpm for 10 min at 4 • C. The fresh pellets were washed twice with PBS buffer and were inoculated in sugar syrup in order to obtain an initial concentration of 10 7 CFU/mL.…”

“…The presence of lactic acid bacteria (LAB) in the honeybee gastrointestinal tract has been consistently reported in literature [32][33][34]. Beneficial bacteria, belonging to LAB, have been shown to promote honeybee health through activating the honeybee's immune defenses and producing antimicrobial compounds inhibiting pathogenic microorganisms [35][36][37][38][39][40][41][42][43][44]. The antagonistic effects of symbiotic LAB against P. larvae can be exploited to develop a new approach to AFB disease control [45][46][47].…”

Low-Fat and High-Quality Fermented Sausages

“…plantarum strains from diverse isolation sources was investigated. In a previous study, a relationship between the isolation sources characterized by harsh environmental conditions (antimicrobial substances and low pH) and the presence of lactic acid bacteria able to produce a strong antimicrobial activity was highlighted [ 39 , 55 ]. To date, more extensive literature is available on protective or anti- Listeria microbial cultures and their advantages and concerns in meat products [ 27 , 56 ].…”

Influence of the Microalga Chlorella vulgaris on the Growth and Metabolic Activity of Lactobacillus spp. Bacteria

“…Moreover, 35 Lactobacillus species meet the European Food Safety Authority (EFSA) criteria for a qualified presumption of safety (QPS) [ 12 ]. Due to their cholesterol-lowering properties [ 13 , 14 ], anti-inflammatory [ 15 ], antioxidant [ 16 ], and antagonistic activity [ 17 , 18 , 19 ], LAB are used in the prevention and treatment of many diseases, such as irritable bowel syndrome [ 20 ], dysbiosis [ 18 ], urinary tract infections [ 17 ], antibiotic-associated diarrhea, infectious diarrhea [ 21 ], allergies [ 15 ], and atopic dermatitis [ 22 , 23 ].…”