Honeybees exposure to natural feed additives: How is the gut microbiota affected?

The role of a balanced gut microbiota to maintain health and prevent diseases is largely established in humans and livestock. Conversely, in honeybees, studies on gut microbiota perturbations by external factors have started only recently. Natural methods alternative to chemical products to preserve honeybee health have been proposed, but their effect on the gut microbiota has not been examined in detail. This study aims to investigate the effect of the administration of a bacterial mixture of bifidobacteria and Lactobacillaceae and a commercial product HiveAlive™ on honeybee gut microbiota. The study was developed in 18 hives of about 2500 bees, with six replicates for each experimental condition for a total of three experimental groups. The absolute abundance of main microbial taxa was studied using qPCR and NGS. The results showed that the majority of the administered strains were detected in the gut. On the whole, great perturbations upon the administration of the bacterial mixture and the plant-based commercial product were not observed in the gut microbiota. Significant variations with respect to the untreated control were only observed for Snodgrassella sp. for the bacterial mixture, Bartonella sp. in HiveAlive™ and Bombilactobacillus sp. for both. Therefore, the studied approaches are respectful of the honeybee microbiota composition, conceivably without compromising the bee nutritional, social and ecological functions

The effect of substituents on the syn-anti conformer ratio in naphthyl-based imidazolinium salts and their corresponding N-heterocyclic carbenes

Eight new N-heterocyclic carbenes (NHCs) featuring substituted naphthyl side chains were synthesized. These molecules are present in solution as a stable mixture of antiand synconformers. Through careful tuning of the substituents on position 2 and 2,7 of the naphthyl moieties, it was possible to synthesize molecules that display a strong preference for the anticonformation (up to 95:5). This will greatly facilitate their optimized use as single isomeric ligands in metal-catalysis and as organocatalysts

The fate of bacteria in urban wastewater-irrigated peach tree: a seasonal evaluation from soil to canopy

Irrigation with wastewater can be a solution to preserve and mitigate freshwater demand, in particular during drought periods. Unfortunately, wastewater, although being treated at different levels, could be a carrier of human pathogens (e.g., E. coli) and potentially contaminate crops for human consumptions.This study investigated the seasonal microbiological concentrations, on soil, shoot and fruit tissues of potted peach trees, following two irrigation treatments: freshwater (FW) and secondary urban wastewater without the final disinfection treatment (SW). E. coli was only detected in SW irrigated soil, whereas total coliforms (TC) and total bacteria counts (TBC) were similar in both treatments throughout the season. EndophyticE. coli, Salmonella spp. and TC were not detected in shoot and fruit, but a higher presence of total bacteria (TBC) was observed in SW-irrigated tree compared to FWirrigated tree. In particular, SW shoots had a higher load compared to fruits, thus showing a potential effect of leaf transpiration, that promoted the transfer of water-borne bacteria from soil to the epigeal part (shoot). The adoption of low-quality SW (even above the microbiological limits of the European Regulation 2020/741 for wastewater re-use in agriculture), when a drip irrigation method is applied, could be a valid alternative to save fresh water without compromising fruit safety

Proteomics as a quality control tool of pharmaceutical probiotic bacterial lysate products

Probiotic bacteria have a wide range of applications in veterinary and human therapeutics. Inactivated probiotics are complex samples and quality control (QC) should measure as many molecular features as possible. Capillary electrophoresis coupled to mass spectrometry (CE/MS) has been used as a multidimensional and high throughput method for the identification and validation of biomarkers of disease in complex biological samples such as biofluids. In this study we evaluate the suitability of CE/MS to measure the consistency of different lots of the probiotic formulation Pro-Symbioflor which is a bacterial lysate of heat-inactivated Escherichia coli and Enterococcus faecalis. Over 5000 peptides were detected by CE/MS in 5 different lots of the bacterial lysate and in a sample of culture medium. 71 to 75% of the total peptide content was identical in all lots. This percentage increased to 87–89% when allowing the absence of a peptide in one of the 5 samples. These results, based on over 2000 peptides, suggest high similarity of the 5 different lots. Sequence analysis identified peptides of both E. coli and E. faecalis and peptides originating from the culture medium, thus confirming the presence of the strains in the formulation. Ontology analysis suggested that the majority of the peptides identified for E. coli originated from the cell membrane or the fimbrium, while peptides identified for E. faecalis were enriched for peptides originating from the cytoplasm. The bacterial lysate peptides as a whole are recognised as highly conserved molecular patterns by the innate immune system as microbe associated molecular pattern (MAMP). Sequence analysis also identified the presence of soybean, yeast and casein protein fragments that are part of the formulation of the culture medium. In conclusion CE/MS seems an appropriate QC tool to analyze complex biological products such as inactivated probiotic formulations and allows determining the similarity between lots

The application of Pathogen Combat research results in practice

The overall objective of \u201cPathogen Combat\u201d is to provide new essential information and methods to the food industry and public authorities on how to reduce the prevalence of new and emerging food borne pathogens. The quality control and monitoring along the food chains is necessary to ensure safe end products; mainly food industry rely on international procedures based on culturing methods to estimate the presence, the viability and enumeration of pathogens throughout the food chain taking into account the large amount of time required to achieve the final results. Since producers, processing industry and consumers increasingly demand higher quality for starting material and food products, there is a rising interest for rapid, sensitive and specific diagnostic methods. In this chapter, some important applications that have been developed within the EU project \u201cPathogenCombat\u201d are described; new faster culture-independent detection methods based on molecular biology have been applied inside SMEs and Industrial partners\u2019 plants involved in the project and new important information about pathogen behaviour has been achieved

Probiotics and prebiotics in animal feeding for safe food production

Recent outbreaks of food-borne diseases highlight the need for reducing bacterial pathogens in foods of animal origin. Animal enteric pathogens are a direct source for food contamination. The ban of antibiotics as growth promoters (AGPs) has been a challenge for animal nutrition increasing the need to find alternative methods to control and prevent pathogenic bacterial colonization. The modulation of the gut microbiota with new feed additives, such as probiotics and prebiotics, towards host-protecting functions to support animal health, is a topical issue in animal breeding and creates fascinating possibilities. Although the knowledge on the effects of such feed additives has increased, essential information concerning their impact on the host are, to date, incomplete. For the future, the most important target, within probiotic and prebiotic research, is a demonstrated health-promoting benefit supported by knowledge on the mechanistic actions. Genomic-based knowledge on the composition and functions of the gut microbiota, as well as its deviations, will advance the selection of new and specific probiotics. Potential combinations of suitable probiotics and prebiotics may prove to be the next step to reduce the risk of intestinal diseases and remove specific microbial disorders. In this review we discuss the current knowledge on the contribution of the gut microbiota to host well-being. Moreover, we review available information on probiotics and prebiotics and their application in animal feeding